1.. SPDX-License-Identifier: GPL-2.0 2 3=================================================================== 4The Definitive KVM (Kernel-based Virtual Machine) API Documentation 5=================================================================== 6 71. General description 8====================== 9 10The kvm API is a set of ioctls that are issued to control various aspects 11of a virtual machine. The ioctls belong to the following classes: 12 13 - System ioctls: These query and set global attributes which affect the 14 whole kvm subsystem. In addition a system ioctl is used to create 15 virtual machines. 16 17 - VM ioctls: These query and set attributes that affect an entire virtual 18 machine, for example memory layout. In addition a VM ioctl is used to 19 create virtual cpus (vcpus) and devices. 20 21 VM ioctls must be issued from the same process (address space) that was 22 used to create the VM. 23 24 - vcpu ioctls: These query and set attributes that control the operation 25 of a single virtual cpu. 26 27 vcpu ioctls should be issued from the same thread that was used to create 28 the vcpu, except for asynchronous vcpu ioctl that are marked as such in 29 the documentation. Otherwise, the first ioctl after switching threads 30 could see a performance impact. 31 32 - device ioctls: These query and set attributes that control the operation 33 of a single device. 34 35 device ioctls must be issued from the same process (address space) that 36 was used to create the VM. 37 382. File descriptors 39=================== 40 41The kvm API is centered around file descriptors. An initial 42open("/dev/kvm") obtains a handle to the kvm subsystem; this handle 43can be used to issue system ioctls. A KVM_CREATE_VM ioctl on this 44handle will create a VM file descriptor which can be used to issue VM 45ioctls. A KVM_CREATE_VCPU or KVM_CREATE_DEVICE ioctl on a VM fd will 46create a virtual cpu or device and return a file descriptor pointing to 47the new resource. Finally, ioctls on a vcpu or device fd can be used 48to control the vcpu or device. For vcpus, this includes the important 49task of actually running guest code. 50 51In general file descriptors can be migrated among processes by means 52of fork() and the SCM_RIGHTS facility of unix domain socket. These 53kinds of tricks are explicitly not supported by kvm. While they will 54not cause harm to the host, their actual behavior is not guaranteed by 55the API. See "General description" for details on the ioctl usage 56model that is supported by KVM. 57 58It is important to note that although VM ioctls may only be issued from 59the process that created the VM, a VM's lifecycle is associated with its 60file descriptor, not its creator (process). In other words, the VM and 61its resources, *including the associated address space*, are not freed 62until the last reference to the VM's file descriptor has been released. 63For example, if fork() is issued after ioctl(KVM_CREATE_VM), the VM will 64not be freed until both the parent (original) process and its child have 65put their references to the VM's file descriptor. 66 67Because a VM's resources are not freed until the last reference to its 68file descriptor is released, creating additional references to a VM 69via fork(), dup(), etc... without careful consideration is strongly 70discouraged and may have unwanted side effects, e.g. memory allocated 71by and on behalf of the VM's process may not be freed/unaccounted when 72the VM is shut down. 73 74 753. Extensions 76============= 77 78As of Linux 2.6.22, the KVM ABI has been stabilized: no backward 79incompatible change are allowed. However, there is an extension 80facility that allows backward-compatible extensions to the API to be 81queried and used. 82 83The extension mechanism is not based on the Linux version number. 84Instead, kvm defines extension identifiers and a facility to query 85whether a particular extension identifier is available. If it is, a 86set of ioctls is available for application use. 87 88 894. API description 90================== 91 92This section describes ioctls that can be used to control kvm guests. 93For each ioctl, the following information is provided along with a 94description: 95 96 Capability: 97 which KVM extension provides this ioctl. Can be 'basic', 98 which means that is will be provided by any kernel that supports 99 API version 12 (see section 4.1), a KVM_CAP_xyz constant, which 100 means availability needs to be checked with KVM_CHECK_EXTENSION 101 (see section 4.4), or 'none' which means that while not all kernels 102 support this ioctl, there's no capability bit to check its 103 availability: for kernels that don't support the ioctl, 104 the ioctl returns -ENOTTY. 105 106 Architectures: 107 which instruction set architectures provide this ioctl. 108 x86 includes both i386 and x86_64. 109 110 Type: 111 system, vm, or vcpu. 112 113 Parameters: 114 what parameters are accepted by the ioctl. 115 116 Returns: 117 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 118 are not detailed, but errors with specific meanings are. 119 120 1214.1 KVM_GET_API_VERSION 122----------------------- 123 124:Capability: basic 125:Architectures: all 126:Type: system ioctl 127:Parameters: none 128:Returns: the constant KVM_API_VERSION (=12) 129 130This identifies the API version as the stable kvm API. It is not 131expected that this number will change. However, Linux 2.6.20 and 1322.6.21 report earlier versions; these are not documented and not 133supported. Applications should refuse to run if KVM_GET_API_VERSION 134returns a value other than 12. If this check passes, all ioctls 135described as 'basic' will be available. 136 137 1384.2 KVM_CREATE_VM 139----------------- 140 141:Capability: basic 142:Architectures: all 143:Type: system ioctl 144:Parameters: machine type identifier (KVM_VM_*) 145:Returns: a VM fd that can be used to control the new virtual machine. 146 147The new VM has no virtual cpus and no memory. 148You probably want to use 0 as machine type. 149 150In order to create user controlled virtual machines on S390, check 151KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as 152privileged user (CAP_SYS_ADMIN). 153 154On arm64, the physical address size for a VM (IPA Size limit) is limited 155to 40bits by default. The limit can be configured if the host supports the 156extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use 157KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type 158identifier, where IPA_Bits is the maximum width of any physical 159address used by the VM. The IPA_Bits is encoded in bits[7-0] of the 160machine type identifier. 161 162e.g, to configure a guest to use 48bit physical address size:: 163 164 vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48)); 165 166The requested size (IPA_Bits) must be: 167 168 == ========================================================= 169 0 Implies default size, 40bits (for backward compatibility) 170 N Implies N bits, where N is a positive integer such that, 171 32 <= N <= Host_IPA_Limit 172 == ========================================================= 173 174Host_IPA_Limit is the maximum possible value for IPA_Bits on the host and 175is dependent on the CPU capability and the kernel configuration. The limit can 176be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the KVM_CHECK_EXTENSION 177ioctl() at run-time. 178 179Creation of the VM will fail if the requested IPA size (whether it is 180implicit or explicit) is unsupported on the host. 181 182Please note that configuring the IPA size does not affect the capability 183exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects 184size of the address translated by the stage2 level (guest physical to 185host physical address translations). 186 187 1884.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST 189---------------------------------------------------------- 190 191:Capability: basic, KVM_CAP_GET_MSR_FEATURES for KVM_GET_MSR_FEATURE_INDEX_LIST 192:Architectures: x86 193:Type: system ioctl 194:Parameters: struct kvm_msr_list (in/out) 195:Returns: 0 on success; -1 on error 196 197Errors: 198 199 ====== ============================================================ 200 EFAULT the msr index list cannot be read from or written to 201 E2BIG the msr index list is too big to fit in the array specified by 202 the user. 203 ====== ============================================================ 204 205:: 206 207 struct kvm_msr_list { 208 __u32 nmsrs; /* number of msrs in entries */ 209 __u32 indices[0]; 210 }; 211 212The user fills in the size of the indices array in nmsrs, and in return 213kvm adjusts nmsrs to reflect the actual number of msrs and fills in the 214indices array with their numbers. 215 216KVM_GET_MSR_INDEX_LIST returns the guest msrs that are supported. The list 217varies by kvm version and host processor, but does not change otherwise. 218 219Note: if kvm indicates supports MCE (KVM_CAP_MCE), then the MCE bank MSRs are 220not returned in the MSR list, as different vcpus can have a different number 221of banks, as set via the KVM_X86_SETUP_MCE ioctl. 222 223KVM_GET_MSR_FEATURE_INDEX_LIST returns the list of MSRs that can be passed 224to the KVM_GET_MSRS system ioctl. This lets userspace probe host capabilities 225and processor features that are exposed via MSRs (e.g., VMX capabilities). 226This list also varies by kvm version and host processor, but does not change 227otherwise. 228 229 2304.4 KVM_CHECK_EXTENSION 231----------------------- 232 233:Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl 234:Architectures: all 235:Type: system ioctl, vm ioctl 236:Parameters: extension identifier (KVM_CAP_*) 237:Returns: 0 if unsupported; 1 (or some other positive integer) if supported 238 239The API allows the application to query about extensions to the core 240kvm API. Userspace passes an extension identifier (an integer) and 241receives an integer that describes the extension availability. 242Generally 0 means no and 1 means yes, but some extensions may report 243additional information in the integer return value. 244 245Based on their initialization different VMs may have different capabilities. 246It is thus encouraged to use the vm ioctl to query for capabilities (available 247with KVM_CAP_CHECK_EXTENSION_VM on the vm fd) 248 2494.5 KVM_GET_VCPU_MMAP_SIZE 250-------------------------- 251 252:Capability: basic 253:Architectures: all 254:Type: system ioctl 255:Parameters: none 256:Returns: size of vcpu mmap area, in bytes 257 258The KVM_RUN ioctl (cf.) communicates with userspace via a shared 259memory region. This ioctl returns the size of that region. See the 260KVM_RUN documentation for details. 261 262Besides the size of the KVM_RUN communication region, other areas of 263the VCPU file descriptor can be mmap-ed, including: 264 265- if KVM_CAP_COALESCED_MMIO is available, a page at 266 KVM_COALESCED_MMIO_PAGE_OFFSET * PAGE_SIZE; for historical reasons, 267 this page is included in the result of KVM_GET_VCPU_MMAP_SIZE. 268 KVM_CAP_COALESCED_MMIO is not documented yet. 269 270- if KVM_CAP_DIRTY_LOG_RING is available, a number of pages at 271 KVM_DIRTY_LOG_PAGE_OFFSET * PAGE_SIZE. For more information on 272 KVM_CAP_DIRTY_LOG_RING, see section 8.3. 273 274 2754.7 KVM_CREATE_VCPU 276------------------- 277 278:Capability: basic 279:Architectures: all 280:Type: vm ioctl 281:Parameters: vcpu id (apic id on x86) 282:Returns: vcpu fd on success, -1 on error 283 284This API adds a vcpu to a virtual machine. No more than max_vcpus may be added. 285The vcpu id is an integer in the range [0, max_vcpu_id). 286 287The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of 288the KVM_CHECK_EXTENSION ioctl() at run-time. 289The maximum possible value for max_vcpus can be retrieved using the 290KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. 291 292If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 293cpus max. 294If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is 295same as the value returned from KVM_CAP_NR_VCPUS. 296 297The maximum possible value for max_vcpu_id can be retrieved using the 298KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time. 299 300If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that max_vcpu_id 301is the same as the value returned from KVM_CAP_MAX_VCPUS. 302 303On powerpc using book3s_hv mode, the vcpus are mapped onto virtual 304threads in one or more virtual CPU cores. (This is because the 305hardware requires all the hardware threads in a CPU core to be in the 306same partition.) The KVM_CAP_PPC_SMT capability indicates the number 307of vcpus per virtual core (vcore). The vcore id is obtained by 308dividing the vcpu id by the number of vcpus per vcore. The vcpus in a 309given vcore will always be in the same physical core as each other 310(though that might be a different physical core from time to time). 311Userspace can control the threading (SMT) mode of the guest by its 312allocation of vcpu ids. For example, if userspace wants 313single-threaded guest vcpus, it should make all vcpu ids be a multiple 314of the number of vcpus per vcore. 315 316For virtual cpus that have been created with S390 user controlled virtual 317machines, the resulting vcpu fd can be memory mapped at page offset 318KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of the virtual 319cpu's hardware control block. 320 321 3224.8 KVM_GET_DIRTY_LOG (vm ioctl) 323-------------------------------- 324 325:Capability: basic 326:Architectures: all 327:Type: vm ioctl 328:Parameters: struct kvm_dirty_log (in/out) 329:Returns: 0 on success, -1 on error 330 331:: 332 333 /* for KVM_GET_DIRTY_LOG */ 334 struct kvm_dirty_log { 335 __u32 slot; 336 __u32 padding; 337 union { 338 void __user *dirty_bitmap; /* one bit per page */ 339 __u64 padding; 340 }; 341 }; 342 343Given a memory slot, return a bitmap containing any pages dirtied 344since the last call to this ioctl. Bit 0 is the first page in the 345memory slot. Ensure the entire structure is cleared to avoid padding 346issues. 347 348If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 349the address space for which you want to return the dirty bitmap. See 350KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 351 352The bits in the dirty bitmap are cleared before the ioctl returns, unless 353KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information, 354see the description of the capability. 355 356Note that the Xen shared info page, if configured, shall always be assumed 357to be dirty. KVM will not explicitly mark it such. 358 359 3604.10 KVM_RUN 361------------ 362 363:Capability: basic 364:Architectures: all 365:Type: vcpu ioctl 366:Parameters: none 367:Returns: 0 on success, -1 on error 368 369Errors: 370 371 ======= ============================================================== 372 EINTR an unmasked signal is pending 373 ENOEXEC the vcpu hasn't been initialized or the guest tried to execute 374 instructions from device memory (arm64) 375 ENOSYS data abort outside memslots with no syndrome info and 376 KVM_CAP_ARM_NISV_TO_USER not enabled (arm64) 377 EPERM SVE feature set but not finalized (arm64) 378 ======= ============================================================== 379 380This ioctl is used to run a guest virtual cpu. While there are no 381explicit parameters, there is an implicit parameter block that can be 382obtained by mmap()ing the vcpu fd at offset 0, with the size given by 383KVM_GET_VCPU_MMAP_SIZE. The parameter block is formatted as a 'struct 384kvm_run' (see below). 385 386 3874.11 KVM_GET_REGS 388----------------- 389 390:Capability: basic 391:Architectures: all except arm64 392:Type: vcpu ioctl 393:Parameters: struct kvm_regs (out) 394:Returns: 0 on success, -1 on error 395 396Reads the general purpose registers from the vcpu. 397 398:: 399 400 /* x86 */ 401 struct kvm_regs { 402 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 403 __u64 rax, rbx, rcx, rdx; 404 __u64 rsi, rdi, rsp, rbp; 405 __u64 r8, r9, r10, r11; 406 __u64 r12, r13, r14, r15; 407 __u64 rip, rflags; 408 }; 409 410 /* mips */ 411 struct kvm_regs { 412 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 413 __u64 gpr[32]; 414 __u64 hi; 415 __u64 lo; 416 __u64 pc; 417 }; 418 419 4204.12 KVM_SET_REGS 421----------------- 422 423:Capability: basic 424:Architectures: all except arm64 425:Type: vcpu ioctl 426:Parameters: struct kvm_regs (in) 427:Returns: 0 on success, -1 on error 428 429Writes the general purpose registers into the vcpu. 430 431See KVM_GET_REGS for the data structure. 432 433 4344.13 KVM_GET_SREGS 435------------------ 436 437:Capability: basic 438:Architectures: x86, ppc 439:Type: vcpu ioctl 440:Parameters: struct kvm_sregs (out) 441:Returns: 0 on success, -1 on error 442 443Reads special registers from the vcpu. 444 445:: 446 447 /* x86 */ 448 struct kvm_sregs { 449 struct kvm_segment cs, ds, es, fs, gs, ss; 450 struct kvm_segment tr, ldt; 451 struct kvm_dtable gdt, idt; 452 __u64 cr0, cr2, cr3, cr4, cr8; 453 __u64 efer; 454 __u64 apic_base; 455 __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64]; 456 }; 457 458 /* ppc -- see arch/powerpc/include/uapi/asm/kvm.h */ 459 460interrupt_bitmap is a bitmap of pending external interrupts. At most 461one bit may be set. This interrupt has been acknowledged by the APIC 462but not yet injected into the cpu core. 463 464 4654.14 KVM_SET_SREGS 466------------------ 467 468:Capability: basic 469:Architectures: x86, ppc 470:Type: vcpu ioctl 471:Parameters: struct kvm_sregs (in) 472:Returns: 0 on success, -1 on error 473 474Writes special registers into the vcpu. See KVM_GET_SREGS for the 475data structures. 476 477 4784.15 KVM_TRANSLATE 479------------------ 480 481:Capability: basic 482:Architectures: x86 483:Type: vcpu ioctl 484:Parameters: struct kvm_translation (in/out) 485:Returns: 0 on success, -1 on error 486 487Translates a virtual address according to the vcpu's current address 488translation mode. 489 490:: 491 492 struct kvm_translation { 493 /* in */ 494 __u64 linear_address; 495 496 /* out */ 497 __u64 physical_address; 498 __u8 valid; 499 __u8 writeable; 500 __u8 usermode; 501 __u8 pad[5]; 502 }; 503 504 5054.16 KVM_INTERRUPT 506------------------ 507 508:Capability: basic 509:Architectures: x86, ppc, mips, riscv 510:Type: vcpu ioctl 511:Parameters: struct kvm_interrupt (in) 512:Returns: 0 on success, negative on failure. 513 514Queues a hardware interrupt vector to be injected. 515 516:: 517 518 /* for KVM_INTERRUPT */ 519 struct kvm_interrupt { 520 /* in */ 521 __u32 irq; 522 }; 523 524X86: 525^^^^ 526 527:Returns: 528 529 ========= =================================== 530 0 on success, 531 -EEXIST if an interrupt is already enqueued 532 -EINVAL the irq number is invalid 533 -ENXIO if the PIC is in the kernel 534 -EFAULT if the pointer is invalid 535 ========= =================================== 536 537Note 'irq' is an interrupt vector, not an interrupt pin or line. This 538ioctl is useful if the in-kernel PIC is not used. 539 540PPC: 541^^^^ 542 543Queues an external interrupt to be injected. This ioctl is overleaded 544with 3 different irq values: 545 546a) KVM_INTERRUPT_SET 547 548 This injects an edge type external interrupt into the guest once it's ready 549 to receive interrupts. When injected, the interrupt is done. 550 551b) KVM_INTERRUPT_UNSET 552 553 This unsets any pending interrupt. 554 555 Only available with KVM_CAP_PPC_UNSET_IRQ. 556 557c) KVM_INTERRUPT_SET_LEVEL 558 559 This injects a level type external interrupt into the guest context. The 560 interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET 561 is triggered. 562 563 Only available with KVM_CAP_PPC_IRQ_LEVEL. 564 565Note that any value for 'irq' other than the ones stated above is invalid 566and incurs unexpected behavior. 567 568This is an asynchronous vcpu ioctl and can be invoked from any thread. 569 570MIPS: 571^^^^^ 572 573Queues an external interrupt to be injected into the virtual CPU. A negative 574interrupt number dequeues the interrupt. 575 576This is an asynchronous vcpu ioctl and can be invoked from any thread. 577 578RISC-V: 579^^^^^^^ 580 581Queues an external interrupt to be injected into the virtual CPU. This ioctl 582is overloaded with 2 different irq values: 583 584a) KVM_INTERRUPT_SET 585 586 This sets external interrupt for a virtual CPU and it will receive 587 once it is ready. 588 589b) KVM_INTERRUPT_UNSET 590 591 This clears pending external interrupt for a virtual CPU. 592 593This is an asynchronous vcpu ioctl and can be invoked from any thread. 594 595 5964.17 KVM_DEBUG_GUEST 597-------------------- 598 599:Capability: basic 600:Architectures: none 601:Type: vcpu ioctl 602:Parameters: none) 603:Returns: -1 on error 604 605Support for this has been removed. Use KVM_SET_GUEST_DEBUG instead. 606 607 6084.18 KVM_GET_MSRS 609----------------- 610 611:Capability: basic (vcpu), KVM_CAP_GET_MSR_FEATURES (system) 612:Architectures: x86 613:Type: system ioctl, vcpu ioctl 614:Parameters: struct kvm_msrs (in/out) 615:Returns: number of msrs successfully returned; 616 -1 on error 617 618When used as a system ioctl: 619Reads the values of MSR-based features that are available for the VM. This 620is similar to KVM_GET_SUPPORTED_CPUID, but it returns MSR indices and values. 621The list of msr-based features can be obtained using KVM_GET_MSR_FEATURE_INDEX_LIST 622in a system ioctl. 623 624When used as a vcpu ioctl: 625Reads model-specific registers from the vcpu. Supported msr indices can 626be obtained using KVM_GET_MSR_INDEX_LIST in a system ioctl. 627 628:: 629 630 struct kvm_msrs { 631 __u32 nmsrs; /* number of msrs in entries */ 632 __u32 pad; 633 634 struct kvm_msr_entry entries[0]; 635 }; 636 637 struct kvm_msr_entry { 638 __u32 index; 639 __u32 reserved; 640 __u64 data; 641 }; 642 643Application code should set the 'nmsrs' member (which indicates the 644size of the entries array) and the 'index' member of each array entry. 645kvm will fill in the 'data' member. 646 647 6484.19 KVM_SET_MSRS 649----------------- 650 651:Capability: basic 652:Architectures: x86 653:Type: vcpu ioctl 654:Parameters: struct kvm_msrs (in) 655:Returns: number of msrs successfully set (see below), -1 on error 656 657Writes model-specific registers to the vcpu. See KVM_GET_MSRS for the 658data structures. 659 660Application code should set the 'nmsrs' member (which indicates the 661size of the entries array), and the 'index' and 'data' members of each 662array entry. 663 664It tries to set the MSRs in array entries[] one by one. If setting an MSR 665fails, e.g., due to setting reserved bits, the MSR isn't supported/emulated 666by KVM, etc..., it stops processing the MSR list and returns the number of 667MSRs that have been set successfully. 668 669 6704.20 KVM_SET_CPUID 671------------------ 672 673:Capability: basic 674:Architectures: x86 675:Type: vcpu ioctl 676:Parameters: struct kvm_cpuid (in) 677:Returns: 0 on success, -1 on error 678 679Defines the vcpu responses to the cpuid instruction. Applications 680should use the KVM_SET_CPUID2 ioctl if available. 681 682Caveat emptor: 683 - If this IOCTL fails, KVM gives no guarantees that previous valid CPUID 684 configuration (if there is) is not corrupted. Userspace can get a copy 685 of the resulting CPUID configuration through KVM_GET_CPUID2 in case. 686 - Using KVM_SET_CPUID{,2} after KVM_RUN, i.e. changing the guest vCPU model 687 after running the guest, may cause guest instability. 688 - Using heterogeneous CPUID configurations, modulo APIC IDs, topology, etc... 689 may cause guest instability. 690 691:: 692 693 struct kvm_cpuid_entry { 694 __u32 function; 695 __u32 eax; 696 __u32 ebx; 697 __u32 ecx; 698 __u32 edx; 699 __u32 padding; 700 }; 701 702 /* for KVM_SET_CPUID */ 703 struct kvm_cpuid { 704 __u32 nent; 705 __u32 padding; 706 struct kvm_cpuid_entry entries[0]; 707 }; 708 709 7104.21 KVM_SET_SIGNAL_MASK 711------------------------ 712 713:Capability: basic 714:Architectures: all 715:Type: vcpu ioctl 716:Parameters: struct kvm_signal_mask (in) 717:Returns: 0 on success, -1 on error 718 719Defines which signals are blocked during execution of KVM_RUN. This 720signal mask temporarily overrides the threads signal mask. Any 721unblocked signal received (except SIGKILL and SIGSTOP, which retain 722their traditional behaviour) will cause KVM_RUN to return with -EINTR. 723 724Note the signal will only be delivered if not blocked by the original 725signal mask. 726 727:: 728 729 /* for KVM_SET_SIGNAL_MASK */ 730 struct kvm_signal_mask { 731 __u32 len; 732 __u8 sigset[0]; 733 }; 734 735 7364.22 KVM_GET_FPU 737---------------- 738 739:Capability: basic 740:Architectures: x86 741:Type: vcpu ioctl 742:Parameters: struct kvm_fpu (out) 743:Returns: 0 on success, -1 on error 744 745Reads the floating point state from the vcpu. 746 747:: 748 749 /* for KVM_GET_FPU and KVM_SET_FPU */ 750 struct kvm_fpu { 751 __u8 fpr[8][16]; 752 __u16 fcw; 753 __u16 fsw; 754 __u8 ftwx; /* in fxsave format */ 755 __u8 pad1; 756 __u16 last_opcode; 757 __u64 last_ip; 758 __u64 last_dp; 759 __u8 xmm[16][16]; 760 __u32 mxcsr; 761 __u32 pad2; 762 }; 763 764 7654.23 KVM_SET_FPU 766---------------- 767 768:Capability: basic 769:Architectures: x86 770:Type: vcpu ioctl 771:Parameters: struct kvm_fpu (in) 772:Returns: 0 on success, -1 on error 773 774Writes the floating point state to the vcpu. 775 776:: 777 778 /* for KVM_GET_FPU and KVM_SET_FPU */ 779 struct kvm_fpu { 780 __u8 fpr[8][16]; 781 __u16 fcw; 782 __u16 fsw; 783 __u8 ftwx; /* in fxsave format */ 784 __u8 pad1; 785 __u16 last_opcode; 786 __u64 last_ip; 787 __u64 last_dp; 788 __u8 xmm[16][16]; 789 __u32 mxcsr; 790 __u32 pad2; 791 }; 792 793 7944.24 KVM_CREATE_IRQCHIP 795----------------------- 796 797:Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390) 798:Architectures: x86, arm64, s390 799:Type: vm ioctl 800:Parameters: none 801:Returns: 0 on success, -1 on error 802 803Creates an interrupt controller model in the kernel. 804On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up 805future vcpus to have a local APIC. IRQ routing for GSIs 0-15 is set to both 806PIC and IOAPIC; GSI 16-23 only go to the IOAPIC. 807On arm64, a GICv2 is created. Any other GIC versions require the usage of 808KVM_CREATE_DEVICE, which also supports creating a GICv2. Using 809KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2. 810On s390, a dummy irq routing table is created. 811 812Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled 813before KVM_CREATE_IRQCHIP can be used. 814 815 8164.25 KVM_IRQ_LINE 817----------------- 818 819:Capability: KVM_CAP_IRQCHIP 820:Architectures: x86, arm64 821:Type: vm ioctl 822:Parameters: struct kvm_irq_level 823:Returns: 0 on success, -1 on error 824 825Sets the level of a GSI input to the interrupt controller model in the kernel. 826On some architectures it is required that an interrupt controller model has 827been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered 828interrupts require the level to be set to 1 and then back to 0. 829 830On real hardware, interrupt pins can be active-low or active-high. This 831does not matter for the level field of struct kvm_irq_level: 1 always 832means active (asserted), 0 means inactive (deasserted). 833 834x86 allows the operating system to program the interrupt polarity 835(active-low/active-high) for level-triggered interrupts, and KVM used 836to consider the polarity. However, due to bitrot in the handling of 837active-low interrupts, the above convention is now valid on x86 too. 838This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace 839should not present interrupts to the guest as active-low unless this 840capability is present (or unless it is not using the in-kernel irqchip, 841of course). 842 843 844arm64 can signal an interrupt either at the CPU level, or at the 845in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to 846use PPIs designated for specific cpus. The irq field is interpreted 847like this:: 848 849 bits: | 31 ... 28 | 27 ... 24 | 23 ... 16 | 15 ... 0 | 850 field: | vcpu2_index | irq_type | vcpu_index | irq_id | 851 852The irq_type field has the following values: 853 854- irq_type[0]: 855 out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ 856- irq_type[1]: 857 in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.) 858 (the vcpu_index field is ignored) 859- irq_type[2]: 860 in-kernel GIC: PPI, irq_id between 16 and 31 (incl.) 861 862(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs) 863 864In both cases, level is used to assert/deassert the line. 865 866When KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 is supported, the target vcpu is 867identified as (256 * vcpu2_index + vcpu_index). Otherwise, vcpu2_index 868must be zero. 869 870Note that on arm64, the KVM_CAP_IRQCHIP capability only conditions 871injection of interrupts for the in-kernel irqchip. KVM_IRQ_LINE can always 872be used for a userspace interrupt controller. 873 874:: 875 876 struct kvm_irq_level { 877 union { 878 __u32 irq; /* GSI */ 879 __s32 status; /* not used for KVM_IRQ_LEVEL */ 880 }; 881 __u32 level; /* 0 or 1 */ 882 }; 883 884 8854.26 KVM_GET_IRQCHIP 886-------------------- 887 888:Capability: KVM_CAP_IRQCHIP 889:Architectures: x86 890:Type: vm ioctl 891:Parameters: struct kvm_irqchip (in/out) 892:Returns: 0 on success, -1 on error 893 894Reads the state of a kernel interrupt controller created with 895KVM_CREATE_IRQCHIP into a buffer provided by the caller. 896 897:: 898 899 struct kvm_irqchip { 900 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ 901 __u32 pad; 902 union { 903 char dummy[512]; /* reserving space */ 904 struct kvm_pic_state pic; 905 struct kvm_ioapic_state ioapic; 906 } chip; 907 }; 908 909 9104.27 KVM_SET_IRQCHIP 911-------------------- 912 913:Capability: KVM_CAP_IRQCHIP 914:Architectures: x86 915:Type: vm ioctl 916:Parameters: struct kvm_irqchip (in) 917:Returns: 0 on success, -1 on error 918 919Sets the state of a kernel interrupt controller created with 920KVM_CREATE_IRQCHIP from a buffer provided by the caller. 921 922:: 923 924 struct kvm_irqchip { 925 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ 926 __u32 pad; 927 union { 928 char dummy[512]; /* reserving space */ 929 struct kvm_pic_state pic; 930 struct kvm_ioapic_state ioapic; 931 } chip; 932 }; 933 934 9354.28 KVM_XEN_HVM_CONFIG 936----------------------- 937 938:Capability: KVM_CAP_XEN_HVM 939:Architectures: x86 940:Type: vm ioctl 941:Parameters: struct kvm_xen_hvm_config (in) 942:Returns: 0 on success, -1 on error 943 944Sets the MSR that the Xen HVM guest uses to initialize its hypercall 945page, and provides the starting address and size of the hypercall 946blobs in userspace. When the guest writes the MSR, kvm copies one 947page of a blob (32- or 64-bit, depending on the vcpu mode) to guest 948memory. 949 950:: 951 952 struct kvm_xen_hvm_config { 953 __u32 flags; 954 __u32 msr; 955 __u64 blob_addr_32; 956 __u64 blob_addr_64; 957 __u8 blob_size_32; 958 __u8 blob_size_64; 959 __u8 pad2[30]; 960 }; 961 962If certain flags are returned from the KVM_CAP_XEN_HVM check, they may 963be set in the flags field of this ioctl: 964 965The KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag requests KVM to generate 966the contents of the hypercall page automatically; hypercalls will be 967intercepted and passed to userspace through KVM_EXIT_XEN. In this 968ase, all of the blob size and address fields must be zero. 969 970The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates to KVM that userspace 971will always use the KVM_XEN_HVM_EVTCHN_SEND ioctl to deliver event 972channel interrupts rather than manipulating the guest's shared_info 973structures directly. This, in turn, may allow KVM to enable features 974such as intercepting the SCHEDOP_poll hypercall to accelerate PV 975spinlock operation for the guest. Userspace may still use the ioctl 976to deliver events if it was advertised, even if userspace does not 977send this indication that it will always do so 978 979No other flags are currently valid in the struct kvm_xen_hvm_config. 980 9814.29 KVM_GET_CLOCK 982------------------ 983 984:Capability: KVM_CAP_ADJUST_CLOCK 985:Architectures: x86 986:Type: vm ioctl 987:Parameters: struct kvm_clock_data (out) 988:Returns: 0 on success, -1 on error 989 990Gets the current timestamp of kvmclock as seen by the current guest. In 991conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios 992such as migration. 993 994When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the 995set of bits that KVM can return in struct kvm_clock_data's flag member. 996 997The following flags are defined: 998 999KVM_CLOCK_TSC_STABLE 1000 If set, the returned value is the exact kvmclock 1001 value seen by all VCPUs at the instant when KVM_GET_CLOCK was called. 1002 If clear, the returned value is simply CLOCK_MONOTONIC plus a constant 1003 offset; the offset can be modified with KVM_SET_CLOCK. KVM will try 1004 to make all VCPUs follow this clock, but the exact value read by each 1005 VCPU could differ, because the host TSC is not stable. 1006 1007KVM_CLOCK_REALTIME 1008 If set, the `realtime` field in the kvm_clock_data 1009 structure is populated with the value of the host's real time 1010 clocksource at the instant when KVM_GET_CLOCK was called. If clear, 1011 the `realtime` field does not contain a value. 1012 1013KVM_CLOCK_HOST_TSC 1014 If set, the `host_tsc` field in the kvm_clock_data 1015 structure is populated with the value of the host's timestamp counter (TSC) 1016 at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field 1017 does not contain a value. 1018 1019:: 1020 1021 struct kvm_clock_data { 1022 __u64 clock; /* kvmclock current value */ 1023 __u32 flags; 1024 __u32 pad0; 1025 __u64 realtime; 1026 __u64 host_tsc; 1027 __u32 pad[4]; 1028 }; 1029 1030 10314.30 KVM_SET_CLOCK 1032------------------ 1033 1034:Capability: KVM_CAP_ADJUST_CLOCK 1035:Architectures: x86 1036:Type: vm ioctl 1037:Parameters: struct kvm_clock_data (in) 1038:Returns: 0 on success, -1 on error 1039 1040Sets the current timestamp of kvmclock to the value specified in its parameter. 1041In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios 1042such as migration. 1043 1044The following flags can be passed: 1045 1046KVM_CLOCK_REALTIME 1047 If set, KVM will compare the value of the `realtime` field 1048 with the value of the host's real time clocksource at the instant when 1049 KVM_SET_CLOCK was called. The difference in elapsed time is added to the final 1050 kvmclock value that will be provided to guests. 1051 1052Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored. 1053 1054:: 1055 1056 struct kvm_clock_data { 1057 __u64 clock; /* kvmclock current value */ 1058 __u32 flags; 1059 __u32 pad0; 1060 __u64 realtime; 1061 __u64 host_tsc; 1062 __u32 pad[4]; 1063 }; 1064 1065 10664.31 KVM_GET_VCPU_EVENTS 1067------------------------ 1068 1069:Capability: KVM_CAP_VCPU_EVENTS 1070:Extended by: KVM_CAP_INTR_SHADOW 1071:Architectures: x86, arm64 1072:Type: vcpu ioctl 1073:Parameters: struct kvm_vcpu_event (out) 1074:Returns: 0 on success, -1 on error 1075 1076X86: 1077^^^^ 1078 1079Gets currently pending exceptions, interrupts, and NMIs as well as related 1080states of the vcpu. 1081 1082:: 1083 1084 struct kvm_vcpu_events { 1085 struct { 1086 __u8 injected; 1087 __u8 nr; 1088 __u8 has_error_code; 1089 __u8 pending; 1090 __u32 error_code; 1091 } exception; 1092 struct { 1093 __u8 injected; 1094 __u8 nr; 1095 __u8 soft; 1096 __u8 shadow; 1097 } interrupt; 1098 struct { 1099 __u8 injected; 1100 __u8 pending; 1101 __u8 masked; 1102 __u8 pad; 1103 } nmi; 1104 __u32 sipi_vector; 1105 __u32 flags; 1106 struct { 1107 __u8 smm; 1108 __u8 pending; 1109 __u8 smm_inside_nmi; 1110 __u8 latched_init; 1111 } smi; 1112 __u8 reserved[27]; 1113 __u8 exception_has_payload; 1114 __u64 exception_payload; 1115 }; 1116 1117The following bits are defined in the flags field: 1118 1119- KVM_VCPUEVENT_VALID_SHADOW may be set to signal that 1120 interrupt.shadow contains a valid state. 1121 1122- KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a 1123 valid state. 1124 1125- KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the 1126 exception_has_payload, exception_payload, and exception.pending 1127 fields contain a valid state. This bit will be set whenever 1128 KVM_CAP_EXCEPTION_PAYLOAD is enabled. 1129 1130- KVM_VCPUEVENT_VALID_TRIPLE_FAULT may be set to signal that the 1131 triple_fault_pending field contains a valid state. This bit will 1132 be set whenever KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled. 1133 1134ARM64: 1135^^^^^^ 1136 1137If the guest accesses a device that is being emulated by the host kernel in 1138such a way that a real device would generate a physical SError, KVM may make 1139a virtual SError pending for that VCPU. This system error interrupt remains 1140pending until the guest takes the exception by unmasking PSTATE.A. 1141 1142Running the VCPU may cause it to take a pending SError, or make an access that 1143causes an SError to become pending. The event's description is only valid while 1144the VPCU is not running. 1145 1146This API provides a way to read and write the pending 'event' state that is not 1147visible to the guest. To save, restore or migrate a VCPU the struct representing 1148the state can be read then written using this GET/SET API, along with the other 1149guest-visible registers. It is not possible to 'cancel' an SError that has been 1150made pending. 1151 1152A device being emulated in user-space may also wish to generate an SError. To do 1153this the events structure can be populated by user-space. The current state 1154should be read first, to ensure no existing SError is pending. If an existing 1155SError is pending, the architecture's 'Multiple SError interrupts' rules should 1156be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and 1157Serviceability (RAS) Specification"). 1158 1159SError exceptions always have an ESR value. Some CPUs have the ability to 1160specify what the virtual SError's ESR value should be. These systems will 1161advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will 1162always have a non-zero value when read, and the agent making an SError pending 1163should specify the ISS field in the lower 24 bits of exception.serror_esr. If 1164the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events 1165with exception.has_esr as zero, KVM will choose an ESR. 1166 1167Specifying exception.has_esr on a system that does not support it will return 1168-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr 1169will return -EINVAL. 1170 1171It is not possible to read back a pending external abort (injected via 1172KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered 1173directly to the virtual CPU). 1174 1175:: 1176 1177 struct kvm_vcpu_events { 1178 struct { 1179 __u8 serror_pending; 1180 __u8 serror_has_esr; 1181 __u8 ext_dabt_pending; 1182 /* Align it to 8 bytes */ 1183 __u8 pad[5]; 1184 __u64 serror_esr; 1185 } exception; 1186 __u32 reserved[12]; 1187 }; 1188 11894.32 KVM_SET_VCPU_EVENTS 1190------------------------ 1191 1192:Capability: KVM_CAP_VCPU_EVENTS 1193:Extended by: KVM_CAP_INTR_SHADOW 1194:Architectures: x86, arm64 1195:Type: vcpu ioctl 1196:Parameters: struct kvm_vcpu_event (in) 1197:Returns: 0 on success, -1 on error 1198 1199X86: 1200^^^^ 1201 1202Set pending exceptions, interrupts, and NMIs as well as related states of the 1203vcpu. 1204 1205See KVM_GET_VCPU_EVENTS for the data structure. 1206 1207Fields that may be modified asynchronously by running VCPUs can be excluded 1208from the update. These fields are nmi.pending, sipi_vector, smi.smm, 1209smi.pending. Keep the corresponding bits in the flags field cleared to 1210suppress overwriting the current in-kernel state. The bits are: 1211 1212=============================== ================================== 1213KVM_VCPUEVENT_VALID_NMI_PENDING transfer nmi.pending to the kernel 1214KVM_VCPUEVENT_VALID_SIPI_VECTOR transfer sipi_vector 1215KVM_VCPUEVENT_VALID_SMM transfer the smi sub-struct. 1216=============================== ================================== 1217 1218If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in 1219the flags field to signal that interrupt.shadow contains a valid state and 1220shall be written into the VCPU. 1221 1222KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. 1223 1224If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD 1225can be set in the flags field to signal that the 1226exception_has_payload, exception_payload, and exception.pending fields 1227contain a valid state and shall be written into the VCPU. 1228 1229If KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled, KVM_VCPUEVENT_VALID_TRIPLE_FAULT 1230can be set in flags field to signal that the triple_fault field contains 1231a valid state and shall be written into the VCPU. 1232 1233ARM64: 1234^^^^^^ 1235 1236User space may need to inject several types of events to the guest. 1237 1238Set the pending SError exception state for this VCPU. It is not possible to 1239'cancel' an Serror that has been made pending. 1240 1241If the guest performed an access to I/O memory which could not be handled by 1242userspace, for example because of missing instruction syndrome decode 1243information or because there is no device mapped at the accessed IPA, then 1244userspace can ask the kernel to inject an external abort using the address 1245from the exiting fault on the VCPU. It is a programming error to set 1246ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or 1247KVM_EXIT_ARM_NISV. This feature is only available if the system supports 1248KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in 1249how userspace reports accesses for the above cases to guests, across different 1250userspace implementations. Nevertheless, userspace can still emulate all Arm 1251exceptions by manipulating individual registers using the KVM_SET_ONE_REG API. 1252 1253See KVM_GET_VCPU_EVENTS for the data structure. 1254 1255 12564.33 KVM_GET_DEBUGREGS 1257---------------------- 1258 1259:Capability: KVM_CAP_DEBUGREGS 1260:Architectures: x86 1261:Type: vm ioctl 1262:Parameters: struct kvm_debugregs (out) 1263:Returns: 0 on success, -1 on error 1264 1265Reads debug registers from the vcpu. 1266 1267:: 1268 1269 struct kvm_debugregs { 1270 __u64 db[4]; 1271 __u64 dr6; 1272 __u64 dr7; 1273 __u64 flags; 1274 __u64 reserved[9]; 1275 }; 1276 1277 12784.34 KVM_SET_DEBUGREGS 1279---------------------- 1280 1281:Capability: KVM_CAP_DEBUGREGS 1282:Architectures: x86 1283:Type: vm ioctl 1284:Parameters: struct kvm_debugregs (in) 1285:Returns: 0 on success, -1 on error 1286 1287Writes debug registers into the vcpu. 1288 1289See KVM_GET_DEBUGREGS for the data structure. The flags field is unused 1290yet and must be cleared on entry. 1291 1292 12934.35 KVM_SET_USER_MEMORY_REGION 1294------------------------------- 1295 1296:Capability: KVM_CAP_USER_MEMORY 1297:Architectures: all 1298:Type: vm ioctl 1299:Parameters: struct kvm_userspace_memory_region (in) 1300:Returns: 0 on success, -1 on error 1301 1302:: 1303 1304 struct kvm_userspace_memory_region { 1305 __u32 slot; 1306 __u32 flags; 1307 __u64 guest_phys_addr; 1308 __u64 memory_size; /* bytes */ 1309 __u64 userspace_addr; /* start of the userspace allocated memory */ 1310 }; 1311 1312 /* for kvm_userspace_memory_region::flags */ 1313 #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) 1314 #define KVM_MEM_READONLY (1UL << 1) 1315 1316This ioctl allows the user to create, modify or delete a guest physical 1317memory slot. Bits 0-15 of "slot" specify the slot id and this value 1318should be less than the maximum number of user memory slots supported per 1319VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS. 1320Slots may not overlap in guest physical address space. 1321 1322If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot" 1323specifies the address space which is being modified. They must be 1324less than the value that KVM_CHECK_EXTENSION returns for the 1325KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces 1326are unrelated; the restriction on overlapping slots only applies within 1327each address space. 1328 1329Deleting a slot is done by passing zero for memory_size. When changing 1330an existing slot, it may be moved in the guest physical memory space, 1331or its flags may be modified, but it may not be resized. 1332 1333Memory for the region is taken starting at the address denoted by the 1334field userspace_addr, which must point at user addressable memory for 1335the entire memory slot size. Any object may back this memory, including 1336anonymous memory, ordinary files, and hugetlbfs. 1337 1338On architectures that support a form of address tagging, userspace_addr must 1339be an untagged address. 1340 1341It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr 1342be identical. This allows large pages in the guest to be backed by large 1343pages in the host. 1344 1345The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and 1346KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of 1347writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to 1348use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it, 1349to make a new slot read-only. In this case, writes to this memory will be 1350posted to userspace as KVM_EXIT_MMIO exits. 1351 1352When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of 1353the memory region are automatically reflected into the guest. For example, an 1354mmap() that affects the region will be made visible immediately. Another 1355example is madvise(MADV_DROP). 1356 1357Note: On arm64, a write generated by the page-table walker (to update 1358the Access and Dirty flags, for example) never results in a 1359KVM_EXIT_MMIO exit when the slot has the KVM_MEM_READONLY flag. This 1360is because KVM cannot provide the data that would be written by the 1361page-table walker, making it impossible to emulate the access. 1362Instead, an abort (data abort if the cause of the page-table update 1363was a load or a store, instruction abort if it was an instruction 1364fetch) is injected in the guest. 1365 13664.36 KVM_SET_TSS_ADDR 1367--------------------- 1368 1369:Capability: KVM_CAP_SET_TSS_ADDR 1370:Architectures: x86 1371:Type: vm ioctl 1372:Parameters: unsigned long tss_address (in) 1373:Returns: 0 on success, -1 on error 1374 1375This ioctl defines the physical address of a three-page region in the guest 1376physical address space. The region must be within the first 4GB of the 1377guest physical address space and must not conflict with any memory slot 1378or any mmio address. The guest may malfunction if it accesses this memory 1379region. 1380 1381This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1382because of a quirk in the virtualization implementation (see the internals 1383documentation when it pops into existence). 1384 1385 13864.37 KVM_ENABLE_CAP 1387------------------- 1388 1389:Capability: KVM_CAP_ENABLE_CAP 1390:Architectures: mips, ppc, s390, x86 1391:Type: vcpu ioctl 1392:Parameters: struct kvm_enable_cap (in) 1393:Returns: 0 on success; -1 on error 1394 1395:Capability: KVM_CAP_ENABLE_CAP_VM 1396:Architectures: all 1397:Type: vm ioctl 1398:Parameters: struct kvm_enable_cap (in) 1399:Returns: 0 on success; -1 on error 1400 1401.. note:: 1402 1403 Not all extensions are enabled by default. Using this ioctl the application 1404 can enable an extension, making it available to the guest. 1405 1406On systems that do not support this ioctl, it always fails. On systems that 1407do support it, it only works for extensions that are supported for enablement. 1408 1409To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should 1410be used. 1411 1412:: 1413 1414 struct kvm_enable_cap { 1415 /* in */ 1416 __u32 cap; 1417 1418The capability that is supposed to get enabled. 1419 1420:: 1421 1422 __u32 flags; 1423 1424A bitfield indicating future enhancements. Has to be 0 for now. 1425 1426:: 1427 1428 __u64 args[4]; 1429 1430Arguments for enabling a feature. If a feature needs initial values to 1431function properly, this is the place to put them. 1432 1433:: 1434 1435 __u8 pad[64]; 1436 }; 1437 1438The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl 1439for vm-wide capabilities. 1440 14414.38 KVM_GET_MP_STATE 1442--------------------- 1443 1444:Capability: KVM_CAP_MP_STATE 1445:Architectures: x86, s390, arm64, riscv 1446:Type: vcpu ioctl 1447:Parameters: struct kvm_mp_state (out) 1448:Returns: 0 on success; -1 on error 1449 1450:: 1451 1452 struct kvm_mp_state { 1453 __u32 mp_state; 1454 }; 1455 1456Returns the vcpu's current "multiprocessing state" (though also valid on 1457uniprocessor guests). 1458 1459Possible values are: 1460 1461 ========================== =============================================== 1462 KVM_MP_STATE_RUNNABLE the vcpu is currently running 1463 [x86,arm64,riscv] 1464 KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP) 1465 which has not yet received an INIT signal [x86] 1466 KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is 1467 now ready for a SIPI [x86] 1468 KVM_MP_STATE_HALTED the vcpu has executed a HLT instruction and 1469 is waiting for an interrupt [x86] 1470 KVM_MP_STATE_SIPI_RECEIVED the vcpu has just received a SIPI (vector 1471 accessible via KVM_GET_VCPU_EVENTS) [x86] 1472 KVM_MP_STATE_STOPPED the vcpu is stopped [s390,arm64,riscv] 1473 KVM_MP_STATE_CHECK_STOP the vcpu is in a special error state [s390] 1474 KVM_MP_STATE_OPERATING the vcpu is operating (running or halted) 1475 [s390] 1476 KVM_MP_STATE_LOAD the vcpu is in a special load/startup state 1477 [s390] 1478 KVM_MP_STATE_SUSPENDED the vcpu is in a suspend state and is waiting 1479 for a wakeup event [arm64] 1480 ========================== =============================================== 1481 1482On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1483in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1484these architectures. 1485 1486For arm64: 1487^^^^^^^^^^ 1488 1489If a vCPU is in the KVM_MP_STATE_SUSPENDED state, KVM will emulate the 1490architectural execution of a WFI instruction. 1491 1492If a wakeup event is recognized, KVM will exit to userspace with a 1493KVM_SYSTEM_EVENT exit, where the event type is KVM_SYSTEM_EVENT_WAKEUP. If 1494userspace wants to honor the wakeup, it must set the vCPU's MP state to 1495KVM_MP_STATE_RUNNABLE. If it does not, KVM will continue to await a wakeup 1496event in subsequent calls to KVM_RUN. 1497 1498.. warning:: 1499 1500 If userspace intends to keep the vCPU in a SUSPENDED state, it is 1501 strongly recommended that userspace take action to suppress the 1502 wakeup event (such as masking an interrupt). Otherwise, subsequent 1503 calls to KVM_RUN will immediately exit with a KVM_SYSTEM_EVENT_WAKEUP 1504 event and inadvertently waste CPU cycles. 1505 1506 Additionally, if userspace takes action to suppress a wakeup event, 1507 it is strongly recommended that it also restores the vCPU to its 1508 original state when the vCPU is made RUNNABLE again. For example, 1509 if userspace masked a pending interrupt to suppress the wakeup, 1510 the interrupt should be unmasked before returning control to the 1511 guest. 1512 1513For riscv: 1514^^^^^^^^^^ 1515 1516The only states that are valid are KVM_MP_STATE_STOPPED and 1517KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not. 1518 15194.39 KVM_SET_MP_STATE 1520--------------------- 1521 1522:Capability: KVM_CAP_MP_STATE 1523:Architectures: x86, s390, arm64, riscv 1524:Type: vcpu ioctl 1525:Parameters: struct kvm_mp_state (in) 1526:Returns: 0 on success; -1 on error 1527 1528Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for 1529arguments. 1530 1531On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1532in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1533these architectures. 1534 1535For arm64/riscv: 1536^^^^^^^^^^^^^^^^ 1537 1538The only states that are valid are KVM_MP_STATE_STOPPED and 1539KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not. 1540 15414.40 KVM_SET_IDENTITY_MAP_ADDR 1542------------------------------ 1543 1544:Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR 1545:Architectures: x86 1546:Type: vm ioctl 1547:Parameters: unsigned long identity (in) 1548:Returns: 0 on success, -1 on error 1549 1550This ioctl defines the physical address of a one-page region in the guest 1551physical address space. The region must be within the first 4GB of the 1552guest physical address space and must not conflict with any memory slot 1553or any mmio address. The guest may malfunction if it accesses this memory 1554region. 1555 1556Setting the address to 0 will result in resetting the address to its default 1557(0xfffbc000). 1558 1559This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1560because of a quirk in the virtualization implementation (see the internals 1561documentation when it pops into existence). 1562 1563Fails if any VCPU has already been created. 1564 15654.41 KVM_SET_BOOT_CPU_ID 1566------------------------ 1567 1568:Capability: KVM_CAP_SET_BOOT_CPU_ID 1569:Architectures: x86 1570:Type: vm ioctl 1571:Parameters: unsigned long vcpu_id 1572:Returns: 0 on success, -1 on error 1573 1574Define which vcpu is the Bootstrap Processor (BSP). Values are the same 1575as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default 1576is vcpu 0. This ioctl has to be called before vcpu creation, 1577otherwise it will return EBUSY error. 1578 1579 15804.42 KVM_GET_XSAVE 1581------------------ 1582 1583:Capability: KVM_CAP_XSAVE 1584:Architectures: x86 1585:Type: vcpu ioctl 1586:Parameters: struct kvm_xsave (out) 1587:Returns: 0 on success, -1 on error 1588 1589 1590:: 1591 1592 struct kvm_xsave { 1593 __u32 region[1024]; 1594 __u32 extra[0]; 1595 }; 1596 1597This ioctl would copy current vcpu's xsave struct to the userspace. 1598 1599 16004.43 KVM_SET_XSAVE 1601------------------ 1602 1603:Capability: KVM_CAP_XSAVE and KVM_CAP_XSAVE2 1604:Architectures: x86 1605:Type: vcpu ioctl 1606:Parameters: struct kvm_xsave (in) 1607:Returns: 0 on success, -1 on error 1608 1609:: 1610 1611 1612 struct kvm_xsave { 1613 __u32 region[1024]; 1614 __u32 extra[0]; 1615 }; 1616 1617This ioctl would copy userspace's xsave struct to the kernel. It copies 1618as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2), 1619when invoked on the vm file descriptor. The size value returned by 1620KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 1621Currently, it is only greater than 4096 if a dynamic feature has been 1622enabled with ``arch_prctl()``, but this may change in the future. 1623 1624The offsets of the state save areas in struct kvm_xsave follow the 1625contents of CPUID leaf 0xD on the host. 1626 1627 16284.44 KVM_GET_XCRS 1629----------------- 1630 1631:Capability: KVM_CAP_XCRS 1632:Architectures: x86 1633:Type: vcpu ioctl 1634:Parameters: struct kvm_xcrs (out) 1635:Returns: 0 on success, -1 on error 1636 1637:: 1638 1639 struct kvm_xcr { 1640 __u32 xcr; 1641 __u32 reserved; 1642 __u64 value; 1643 }; 1644 1645 struct kvm_xcrs { 1646 __u32 nr_xcrs; 1647 __u32 flags; 1648 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1649 __u64 padding[16]; 1650 }; 1651 1652This ioctl would copy current vcpu's xcrs to the userspace. 1653 1654 16554.45 KVM_SET_XCRS 1656----------------- 1657 1658:Capability: KVM_CAP_XCRS 1659:Architectures: x86 1660:Type: vcpu ioctl 1661:Parameters: struct kvm_xcrs (in) 1662:Returns: 0 on success, -1 on error 1663 1664:: 1665 1666 struct kvm_xcr { 1667 __u32 xcr; 1668 __u32 reserved; 1669 __u64 value; 1670 }; 1671 1672 struct kvm_xcrs { 1673 __u32 nr_xcrs; 1674 __u32 flags; 1675 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1676 __u64 padding[16]; 1677 }; 1678 1679This ioctl would set vcpu's xcr to the value userspace specified. 1680 1681 16824.46 KVM_GET_SUPPORTED_CPUID 1683---------------------------- 1684 1685:Capability: KVM_CAP_EXT_CPUID 1686:Architectures: x86 1687:Type: system ioctl 1688:Parameters: struct kvm_cpuid2 (in/out) 1689:Returns: 0 on success, -1 on error 1690 1691:: 1692 1693 struct kvm_cpuid2 { 1694 __u32 nent; 1695 __u32 padding; 1696 struct kvm_cpuid_entry2 entries[0]; 1697 }; 1698 1699 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 1700 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 1701 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 1702 1703 struct kvm_cpuid_entry2 { 1704 __u32 function; 1705 __u32 index; 1706 __u32 flags; 1707 __u32 eax; 1708 __u32 ebx; 1709 __u32 ecx; 1710 __u32 edx; 1711 __u32 padding[3]; 1712 }; 1713 1714This ioctl returns x86 cpuid features which are supported by both the 1715hardware and kvm in its default configuration. Userspace can use the 1716information returned by this ioctl to construct cpuid information (for 1717KVM_SET_CPUID2) that is consistent with hardware, kernel, and 1718userspace capabilities, and with user requirements (for example, the 1719user may wish to constrain cpuid to emulate older hardware, or for 1720feature consistency across a cluster). 1721 1722Dynamically-enabled feature bits need to be requested with 1723``arch_prctl()`` before calling this ioctl. Feature bits that have not 1724been requested are excluded from the result. 1725 1726Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may 1727expose cpuid features (e.g. MONITOR) which are not supported by kvm in 1728its default configuration. If userspace enables such capabilities, it 1729is responsible for modifying the results of this ioctl appropriately. 1730 1731Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure 1732with the 'nent' field indicating the number of entries in the variable-size 1733array 'entries'. If the number of entries is too low to describe the cpu 1734capabilities, an error (E2BIG) is returned. If the number is too high, 1735the 'nent' field is adjusted and an error (ENOMEM) is returned. If the 1736number is just right, the 'nent' field is adjusted to the number of valid 1737entries in the 'entries' array, which is then filled. 1738 1739The entries returned are the host cpuid as returned by the cpuid instruction, 1740with unknown or unsupported features masked out. Some features (for example, 1741x2apic), may not be present in the host cpu, but are exposed by kvm if it can 1742emulate them efficiently. The fields in each entry are defined as follows: 1743 1744 function: 1745 the eax value used to obtain the entry 1746 1747 index: 1748 the ecx value used to obtain the entry (for entries that are 1749 affected by ecx) 1750 1751 flags: 1752 an OR of zero or more of the following: 1753 1754 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 1755 if the index field is valid 1756 1757 eax, ebx, ecx, edx: 1758 the values returned by the cpuid instruction for 1759 this function/index combination 1760 1761The TSC deadline timer feature (CPUID leaf 1, ecx[24]) is always returned 1762as false, since the feature depends on KVM_CREATE_IRQCHIP for local APIC 1763support. Instead it is reported via:: 1764 1765 ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER) 1766 1767if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the 1768feature in userspace, then you can enable the feature for KVM_SET_CPUID2. 1769 1770 17714.47 KVM_PPC_GET_PVINFO 1772----------------------- 1773 1774:Capability: KVM_CAP_PPC_GET_PVINFO 1775:Architectures: ppc 1776:Type: vm ioctl 1777:Parameters: struct kvm_ppc_pvinfo (out) 1778:Returns: 0 on success, !0 on error 1779 1780:: 1781 1782 struct kvm_ppc_pvinfo { 1783 __u32 flags; 1784 __u32 hcall[4]; 1785 __u8 pad[108]; 1786 }; 1787 1788This ioctl fetches PV specific information that need to be passed to the guest 1789using the device tree or other means from vm context. 1790 1791The hcall array defines 4 instructions that make up a hypercall. 1792 1793If any additional field gets added to this structure later on, a bit for that 1794additional piece of information will be set in the flags bitmap. 1795 1796The flags bitmap is defined as:: 1797 1798 /* the host supports the ePAPR idle hcall 1799 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0) 1800 18014.52 KVM_SET_GSI_ROUTING 1802------------------------ 1803 1804:Capability: KVM_CAP_IRQ_ROUTING 1805:Architectures: x86 s390 arm64 1806:Type: vm ioctl 1807:Parameters: struct kvm_irq_routing (in) 1808:Returns: 0 on success, -1 on error 1809 1810Sets the GSI routing table entries, overwriting any previously set entries. 1811 1812On arm64, GSI routing has the following limitation: 1813 1814- GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD. 1815 1816:: 1817 1818 struct kvm_irq_routing { 1819 __u32 nr; 1820 __u32 flags; 1821 struct kvm_irq_routing_entry entries[0]; 1822 }; 1823 1824No flags are specified so far, the corresponding field must be set to zero. 1825 1826:: 1827 1828 struct kvm_irq_routing_entry { 1829 __u32 gsi; 1830 __u32 type; 1831 __u32 flags; 1832 __u32 pad; 1833 union { 1834 struct kvm_irq_routing_irqchip irqchip; 1835 struct kvm_irq_routing_msi msi; 1836 struct kvm_irq_routing_s390_adapter adapter; 1837 struct kvm_irq_routing_hv_sint hv_sint; 1838 struct kvm_irq_routing_xen_evtchn xen_evtchn; 1839 __u32 pad[8]; 1840 } u; 1841 }; 1842 1843 /* gsi routing entry types */ 1844 #define KVM_IRQ_ROUTING_IRQCHIP 1 1845 #define KVM_IRQ_ROUTING_MSI 2 1846 #define KVM_IRQ_ROUTING_S390_ADAPTER 3 1847 #define KVM_IRQ_ROUTING_HV_SINT 4 1848 #define KVM_IRQ_ROUTING_XEN_EVTCHN 5 1849 1850flags: 1851 1852- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry 1853 type, specifies that the devid field contains a valid value. The per-VM 1854 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 1855 the device ID. If this capability is not available, userspace should 1856 never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 1857- zero otherwise 1858 1859:: 1860 1861 struct kvm_irq_routing_irqchip { 1862 __u32 irqchip; 1863 __u32 pin; 1864 }; 1865 1866 struct kvm_irq_routing_msi { 1867 __u32 address_lo; 1868 __u32 address_hi; 1869 __u32 data; 1870 union { 1871 __u32 pad; 1872 __u32 devid; 1873 }; 1874 }; 1875 1876If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 1877for the device that wrote the MSI message. For PCI, this is usually a 1878BFD identifier in the lower 16 bits. 1879 1880On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 1881feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 1882address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 1883address_hi must be zero. 1884 1885:: 1886 1887 struct kvm_irq_routing_s390_adapter { 1888 __u64 ind_addr; 1889 __u64 summary_addr; 1890 __u64 ind_offset; 1891 __u32 summary_offset; 1892 __u32 adapter_id; 1893 }; 1894 1895 struct kvm_irq_routing_hv_sint { 1896 __u32 vcpu; 1897 __u32 sint; 1898 }; 1899 1900 struct kvm_irq_routing_xen_evtchn { 1901 __u32 port; 1902 __u32 vcpu; 1903 __u32 priority; 1904 }; 1905 1906 1907When KVM_CAP_XEN_HVM includes the KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL bit 1908in its indication of supported features, routing to Xen event channels 1909is supported. Although the priority field is present, only the value 1910KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL is supported, which means delivery by 19112 level event channels. FIFO event channel support may be added in 1912the future. 1913 1914 19154.55 KVM_SET_TSC_KHZ 1916-------------------- 1917 1918:Capability: KVM_CAP_TSC_CONTROL / KVM_CAP_VM_TSC_CONTROL 1919:Architectures: x86 1920:Type: vcpu ioctl / vm ioctl 1921:Parameters: virtual tsc_khz 1922:Returns: 0 on success, -1 on error 1923 1924Specifies the tsc frequency for the virtual machine. The unit of the 1925frequency is KHz. 1926 1927If the KVM_CAP_VM_TSC_CONTROL capability is advertised, this can also 1928be used as a vm ioctl to set the initial tsc frequency of subsequently 1929created vCPUs. 1930 19314.56 KVM_GET_TSC_KHZ 1932-------------------- 1933 1934:Capability: KVM_CAP_GET_TSC_KHZ / KVM_CAP_VM_TSC_CONTROL 1935:Architectures: x86 1936:Type: vcpu ioctl / vm ioctl 1937:Parameters: none 1938:Returns: virtual tsc-khz on success, negative value on error 1939 1940Returns the tsc frequency of the guest. The unit of the return value is 1941KHz. If the host has unstable tsc this ioctl returns -EIO instead as an 1942error. 1943 1944 19454.57 KVM_GET_LAPIC 1946------------------ 1947 1948:Capability: KVM_CAP_IRQCHIP 1949:Architectures: x86 1950:Type: vcpu ioctl 1951:Parameters: struct kvm_lapic_state (out) 1952:Returns: 0 on success, -1 on error 1953 1954:: 1955 1956 #define KVM_APIC_REG_SIZE 0x400 1957 struct kvm_lapic_state { 1958 char regs[KVM_APIC_REG_SIZE]; 1959 }; 1960 1961Reads the Local APIC registers and copies them into the input argument. The 1962data format and layout are the same as documented in the architecture manual. 1963 1964If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is 1965enabled, then the format of APIC_ID register depends on the APIC mode 1966(reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in 1967the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID 1968which is stored in bits 31-24 of the APIC register, or equivalently in 1969byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then 1970be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR. 1971 1972If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state 1973always uses xAPIC format. 1974 1975 19764.58 KVM_SET_LAPIC 1977------------------ 1978 1979:Capability: KVM_CAP_IRQCHIP 1980:Architectures: x86 1981:Type: vcpu ioctl 1982:Parameters: struct kvm_lapic_state (in) 1983:Returns: 0 on success, -1 on error 1984 1985:: 1986 1987 #define KVM_APIC_REG_SIZE 0x400 1988 struct kvm_lapic_state { 1989 char regs[KVM_APIC_REG_SIZE]; 1990 }; 1991 1992Copies the input argument into the Local APIC registers. The data format 1993and layout are the same as documented in the architecture manual. 1994 1995The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's 1996regs field) depends on the state of the KVM_CAP_X2APIC_API capability. 1997See the note in KVM_GET_LAPIC. 1998 1999 20004.59 KVM_IOEVENTFD 2001------------------ 2002 2003:Capability: KVM_CAP_IOEVENTFD 2004:Architectures: all 2005:Type: vm ioctl 2006:Parameters: struct kvm_ioeventfd (in) 2007:Returns: 0 on success, !0 on error 2008 2009This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address 2010within the guest. A guest write in the registered address will signal the 2011provided event instead of triggering an exit. 2012 2013:: 2014 2015 struct kvm_ioeventfd { 2016 __u64 datamatch; 2017 __u64 addr; /* legal pio/mmio address */ 2018 __u32 len; /* 0, 1, 2, 4, or 8 bytes */ 2019 __s32 fd; 2020 __u32 flags; 2021 __u8 pad[36]; 2022 }; 2023 2024For the special case of virtio-ccw devices on s390, the ioevent is matched 2025to a subchannel/virtqueue tuple instead. 2026 2027The following flags are defined:: 2028 2029 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) 2030 #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) 2031 #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) 2032 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \ 2033 (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify) 2034 2035If datamatch flag is set, the event will be signaled only if the written value 2036to the registered address is equal to datamatch in struct kvm_ioeventfd. 2037 2038For virtio-ccw devices, addr contains the subchannel id and datamatch the 2039virtqueue index. 2040 2041With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and 2042the kernel will ignore the length of guest write and may get a faster vmexit. 2043The speedup may only apply to specific architectures, but the ioeventfd will 2044work anyway. 2045 20464.60 KVM_DIRTY_TLB 2047------------------ 2048 2049:Capability: KVM_CAP_SW_TLB 2050:Architectures: ppc 2051:Type: vcpu ioctl 2052:Parameters: struct kvm_dirty_tlb (in) 2053:Returns: 0 on success, -1 on error 2054 2055:: 2056 2057 struct kvm_dirty_tlb { 2058 __u64 bitmap; 2059 __u32 num_dirty; 2060 }; 2061 2062This must be called whenever userspace has changed an entry in the shared 2063TLB, prior to calling KVM_RUN on the associated vcpu. 2064 2065The "bitmap" field is the userspace address of an array. This array 2066consists of a number of bits, equal to the total number of TLB entries as 2067determined by the last successful call to KVM_CONFIG_TLB, rounded up to the 2068nearest multiple of 64. 2069 2070Each bit corresponds to one TLB entry, ordered the same as in the shared TLB 2071array. 2072 2073The array is little-endian: the bit 0 is the least significant bit of the 2074first byte, bit 8 is the least significant bit of the second byte, etc. 2075This avoids any complications with differing word sizes. 2076 2077The "num_dirty" field is a performance hint for KVM to determine whether it 2078should skip processing the bitmap and just invalidate everything. It must 2079be set to the number of set bits in the bitmap. 2080 2081 20824.62 KVM_CREATE_SPAPR_TCE 2083------------------------- 2084 2085:Capability: KVM_CAP_SPAPR_TCE 2086:Architectures: powerpc 2087:Type: vm ioctl 2088:Parameters: struct kvm_create_spapr_tce (in) 2089:Returns: file descriptor for manipulating the created TCE table 2090 2091This creates a virtual TCE (translation control entry) table, which 2092is an IOMMU for PAPR-style virtual I/O. It is used to translate 2093logical addresses used in virtual I/O into guest physical addresses, 2094and provides a scatter/gather capability for PAPR virtual I/O. 2095 2096:: 2097 2098 /* for KVM_CAP_SPAPR_TCE */ 2099 struct kvm_create_spapr_tce { 2100 __u64 liobn; 2101 __u32 window_size; 2102 }; 2103 2104The liobn field gives the logical IO bus number for which to create a 2105TCE table. The window_size field specifies the size of the DMA window 2106which this TCE table will translate - the table will contain one 64 2107bit TCE entry for every 4kiB of the DMA window. 2108 2109When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE 2110table has been created using this ioctl(), the kernel will handle it 2111in real mode, updating the TCE table. H_PUT_TCE calls for other 2112liobns will cause a vm exit and must be handled by userspace. 2113 2114The return value is a file descriptor which can be passed to mmap(2) 2115to map the created TCE table into userspace. This lets userspace read 2116the entries written by kernel-handled H_PUT_TCE calls, and also lets 2117userspace update the TCE table directly which is useful in some 2118circumstances. 2119 2120 21214.63 KVM_ALLOCATE_RMA 2122--------------------- 2123 2124:Capability: KVM_CAP_PPC_RMA 2125:Architectures: powerpc 2126:Type: vm ioctl 2127:Parameters: struct kvm_allocate_rma (out) 2128:Returns: file descriptor for mapping the allocated RMA 2129 2130This allocates a Real Mode Area (RMA) from the pool allocated at boot 2131time by the kernel. An RMA is a physically-contiguous, aligned region 2132of memory used on older POWER processors to provide the memory which 2133will be accessed by real-mode (MMU off) accesses in a KVM guest. 2134POWER processors support a set of sizes for the RMA that usually 2135includes 64MB, 128MB, 256MB and some larger powers of two. 2136 2137:: 2138 2139 /* for KVM_ALLOCATE_RMA */ 2140 struct kvm_allocate_rma { 2141 __u64 rma_size; 2142 }; 2143 2144The return value is a file descriptor which can be passed to mmap(2) 2145to map the allocated RMA into userspace. The mapped area can then be 2146passed to the KVM_SET_USER_MEMORY_REGION ioctl to establish it as the 2147RMA for a virtual machine. The size of the RMA in bytes (which is 2148fixed at host kernel boot time) is returned in the rma_size field of 2149the argument structure. 2150 2151The KVM_CAP_PPC_RMA capability is 1 or 2 if the KVM_ALLOCATE_RMA ioctl 2152is supported; 2 if the processor requires all virtual machines to have 2153an RMA, or 1 if the processor can use an RMA but doesn't require it, 2154because it supports the Virtual RMA (VRMA) facility. 2155 2156 21574.64 KVM_NMI 2158------------ 2159 2160:Capability: KVM_CAP_USER_NMI 2161:Architectures: x86 2162:Type: vcpu ioctl 2163:Parameters: none 2164:Returns: 0 on success, -1 on error 2165 2166Queues an NMI on the thread's vcpu. Note this is well defined only 2167when KVM_CREATE_IRQCHIP has not been called, since this is an interface 2168between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP 2169has been called, this interface is completely emulated within the kernel. 2170 2171To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the 2172following algorithm: 2173 2174 - pause the vcpu 2175 - read the local APIC's state (KVM_GET_LAPIC) 2176 - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1) 2177 - if so, issue KVM_NMI 2178 - resume the vcpu 2179 2180Some guests configure the LINT1 NMI input to cause a panic, aiding in 2181debugging. 2182 2183 21844.65 KVM_S390_UCAS_MAP 2185---------------------- 2186 2187:Capability: KVM_CAP_S390_UCONTROL 2188:Architectures: s390 2189:Type: vcpu ioctl 2190:Parameters: struct kvm_s390_ucas_mapping (in) 2191:Returns: 0 in case of success 2192 2193The parameter is defined like this:: 2194 2195 struct kvm_s390_ucas_mapping { 2196 __u64 user_addr; 2197 __u64 vcpu_addr; 2198 __u64 length; 2199 }; 2200 2201This ioctl maps the memory at "user_addr" with the length "length" to 2202the vcpu's address space starting at "vcpu_addr". All parameters need to 2203be aligned by 1 megabyte. 2204 2205 22064.66 KVM_S390_UCAS_UNMAP 2207------------------------ 2208 2209:Capability: KVM_CAP_S390_UCONTROL 2210:Architectures: s390 2211:Type: vcpu ioctl 2212:Parameters: struct kvm_s390_ucas_mapping (in) 2213:Returns: 0 in case of success 2214 2215The parameter is defined like this:: 2216 2217 struct kvm_s390_ucas_mapping { 2218 __u64 user_addr; 2219 __u64 vcpu_addr; 2220 __u64 length; 2221 }; 2222 2223This ioctl unmaps the memory in the vcpu's address space starting at 2224"vcpu_addr" with the length "length". The field "user_addr" is ignored. 2225All parameters need to be aligned by 1 megabyte. 2226 2227 22284.67 KVM_S390_VCPU_FAULT 2229------------------------ 2230 2231:Capability: KVM_CAP_S390_UCONTROL 2232:Architectures: s390 2233:Type: vcpu ioctl 2234:Parameters: vcpu absolute address (in) 2235:Returns: 0 in case of success 2236 2237This call creates a page table entry on the virtual cpu's address space 2238(for user controlled virtual machines) or the virtual machine's address 2239space (for regular virtual machines). This only works for minor faults, 2240thus it's recommended to access subject memory page via the user page 2241table upfront. This is useful to handle validity intercepts for user 2242controlled virtual machines to fault in the virtual cpu's lowcore pages 2243prior to calling the KVM_RUN ioctl. 2244 2245 22464.68 KVM_SET_ONE_REG 2247-------------------- 2248 2249:Capability: KVM_CAP_ONE_REG 2250:Architectures: all 2251:Type: vcpu ioctl 2252:Parameters: struct kvm_one_reg (in) 2253:Returns: 0 on success, negative value on failure 2254 2255Errors: 2256 2257 ====== ============================================================ 2258 ENOENT no such register 2259 EINVAL invalid register ID, or no such register or used with VMs in 2260 protected virtualization mode on s390 2261 EPERM (arm64) register access not allowed before vcpu finalization 2262 EBUSY (riscv) changing register value not allowed after the vcpu 2263 has run at least once 2264 ====== ============================================================ 2265 2266(These error codes are indicative only: do not rely on a specific error 2267code being returned in a specific situation.) 2268 2269:: 2270 2271 struct kvm_one_reg { 2272 __u64 id; 2273 __u64 addr; 2274 }; 2275 2276Using this ioctl, a single vcpu register can be set to a specific value 2277defined by user space with the passed in struct kvm_one_reg, where id 2278refers to the register identifier as described below and addr is a pointer 2279to a variable with the respective size. There can be architecture agnostic 2280and architecture specific registers. Each have their own range of operation 2281and their own constants and width. To keep track of the implemented 2282registers, find a list below: 2283 2284 ======= =============================== ============ 2285 Arch Register Width (bits) 2286 ======= =============================== ============ 2287 PPC KVM_REG_PPC_HIOR 64 2288 PPC KVM_REG_PPC_IAC1 64 2289 PPC KVM_REG_PPC_IAC2 64 2290 PPC KVM_REG_PPC_IAC3 64 2291 PPC KVM_REG_PPC_IAC4 64 2292 PPC KVM_REG_PPC_DAC1 64 2293 PPC KVM_REG_PPC_DAC2 64 2294 PPC KVM_REG_PPC_DABR 64 2295 PPC KVM_REG_PPC_DSCR 64 2296 PPC KVM_REG_PPC_PURR 64 2297 PPC KVM_REG_PPC_SPURR 64 2298 PPC KVM_REG_PPC_DAR 64 2299 PPC KVM_REG_PPC_DSISR 32 2300 PPC KVM_REG_PPC_AMR 64 2301 PPC KVM_REG_PPC_UAMOR 64 2302 PPC KVM_REG_PPC_MMCR0 64 2303 PPC KVM_REG_PPC_MMCR1 64 2304 PPC KVM_REG_PPC_MMCRA 64 2305 PPC KVM_REG_PPC_MMCR2 64 2306 PPC KVM_REG_PPC_MMCRS 64 2307 PPC KVM_REG_PPC_MMCR3 64 2308 PPC KVM_REG_PPC_SIAR 64 2309 PPC KVM_REG_PPC_SDAR 64 2310 PPC KVM_REG_PPC_SIER 64 2311 PPC KVM_REG_PPC_SIER2 64 2312 PPC KVM_REG_PPC_SIER3 64 2313 PPC KVM_REG_PPC_PMC1 32 2314 PPC KVM_REG_PPC_PMC2 32 2315 PPC KVM_REG_PPC_PMC3 32 2316 PPC KVM_REG_PPC_PMC4 32 2317 PPC KVM_REG_PPC_PMC5 32 2318 PPC KVM_REG_PPC_PMC6 32 2319 PPC KVM_REG_PPC_PMC7 32 2320 PPC KVM_REG_PPC_PMC8 32 2321 PPC KVM_REG_PPC_FPR0 64 2322 ... 2323 PPC KVM_REG_PPC_FPR31 64 2324 PPC KVM_REG_PPC_VR0 128 2325 ... 2326 PPC KVM_REG_PPC_VR31 128 2327 PPC KVM_REG_PPC_VSR0 128 2328 ... 2329 PPC KVM_REG_PPC_VSR31 128 2330 PPC KVM_REG_PPC_FPSCR 64 2331 PPC KVM_REG_PPC_VSCR 32 2332 PPC KVM_REG_PPC_VPA_ADDR 64 2333 PPC KVM_REG_PPC_VPA_SLB 128 2334 PPC KVM_REG_PPC_VPA_DTL 128 2335 PPC KVM_REG_PPC_EPCR 32 2336 PPC KVM_REG_PPC_EPR 32 2337 PPC KVM_REG_PPC_TCR 32 2338 PPC KVM_REG_PPC_TSR 32 2339 PPC KVM_REG_PPC_OR_TSR 32 2340 PPC KVM_REG_PPC_CLEAR_TSR 32 2341 PPC KVM_REG_PPC_MAS0 32 2342 PPC KVM_REG_PPC_MAS1 32 2343 PPC KVM_REG_PPC_MAS2 64 2344 PPC KVM_REG_PPC_MAS7_3 64 2345 PPC KVM_REG_PPC_MAS4 32 2346 PPC KVM_REG_PPC_MAS6 32 2347 PPC KVM_REG_PPC_MMUCFG 32 2348 PPC KVM_REG_PPC_TLB0CFG 32 2349 PPC KVM_REG_PPC_TLB1CFG 32 2350 PPC KVM_REG_PPC_TLB2CFG 32 2351 PPC KVM_REG_PPC_TLB3CFG 32 2352 PPC KVM_REG_PPC_TLB0PS 32 2353 PPC KVM_REG_PPC_TLB1PS 32 2354 PPC KVM_REG_PPC_TLB2PS 32 2355 PPC KVM_REG_PPC_TLB3PS 32 2356 PPC KVM_REG_PPC_EPTCFG 32 2357 PPC KVM_REG_PPC_ICP_STATE 64 2358 PPC KVM_REG_PPC_VP_STATE 128 2359 PPC KVM_REG_PPC_TB_OFFSET 64 2360 PPC KVM_REG_PPC_SPMC1 32 2361 PPC KVM_REG_PPC_SPMC2 32 2362 PPC KVM_REG_PPC_IAMR 64 2363 PPC KVM_REG_PPC_TFHAR 64 2364 PPC KVM_REG_PPC_TFIAR 64 2365 PPC KVM_REG_PPC_TEXASR 64 2366 PPC KVM_REG_PPC_FSCR 64 2367 PPC KVM_REG_PPC_PSPB 32 2368 PPC KVM_REG_PPC_EBBHR 64 2369 PPC KVM_REG_PPC_EBBRR 64 2370 PPC KVM_REG_PPC_BESCR 64 2371 PPC KVM_REG_PPC_TAR 64 2372 PPC KVM_REG_PPC_DPDES 64 2373 PPC KVM_REG_PPC_DAWR 64 2374 PPC KVM_REG_PPC_DAWRX 64 2375 PPC KVM_REG_PPC_CIABR 64 2376 PPC KVM_REG_PPC_IC 64 2377 PPC KVM_REG_PPC_VTB 64 2378 PPC KVM_REG_PPC_CSIGR 64 2379 PPC KVM_REG_PPC_TACR 64 2380 PPC KVM_REG_PPC_TCSCR 64 2381 PPC KVM_REG_PPC_PID 64 2382 PPC KVM_REG_PPC_ACOP 64 2383 PPC KVM_REG_PPC_VRSAVE 32 2384 PPC KVM_REG_PPC_LPCR 32 2385 PPC KVM_REG_PPC_LPCR_64 64 2386 PPC KVM_REG_PPC_PPR 64 2387 PPC KVM_REG_PPC_ARCH_COMPAT 32 2388 PPC KVM_REG_PPC_DABRX 32 2389 PPC KVM_REG_PPC_WORT 64 2390 PPC KVM_REG_PPC_SPRG9 64 2391 PPC KVM_REG_PPC_DBSR 32 2392 PPC KVM_REG_PPC_TIDR 64 2393 PPC KVM_REG_PPC_PSSCR 64 2394 PPC KVM_REG_PPC_DEC_EXPIRY 64 2395 PPC KVM_REG_PPC_PTCR 64 2396 PPC KVM_REG_PPC_DAWR1 64 2397 PPC KVM_REG_PPC_DAWRX1 64 2398 PPC KVM_REG_PPC_TM_GPR0 64 2399 ... 2400 PPC KVM_REG_PPC_TM_GPR31 64 2401 PPC KVM_REG_PPC_TM_VSR0 128 2402 ... 2403 PPC KVM_REG_PPC_TM_VSR63 128 2404 PPC KVM_REG_PPC_TM_CR 64 2405 PPC KVM_REG_PPC_TM_LR 64 2406 PPC KVM_REG_PPC_TM_CTR 64 2407 PPC KVM_REG_PPC_TM_FPSCR 64 2408 PPC KVM_REG_PPC_TM_AMR 64 2409 PPC KVM_REG_PPC_TM_PPR 64 2410 PPC KVM_REG_PPC_TM_VRSAVE 64 2411 PPC KVM_REG_PPC_TM_VSCR 32 2412 PPC KVM_REG_PPC_TM_DSCR 64 2413 PPC KVM_REG_PPC_TM_TAR 64 2414 PPC KVM_REG_PPC_TM_XER 64 2415 2416 MIPS KVM_REG_MIPS_R0 64 2417 ... 2418 MIPS KVM_REG_MIPS_R31 64 2419 MIPS KVM_REG_MIPS_HI 64 2420 MIPS KVM_REG_MIPS_LO 64 2421 MIPS KVM_REG_MIPS_PC 64 2422 MIPS KVM_REG_MIPS_CP0_INDEX 32 2423 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64 2424 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64 2425 MIPS KVM_REG_MIPS_CP0_CONTEXT 64 2426 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32 2427 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64 2428 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64 2429 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32 2430 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32 2431 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64 2432 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64 2433 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64 2434 MIPS KVM_REG_MIPS_CP0_PWBASE 64 2435 MIPS KVM_REG_MIPS_CP0_PWFIELD 64 2436 MIPS KVM_REG_MIPS_CP0_PWSIZE 64 2437 MIPS KVM_REG_MIPS_CP0_WIRED 32 2438 MIPS KVM_REG_MIPS_CP0_PWCTL 32 2439 MIPS KVM_REG_MIPS_CP0_HWRENA 32 2440 MIPS KVM_REG_MIPS_CP0_BADVADDR 64 2441 MIPS KVM_REG_MIPS_CP0_BADINSTR 32 2442 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32 2443 MIPS KVM_REG_MIPS_CP0_COUNT 32 2444 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64 2445 MIPS KVM_REG_MIPS_CP0_COMPARE 32 2446 MIPS KVM_REG_MIPS_CP0_STATUS 32 2447 MIPS KVM_REG_MIPS_CP0_INTCTL 32 2448 MIPS KVM_REG_MIPS_CP0_CAUSE 32 2449 MIPS KVM_REG_MIPS_CP0_EPC 64 2450 MIPS KVM_REG_MIPS_CP0_PRID 32 2451 MIPS KVM_REG_MIPS_CP0_EBASE 64 2452 MIPS KVM_REG_MIPS_CP0_CONFIG 32 2453 MIPS KVM_REG_MIPS_CP0_CONFIG1 32 2454 MIPS KVM_REG_MIPS_CP0_CONFIG2 32 2455 MIPS KVM_REG_MIPS_CP0_CONFIG3 32 2456 MIPS KVM_REG_MIPS_CP0_CONFIG4 32 2457 MIPS KVM_REG_MIPS_CP0_CONFIG5 32 2458 MIPS KVM_REG_MIPS_CP0_CONFIG7 32 2459 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64 2460 MIPS KVM_REG_MIPS_CP0_ERROREPC 64 2461 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64 2462 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64 2463 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64 2464 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64 2465 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64 2466 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64 2467 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64 2468 MIPS KVM_REG_MIPS_COUNT_CTL 64 2469 MIPS KVM_REG_MIPS_COUNT_RESUME 64 2470 MIPS KVM_REG_MIPS_COUNT_HZ 64 2471 MIPS KVM_REG_MIPS_FPR_32(0..31) 32 2472 MIPS KVM_REG_MIPS_FPR_64(0..31) 64 2473 MIPS KVM_REG_MIPS_VEC_128(0..31) 128 2474 MIPS KVM_REG_MIPS_FCR_IR 32 2475 MIPS KVM_REG_MIPS_FCR_CSR 32 2476 MIPS KVM_REG_MIPS_MSA_IR 32 2477 MIPS KVM_REG_MIPS_MSA_CSR 32 2478 ======= =============================== ============ 2479 2480ARM registers are mapped using the lower 32 bits. The upper 16 of that 2481is the register group type, or coprocessor number: 2482 2483ARM core registers have the following id bit patterns:: 2484 2485 0x4020 0000 0010 <index into the kvm_regs struct:16> 2486 2487ARM 32-bit CP15 registers have the following id bit patterns:: 2488 2489 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3> 2490 2491ARM 64-bit CP15 registers have the following id bit patterns:: 2492 2493 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3> 2494 2495ARM CCSIDR registers are demultiplexed by CSSELR value:: 2496 2497 0x4020 0000 0011 00 <csselr:8> 2498 2499ARM 32-bit VFP control registers have the following id bit patterns:: 2500 2501 0x4020 0000 0012 1 <regno:12> 2502 2503ARM 64-bit FP registers have the following id bit patterns:: 2504 2505 0x4030 0000 0012 0 <regno:12> 2506 2507ARM firmware pseudo-registers have the following bit pattern:: 2508 2509 0x4030 0000 0014 <regno:16> 2510 2511 2512arm64 registers are mapped using the lower 32 bits. The upper 16 of 2513that is the register group type, or coprocessor number: 2514 2515arm64 core/FP-SIMD registers have the following id bit patterns. Note 2516that the size of the access is variable, as the kvm_regs structure 2517contains elements ranging from 32 to 128 bits. The index is a 32bit 2518value in the kvm_regs structure seen as a 32bit array:: 2519 2520 0x60x0 0000 0010 <index into the kvm_regs struct:16> 2521 2522Specifically: 2523 2524======================= ========= ===== ======================================= 2525 Encoding Register Bits kvm_regs member 2526======================= ========= ===== ======================================= 2527 0x6030 0000 0010 0000 X0 64 regs.regs[0] 2528 0x6030 0000 0010 0002 X1 64 regs.regs[1] 2529 ... 2530 0x6030 0000 0010 003c X30 64 regs.regs[30] 2531 0x6030 0000 0010 003e SP 64 regs.sp 2532 0x6030 0000 0010 0040 PC 64 regs.pc 2533 0x6030 0000 0010 0042 PSTATE 64 regs.pstate 2534 0x6030 0000 0010 0044 SP_EL1 64 sp_el1 2535 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1 2536 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC) 2537 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT] 2538 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND] 2539 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ] 2540 0x6060 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ] 2541 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_ 2542 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_ 2543 ... 2544 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_ 2545 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr 2546 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr 2547======================= ========= ===== ======================================= 2548 2549.. [1] These encodings are not accepted for SVE-enabled vcpus. See 2550 KVM_ARM_VCPU_INIT. 2551 2552 The equivalent register content can be accessed via bits [127:0] of 2553 the corresponding SVE Zn registers instead for vcpus that have SVE 2554 enabled (see below). 2555 2556arm64 CCSIDR registers are demultiplexed by CSSELR value:: 2557 2558 0x6020 0000 0011 00 <csselr:8> 2559 2560arm64 system registers have the following id bit patterns:: 2561 2562 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3> 2563 2564.. warning:: 2565 2566 Two system register IDs do not follow the specified pattern. These 2567 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to 2568 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These 2569 two had their values accidentally swapped, which means TIMER_CVAL is 2570 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is 2571 derived from the register encoding for CNTV_CVAL_EL0. As this is 2572 API, it must remain this way. 2573 2574arm64 firmware pseudo-registers have the following bit pattern:: 2575 2576 0x6030 0000 0014 <regno:16> 2577 2578arm64 SVE registers have the following bit patterns:: 2579 2580 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice] 2581 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice] 2582 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice] 2583 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register 2584 2585Access to register IDs where 2048 * slice >= 128 * max_vq will fail with 2586ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit 2587quadwords: see [2]_ below. 2588 2589These registers are only accessible on vcpus for which SVE is enabled. 2590See KVM_ARM_VCPU_INIT for details. 2591 2592In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not 2593accessible until the vcpu's SVE configuration has been finalized 2594using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT 2595and KVM_ARM_VCPU_FINALIZE for more information about this procedure. 2596 2597KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector 2598lengths supported by the vcpu to be discovered and configured by 2599userspace. When transferred to or from user memory via KVM_GET_ONE_REG 2600or KVM_SET_ONE_REG, the value of this register is of type 2601__u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as 2602follows:: 2603 2604 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS]; 2605 2606 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX && 2607 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >> 2608 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1)) 2609 /* Vector length vq * 16 bytes supported */ 2610 else 2611 /* Vector length vq * 16 bytes not supported */ 2612 2613.. [2] The maximum value vq for which the above condition is true is 2614 max_vq. This is the maximum vector length available to the guest on 2615 this vcpu, and determines which register slices are visible through 2616 this ioctl interface. 2617 2618(See Documentation/arch/arm64/sve.rst for an explanation of the "vq" 2619nomenclature.) 2620 2621KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT. 2622KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that 2623the host supports. 2624 2625Userspace may subsequently modify it if desired until the vcpu's SVE 2626configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). 2627 2628Apart from simply removing all vector lengths from the host set that 2629exceed some value, support for arbitrarily chosen sets of vector lengths 2630is hardware-dependent and may not be available. Attempting to configure 2631an invalid set of vector lengths via KVM_SET_ONE_REG will fail with 2632EINVAL. 2633 2634After the vcpu's SVE configuration is finalized, further attempts to 2635write this register will fail with EPERM. 2636 2637arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: 2638 2639 0x6030 0000 0016 <regno:16> 2640 2641The bitmap feature firmware registers exposes the hypercall services that 2642are available for userspace to configure. The set bits corresponds to the 2643services that are available for the guests to access. By default, KVM 2644sets all the supported bits during VM initialization. The userspace can 2645discover the available services via KVM_GET_ONE_REG, and write back the 2646bitmap corresponding to the features that it wishes guests to see via 2647KVM_SET_ONE_REG. 2648 2649Note: These registers are immutable once any of the vCPUs of the VM has 2650run at least once. A KVM_SET_ONE_REG in such a scenario will return 2651a -EBUSY to userspace. 2652 2653(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) 2654 2655 2656MIPS registers are mapped using the lower 32 bits. The upper 16 of that is 2657the register group type: 2658 2659MIPS core registers (see above) have the following id bit patterns:: 2660 2661 0x7030 0000 0000 <reg:16> 2662 2663MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit 2664patterns depending on whether they're 32-bit or 64-bit registers:: 2665 2666 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit) 2667 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2668 2669Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64 2670versions of the EntryLo registers regardless of the word size of the host 2671hardware, host kernel, guest, and whether XPA is present in the guest, i.e. 2672with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and 2673the PFNX field starting at bit 30. 2674 2675MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit 2676patterns:: 2677 2678 0x7030 0000 0001 01 <reg:8> 2679 2680MIPS KVM control registers (see above) have the following id bit patterns:: 2681 2682 0x7030 0000 0002 <reg:16> 2683 2684MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following 2685id bit patterns depending on the size of the register being accessed. They are 2686always accessed according to the current guest FPU mode (Status.FR and 2687Config5.FRE), i.e. as the guest would see them, and they become unpredictable 2688if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector 2689registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they 2690overlap the FPU registers:: 2691 2692 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers) 2693 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers) 2694 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers) 2695 2696MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the 2697following id bit patterns:: 2698 2699 0x7020 0000 0003 01 <0:3> <reg:5> 2700 2701MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the 2702following id bit patterns:: 2703 2704 0x7020 0000 0003 02 <0:3> <reg:5> 2705 2706RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of 2707that is the register group type. 2708 2709RISC-V config registers are meant for configuring a Guest VCPU and it has 2710the following id bit patterns:: 2711 2712 0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host) 2713 0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host) 2714 2715Following are the RISC-V config registers: 2716 2717======================= ========= ============================================= 2718 Encoding Register Description 2719======================= ========= ============================================= 2720 0x80x0 0000 0100 0000 isa ISA feature bitmap of Guest VCPU 2721======================= ========= ============================================= 2722 2723The isa config register can be read anytime but can only be written before 2724a Guest VCPU runs. It will have ISA feature bits matching underlying host 2725set by default. 2726 2727RISC-V core registers represent the general execution state of a Guest VCPU 2728and it has the following id bit patterns:: 2729 2730 0x8020 0000 02 <index into the kvm_riscv_core struct:24> (32bit Host) 2731 0x8030 0000 02 <index into the kvm_riscv_core struct:24> (64bit Host) 2732 2733Following are the RISC-V core registers: 2734 2735======================= ========= ============================================= 2736 Encoding Register Description 2737======================= ========= ============================================= 2738 0x80x0 0000 0200 0000 regs.pc Program counter 2739 0x80x0 0000 0200 0001 regs.ra Return address 2740 0x80x0 0000 0200 0002 regs.sp Stack pointer 2741 0x80x0 0000 0200 0003 regs.gp Global pointer 2742 0x80x0 0000 0200 0004 regs.tp Task pointer 2743 0x80x0 0000 0200 0005 regs.t0 Caller saved register 0 2744 0x80x0 0000 0200 0006 regs.t1 Caller saved register 1 2745 0x80x0 0000 0200 0007 regs.t2 Caller saved register 2 2746 0x80x0 0000 0200 0008 regs.s0 Callee saved register 0 2747 0x80x0 0000 0200 0009 regs.s1 Callee saved register 1 2748 0x80x0 0000 0200 000a regs.a0 Function argument (or return value) 0 2749 0x80x0 0000 0200 000b regs.a1 Function argument (or return value) 1 2750 0x80x0 0000 0200 000c regs.a2 Function argument 2 2751 0x80x0 0000 0200 000d regs.a3 Function argument 3 2752 0x80x0 0000 0200 000e regs.a4 Function argument 4 2753 0x80x0 0000 0200 000f regs.a5 Function argument 5 2754 0x80x0 0000 0200 0010 regs.a6 Function argument 6 2755 0x80x0 0000 0200 0011 regs.a7 Function argument 7 2756 0x80x0 0000 0200 0012 regs.s2 Callee saved register 2 2757 0x80x0 0000 0200 0013 regs.s3 Callee saved register 3 2758 0x80x0 0000 0200 0014 regs.s4 Callee saved register 4 2759 0x80x0 0000 0200 0015 regs.s5 Callee saved register 5 2760 0x80x0 0000 0200 0016 regs.s6 Callee saved register 6 2761 0x80x0 0000 0200 0017 regs.s7 Callee saved register 7 2762 0x80x0 0000 0200 0018 regs.s8 Callee saved register 8 2763 0x80x0 0000 0200 0019 regs.s9 Callee saved register 9 2764 0x80x0 0000 0200 001a regs.s10 Callee saved register 10 2765 0x80x0 0000 0200 001b regs.s11 Callee saved register 11 2766 0x80x0 0000 0200 001c regs.t3 Caller saved register 3 2767 0x80x0 0000 0200 001d regs.t4 Caller saved register 4 2768 0x80x0 0000 0200 001e regs.t5 Caller saved register 5 2769 0x80x0 0000 0200 001f regs.t6 Caller saved register 6 2770 0x80x0 0000 0200 0020 mode Privilege mode (1 = S-mode or 0 = U-mode) 2771======================= ========= ============================================= 2772 2773RISC-V csr registers represent the supervisor mode control/status registers 2774of a Guest VCPU and it has the following id bit patterns:: 2775 2776 0x8020 0000 03 <index into the kvm_riscv_csr struct:24> (32bit Host) 2777 0x8030 0000 03 <index into the kvm_riscv_csr struct:24> (64bit Host) 2778 2779Following are the RISC-V csr registers: 2780 2781======================= ========= ============================================= 2782 Encoding Register Description 2783======================= ========= ============================================= 2784 0x80x0 0000 0300 0000 sstatus Supervisor status 2785 0x80x0 0000 0300 0001 sie Supervisor interrupt enable 2786 0x80x0 0000 0300 0002 stvec Supervisor trap vector base 2787 0x80x0 0000 0300 0003 sscratch Supervisor scratch register 2788 0x80x0 0000 0300 0004 sepc Supervisor exception program counter 2789 0x80x0 0000 0300 0005 scause Supervisor trap cause 2790 0x80x0 0000 0300 0006 stval Supervisor bad address or instruction 2791 0x80x0 0000 0300 0007 sip Supervisor interrupt pending 2792 0x80x0 0000 0300 0008 satp Supervisor address translation and protection 2793======================= ========= ============================================= 2794 2795RISC-V timer registers represent the timer state of a Guest VCPU and it has 2796the following id bit patterns:: 2797 2798 0x8030 0000 04 <index into the kvm_riscv_timer struct:24> 2799 2800Following are the RISC-V timer registers: 2801 2802======================= ========= ============================================= 2803 Encoding Register Description 2804======================= ========= ============================================= 2805 0x8030 0000 0400 0000 frequency Time base frequency (read-only) 2806 0x8030 0000 0400 0001 time Time value visible to Guest 2807 0x8030 0000 0400 0002 compare Time compare programmed by Guest 2808 0x8030 0000 0400 0003 state Time compare state (1 = ON or 0 = OFF) 2809======================= ========= ============================================= 2810 2811RISC-V F-extension registers represent the single precision floating point 2812state of a Guest VCPU and it has the following id bit patterns:: 2813 2814 0x8020 0000 05 <index into the __riscv_f_ext_state struct:24> 2815 2816Following are the RISC-V F-extension registers: 2817 2818======================= ========= ============================================= 2819 Encoding Register Description 2820======================= ========= ============================================= 2821 0x8020 0000 0500 0000 f[0] Floating point register 0 2822 ... 2823 0x8020 0000 0500 001f f[31] Floating point register 31 2824 0x8020 0000 0500 0020 fcsr Floating point control and status register 2825======================= ========= ============================================= 2826 2827RISC-V D-extension registers represent the double precision floating point 2828state of a Guest VCPU and it has the following id bit patterns:: 2829 2830 0x8020 0000 06 <index into the __riscv_d_ext_state struct:24> (fcsr) 2831 0x8030 0000 06 <index into the __riscv_d_ext_state struct:24> (non-fcsr) 2832 2833Following are the RISC-V D-extension registers: 2834 2835======================= ========= ============================================= 2836 Encoding Register Description 2837======================= ========= ============================================= 2838 0x8030 0000 0600 0000 f[0] Floating point register 0 2839 ... 2840 0x8030 0000 0600 001f f[31] Floating point register 31 2841 0x8020 0000 0600 0020 fcsr Floating point control and status register 2842======================= ========= ============================================= 2843 2844 28454.69 KVM_GET_ONE_REG 2846-------------------- 2847 2848:Capability: KVM_CAP_ONE_REG 2849:Architectures: all 2850:Type: vcpu ioctl 2851:Parameters: struct kvm_one_reg (in and out) 2852:Returns: 0 on success, negative value on failure 2853 2854Errors include: 2855 2856 ======== ============================================================ 2857 ENOENT no such register 2858 EINVAL invalid register ID, or no such register or used with VMs in 2859 protected virtualization mode on s390 2860 EPERM (arm64) register access not allowed before vcpu finalization 2861 ======== ============================================================ 2862 2863(These error codes are indicative only: do not rely on a specific error 2864code being returned in a specific situation.) 2865 2866This ioctl allows to receive the value of a single register implemented 2867in a vcpu. The register to read is indicated by the "id" field of the 2868kvm_one_reg struct passed in. On success, the register value can be found 2869at the memory location pointed to by "addr". 2870 2871The list of registers accessible using this interface is identical to the 2872list in 4.68. 2873 2874 28754.70 KVM_KVMCLOCK_CTRL 2876---------------------- 2877 2878:Capability: KVM_CAP_KVMCLOCK_CTRL 2879:Architectures: Any that implement pvclocks (currently x86 only) 2880:Type: vcpu ioctl 2881:Parameters: None 2882:Returns: 0 on success, -1 on error 2883 2884This ioctl sets a flag accessible to the guest indicating that the specified 2885vCPU has been paused by the host userspace. 2886 2887The host will set a flag in the pvclock structure that is checked from the 2888soft lockup watchdog. The flag is part of the pvclock structure that is 2889shared between guest and host, specifically the second bit of the flags 2890field of the pvclock_vcpu_time_info structure. It will be set exclusively by 2891the host and read/cleared exclusively by the guest. The guest operation of 2892checking and clearing the flag must be an atomic operation so 2893load-link/store-conditional, or equivalent must be used. There are two cases 2894where the guest will clear the flag: when the soft lockup watchdog timer resets 2895itself or when a soft lockup is detected. This ioctl can be called any time 2896after pausing the vcpu, but before it is resumed. 2897 2898 28994.71 KVM_SIGNAL_MSI 2900------------------- 2901 2902:Capability: KVM_CAP_SIGNAL_MSI 2903:Architectures: x86 arm64 2904:Type: vm ioctl 2905:Parameters: struct kvm_msi (in) 2906:Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error 2907 2908Directly inject a MSI message. Only valid with in-kernel irqchip that handles 2909MSI messages. 2910 2911:: 2912 2913 struct kvm_msi { 2914 __u32 address_lo; 2915 __u32 address_hi; 2916 __u32 data; 2917 __u32 flags; 2918 __u32 devid; 2919 __u8 pad[12]; 2920 }; 2921 2922flags: 2923 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM 2924 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 2925 the device ID. If this capability is not available, userspace 2926 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 2927 2928If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 2929for the device that wrote the MSI message. For PCI, this is usually a 2930BFD identifier in the lower 16 bits. 2931 2932On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 2933feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 2934address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 2935address_hi must be zero. 2936 2937 29384.71 KVM_CREATE_PIT2 2939-------------------- 2940 2941:Capability: KVM_CAP_PIT2 2942:Architectures: x86 2943:Type: vm ioctl 2944:Parameters: struct kvm_pit_config (in) 2945:Returns: 0 on success, -1 on error 2946 2947Creates an in-kernel device model for the i8254 PIT. This call is only valid 2948after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following 2949parameters have to be passed:: 2950 2951 struct kvm_pit_config { 2952 __u32 flags; 2953 __u32 pad[15]; 2954 }; 2955 2956Valid flags are:: 2957 2958 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */ 2959 2960PIT timer interrupts may use a per-VM kernel thread for injection. If it 2961exists, this thread will have a name of the following pattern:: 2962 2963 kvm-pit/<owner-process-pid> 2964 2965When running a guest with elevated priorities, the scheduling parameters of 2966this thread may have to be adjusted accordingly. 2967 2968This IOCTL replaces the obsolete KVM_CREATE_PIT. 2969 2970 29714.72 KVM_GET_PIT2 2972----------------- 2973 2974:Capability: KVM_CAP_PIT_STATE2 2975:Architectures: x86 2976:Type: vm ioctl 2977:Parameters: struct kvm_pit_state2 (out) 2978:Returns: 0 on success, -1 on error 2979 2980Retrieves the state of the in-kernel PIT model. Only valid after 2981KVM_CREATE_PIT2. The state is returned in the following structure:: 2982 2983 struct kvm_pit_state2 { 2984 struct kvm_pit_channel_state channels[3]; 2985 __u32 flags; 2986 __u32 reserved[9]; 2987 }; 2988 2989Valid flags are:: 2990 2991 /* disable PIT in HPET legacy mode */ 2992 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 2993 /* speaker port data bit enabled */ 2994 #define KVM_PIT_FLAGS_SPEAKER_DATA_ON 0x00000002 2995 2996This IOCTL replaces the obsolete KVM_GET_PIT. 2997 2998 29994.73 KVM_SET_PIT2 3000----------------- 3001 3002:Capability: KVM_CAP_PIT_STATE2 3003:Architectures: x86 3004:Type: vm ioctl 3005:Parameters: struct kvm_pit_state2 (in) 3006:Returns: 0 on success, -1 on error 3007 3008Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. 3009See KVM_GET_PIT2 for details on struct kvm_pit_state2. 3010 3011This IOCTL replaces the obsolete KVM_SET_PIT. 3012 3013 30144.74 KVM_PPC_GET_SMMU_INFO 3015-------------------------- 3016 3017:Capability: KVM_CAP_PPC_GET_SMMU_INFO 3018:Architectures: powerpc 3019:Type: vm ioctl 3020:Parameters: None 3021:Returns: 0 on success, -1 on error 3022 3023This populates and returns a structure describing the features of 3024the "Server" class MMU emulation supported by KVM. 3025This can in turn be used by userspace to generate the appropriate 3026device-tree properties for the guest operating system. 3027 3028The structure contains some global information, followed by an 3029array of supported segment page sizes:: 3030 3031 struct kvm_ppc_smmu_info { 3032 __u64 flags; 3033 __u32 slb_size; 3034 __u32 pad; 3035 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3036 }; 3037 3038The supported flags are: 3039 3040 - KVM_PPC_PAGE_SIZES_REAL: 3041 When that flag is set, guest page sizes must "fit" the backing 3042 store page sizes. When not set, any page size in the list can 3043 be used regardless of how they are backed by userspace. 3044 3045 - KVM_PPC_1T_SEGMENTS 3046 The emulated MMU supports 1T segments in addition to the 3047 standard 256M ones. 3048 3049 - KVM_PPC_NO_HASH 3050 This flag indicates that HPT guests are not supported by KVM, 3051 thus all guests must use radix MMU mode. 3052 3053The "slb_size" field indicates how many SLB entries are supported 3054 3055The "sps" array contains 8 entries indicating the supported base 3056page sizes for a segment in increasing order. Each entry is defined 3057as follow:: 3058 3059 struct kvm_ppc_one_seg_page_size { 3060 __u32 page_shift; /* Base page shift of segment (or 0) */ 3061 __u32 slb_enc; /* SLB encoding for BookS */ 3062 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3063 }; 3064 3065An entry with a "page_shift" of 0 is unused. Because the array is 3066organized in increasing order, a lookup can stop when encoutering 3067such an entry. 3068 3069The "slb_enc" field provides the encoding to use in the SLB for the 3070page size. The bits are in positions such as the value can directly 3071be OR'ed into the "vsid" argument of the slbmte instruction. 3072 3073The "enc" array is a list which for each of those segment base page 3074size provides the list of supported actual page sizes (which can be 3075only larger or equal to the base page size), along with the 3076corresponding encoding in the hash PTE. Similarly, the array is 30778 entries sorted by increasing sizes and an entry with a "0" shift 3078is an empty entry and a terminator:: 3079 3080 struct kvm_ppc_one_page_size { 3081 __u32 page_shift; /* Page shift (or 0) */ 3082 __u32 pte_enc; /* Encoding in the HPTE (>>12) */ 3083 }; 3084 3085The "pte_enc" field provides a value that can OR'ed into the hash 3086PTE's RPN field (ie, it needs to be shifted left by 12 to OR it 3087into the hash PTE second double word). 3088 30894.75 KVM_IRQFD 3090-------------- 3091 3092:Capability: KVM_CAP_IRQFD 3093:Architectures: x86 s390 arm64 3094:Type: vm ioctl 3095:Parameters: struct kvm_irqfd (in) 3096:Returns: 0 on success, -1 on error 3097 3098Allows setting an eventfd to directly trigger a guest interrupt. 3099kvm_irqfd.fd specifies the file descriptor to use as the eventfd and 3100kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When 3101an event is triggered on the eventfd, an interrupt is injected into 3102the guest using the specified gsi pin. The irqfd is removed using 3103the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd 3104and kvm_irqfd.gsi. 3105 3106With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify 3107mechanism allowing emulation of level-triggered, irqfd-based 3108interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an 3109additional eventfd in the kvm_irqfd.resamplefd field. When operating 3110in resample mode, posting of an interrupt through kvm_irq.fd asserts 3111the specified gsi in the irqchip. When the irqchip is resampled, such 3112as from an EOI, the gsi is de-asserted and the user is notified via 3113kvm_irqfd.resamplefd. It is the user's responsibility to re-queue 3114the interrupt if the device making use of it still requires service. 3115Note that closing the resamplefd is not sufficient to disable the 3116irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment 3117and need not be specified with KVM_IRQFD_FLAG_DEASSIGN. 3118 3119On arm64, gsi routing being supported, the following can happen: 3120 3121- in case no routing entry is associated to this gsi, injection fails 3122- in case the gsi is associated to an irqchip routing entry, 3123 irqchip.pin + 32 corresponds to the injected SPI ID. 3124- in case the gsi is associated to an MSI routing entry, the MSI 3125 message and device ID are translated into an LPI (support restricted 3126 to GICv3 ITS in-kernel emulation). 3127 31284.76 KVM_PPC_ALLOCATE_HTAB 3129-------------------------- 3130 3131:Capability: KVM_CAP_PPC_ALLOC_HTAB 3132:Architectures: powerpc 3133:Type: vm ioctl 3134:Parameters: Pointer to u32 containing hash table order (in/out) 3135:Returns: 0 on success, -1 on error 3136 3137This requests the host kernel to allocate an MMU hash table for a 3138guest using the PAPR paravirtualization interface. This only does 3139anything if the kernel is configured to use the Book 3S HV style of 3140virtualization. Otherwise the capability doesn't exist and the ioctl 3141returns an ENOTTY error. The rest of this description assumes Book 3S 3142HV. 3143 3144There must be no vcpus running when this ioctl is called; if there 3145are, it will do nothing and return an EBUSY error. 3146 3147The parameter is a pointer to a 32-bit unsigned integer variable 3148containing the order (log base 2) of the desired size of the hash 3149table, which must be between 18 and 46. On successful return from the 3150ioctl, the value will not be changed by the kernel. 3151 3152If no hash table has been allocated when any vcpu is asked to run 3153(with the KVM_RUN ioctl), the host kernel will allocate a 3154default-sized hash table (16 MB). 3155 3156If this ioctl is called when a hash table has already been allocated, 3157with a different order from the existing hash table, the existing hash 3158table will be freed and a new one allocated. If this is ioctl is 3159called when a hash table has already been allocated of the same order 3160as specified, the kernel will clear out the existing hash table (zero 3161all HPTEs). In either case, if the guest is using the virtualized 3162real-mode area (VRMA) facility, the kernel will re-create the VMRA 3163HPTEs on the next KVM_RUN of any vcpu. 3164 31654.77 KVM_S390_INTERRUPT 3166----------------------- 3167 3168:Capability: basic 3169:Architectures: s390 3170:Type: vm ioctl, vcpu ioctl 3171:Parameters: struct kvm_s390_interrupt (in) 3172:Returns: 0 on success, -1 on error 3173 3174Allows to inject an interrupt to the guest. Interrupts can be floating 3175(vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type. 3176 3177Interrupt parameters are passed via kvm_s390_interrupt:: 3178 3179 struct kvm_s390_interrupt { 3180 __u32 type; 3181 __u32 parm; 3182 __u64 parm64; 3183 }; 3184 3185type can be one of the following: 3186 3187KVM_S390_SIGP_STOP (vcpu) 3188 - sigp stop; optional flags in parm 3189KVM_S390_PROGRAM_INT (vcpu) 3190 - program check; code in parm 3191KVM_S390_SIGP_SET_PREFIX (vcpu) 3192 - sigp set prefix; prefix address in parm 3193KVM_S390_RESTART (vcpu) 3194 - restart 3195KVM_S390_INT_CLOCK_COMP (vcpu) 3196 - clock comparator interrupt 3197KVM_S390_INT_CPU_TIMER (vcpu) 3198 - CPU timer interrupt 3199KVM_S390_INT_VIRTIO (vm) 3200 - virtio external interrupt; external interrupt 3201 parameters in parm and parm64 3202KVM_S390_INT_SERVICE (vm) 3203 - sclp external interrupt; sclp parameter in parm 3204KVM_S390_INT_EMERGENCY (vcpu) 3205 - sigp emergency; source cpu in parm 3206KVM_S390_INT_EXTERNAL_CALL (vcpu) 3207 - sigp external call; source cpu in parm 3208KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) 3209 - compound value to indicate an 3210 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel); 3211 I/O interruption parameters in parm (subchannel) and parm64 (intparm, 3212 interruption subclass) 3213KVM_S390_MCHK (vm, vcpu) 3214 - machine check interrupt; cr 14 bits in parm, machine check interrupt 3215 code in parm64 (note that machine checks needing further payload are not 3216 supported by this ioctl) 3217 3218This is an asynchronous vcpu ioctl and can be invoked from any thread. 3219 32204.78 KVM_PPC_GET_HTAB_FD 3221------------------------ 3222 3223:Capability: KVM_CAP_PPC_HTAB_FD 3224:Architectures: powerpc 3225:Type: vm ioctl 3226:Parameters: Pointer to struct kvm_get_htab_fd (in) 3227:Returns: file descriptor number (>= 0) on success, -1 on error 3228 3229This returns a file descriptor that can be used either to read out the 3230entries in the guest's hashed page table (HPT), or to write entries to 3231initialize the HPT. The returned fd can only be written to if the 3232KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and 3233can only be read if that bit is clear. The argument struct looks like 3234this:: 3235 3236 /* For KVM_PPC_GET_HTAB_FD */ 3237 struct kvm_get_htab_fd { 3238 __u64 flags; 3239 __u64 start_index; 3240 __u64 reserved[2]; 3241 }; 3242 3243 /* Values for kvm_get_htab_fd.flags */ 3244 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1) 3245 #define KVM_GET_HTAB_WRITE ((__u64)0x2) 3246 3247The 'start_index' field gives the index in the HPT of the entry at 3248which to start reading. It is ignored when writing. 3249 3250Reads on the fd will initially supply information about all 3251"interesting" HPT entries. Interesting entries are those with the 3252bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise 3253all entries. When the end of the HPT is reached, the read() will 3254return. If read() is called again on the fd, it will start again from 3255the beginning of the HPT, but will only return HPT entries that have 3256changed since they were last read. 3257 3258Data read or written is structured as a header (8 bytes) followed by a 3259series of valid HPT entries (16 bytes) each. The header indicates how 3260many valid HPT entries there are and how many invalid entries follow 3261the valid entries. The invalid entries are not represented explicitly 3262in the stream. The header format is:: 3263 3264 struct kvm_get_htab_header { 3265 __u32 index; 3266 __u16 n_valid; 3267 __u16 n_invalid; 3268 }; 3269 3270Writes to the fd create HPT entries starting at the index given in the 3271header; first 'n_valid' valid entries with contents from the data 3272written, then 'n_invalid' invalid entries, invalidating any previously 3273valid entries found. 3274 32754.79 KVM_CREATE_DEVICE 3276---------------------- 3277 3278:Capability: KVM_CAP_DEVICE_CTRL 3279:Architectures: all 3280:Type: vm ioctl 3281:Parameters: struct kvm_create_device (in/out) 3282:Returns: 0 on success, -1 on error 3283 3284Errors: 3285 3286 ====== ======================================================= 3287 ENODEV The device type is unknown or unsupported 3288 EEXIST Device already created, and this type of device may not 3289 be instantiated multiple times 3290 ====== ======================================================= 3291 3292 Other error conditions may be defined by individual device types or 3293 have their standard meanings. 3294 3295Creates an emulated device in the kernel. The file descriptor returned 3296in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR. 3297 3298If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the 3299device type is supported (not necessarily whether it can be created 3300in the current vm). 3301 3302Individual devices should not define flags. Attributes should be used 3303for specifying any behavior that is not implied by the device type 3304number. 3305 3306:: 3307 3308 struct kvm_create_device { 3309 __u32 type; /* in: KVM_DEV_TYPE_xxx */ 3310 __u32 fd; /* out: device handle */ 3311 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ 3312 }; 3313 33144.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR 3315-------------------------------------------- 3316 3317:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3318 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3319 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device (no set) 3320:Architectures: x86, arm64, s390 3321:Type: device ioctl, vm ioctl, vcpu ioctl 3322:Parameters: struct kvm_device_attr 3323:Returns: 0 on success, -1 on error 3324 3325Errors: 3326 3327 ===== ============================================================= 3328 ENXIO The group or attribute is unknown/unsupported for this device 3329 or hardware support is missing. 3330 EPERM The attribute cannot (currently) be accessed this way 3331 (e.g. read-only attribute, or attribute that only makes 3332 sense when the device is in a different state) 3333 ===== ============================================================= 3334 3335 Other error conditions may be defined by individual device types. 3336 3337Gets/sets a specified piece of device configuration and/or state. The 3338semantics are device-specific. See individual device documentation in 3339the "devices" directory. As with ONE_REG, the size of the data 3340transferred is defined by the particular attribute. 3341 3342:: 3343 3344 struct kvm_device_attr { 3345 __u32 flags; /* no flags currently defined */ 3346 __u32 group; /* device-defined */ 3347 __u64 attr; /* group-defined */ 3348 __u64 addr; /* userspace address of attr data */ 3349 }; 3350 33514.81 KVM_HAS_DEVICE_ATTR 3352------------------------ 3353 3354:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3355 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3356 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device 3357:Type: device ioctl, vm ioctl, vcpu ioctl 3358:Parameters: struct kvm_device_attr 3359:Returns: 0 on success, -1 on error 3360 3361Errors: 3362 3363 ===== ============================================================= 3364 ENXIO The group or attribute is unknown/unsupported for this device 3365 or hardware support is missing. 3366 ===== ============================================================= 3367 3368Tests whether a device supports a particular attribute. A successful 3369return indicates the attribute is implemented. It does not necessarily 3370indicate that the attribute can be read or written in the device's 3371current state. "addr" is ignored. 3372 33734.82 KVM_ARM_VCPU_INIT 3374---------------------- 3375 3376:Capability: basic 3377:Architectures: arm64 3378:Type: vcpu ioctl 3379:Parameters: struct kvm_vcpu_init (in) 3380:Returns: 0 on success; -1 on error 3381 3382Errors: 3383 3384 ====== ================================================================= 3385 EINVAL the target is unknown, or the combination of features is invalid. 3386 ENOENT a features bit specified is unknown. 3387 ====== ================================================================= 3388 3389This tells KVM what type of CPU to present to the guest, and what 3390optional features it should have. This will cause a reset of the cpu 3391registers to their initial values. If this is not called, KVM_RUN will 3392return ENOEXEC for that vcpu. 3393 3394The initial values are defined as: 3395 - Processor state: 3396 * AArch64: EL1h, D, A, I and F bits set. All other bits 3397 are cleared. 3398 * AArch32: SVC, A, I and F bits set. All other bits are 3399 cleared. 3400 - General Purpose registers, including PC and SP: set to 0 3401 - FPSIMD/NEON registers: set to 0 3402 - SVE registers: set to 0 3403 - System registers: Reset to their architecturally defined 3404 values as for a warm reset to EL1 (resp. SVC) 3405 3406Note that because some registers reflect machine topology, all vcpus 3407should be created before this ioctl is invoked. 3408 3409Userspace can call this function multiple times for a given vcpu, including 3410after the vcpu has been run. This will reset the vcpu to its initial 3411state. All calls to this function after the initial call must use the same 3412target and same set of feature flags, otherwise EINVAL will be returned. 3413 3414Possible features: 3415 3416 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. 3417 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on 3418 and execute guest code when KVM_RUN is called. 3419 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. 3420 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). 3421 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision 3422 backward compatible with v0.2) for the CPU. 3423 Depends on KVM_CAP_ARM_PSCI_0_2. 3424 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. 3425 Depends on KVM_CAP_ARM_PMU_V3. 3426 3427 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication 3428 for arm64 only. 3429 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. 3430 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3431 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3432 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3433 requested. 3434 3435 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication 3436 for arm64 only. 3437 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. 3438 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3439 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3440 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3441 requested. 3442 3443 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). 3444 Depends on KVM_CAP_ARM_SVE. 3445 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3446 3447 * After KVM_ARM_VCPU_INIT: 3448 3449 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the 3450 initial value of this pseudo-register indicates the best set of 3451 vector lengths possible for a vcpu on this host. 3452 3453 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3454 3455 - KVM_RUN and KVM_GET_REG_LIST are not available; 3456 3457 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access 3458 the scalable archietctural SVE registers 3459 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or 3460 KVM_REG_ARM64_SVE_FFR; 3461 3462 - KVM_REG_ARM64_SVE_VLS may optionally be written using 3463 KVM_SET_ONE_REG, to modify the set of vector lengths available 3464 for the vcpu. 3465 3466 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3467 3468 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can 3469 no longer be written using KVM_SET_ONE_REG. 3470 34714.83 KVM_ARM_PREFERRED_TARGET 3472----------------------------- 3473 3474:Capability: basic 3475:Architectures: arm64 3476:Type: vm ioctl 3477:Parameters: struct kvm_vcpu_init (out) 3478:Returns: 0 on success; -1 on error 3479 3480Errors: 3481 3482 ====== ========================================== 3483 ENODEV no preferred target available for the host 3484 ====== ========================================== 3485 3486This queries KVM for preferred CPU target type which can be emulated 3487by KVM on underlying host. 3488 3489The ioctl returns struct kvm_vcpu_init instance containing information 3490about preferred CPU target type and recommended features for it. The 3491kvm_vcpu_init->features bitmap returned will have feature bits set if 3492the preferred target recommends setting these features, but this is 3493not mandatory. 3494 3495The information returned by this ioctl can be used to prepare an instance 3496of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in 3497VCPU matching underlying host. 3498 3499 35004.84 KVM_GET_REG_LIST 3501--------------------- 3502 3503:Capability: basic 3504:Architectures: arm64, mips, riscv 3505:Type: vcpu ioctl 3506:Parameters: struct kvm_reg_list (in/out) 3507:Returns: 0 on success; -1 on error 3508 3509Errors: 3510 3511 ===== ============================================================== 3512 E2BIG the reg index list is too big to fit in the array specified by 3513 the user (the number required will be written into n). 3514 ===== ============================================================== 3515 3516:: 3517 3518 struct kvm_reg_list { 3519 __u64 n; /* number of registers in reg[] */ 3520 __u64 reg[0]; 3521 }; 3522 3523This ioctl returns the guest registers that are supported for the 3524KVM_GET_ONE_REG/KVM_SET_ONE_REG calls. 3525 3526 35274.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) 3528----------------------------------------- 3529 3530:Capability: KVM_CAP_ARM_SET_DEVICE_ADDR 3531:Architectures: arm64 3532:Type: vm ioctl 3533:Parameters: struct kvm_arm_device_address (in) 3534:Returns: 0 on success, -1 on error 3535 3536Errors: 3537 3538 ====== ============================================ 3539 ENODEV The device id is unknown 3540 ENXIO Device not supported on current system 3541 EEXIST Address already set 3542 E2BIG Address outside guest physical address space 3543 EBUSY Address overlaps with other device range 3544 ====== ============================================ 3545 3546:: 3547 3548 struct kvm_arm_device_addr { 3549 __u64 id; 3550 __u64 addr; 3551 }; 3552 3553Specify a device address in the guest's physical address space where guests 3554can access emulated or directly exposed devices, which the host kernel needs 3555to know about. The id field is an architecture specific identifier for a 3556specific device. 3557 3558arm64 divides the id field into two parts, a device id and an 3559address type id specific to the individual device:: 3560 3561 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 | 3562 field: | 0x00000000 | device id | addr type id | 3563 3564arm64 currently only require this when using the in-kernel GIC 3565support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 3566as the device id. When setting the base address for the guest's 3567mapping of the VGIC virtual CPU and distributor interface, the ioctl 3568must be called after calling KVM_CREATE_IRQCHIP, but before calling 3569KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the 3570base addresses will return -EEXIST. 3571 3572Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API 3573should be used instead. 3574 3575 35764.86 KVM_PPC_RTAS_DEFINE_TOKEN 3577------------------------------ 3578 3579:Capability: KVM_CAP_PPC_RTAS 3580:Architectures: ppc 3581:Type: vm ioctl 3582:Parameters: struct kvm_rtas_token_args 3583:Returns: 0 on success, -1 on error 3584 3585Defines a token value for a RTAS (Run Time Abstraction Services) 3586service in order to allow it to be handled in the kernel. The 3587argument struct gives the name of the service, which must be the name 3588of a service that has a kernel-side implementation. If the token 3589value is non-zero, it will be associated with that service, and 3590subsequent RTAS calls by the guest specifying that token will be 3591handled by the kernel. If the token value is 0, then any token 3592associated with the service will be forgotten, and subsequent RTAS 3593calls by the guest for that service will be passed to userspace to be 3594handled. 3595 35964.87 KVM_SET_GUEST_DEBUG 3597------------------------ 3598 3599:Capability: KVM_CAP_SET_GUEST_DEBUG 3600:Architectures: x86, s390, ppc, arm64 3601:Type: vcpu ioctl 3602:Parameters: struct kvm_guest_debug (in) 3603:Returns: 0 on success; -1 on error 3604 3605:: 3606 3607 struct kvm_guest_debug { 3608 __u32 control; 3609 __u32 pad; 3610 struct kvm_guest_debug_arch arch; 3611 }; 3612 3613Set up the processor specific debug registers and configure vcpu for 3614handling guest debug events. There are two parts to the structure, the 3615first a control bitfield indicates the type of debug events to handle 3616when running. Common control bits are: 3617 3618 - KVM_GUESTDBG_ENABLE: guest debugging is enabled 3619 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step 3620 3621The top 16 bits of the control field are architecture specific control 3622flags which can include the following: 3623 3624 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] 3625 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] 3626 - KVM_GUESTDBG_USE_HW: using hardware debug events [arm64] 3627 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] 3628 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] 3629 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] 3630 - KVM_GUESTDBG_BLOCKIRQ: avoid injecting interrupts/NMI/SMI [x86] 3631 3632For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints 3633are enabled in memory so we need to ensure breakpoint exceptions are 3634correctly trapped and the KVM run loop exits at the breakpoint and not 3635running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP 3636we need to ensure the guest vCPUs architecture specific registers are 3637updated to the correct (supplied) values. 3638 3639The second part of the structure is architecture specific and 3640typically contains a set of debug registers. 3641 3642For arm64 the number of debug registers is implementation defined and 3643can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and 3644KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number 3645indicating the number of supported registers. 3646 3647For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether 3648the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported. 3649 3650Also when supported, KVM_CAP_SET_GUEST_DEBUG2 capability indicates the 3651supported KVM_GUESTDBG_* bits in the control field. 3652 3653When debug events exit the main run loop with the reason 3654KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run 3655structure containing architecture specific debug information. 3656 36574.88 KVM_GET_EMULATED_CPUID 3658--------------------------- 3659 3660:Capability: KVM_CAP_EXT_EMUL_CPUID 3661:Architectures: x86 3662:Type: system ioctl 3663:Parameters: struct kvm_cpuid2 (in/out) 3664:Returns: 0 on success, -1 on error 3665 3666:: 3667 3668 struct kvm_cpuid2 { 3669 __u32 nent; 3670 __u32 flags; 3671 struct kvm_cpuid_entry2 entries[0]; 3672 }; 3673 3674The member 'flags' is used for passing flags from userspace. 3675 3676:: 3677 3678 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 3679 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 3680 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 3681 3682 struct kvm_cpuid_entry2 { 3683 __u32 function; 3684 __u32 index; 3685 __u32 flags; 3686 __u32 eax; 3687 __u32 ebx; 3688 __u32 ecx; 3689 __u32 edx; 3690 __u32 padding[3]; 3691 }; 3692 3693This ioctl returns x86 cpuid features which are emulated by 3694kvm.Userspace can use the information returned by this ioctl to query 3695which features are emulated by kvm instead of being present natively. 3696 3697Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2 3698structure with the 'nent' field indicating the number of entries in 3699the variable-size array 'entries'. If the number of entries is too low 3700to describe the cpu capabilities, an error (E2BIG) is returned. If the 3701number is too high, the 'nent' field is adjusted and an error (ENOMEM) 3702is returned. If the number is just right, the 'nent' field is adjusted 3703to the number of valid entries in the 'entries' array, which is then 3704filled. 3705 3706The entries returned are the set CPUID bits of the respective features 3707which kvm emulates, as returned by the CPUID instruction, with unknown 3708or unsupported feature bits cleared. 3709 3710Features like x2apic, for example, may not be present in the host cpu 3711but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be 3712emulated efficiently and thus not included here. 3713 3714The fields in each entry are defined as follows: 3715 3716 function: 3717 the eax value used to obtain the entry 3718 index: 3719 the ecx value used to obtain the entry (for entries that are 3720 affected by ecx) 3721 flags: 3722 an OR of zero or more of the following: 3723 3724 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 3725 if the index field is valid 3726 3727 eax, ebx, ecx, edx: 3728 3729 the values returned by the cpuid instruction for 3730 this function/index combination 3731 37324.89 KVM_S390_MEM_OP 3733-------------------- 3734 3735:Capability: KVM_CAP_S390_MEM_OP, KVM_CAP_S390_PROTECTED, KVM_CAP_S390_MEM_OP_EXTENSION 3736:Architectures: s390 3737:Type: vm ioctl, vcpu ioctl 3738:Parameters: struct kvm_s390_mem_op (in) 3739:Returns: = 0 on success, 3740 < 0 on generic error (e.g. -EFAULT or -ENOMEM), 3741 16 bit program exception code if the access causes such an exception 3742 3743Read or write data from/to the VM's memory. 3744The KVM_CAP_S390_MEM_OP_EXTENSION capability specifies what functionality is 3745supported. 3746 3747Parameters are specified via the following structure:: 3748 3749 struct kvm_s390_mem_op { 3750 __u64 gaddr; /* the guest address */ 3751 __u64 flags; /* flags */ 3752 __u32 size; /* amount of bytes */ 3753 __u32 op; /* type of operation */ 3754 __u64 buf; /* buffer in userspace */ 3755 union { 3756 struct { 3757 __u8 ar; /* the access register number */ 3758 __u8 key; /* access key, ignored if flag unset */ 3759 __u8 pad1[6]; /* ignored */ 3760 __u64 old_addr; /* ignored if flag unset */ 3761 }; 3762 __u32 sida_offset; /* offset into the sida */ 3763 __u8 reserved[32]; /* ignored */ 3764 }; 3765 }; 3766 3767The start address of the memory region has to be specified in the "gaddr" 3768field, and the length of the region in the "size" field (which must not 3769be 0). The maximum value for "size" can be obtained by checking the 3770KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the 3771userspace application where the read data should be written to for 3772a read access, or where the data that should be written is stored for 3773a write access. The "reserved" field is meant for future extensions. 3774Reserved and unused values are ignored. Future extension that add members must 3775introduce new flags. 3776 3777The type of operation is specified in the "op" field. Flags modifying 3778their behavior can be set in the "flags" field. Undefined flag bits must 3779be set to 0. 3780 3781Possible operations are: 3782 * ``KVM_S390_MEMOP_LOGICAL_READ`` 3783 * ``KVM_S390_MEMOP_LOGICAL_WRITE`` 3784 * ``KVM_S390_MEMOP_ABSOLUTE_READ`` 3785 * ``KVM_S390_MEMOP_ABSOLUTE_WRITE`` 3786 * ``KVM_S390_MEMOP_SIDA_READ`` 3787 * ``KVM_S390_MEMOP_SIDA_WRITE`` 3788 * ``KVM_S390_MEMOP_ABSOLUTE_CMPXCHG`` 3789 3790Logical read/write: 3791^^^^^^^^^^^^^^^^^^^ 3792 3793Access logical memory, i.e. translate the given guest address to an absolute 3794address given the state of the VCPU and use the absolute address as target of 3795the access. "ar" designates the access register number to be used; the valid 3796range is 0..15. 3797Logical accesses are permitted for the VCPU ioctl only. 3798Logical accesses are permitted for non-protected guests only. 3799 3800Supported flags: 3801 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3802 * ``KVM_S390_MEMOP_F_INJECT_EXCEPTION`` 3803 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3804 3805The KVM_S390_MEMOP_F_CHECK_ONLY flag can be set to check whether the 3806corresponding memory access would cause an access exception; however, 3807no actual access to the data in memory at the destination is performed. 3808In this case, "buf" is unused and can be NULL. 3809 3810In case an access exception occurred during the access (or would occur 3811in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive 3812error number indicating the type of exception. This exception is also 3813raised directly at the corresponding VCPU if the flag 3814KVM_S390_MEMOP_F_INJECT_EXCEPTION is set. 3815On protection exceptions, unless specified otherwise, the injected 3816translation-exception identifier (TEID) indicates suppression. 3817 3818If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key 3819protection is also in effect and may cause exceptions if accesses are 3820prohibited given the access key designated by "key"; the valid range is 0..15. 3821KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION 3822is > 0. 3823Since the accessed memory may span multiple pages and those pages might have 3824different storage keys, it is possible that a protection exception occurs 3825after memory has been modified. In this case, if the exception is injected, 3826the TEID does not indicate suppression. 3827 3828Absolute read/write: 3829^^^^^^^^^^^^^^^^^^^^ 3830 3831Access absolute memory. This operation is intended to be used with the 3832KVM_S390_MEMOP_F_SKEY_PROTECTION flag, to allow accessing memory and performing 3833the checks required for storage key protection as one operation (as opposed to 3834user space getting the storage keys, performing the checks, and accessing 3835memory thereafter, which could lead to a delay between check and access). 3836Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION 3837has the KVM_S390_MEMOP_EXTENSION_CAP_BASE bit set. 3838Currently absolute accesses are not permitted for VCPU ioctls. 3839Absolute accesses are permitted for non-protected guests only. 3840 3841Supported flags: 3842 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3843 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3844 3845The semantics of the flags common with logical accesses are as for logical 3846accesses. 3847 3848Absolute cmpxchg: 3849^^^^^^^^^^^^^^^^^ 3850 3851Perform cmpxchg on absolute guest memory. Intended for use with the 3852KVM_S390_MEMOP_F_SKEY_PROTECTION flag. 3853Instead of doing an unconditional write, the access occurs only if the target 3854location contains the value pointed to by "old_addr". 3855This is performed as an atomic cmpxchg with the length specified by the "size" 3856parameter. "size" must be a power of two up to and including 16. 3857If the exchange did not take place because the target value doesn't match the 3858old value, the value "old_addr" points to is replaced by the target value. 3859User space can tell if an exchange took place by checking if this replacement 3860occurred. The cmpxchg op is permitted for the VM ioctl if 3861KVM_CAP_S390_MEM_OP_EXTENSION has flag KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG set. 3862 3863Supported flags: 3864 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3865 3866SIDA read/write: 3867^^^^^^^^^^^^^^^^ 3868 3869Access the secure instruction data area which contains memory operands necessary 3870for instruction emulation for protected guests. 3871SIDA accesses are available if the KVM_CAP_S390_PROTECTED capability is available. 3872SIDA accesses are permitted for the VCPU ioctl only. 3873SIDA accesses are permitted for protected guests only. 3874 3875No flags are supported. 3876 38774.90 KVM_S390_GET_SKEYS 3878----------------------- 3879 3880:Capability: KVM_CAP_S390_SKEYS 3881:Architectures: s390 3882:Type: vm ioctl 3883:Parameters: struct kvm_s390_skeys 3884:Returns: 0 on success, KVM_S390_GET_SKEYS_NONE if guest is not using storage 3885 keys, negative value on error 3886 3887This ioctl is used to get guest storage key values on the s390 3888architecture. The ioctl takes parameters via the kvm_s390_skeys struct:: 3889 3890 struct kvm_s390_skeys { 3891 __u64 start_gfn; 3892 __u64 count; 3893 __u64 skeydata_addr; 3894 __u32 flags; 3895 __u32 reserved[9]; 3896 }; 3897 3898The start_gfn field is the number of the first guest frame whose storage keys 3899you want to get. 3900 3901The count field is the number of consecutive frames (starting from start_gfn) 3902whose storage keys to get. The count field must be at least 1 and the maximum 3903allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3904will cause the ioctl to return -EINVAL. 3905 3906The skeydata_addr field is the address to a buffer large enough to hold count 3907bytes. This buffer will be filled with storage key data by the ioctl. 3908 39094.91 KVM_S390_SET_SKEYS 3910----------------------- 3911 3912:Capability: KVM_CAP_S390_SKEYS 3913:Architectures: s390 3914:Type: vm ioctl 3915:Parameters: struct kvm_s390_skeys 3916:Returns: 0 on success, negative value on error 3917 3918This ioctl is used to set guest storage key values on the s390 3919architecture. The ioctl takes parameters via the kvm_s390_skeys struct. 3920See section on KVM_S390_GET_SKEYS for struct definition. 3921 3922The start_gfn field is the number of the first guest frame whose storage keys 3923you want to set. 3924 3925The count field is the number of consecutive frames (starting from start_gfn) 3926whose storage keys to get. The count field must be at least 1 and the maximum 3927allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3928will cause the ioctl to return -EINVAL. 3929 3930The skeydata_addr field is the address to a buffer containing count bytes of 3931storage keys. Each byte in the buffer will be set as the storage key for a 3932single frame starting at start_gfn for count frames. 3933 3934Note: If any architecturally invalid key value is found in the given data then 3935the ioctl will return -EINVAL. 3936 39374.92 KVM_S390_IRQ 3938----------------- 3939 3940:Capability: KVM_CAP_S390_INJECT_IRQ 3941:Architectures: s390 3942:Type: vcpu ioctl 3943:Parameters: struct kvm_s390_irq (in) 3944:Returns: 0 on success, -1 on error 3945 3946Errors: 3947 3948 3949 ====== ================================================================= 3950 EINVAL interrupt type is invalid 3951 type is KVM_S390_SIGP_STOP and flag parameter is invalid value, 3952 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger 3953 than the maximum of VCPUs 3954 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped, 3955 type is KVM_S390_SIGP_STOP and a stop irq is already pending, 3956 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt 3957 is already pending 3958 ====== ================================================================= 3959 3960Allows to inject an interrupt to the guest. 3961 3962Using struct kvm_s390_irq as a parameter allows 3963to inject additional payload which is not 3964possible via KVM_S390_INTERRUPT. 3965 3966Interrupt parameters are passed via kvm_s390_irq:: 3967 3968 struct kvm_s390_irq { 3969 __u64 type; 3970 union { 3971 struct kvm_s390_io_info io; 3972 struct kvm_s390_ext_info ext; 3973 struct kvm_s390_pgm_info pgm; 3974 struct kvm_s390_emerg_info emerg; 3975 struct kvm_s390_extcall_info extcall; 3976 struct kvm_s390_prefix_info prefix; 3977 struct kvm_s390_stop_info stop; 3978 struct kvm_s390_mchk_info mchk; 3979 char reserved[64]; 3980 } u; 3981 }; 3982 3983type can be one of the following: 3984 3985- KVM_S390_SIGP_STOP - sigp stop; parameter in .stop 3986- KVM_S390_PROGRAM_INT - program check; parameters in .pgm 3987- KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix 3988- KVM_S390_RESTART - restart; no parameters 3989- KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters 3990- KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters 3991- KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg 3992- KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall 3993- KVM_S390_MCHK - machine check interrupt; parameters in .mchk 3994 3995This is an asynchronous vcpu ioctl and can be invoked from any thread. 3996 39974.94 KVM_S390_GET_IRQ_STATE 3998--------------------------- 3999 4000:Capability: KVM_CAP_S390_IRQ_STATE 4001:Architectures: s390 4002:Type: vcpu ioctl 4003:Parameters: struct kvm_s390_irq_state (out) 4004:Returns: >= number of bytes copied into buffer, 4005 -EINVAL if buffer size is 0, 4006 -ENOBUFS if buffer size is too small to fit all pending interrupts, 4007 -EFAULT if the buffer address was invalid 4008 4009This ioctl allows userspace to retrieve the complete state of all currently 4010pending interrupts in a single buffer. Use cases include migration 4011and introspection. The parameter structure contains the address of a 4012userspace buffer and its length:: 4013 4014 struct kvm_s390_irq_state { 4015 __u64 buf; 4016 __u32 flags; /* will stay unused for compatibility reasons */ 4017 __u32 len; 4018 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4019 }; 4020 4021Userspace passes in the above struct and for each pending interrupt a 4022struct kvm_s390_irq is copied to the provided buffer. 4023 4024The structure contains a flags and a reserved field for future extensions. As 4025the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and 4026reserved, these fields can not be used in the future without breaking 4027compatibility. 4028 4029If -ENOBUFS is returned the buffer provided was too small and userspace 4030may retry with a bigger buffer. 4031 40324.95 KVM_S390_SET_IRQ_STATE 4033--------------------------- 4034 4035:Capability: KVM_CAP_S390_IRQ_STATE 4036:Architectures: s390 4037:Type: vcpu ioctl 4038:Parameters: struct kvm_s390_irq_state (in) 4039:Returns: 0 on success, 4040 -EFAULT if the buffer address was invalid, 4041 -EINVAL for an invalid buffer length (see below), 4042 -EBUSY if there were already interrupts pending, 4043 errors occurring when actually injecting the 4044 interrupt. See KVM_S390_IRQ. 4045 4046This ioctl allows userspace to set the complete state of all cpu-local 4047interrupts currently pending for the vcpu. It is intended for restoring 4048interrupt state after a migration. The input parameter is a userspace buffer 4049containing a struct kvm_s390_irq_state:: 4050 4051 struct kvm_s390_irq_state { 4052 __u64 buf; 4053 __u32 flags; /* will stay unused for compatibility reasons */ 4054 __u32 len; 4055 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4056 }; 4057 4058The restrictions for flags and reserved apply as well. 4059(see KVM_S390_GET_IRQ_STATE) 4060 4061The userspace memory referenced by buf contains a struct kvm_s390_irq 4062for each interrupt to be injected into the guest. 4063If one of the interrupts could not be injected for some reason the 4064ioctl aborts. 4065 4066len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0 4067and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq), 4068which is the maximum number of possibly pending cpu-local interrupts. 4069 40704.96 KVM_SMI 4071------------ 4072 4073:Capability: KVM_CAP_X86_SMM 4074:Architectures: x86 4075:Type: vcpu ioctl 4076:Parameters: none 4077:Returns: 0 on success, -1 on error 4078 4079Queues an SMI on the thread's vcpu. 4080 40814.97 KVM_X86_SET_MSR_FILTER 4082---------------------------- 4083 4084:Capability: KVM_CAP_X86_MSR_FILTER 4085:Architectures: x86 4086:Type: vm ioctl 4087:Parameters: struct kvm_msr_filter 4088:Returns: 0 on success, < 0 on error 4089 4090:: 4091 4092 struct kvm_msr_filter_range { 4093 #define KVM_MSR_FILTER_READ (1 << 0) 4094 #define KVM_MSR_FILTER_WRITE (1 << 1) 4095 __u32 flags; 4096 __u32 nmsrs; /* number of msrs in bitmap */ 4097 __u32 base; /* MSR index the bitmap starts at */ 4098 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ 4099 }; 4100 4101 #define KVM_MSR_FILTER_MAX_RANGES 16 4102 struct kvm_msr_filter { 4103 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) 4104 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) 4105 __u32 flags; 4106 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; 4107 }; 4108 4109flags values for ``struct kvm_msr_filter_range``: 4110 4111``KVM_MSR_FILTER_READ`` 4112 4113 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap 4114 indicates that read accesses should be denied, while a 1 indicates that 4115 a read for a particular MSR should be allowed regardless of the default 4116 filter action. 4117 4118``KVM_MSR_FILTER_WRITE`` 4119 4120 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap 4121 indicates that write accesses should be denied, while a 1 indicates that 4122 a write for a particular MSR should be allowed regardless of the default 4123 filter action. 4124 4125flags values for ``struct kvm_msr_filter``: 4126 4127``KVM_MSR_FILTER_DEFAULT_ALLOW`` 4128 4129 If no filter range matches an MSR index that is getting accessed, KVM will 4130 allow accesses to all MSRs by default. 4131 4132``KVM_MSR_FILTER_DEFAULT_DENY`` 4133 4134 If no filter range matches an MSR index that is getting accessed, KVM will 4135 deny accesses to all MSRs by default. 4136 4137This ioctl allows userspace to define up to 16 bitmaps of MSR ranges to deny 4138guest MSR accesses that would normally be allowed by KVM. If an MSR is not 4139covered by a specific range, the "default" filtering behavior applies. Each 4140bitmap range covers MSRs from [base .. base+nmsrs). 4141 4142If an MSR access is denied by userspace, the resulting KVM behavior depends on 4143whether or not KVM_CAP_X86_USER_SPACE_MSR's KVM_MSR_EXIT_REASON_FILTER is 4144enabled. If KVM_MSR_EXIT_REASON_FILTER is enabled, KVM will exit to userspace 4145on denied accesses, i.e. userspace effectively intercepts the MSR access. If 4146KVM_MSR_EXIT_REASON_FILTER is not enabled, KVM will inject a #GP into the guest 4147on denied accesses. 4148 4149If an MSR access is allowed by userspace, KVM will emulate and/or virtualize 4150the access in accordance with the vCPU model. Note, KVM may still ultimately 4151inject a #GP if an access is allowed by userspace, e.g. if KVM doesn't support 4152the MSR, or to follow architectural behavior for the MSR. 4153 4154By default, KVM operates in KVM_MSR_FILTER_DEFAULT_ALLOW mode with no MSR range 4155filters. 4156 4157Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR 4158filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes 4159an error. 4160 4161.. warning:: 4162 MSR accesses as part of nested VM-Enter/VM-Exit are not filtered. 4163 This includes both writes to individual VMCS fields and reads/writes 4164 through the MSR lists pointed to by the VMCS. 4165 4166 x2APIC MSR accesses cannot be filtered (KVM silently ignores filters that 4167 cover any x2APIC MSRs). 4168 4169Note, invoking this ioctl while a vCPU is running is inherently racy. However, 4170KVM does guarantee that vCPUs will see either the previous filter or the new 4171filter, e.g. MSRs with identical settings in both the old and new filter will 4172have deterministic behavior. 4173 4174Similarly, if userspace wishes to intercept on denied accesses, 4175KVM_MSR_EXIT_REASON_FILTER must be enabled before activating any filters, and 4176left enabled until after all filters are deactivated. Failure to do so may 4177result in KVM injecting a #GP instead of exiting to userspace. 4178 41794.98 KVM_CREATE_SPAPR_TCE_64 4180---------------------------- 4181 4182:Capability: KVM_CAP_SPAPR_TCE_64 4183:Architectures: powerpc 4184:Type: vm ioctl 4185:Parameters: struct kvm_create_spapr_tce_64 (in) 4186:Returns: file descriptor for manipulating the created TCE table 4187 4188This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit 4189windows, described in 4.62 KVM_CREATE_SPAPR_TCE 4190 4191This capability uses extended struct in ioctl interface:: 4192 4193 /* for KVM_CAP_SPAPR_TCE_64 */ 4194 struct kvm_create_spapr_tce_64 { 4195 __u64 liobn; 4196 __u32 page_shift; 4197 __u32 flags; 4198 __u64 offset; /* in pages */ 4199 __u64 size; /* in pages */ 4200 }; 4201 4202The aim of extension is to support an additional bigger DMA window with 4203a variable page size. 4204KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and 4205a bus offset of the corresponding DMA window, @size and @offset are numbers 4206of IOMMU pages. 4207 4208@flags are not used at the moment. 4209 4210The rest of functionality is identical to KVM_CREATE_SPAPR_TCE. 4211 42124.99 KVM_REINJECT_CONTROL 4213------------------------- 4214 4215:Capability: KVM_CAP_REINJECT_CONTROL 4216:Architectures: x86 4217:Type: vm ioctl 4218:Parameters: struct kvm_reinject_control (in) 4219:Returns: 0 on success, 4220 -EFAULT if struct kvm_reinject_control cannot be read, 4221 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier. 4222 4223i8254 (PIT) has two modes, reinject and !reinject. The default is reinject, 4224where KVM queues elapsed i8254 ticks and monitors completion of interrupt from 4225vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its 4226interrupt whenever there isn't a pending interrupt from i8254. 4227!reinject mode injects an interrupt as soon as a tick arrives. 4228 4229:: 4230 4231 struct kvm_reinject_control { 4232 __u8 pit_reinject; 4233 __u8 reserved[31]; 4234 }; 4235 4236pit_reinject = 0 (!reinject mode) is recommended, unless running an old 4237operating system that uses the PIT for timing (e.g. Linux 2.4.x). 4238 42394.100 KVM_PPC_CONFIGURE_V3_MMU 4240------------------------------ 4241 4242:Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3 4243:Architectures: ppc 4244:Type: vm ioctl 4245:Parameters: struct kvm_ppc_mmuv3_cfg (in) 4246:Returns: 0 on success, 4247 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read, 4248 -EINVAL if the configuration is invalid 4249 4250This ioctl controls whether the guest will use radix or HPT (hashed 4251page table) translation, and sets the pointer to the process table for 4252the guest. 4253 4254:: 4255 4256 struct kvm_ppc_mmuv3_cfg { 4257 __u64 flags; 4258 __u64 process_table; 4259 }; 4260 4261There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and 4262KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest 4263to use radix tree translation, and if clear, to use HPT translation. 4264KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest 4265to be able to use the global TLB and SLB invalidation instructions; 4266if clear, the guest may not use these instructions. 4267 4268The process_table field specifies the address and size of the guest 4269process table, which is in the guest's space. This field is formatted 4270as the second doubleword of the partition table entry, as defined in 4271the Power ISA V3.00, Book III section 5.7.6.1. 4272 42734.101 KVM_PPC_GET_RMMU_INFO 4274--------------------------- 4275 4276:Capability: KVM_CAP_PPC_RADIX_MMU 4277:Architectures: ppc 4278:Type: vm ioctl 4279:Parameters: struct kvm_ppc_rmmu_info (out) 4280:Returns: 0 on success, 4281 -EFAULT if struct kvm_ppc_rmmu_info cannot be written, 4282 -EINVAL if no useful information can be returned 4283 4284This ioctl returns a structure containing two things: (a) a list 4285containing supported radix tree geometries, and (b) a list that maps 4286page sizes to put in the "AP" (actual page size) field for the tlbie 4287(TLB invalidate entry) instruction. 4288 4289:: 4290 4291 struct kvm_ppc_rmmu_info { 4292 struct kvm_ppc_radix_geom { 4293 __u8 page_shift; 4294 __u8 level_bits[4]; 4295 __u8 pad[3]; 4296 } geometries[8]; 4297 __u32 ap_encodings[8]; 4298 }; 4299 4300The geometries[] field gives up to 8 supported geometries for the 4301radix page table, in terms of the log base 2 of the smallest page 4302size, and the number of bits indexed at each level of the tree, from 4303the PTE level up to the PGD level in that order. Any unused entries 4304will have 0 in the page_shift field. 4305 4306The ap_encodings gives the supported page sizes and their AP field 4307encodings, encoded with the AP value in the top 3 bits and the log 4308base 2 of the page size in the bottom 6 bits. 4309 43104.102 KVM_PPC_RESIZE_HPT_PREPARE 4311-------------------------------- 4312 4313:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4314:Architectures: powerpc 4315:Type: vm ioctl 4316:Parameters: struct kvm_ppc_resize_hpt (in) 4317:Returns: 0 on successful completion, 4318 >0 if a new HPT is being prepared, the value is an estimated 4319 number of milliseconds until preparation is complete, 4320 -EFAULT if struct kvm_reinject_control cannot be read, 4321 -EINVAL if the supplied shift or flags are invalid, 4322 -ENOMEM if unable to allocate the new HPT, 4323 4324Used to implement the PAPR extension for runtime resizing of a guest's 4325Hashed Page Table (HPT). Specifically this starts, stops or monitors 4326the preparation of a new potential HPT for the guest, essentially 4327implementing the H_RESIZE_HPT_PREPARE hypercall. 4328 4329:: 4330 4331 struct kvm_ppc_resize_hpt { 4332 __u64 flags; 4333 __u32 shift; 4334 __u32 pad; 4335 }; 4336 4337If called with shift > 0 when there is no pending HPT for the guest, 4338this begins preparation of a new pending HPT of size 2^(shift) bytes. 4339It then returns a positive integer with the estimated number of 4340milliseconds until preparation is complete. 4341 4342If called when there is a pending HPT whose size does not match that 4343requested in the parameters, discards the existing pending HPT and 4344creates a new one as above. 4345 4346If called when there is a pending HPT of the size requested, will: 4347 4348 * If preparation of the pending HPT is already complete, return 0 4349 * If preparation of the pending HPT has failed, return an error 4350 code, then discard the pending HPT. 4351 * If preparation of the pending HPT is still in progress, return an 4352 estimated number of milliseconds until preparation is complete. 4353 4354If called with shift == 0, discards any currently pending HPT and 4355returns 0 (i.e. cancels any in-progress preparation). 4356 4357flags is reserved for future expansion, currently setting any bits in 4358flags will result in an -EINVAL. 4359 4360Normally this will be called repeatedly with the same parameters until 4361it returns <= 0. The first call will initiate preparation, subsequent 4362ones will monitor preparation until it completes or fails. 4363 43644.103 KVM_PPC_RESIZE_HPT_COMMIT 4365------------------------------- 4366 4367:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4368:Architectures: powerpc 4369:Type: vm ioctl 4370:Parameters: struct kvm_ppc_resize_hpt (in) 4371:Returns: 0 on successful completion, 4372 -EFAULT if struct kvm_reinject_control cannot be read, 4373 -EINVAL if the supplied shift or flags are invalid, 4374 -ENXIO is there is no pending HPT, or the pending HPT doesn't 4375 have the requested size, 4376 -EBUSY if the pending HPT is not fully prepared, 4377 -ENOSPC if there was a hash collision when moving existing 4378 HPT entries to the new HPT, 4379 -EIO on other error conditions 4380 4381Used to implement the PAPR extension for runtime resizing of a guest's 4382Hashed Page Table (HPT). Specifically this requests that the guest be 4383transferred to working with the new HPT, essentially implementing the 4384H_RESIZE_HPT_COMMIT hypercall. 4385 4386:: 4387 4388 struct kvm_ppc_resize_hpt { 4389 __u64 flags; 4390 __u32 shift; 4391 __u32 pad; 4392 }; 4393 4394This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has 4395returned 0 with the same parameters. In other cases 4396KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or 4397-EBUSY, though others may be possible if the preparation was started, 4398but failed). 4399 4400This will have undefined effects on the guest if it has not already 4401placed itself in a quiescent state where no vcpu will make MMU enabled 4402memory accesses. 4403 4404On succsful completion, the pending HPT will become the guest's active 4405HPT and the previous HPT will be discarded. 4406 4407On failure, the guest will still be operating on its previous HPT. 4408 44094.104 KVM_X86_GET_MCE_CAP_SUPPORTED 4410----------------------------------- 4411 4412:Capability: KVM_CAP_MCE 4413:Architectures: x86 4414:Type: system ioctl 4415:Parameters: u64 mce_cap (out) 4416:Returns: 0 on success, -1 on error 4417 4418Returns supported MCE capabilities. The u64 mce_cap parameter 4419has the same format as the MSR_IA32_MCG_CAP register. Supported 4420capabilities will have the corresponding bits set. 4421 44224.105 KVM_X86_SETUP_MCE 4423----------------------- 4424 4425:Capability: KVM_CAP_MCE 4426:Architectures: x86 4427:Type: vcpu ioctl 4428:Parameters: u64 mcg_cap (in) 4429:Returns: 0 on success, 4430 -EFAULT if u64 mcg_cap cannot be read, 4431 -EINVAL if the requested number of banks is invalid, 4432 -EINVAL if requested MCE capability is not supported. 4433 4434Initializes MCE support for use. The u64 mcg_cap parameter 4435has the same format as the MSR_IA32_MCG_CAP register and 4436specifies which capabilities should be enabled. The maximum 4437supported number of error-reporting banks can be retrieved when 4438checking for KVM_CAP_MCE. The supported capabilities can be 4439retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED. 4440 44414.106 KVM_X86_SET_MCE 4442--------------------- 4443 4444:Capability: KVM_CAP_MCE 4445:Architectures: x86 4446:Type: vcpu ioctl 4447:Parameters: struct kvm_x86_mce (in) 4448:Returns: 0 on success, 4449 -EFAULT if struct kvm_x86_mce cannot be read, 4450 -EINVAL if the bank number is invalid, 4451 -EINVAL if VAL bit is not set in status field. 4452 4453Inject a machine check error (MCE) into the guest. The input 4454parameter is:: 4455 4456 struct kvm_x86_mce { 4457 __u64 status; 4458 __u64 addr; 4459 __u64 misc; 4460 __u64 mcg_status; 4461 __u8 bank; 4462 __u8 pad1[7]; 4463 __u64 pad2[3]; 4464 }; 4465 4466If the MCE being reported is an uncorrected error, KVM will 4467inject it as an MCE exception into the guest. If the guest 4468MCG_STATUS register reports that an MCE is in progress, KVM 4469causes an KVM_EXIT_SHUTDOWN vmexit. 4470 4471Otherwise, if the MCE is a corrected error, KVM will just 4472store it in the corresponding bank (provided this bank is 4473not holding a previously reported uncorrected error). 4474 44754.107 KVM_S390_GET_CMMA_BITS 4476---------------------------- 4477 4478:Capability: KVM_CAP_S390_CMMA_MIGRATION 4479:Architectures: s390 4480:Type: vm ioctl 4481:Parameters: struct kvm_s390_cmma_log (in, out) 4482:Returns: 0 on success, a negative value on error 4483 4484Errors: 4485 4486 ====== ============================================================= 4487 ENOMEM not enough memory can be allocated to complete the task 4488 ENXIO if CMMA is not enabled 4489 EINVAL if KVM_S390_CMMA_PEEK is not set but migration mode was not enabled 4490 EINVAL if KVM_S390_CMMA_PEEK is not set but dirty tracking has been 4491 disabled (and thus migration mode was automatically disabled) 4492 EFAULT if the userspace address is invalid or if no page table is 4493 present for the addresses (e.g. when using hugepages). 4494 ====== ============================================================= 4495 4496This ioctl is used to get the values of the CMMA bits on the s390 4497architecture. It is meant to be used in two scenarios: 4498 4499- During live migration to save the CMMA values. Live migration needs 4500 to be enabled via the KVM_REQ_START_MIGRATION VM property. 4501- To non-destructively peek at the CMMA values, with the flag 4502 KVM_S390_CMMA_PEEK set. 4503 4504The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired 4505values are written to a buffer whose location is indicated via the "values" 4506member in the kvm_s390_cmma_log struct. The values in the input struct are 4507also updated as needed. 4508 4509Each CMMA value takes up one byte. 4510 4511:: 4512 4513 struct kvm_s390_cmma_log { 4514 __u64 start_gfn; 4515 __u32 count; 4516 __u32 flags; 4517 union { 4518 __u64 remaining; 4519 __u64 mask; 4520 }; 4521 __u64 values; 4522 }; 4523 4524start_gfn is the number of the first guest frame whose CMMA values are 4525to be retrieved, 4526 4527count is the length of the buffer in bytes, 4528 4529values points to the buffer where the result will be written to. 4530 4531If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be 4532KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with 4533other ioctls. 4534 4535The result is written in the buffer pointed to by the field values, and 4536the values of the input parameter are updated as follows. 4537 4538Depending on the flags, different actions are performed. The only 4539supported flag so far is KVM_S390_CMMA_PEEK. 4540 4541The default behaviour if KVM_S390_CMMA_PEEK is not set is: 4542start_gfn will indicate the first page frame whose CMMA bits were dirty. 4543It is not necessarily the same as the one passed as input, as clean pages 4544are skipped. 4545 4546count will indicate the number of bytes actually written in the buffer. 4547It can (and very often will) be smaller than the input value, since the 4548buffer is only filled until 16 bytes of clean values are found (which 4549are then not copied in the buffer). Since a CMMA migration block needs 4550the base address and the length, for a total of 16 bytes, we will send 4551back some clean data if there is some dirty data afterwards, as long as 4552the size of the clean data does not exceed the size of the header. This 4553allows to minimize the amount of data to be saved or transferred over 4554the network at the expense of more roundtrips to userspace. The next 4555invocation of the ioctl will skip over all the clean values, saving 4556potentially more than just the 16 bytes we found. 4557 4558If KVM_S390_CMMA_PEEK is set: 4559the existing storage attributes are read even when not in migration 4560mode, and no other action is performed; 4561 4562the output start_gfn will be equal to the input start_gfn, 4563 4564the output count will be equal to the input count, except if the end of 4565memory has been reached. 4566 4567In both cases: 4568the field "remaining" will indicate the total number of dirty CMMA values 4569still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is 4570not enabled. 4571 4572mask is unused. 4573 4574values points to the userspace buffer where the result will be stored. 4575 45764.108 KVM_S390_SET_CMMA_BITS 4577---------------------------- 4578 4579:Capability: KVM_CAP_S390_CMMA_MIGRATION 4580:Architectures: s390 4581:Type: vm ioctl 4582:Parameters: struct kvm_s390_cmma_log (in) 4583:Returns: 0 on success, a negative value on error 4584 4585This ioctl is used to set the values of the CMMA bits on the s390 4586architecture. It is meant to be used during live migration to restore 4587the CMMA values, but there are no restrictions on its use. 4588The ioctl takes parameters via the kvm_s390_cmma_values struct. 4589Each CMMA value takes up one byte. 4590 4591:: 4592 4593 struct kvm_s390_cmma_log { 4594 __u64 start_gfn; 4595 __u32 count; 4596 __u32 flags; 4597 union { 4598 __u64 remaining; 4599 __u64 mask; 4600 }; 4601 __u64 values; 4602 }; 4603 4604start_gfn indicates the starting guest frame number, 4605 4606count indicates how many values are to be considered in the buffer, 4607 4608flags is not used and must be 0. 4609 4610mask indicates which PGSTE bits are to be considered. 4611 4612remaining is not used. 4613 4614values points to the buffer in userspace where to store the values. 4615 4616This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4617complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4618the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or 4619if the flags field was not 0, with -EFAULT if the userspace address is 4620invalid, if invalid pages are written to (e.g. after the end of memory) 4621or if no page table is present for the addresses (e.g. when using 4622hugepages). 4623 46244.109 KVM_PPC_GET_CPU_CHAR 4625-------------------------- 4626 4627:Capability: KVM_CAP_PPC_GET_CPU_CHAR 4628:Architectures: powerpc 4629:Type: vm ioctl 4630:Parameters: struct kvm_ppc_cpu_char (out) 4631:Returns: 0 on successful completion, 4632 -EFAULT if struct kvm_ppc_cpu_char cannot be written 4633 4634This ioctl gives userspace information about certain characteristics 4635of the CPU relating to speculative execution of instructions and 4636possible information leakage resulting from speculative execution (see 4637CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is 4638returned in struct kvm_ppc_cpu_char, which looks like this:: 4639 4640 struct kvm_ppc_cpu_char { 4641 __u64 character; /* characteristics of the CPU */ 4642 __u64 behaviour; /* recommended software behaviour */ 4643 __u64 character_mask; /* valid bits in character */ 4644 __u64 behaviour_mask; /* valid bits in behaviour */ 4645 }; 4646 4647For extensibility, the character_mask and behaviour_mask fields 4648indicate which bits of character and behaviour have been filled in by 4649the kernel. If the set of defined bits is extended in future then 4650userspace will be able to tell whether it is running on a kernel that 4651knows about the new bits. 4652 4653The character field describes attributes of the CPU which can help 4654with preventing inadvertent information disclosure - specifically, 4655whether there is an instruction to flash-invalidate the L1 data cache 4656(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set 4657to a mode where entries can only be used by the thread that created 4658them, whether the bcctr[l] instruction prevents speculation, and 4659whether a speculation barrier instruction (ori 31,31,0) is provided. 4660 4661The behaviour field describes actions that software should take to 4662prevent inadvertent information disclosure, and thus describes which 4663vulnerabilities the hardware is subject to; specifically whether the 4664L1 data cache should be flushed when returning to user mode from the 4665kernel, and whether a speculation barrier should be placed between an 4666array bounds check and the array access. 4667 4668These fields use the same bit definitions as the new 4669H_GET_CPU_CHARACTERISTICS hypercall. 4670 46714.110 KVM_MEMORY_ENCRYPT_OP 4672--------------------------- 4673 4674:Capability: basic 4675:Architectures: x86 4676:Type: vm 4677:Parameters: an opaque platform specific structure (in/out) 4678:Returns: 0 on success; -1 on error 4679 4680If the platform supports creating encrypted VMs then this ioctl can be used 4681for issuing platform-specific memory encryption commands to manage those 4682encrypted VMs. 4683 4684Currently, this ioctl is used for issuing Secure Encrypted Virtualization 4685(SEV) commands on AMD Processors. The SEV commands are defined in 4686Documentation/virt/kvm/x86/amd-memory-encryption.rst. 4687 46884.111 KVM_MEMORY_ENCRYPT_REG_REGION 4689----------------------------------- 4690 4691:Capability: basic 4692:Architectures: x86 4693:Type: system 4694:Parameters: struct kvm_enc_region (in) 4695:Returns: 0 on success; -1 on error 4696 4697This ioctl can be used to register a guest memory region which may 4698contain encrypted data (e.g. guest RAM, SMRAM etc). 4699 4700It is used in the SEV-enabled guest. When encryption is enabled, a guest 4701memory region may contain encrypted data. The SEV memory encryption 4702engine uses a tweak such that two identical plaintext pages, each at 4703different locations will have differing ciphertexts. So swapping or 4704moving ciphertext of those pages will not result in plaintext being 4705swapped. So relocating (or migrating) physical backing pages for the SEV 4706guest will require some additional steps. 4707 4708Note: The current SEV key management spec does not provide commands to 4709swap or migrate (move) ciphertext pages. Hence, for now we pin the guest 4710memory region registered with the ioctl. 4711 47124.112 KVM_MEMORY_ENCRYPT_UNREG_REGION 4713------------------------------------- 4714 4715:Capability: basic 4716:Architectures: x86 4717:Type: system 4718:Parameters: struct kvm_enc_region (in) 4719:Returns: 0 on success; -1 on error 4720 4721This ioctl can be used to unregister the guest memory region registered 4722with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above. 4723 47244.113 KVM_HYPERV_EVENTFD 4725------------------------ 4726 4727:Capability: KVM_CAP_HYPERV_EVENTFD 4728:Architectures: x86 4729:Type: vm ioctl 4730:Parameters: struct kvm_hyperv_eventfd (in) 4731 4732This ioctl (un)registers an eventfd to receive notifications from the guest on 4733the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without 4734causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number 4735(bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit. 4736 4737:: 4738 4739 struct kvm_hyperv_eventfd { 4740 __u32 conn_id; 4741 __s32 fd; 4742 __u32 flags; 4743 __u32 padding[3]; 4744 }; 4745 4746The conn_id field should fit within 24 bits:: 4747 4748 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff 4749 4750The acceptable values for the flags field are:: 4751 4752 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) 4753 4754:Returns: 0 on success, 4755 -EINVAL if conn_id or flags is outside the allowed range, 4756 -ENOENT on deassign if the conn_id isn't registered, 4757 -EEXIST on assign if the conn_id is already registered 4758 47594.114 KVM_GET_NESTED_STATE 4760-------------------------- 4761 4762:Capability: KVM_CAP_NESTED_STATE 4763:Architectures: x86 4764:Type: vcpu ioctl 4765:Parameters: struct kvm_nested_state (in/out) 4766:Returns: 0 on success, -1 on error 4767 4768Errors: 4769 4770 ===== ============================================================= 4771 E2BIG the total state size exceeds the value of 'size' specified by 4772 the user; the size required will be written into size. 4773 ===== ============================================================= 4774 4775:: 4776 4777 struct kvm_nested_state { 4778 __u16 flags; 4779 __u16 format; 4780 __u32 size; 4781 4782 union { 4783 struct kvm_vmx_nested_state_hdr vmx; 4784 struct kvm_svm_nested_state_hdr svm; 4785 4786 /* Pad the header to 128 bytes. */ 4787 __u8 pad[120]; 4788 } hdr; 4789 4790 union { 4791 struct kvm_vmx_nested_state_data vmx[0]; 4792 struct kvm_svm_nested_state_data svm[0]; 4793 } data; 4794 }; 4795 4796 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001 4797 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002 4798 #define KVM_STATE_NESTED_EVMCS 0x00000004 4799 4800 #define KVM_STATE_NESTED_FORMAT_VMX 0 4801 #define KVM_STATE_NESTED_FORMAT_SVM 1 4802 4803 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000 4804 4805 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001 4806 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002 4807 4808 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001 4809 4810 struct kvm_vmx_nested_state_hdr { 4811 __u64 vmxon_pa; 4812 __u64 vmcs12_pa; 4813 4814 struct { 4815 __u16 flags; 4816 } smm; 4817 4818 __u32 flags; 4819 __u64 preemption_timer_deadline; 4820 }; 4821 4822 struct kvm_vmx_nested_state_data { 4823 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4824 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4825 }; 4826 4827This ioctl copies the vcpu's nested virtualization state from the kernel to 4828userspace. 4829 4830The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE 4831to the KVM_CHECK_EXTENSION ioctl(). 4832 48334.115 KVM_SET_NESTED_STATE 4834-------------------------- 4835 4836:Capability: KVM_CAP_NESTED_STATE 4837:Architectures: x86 4838:Type: vcpu ioctl 4839:Parameters: struct kvm_nested_state (in) 4840:Returns: 0 on success, -1 on error 4841 4842This copies the vcpu's kvm_nested_state struct from userspace to the kernel. 4843For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE. 4844 48454.116 KVM_(UN)REGISTER_COALESCED_MMIO 4846------------------------------------- 4847 4848:Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio) 4849 KVM_CAP_COALESCED_PIO (for coalesced pio) 4850:Architectures: all 4851:Type: vm ioctl 4852:Parameters: struct kvm_coalesced_mmio_zone 4853:Returns: 0 on success, < 0 on error 4854 4855Coalesced I/O is a performance optimization that defers hardware 4856register write emulation so that userspace exits are avoided. It is 4857typically used to reduce the overhead of emulating frequently accessed 4858hardware registers. 4859 4860When a hardware register is configured for coalesced I/O, write accesses 4861do not exit to userspace and their value is recorded in a ring buffer 4862that is shared between kernel and userspace. 4863 4864Coalesced I/O is used if one or more write accesses to a hardware 4865register can be deferred until a read or a write to another hardware 4866register on the same device. This last access will cause a vmexit and 4867userspace will process accesses from the ring buffer before emulating 4868it. That will avoid exiting to userspace on repeated writes. 4869 4870Coalesced pio is based on coalesced mmio. There is little difference 4871between coalesced mmio and pio except that coalesced pio records accesses 4872to I/O ports. 4873 48744.117 KVM_CLEAR_DIRTY_LOG (vm ioctl) 4875------------------------------------ 4876 4877:Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4878:Architectures: x86, arm64, mips 4879:Type: vm ioctl 4880:Parameters: struct kvm_clear_dirty_log (in) 4881:Returns: 0 on success, -1 on error 4882 4883:: 4884 4885 /* for KVM_CLEAR_DIRTY_LOG */ 4886 struct kvm_clear_dirty_log { 4887 __u32 slot; 4888 __u32 num_pages; 4889 __u64 first_page; 4890 union { 4891 void __user *dirty_bitmap; /* one bit per page */ 4892 __u64 padding; 4893 }; 4894 }; 4895 4896The ioctl clears the dirty status of pages in a memory slot, according to 4897the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap 4898field. Bit 0 of the bitmap corresponds to page "first_page" in the 4899memory slot, and num_pages is the size in bits of the input bitmap. 4900first_page must be a multiple of 64; num_pages must also be a multiple of 490164 unless first_page + num_pages is the size of the memory slot. For each 4902bit that is set in the input bitmap, the corresponding page is marked "clean" 4903in KVM's dirty bitmap, and dirty tracking is re-enabled for that page 4904(for example via write-protection, or by clearing the dirty bit in 4905a page table entry). 4906 4907If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 4908the address space for which you want to clear the dirty status. See 4909KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 4910 4911This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4912is enabled; for more information, see the description of the capability. 4913However, it can always be used as long as KVM_CHECK_EXTENSION confirms 4914that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. 4915 49164.118 KVM_GET_SUPPORTED_HV_CPUID 4917-------------------------------- 4918 4919:Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system) 4920:Architectures: x86 4921:Type: system ioctl, vcpu ioctl 4922:Parameters: struct kvm_cpuid2 (in/out) 4923:Returns: 0 on success, -1 on error 4924 4925:: 4926 4927 struct kvm_cpuid2 { 4928 __u32 nent; 4929 __u32 padding; 4930 struct kvm_cpuid_entry2 entries[0]; 4931 }; 4932 4933 struct kvm_cpuid_entry2 { 4934 __u32 function; 4935 __u32 index; 4936 __u32 flags; 4937 __u32 eax; 4938 __u32 ebx; 4939 __u32 ecx; 4940 __u32 edx; 4941 __u32 padding[3]; 4942 }; 4943 4944This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in 4945KVM. Userspace can use the information returned by this ioctl to construct 4946cpuid information presented to guests consuming Hyper-V enlightenments (e.g. 4947Windows or Hyper-V guests). 4948 4949CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level 4950Functional Specification (TLFS). These leaves can't be obtained with 4951KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature 4952leaves (0x40000000, 0x40000001). 4953 4954Currently, the following list of CPUID leaves are returned: 4955 4956 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS 4957 - HYPERV_CPUID_INTERFACE 4958 - HYPERV_CPUID_VERSION 4959 - HYPERV_CPUID_FEATURES 4960 - HYPERV_CPUID_ENLIGHTMENT_INFO 4961 - HYPERV_CPUID_IMPLEMENT_LIMITS 4962 - HYPERV_CPUID_NESTED_FEATURES 4963 - HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS 4964 - HYPERV_CPUID_SYNDBG_INTERFACE 4965 - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES 4966 4967Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure 4968with the 'nent' field indicating the number of entries in the variable-size 4969array 'entries'. If the number of entries is too low to describe all Hyper-V 4970feature leaves, an error (E2BIG) is returned. If the number is more or equal 4971to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the 4972number of valid entries in the 'entries' array, which is then filled. 4973 4974'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, 4975userspace should not expect to get any particular value there. 4976 4977Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike 4978system ioctl which exposes all supported feature bits unconditionally, vcpu 4979version has the following quirks: 4980 4981- HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED 4982 feature bit are only exposed when Enlightened VMCS was previously enabled 4983 on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). 4984- HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC. 4985 (presumes KVM_CREATE_IRQCHIP has already been called). 4986 49874.119 KVM_ARM_VCPU_FINALIZE 4988--------------------------- 4989 4990:Architectures: arm64 4991:Type: vcpu ioctl 4992:Parameters: int feature (in) 4993:Returns: 0 on success, -1 on error 4994 4995Errors: 4996 4997 ====== ============================================================== 4998 EPERM feature not enabled, needs configuration, or already finalized 4999 EINVAL feature unknown or not present 5000 ====== ============================================================== 5001 5002Recognised values for feature: 5003 5004 ===== =========================================== 5005 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE) 5006 ===== =========================================== 5007 5008Finalizes the configuration of the specified vcpu feature. 5009 5010The vcpu must already have been initialised, enabling the affected feature, by 5011means of a successful KVM_ARM_VCPU_INIT call with the appropriate flag set in 5012features[]. 5013 5014For affected vcpu features, this is a mandatory step that must be performed 5015before the vcpu is fully usable. 5016 5017Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be 5018configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration 5019that should be performaned and how to do it are feature-dependent. 5020 5021Other calls that depend on a particular feature being finalized, such as 5022KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with 5023-EPERM unless the feature has already been finalized by means of a 5024KVM_ARM_VCPU_FINALIZE call. 5025 5026See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization 5027using this ioctl. 5028 50294.120 KVM_SET_PMU_EVENT_FILTER 5030------------------------------ 5031 5032:Capability: KVM_CAP_PMU_EVENT_FILTER 5033:Architectures: x86 5034:Type: vm ioctl 5035:Parameters: struct kvm_pmu_event_filter (in) 5036:Returns: 0 on success, -1 on error 5037 5038Errors: 5039 5040 ====== ============================================================ 5041 EFAULT args[0] cannot be accessed 5042 EINVAL args[0] contains invalid data in the filter or filter events 5043 E2BIG nevents is too large 5044 EBUSY not enough memory to allocate the filter 5045 ====== ============================================================ 5046 5047:: 5048 5049 struct kvm_pmu_event_filter { 5050 __u32 action; 5051 __u32 nevents; 5052 __u32 fixed_counter_bitmap; 5053 __u32 flags; 5054 __u32 pad[4]; 5055 __u64 events[0]; 5056 }; 5057 5058This ioctl restricts the set of PMU events the guest can program by limiting 5059which event select and unit mask combinations are permitted. 5060 5061The argument holds a list of filter events which will be allowed or denied. 5062 5063Filter events only control general purpose counters; fixed purpose counters 5064are controlled by the fixed_counter_bitmap. 5065 5066Valid values for 'flags':: 5067 5068``0`` 5069 5070To use this mode, clear the 'flags' field. 5071 5072In this mode each event will contain an event select + unit mask. 5073 5074When the guest attempts to program the PMU the guest's event select + 5075unit mask is compared against the filter events to determine whether the 5076guest should have access. 5077 5078``KVM_PMU_EVENT_FLAG_MASKED_EVENTS`` 5079:Capability: KVM_CAP_PMU_EVENT_MASKED_EVENTS 5080 5081In this mode each filter event will contain an event select, mask, match, and 5082exclude value. To encode a masked event use:: 5083 5084 KVM_PMU_ENCODE_MASKED_ENTRY() 5085 5086An encoded event will follow this layout:: 5087 5088 Bits Description 5089 ---- ----------- 5090 7:0 event select (low bits) 5091 15:8 umask match 5092 31:16 unused 5093 35:32 event select (high bits) 5094 36:54 unused 5095 55 exclude bit 5096 63:56 umask mask 5097 5098When the guest attempts to program the PMU, these steps are followed in 5099determining if the guest should have access: 5100 5101 1. Match the event select from the guest against the filter events. 5102 2. If a match is found, match the guest's unit mask to the mask and match 5103 values of the included filter events. 5104 I.e. (unit mask & mask) == match && !exclude. 5105 3. If a match is found, match the guest's unit mask to the mask and match 5106 values of the excluded filter events. 5107 I.e. (unit mask & mask) == match && exclude. 5108 4. 5109 a. If an included match is found and an excluded match is not found, filter 5110 the event. 5111 b. For everything else, do not filter the event. 5112 5. 5113 a. If the event is filtered and it's an allow list, allow the guest to 5114 program the event. 5115 b. If the event is filtered and it's a deny list, do not allow the guest to 5116 program the event. 5117 5118When setting a new pmu event filter, -EINVAL will be returned if any of the 5119unused fields are set or if any of the high bits (35:32) in the event 5120select are set when called on Intel. 5121 5122Valid values for 'action':: 5123 5124 #define KVM_PMU_EVENT_ALLOW 0 5125 #define KVM_PMU_EVENT_DENY 1 5126 51274.121 KVM_PPC_SVM_OFF 5128--------------------- 5129 5130:Capability: basic 5131:Architectures: powerpc 5132:Type: vm ioctl 5133:Parameters: none 5134:Returns: 0 on successful completion, 5135 5136Errors: 5137 5138 ====== ================================================================ 5139 EINVAL if ultravisor failed to terminate the secure guest 5140 ENOMEM if hypervisor failed to allocate new radix page tables for guest 5141 ====== ================================================================ 5142 5143This ioctl is used to turn off the secure mode of the guest or transition 5144the guest from secure mode to normal mode. This is invoked when the guest 5145is reset. This has no effect if called for a normal guest. 5146 5147This ioctl issues an ultravisor call to terminate the secure guest, 5148unpins the VPA pages and releases all the device pages that are used to 5149track the secure pages by hypervisor. 5150 51514.122 KVM_S390_NORMAL_RESET 5152--------------------------- 5153 5154:Capability: KVM_CAP_S390_VCPU_RESETS 5155:Architectures: s390 5156:Type: vcpu ioctl 5157:Parameters: none 5158:Returns: 0 5159 5160This ioctl resets VCPU registers and control structures according to 5161the cpu reset definition in the POP (Principles Of Operation). 5162 51634.123 KVM_S390_INITIAL_RESET 5164---------------------------- 5165 5166:Capability: none 5167:Architectures: s390 5168:Type: vcpu ioctl 5169:Parameters: none 5170:Returns: 0 5171 5172This ioctl resets VCPU registers and control structures according to 5173the initial cpu reset definition in the POP. However, the cpu is not 5174put into ESA mode. This reset is a superset of the normal reset. 5175 51764.124 KVM_S390_CLEAR_RESET 5177-------------------------- 5178 5179:Capability: KVM_CAP_S390_VCPU_RESETS 5180:Architectures: s390 5181:Type: vcpu ioctl 5182:Parameters: none 5183:Returns: 0 5184 5185This ioctl resets VCPU registers and control structures according to 5186the clear cpu reset definition in the POP. However, the cpu is not put 5187into ESA mode. This reset is a superset of the initial reset. 5188 5189 51904.125 KVM_S390_PV_COMMAND 5191------------------------- 5192 5193:Capability: KVM_CAP_S390_PROTECTED 5194:Architectures: s390 5195:Type: vm ioctl 5196:Parameters: struct kvm_pv_cmd 5197:Returns: 0 on success, < 0 on error 5198 5199:: 5200 5201 struct kvm_pv_cmd { 5202 __u32 cmd; /* Command to be executed */ 5203 __u16 rc; /* Ultravisor return code */ 5204 __u16 rrc; /* Ultravisor return reason code */ 5205 __u64 data; /* Data or address */ 5206 __u32 flags; /* flags for future extensions. Must be 0 for now */ 5207 __u32 reserved[3]; 5208 }; 5209 5210**Ultravisor return codes** 5211The Ultravisor return (reason) codes are provided by the kernel if a 5212Ultravisor call has been executed to achieve the results expected by 5213the command. Therefore they are independent of the IOCTL return 5214code. If KVM changes `rc`, its value will always be greater than 0 5215hence setting it to 0 before issuing a PV command is advised to be 5216able to detect a change of `rc`. 5217 5218**cmd values:** 5219 5220KVM_PV_ENABLE 5221 Allocate memory and register the VM with the Ultravisor, thereby 5222 donating memory to the Ultravisor that will become inaccessible to 5223 KVM. All existing CPUs are converted to protected ones. After this 5224 command has succeeded, any CPU added via hotplug will become 5225 protected during its creation as well. 5226 5227 Errors: 5228 5229 ===== ============================= 5230 EINTR an unmasked signal is pending 5231 ===== ============================= 5232 5233KVM_PV_DISABLE 5234 Deregister the VM from the Ultravisor and reclaim the memory that had 5235 been donated to the Ultravisor, making it usable by the kernel again. 5236 All registered VCPUs are converted back to non-protected ones. If a 5237 previous protected VM had been prepared for asynchronous teardown with 5238 KVM_PV_ASYNC_CLEANUP_PREPARE and not subsequently torn down with 5239 KVM_PV_ASYNC_CLEANUP_PERFORM, it will be torn down in this call 5240 together with the current protected VM. 5241 5242KVM_PV_VM_SET_SEC_PARMS 5243 Pass the image header from VM memory to the Ultravisor in 5244 preparation of image unpacking and verification. 5245 5246KVM_PV_VM_UNPACK 5247 Unpack (protect and decrypt) a page of the encrypted boot image. 5248 5249KVM_PV_VM_VERIFY 5250 Verify the integrity of the unpacked image. Only if this succeeds, 5251 KVM is allowed to start protected VCPUs. 5252 5253KVM_PV_INFO 5254 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5255 5256 Presents an API that provides Ultravisor related data to userspace 5257 via subcommands. len_max is the size of the user space buffer, 5258 len_written is KVM's indication of how much bytes of that buffer 5259 were actually written to. len_written can be used to determine the 5260 valid fields if more response fields are added in the future. 5261 5262 :: 5263 5264 enum pv_cmd_info_id { 5265 KVM_PV_INFO_VM, 5266 KVM_PV_INFO_DUMP, 5267 }; 5268 5269 struct kvm_s390_pv_info_header { 5270 __u32 id; 5271 __u32 len_max; 5272 __u32 len_written; 5273 __u32 reserved; 5274 }; 5275 5276 struct kvm_s390_pv_info { 5277 struct kvm_s390_pv_info_header header; 5278 struct kvm_s390_pv_info_dump dump; 5279 struct kvm_s390_pv_info_vm vm; 5280 }; 5281 5282**subcommands:** 5283 5284 KVM_PV_INFO_VM 5285 This subcommand provides basic Ultravisor information for PV 5286 hosts. These values are likely also exported as files in the sysfs 5287 firmware UV query interface but they are more easily available to 5288 programs in this API. 5289 5290 The installed calls and feature_indication members provide the 5291 installed UV calls and the UV's other feature indications. 5292 5293 The max_* members provide information about the maximum number of PV 5294 vcpus, PV guests and PV guest memory size. 5295 5296 :: 5297 5298 struct kvm_s390_pv_info_vm { 5299 __u64 inst_calls_list[4]; 5300 __u64 max_cpus; 5301 __u64 max_guests; 5302 __u64 max_guest_addr; 5303 __u64 feature_indication; 5304 }; 5305 5306 5307 KVM_PV_INFO_DUMP 5308 This subcommand provides information related to dumping PV guests. 5309 5310 :: 5311 5312 struct kvm_s390_pv_info_dump { 5313 __u64 dump_cpu_buffer_len; 5314 __u64 dump_config_mem_buffer_per_1m; 5315 __u64 dump_config_finalize_len; 5316 }; 5317 5318KVM_PV_DUMP 5319 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5320 5321 Presents an API that provides calls which facilitate dumping a 5322 protected VM. 5323 5324 :: 5325 5326 struct kvm_s390_pv_dmp { 5327 __u64 subcmd; 5328 __u64 buff_addr; 5329 __u64 buff_len; 5330 __u64 gaddr; /* For dump storage state */ 5331 }; 5332 5333 **subcommands:** 5334 5335 KVM_PV_DUMP_INIT 5336 Initializes the dump process of a protected VM. If this call does 5337 not succeed all other subcommands will fail with -EINVAL. This 5338 subcommand will return -EINVAL if a dump process has not yet been 5339 completed. 5340 5341 Not all PV vms can be dumped, the owner needs to set `dump 5342 allowed` PCF bit 34 in the SE header to allow dumping. 5343 5344 KVM_PV_DUMP_CONFIG_STOR_STATE 5345 Stores `buff_len` bytes of tweak component values starting with 5346 the 1MB block specified by the absolute guest address 5347 (`gaddr`). `buff_len` needs to be `conf_dump_storage_state_len` 5348 aligned and at least >= the `conf_dump_storage_state_len` value 5349 provided by the dump uv_info data. buff_user might be written to 5350 even if an error rc is returned. For instance if we encounter a 5351 fault after writing the first page of data. 5352 5353 KVM_PV_DUMP_COMPLETE 5354 If the subcommand succeeds it completes the dump process and lets 5355 KVM_PV_DUMP_INIT be called again. 5356 5357 On success `conf_dump_finalize_len` bytes of completion data will be 5358 stored to the `buff_addr`. The completion data contains a key 5359 derivation seed, IV, tweak nonce and encryption keys as well as an 5360 authentication tag all of which are needed to decrypt the dump at a 5361 later time. 5362 5363KVM_PV_ASYNC_CLEANUP_PREPARE 5364 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5365 5366 Prepare the current protected VM for asynchronous teardown. Most 5367 resources used by the current protected VM will be set aside for a 5368 subsequent asynchronous teardown. The current protected VM will then 5369 resume execution immediately as non-protected. There can be at most 5370 one protected VM prepared for asynchronous teardown at any time. If 5371 a protected VM had already been prepared for teardown without 5372 subsequently calling KVM_PV_ASYNC_CLEANUP_PERFORM, this call will 5373 fail. In that case, the userspace process should issue a normal 5374 KVM_PV_DISABLE. The resources set aside with this call will need to 5375 be cleaned up with a subsequent call to KVM_PV_ASYNC_CLEANUP_PERFORM 5376 or KVM_PV_DISABLE, otherwise they will be cleaned up when KVM 5377 terminates. KVM_PV_ASYNC_CLEANUP_PREPARE can be called again as soon 5378 as cleanup starts, i.e. before KVM_PV_ASYNC_CLEANUP_PERFORM finishes. 5379 5380KVM_PV_ASYNC_CLEANUP_PERFORM 5381 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5382 5383 Tear down the protected VM previously prepared for teardown with 5384 KVM_PV_ASYNC_CLEANUP_PREPARE. The resources that had been set aside 5385 will be freed during the execution of this command. This PV command 5386 should ideally be issued by userspace from a separate thread. If a 5387 fatal signal is received (or the process terminates naturally), the 5388 command will terminate immediately without completing, and the normal 5389 KVM shutdown procedure will take care of cleaning up all remaining 5390 protected VMs, including the ones whose teardown was interrupted by 5391 process termination. 5392 53934.126 KVM_XEN_HVM_SET_ATTR 5394-------------------------- 5395 5396:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5397:Architectures: x86 5398:Type: vm ioctl 5399:Parameters: struct kvm_xen_hvm_attr 5400:Returns: 0 on success, < 0 on error 5401 5402:: 5403 5404 struct kvm_xen_hvm_attr { 5405 __u16 type; 5406 __u16 pad[3]; 5407 union { 5408 __u8 long_mode; 5409 __u8 vector; 5410 __u8 runstate_update_flag; 5411 struct { 5412 __u64 gfn; 5413 } shared_info; 5414 struct { 5415 __u32 send_port; 5416 __u32 type; /* EVTCHNSTAT_ipi / EVTCHNSTAT_interdomain */ 5417 __u32 flags; 5418 union { 5419 struct { 5420 __u32 port; 5421 __u32 vcpu; 5422 __u32 priority; 5423 } port; 5424 struct { 5425 __u32 port; /* Zero for eventfd */ 5426 __s32 fd; 5427 } eventfd; 5428 __u32 padding[4]; 5429 } deliver; 5430 } evtchn; 5431 __u32 xen_version; 5432 __u64 pad[8]; 5433 } u; 5434 }; 5435 5436type values: 5437 5438KVM_XEN_ATTR_TYPE_LONG_MODE 5439 Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This 5440 determines the layout of the shared info pages exposed to the VM. 5441 5442KVM_XEN_ATTR_TYPE_SHARED_INFO 5443 Sets the guest physical frame number at which the Xen "shared info" 5444 page resides. Note that although Xen places vcpu_info for the first 5445 32 vCPUs in the shared_info page, KVM does not automatically do so 5446 and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO be used 5447 explicitly even when the vcpu_info for a given vCPU resides at the 5448 "default" location in the shared_info page. This is because KVM may 5449 not be aware of the Xen CPU id which is used as the index into the 5450 vcpu_info[] array, so may know the correct default location. 5451 5452 Note that the shared info page may be constantly written to by KVM; 5453 it contains the event channel bitmap used to deliver interrupts to 5454 a Xen guest, amongst other things. It is exempt from dirty tracking 5455 mechanisms — KVM will not explicitly mark the page as dirty each 5456 time an event channel interrupt is delivered to the guest! Thus, 5457 userspace should always assume that the designated GFN is dirty if 5458 any vCPU has been running or any event channel interrupts can be 5459 routed to the guest. 5460 5461 Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared info 5462 page. 5463 5464KVM_XEN_ATTR_TYPE_UPCALL_VECTOR 5465 Sets the exception vector used to deliver Xen event channel upcalls. 5466 This is the HVM-wide vector injected directly by the hypervisor 5467 (not through the local APIC), typically configured by a guest via 5468 HVM_PARAM_CALLBACK_IRQ. This can be disabled again (e.g. for guest 5469 SHUTDOWN_soft_reset) by setting it to zero. 5470 5471KVM_XEN_ATTR_TYPE_EVTCHN 5472 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5473 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5474 an outbound port number for interception of EVTCHNOP_send requests 5475 from the guest. A given sending port number may be directed back to 5476 a specified vCPU (by APIC ID) / port / priority on the guest, or to 5477 trigger events on an eventfd. The vCPU and priority can be changed 5478 by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but but other 5479 fields cannot change for a given sending port. A port mapping is 5480 removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing 5481 KVM_XEN_EVTCHN_RESET in the flags field removes all interception of 5482 outbound event channels. The values of the flags field are mutually 5483 exclusive and cannot be combined as a bitmask. 5484 5485KVM_XEN_ATTR_TYPE_XEN_VERSION 5486 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5487 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5488 the 32-bit version code returned to the guest when it invokes the 5489 XENVER_version call; typically (XEN_MAJOR << 16 | XEN_MINOR). PV 5490 Xen guests will often use this to as a dummy hypercall to trigger 5491 event channel delivery, so responding within the kernel without 5492 exiting to userspace is beneficial. 5493 5494KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG 5495 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5496 support for KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG. It enables the 5497 XEN_RUNSTATE_UPDATE flag which allows guest vCPUs to safely read 5498 other vCPUs' vcpu_runstate_info. Xen guests enable this feature via 5499 the VMASST_TYPE_runstate_update_flag of the HYPERVISOR_vm_assist 5500 hypercall. 5501 55024.127 KVM_XEN_HVM_GET_ATTR 5503-------------------------- 5504 5505:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5506:Architectures: x86 5507:Type: vm ioctl 5508:Parameters: struct kvm_xen_hvm_attr 5509:Returns: 0 on success, < 0 on error 5510 5511Allows Xen VM attributes to be read. For the structure and types, 5512see KVM_XEN_HVM_SET_ATTR above. The KVM_XEN_ATTR_TYPE_EVTCHN 5513attribute cannot be read. 5514 55154.128 KVM_XEN_VCPU_SET_ATTR 5516--------------------------- 5517 5518:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5519:Architectures: x86 5520:Type: vcpu ioctl 5521:Parameters: struct kvm_xen_vcpu_attr 5522:Returns: 0 on success, < 0 on error 5523 5524:: 5525 5526 struct kvm_xen_vcpu_attr { 5527 __u16 type; 5528 __u16 pad[3]; 5529 union { 5530 __u64 gpa; 5531 __u64 pad[4]; 5532 struct { 5533 __u64 state; 5534 __u64 state_entry_time; 5535 __u64 time_running; 5536 __u64 time_runnable; 5537 __u64 time_blocked; 5538 __u64 time_offline; 5539 } runstate; 5540 __u32 vcpu_id; 5541 struct { 5542 __u32 port; 5543 __u32 priority; 5544 __u64 expires_ns; 5545 } timer; 5546 __u8 vector; 5547 } u; 5548 }; 5549 5550type values: 5551 5552KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO 5553 Sets the guest physical address of the vcpu_info for a given vCPU. 5554 As with the shared_info page for the VM, the corresponding page may be 5555 dirtied at any time if event channel interrupt delivery is enabled, so 5556 userspace should always assume that the page is dirty without relying 5557 on dirty logging. Setting the gpa to KVM_XEN_INVALID_GPA will disable 5558 the vcpu_info. 5559 5560KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO 5561 Sets the guest physical address of an additional pvclock structure 5562 for a given vCPU. This is typically used for guest vsyscall support. 5563 Setting the gpa to KVM_XEN_INVALID_GPA will disable the structure. 5564 5565KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR 5566 Sets the guest physical address of the vcpu_runstate_info for a given 5567 vCPU. This is how a Xen guest tracks CPU state such as steal time. 5568 Setting the gpa to KVM_XEN_INVALID_GPA will disable the runstate area. 5569 5570KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT 5571 Sets the runstate (RUNSTATE_running/_runnable/_blocked/_offline) of 5572 the given vCPU from the .u.runstate.state member of the structure. 5573 KVM automatically accounts running and runnable time but blocked 5574 and offline states are only entered explicitly. 5575 5576KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA 5577 Sets all fields of the vCPU runstate data from the .u.runstate member 5578 of the structure, including the current runstate. The state_entry_time 5579 must equal the sum of the other four times. 5580 5581KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST 5582 This *adds* the contents of the .u.runstate members of the structure 5583 to the corresponding members of the given vCPU's runstate data, thus 5584 permitting atomic adjustments to the runstate times. The adjustment 5585 to the state_entry_time must equal the sum of the adjustments to the 5586 other four times. The state field must be set to -1, or to a valid 5587 runstate value (RUNSTATE_running, RUNSTATE_runnable, RUNSTATE_blocked 5588 or RUNSTATE_offline) to set the current accounted state as of the 5589 adjusted state_entry_time. 5590 5591KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID 5592 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5593 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the Xen 5594 vCPU ID of the given vCPU, to allow timer-related VCPU operations to 5595 be intercepted by KVM. 5596 5597KVM_XEN_VCPU_ATTR_TYPE_TIMER 5598 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5599 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5600 event channel port/priority for the VIRQ_TIMER of the vCPU, as well 5601 as allowing a pending timer to be saved/restored. Setting the timer 5602 port to zero disables kernel handling of the singleshot timer. 5603 5604KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR 5605 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5606 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5607 per-vCPU local APIC upcall vector, configured by a Xen guest with 5608 the HVMOP_set_evtchn_upcall_vector hypercall. This is typically 5609 used by Windows guests, and is distinct from the HVM-wide upcall 5610 vector configured with HVM_PARAM_CALLBACK_IRQ. It is disabled by 5611 setting the vector to zero. 5612 5613 56144.129 KVM_XEN_VCPU_GET_ATTR 5615--------------------------- 5616 5617:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5618:Architectures: x86 5619:Type: vcpu ioctl 5620:Parameters: struct kvm_xen_vcpu_attr 5621:Returns: 0 on success, < 0 on error 5622 5623Allows Xen vCPU attributes to be read. For the structure and types, 5624see KVM_XEN_VCPU_SET_ATTR above. 5625 5626The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used 5627with the KVM_XEN_VCPU_GET_ATTR ioctl. 5628 56294.130 KVM_ARM_MTE_COPY_TAGS 5630--------------------------- 5631 5632:Capability: KVM_CAP_ARM_MTE 5633:Architectures: arm64 5634:Type: vm ioctl 5635:Parameters: struct kvm_arm_copy_mte_tags 5636:Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect 5637 arguments, -EFAULT if memory cannot be accessed). 5638 5639:: 5640 5641 struct kvm_arm_copy_mte_tags { 5642 __u64 guest_ipa; 5643 __u64 length; 5644 void __user *addr; 5645 __u64 flags; 5646 __u64 reserved[2]; 5647 }; 5648 5649Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The 5650``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. 5651``length`` must not be bigger than 2^31 - PAGE_SIZE bytes. The ``addr`` 5652field must point to a buffer which the tags will be copied to or from. 5653 5654``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or 5655``KVM_ARM_TAGS_FROM_GUEST``. 5656 5657The size of the buffer to store the tags is ``(length / 16)`` bytes 5658(granules in MTE are 16 bytes long). Each byte contains a single tag 5659value. This matches the format of ``PTRACE_PEEKMTETAGS`` and 5660``PTRACE_POKEMTETAGS``. 5661 5662If an error occurs before any data is copied then a negative error code is 5663returned. If some tags have been copied before an error occurs then the number 5664of bytes successfully copied is returned. If the call completes successfully 5665then ``length`` is returned. 5666 56674.131 KVM_GET_SREGS2 5668-------------------- 5669 5670:Capability: KVM_CAP_SREGS2 5671:Architectures: x86 5672:Type: vcpu ioctl 5673:Parameters: struct kvm_sregs2 (out) 5674:Returns: 0 on success, -1 on error 5675 5676Reads special registers from the vcpu. 5677This ioctl (when supported) replaces the KVM_GET_SREGS. 5678 5679:: 5680 5681 struct kvm_sregs2 { 5682 /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ 5683 struct kvm_segment cs, ds, es, fs, gs, ss; 5684 struct kvm_segment tr, ldt; 5685 struct kvm_dtable gdt, idt; 5686 __u64 cr0, cr2, cr3, cr4, cr8; 5687 __u64 efer; 5688 __u64 apic_base; 5689 __u64 flags; 5690 __u64 pdptrs[4]; 5691 }; 5692 5693flags values for ``kvm_sregs2``: 5694 5695``KVM_SREGS2_FLAGS_PDPTRS_VALID`` 5696 5697 Indicates that the struct contains valid PDPTR values. 5698 5699 57004.132 KVM_SET_SREGS2 5701-------------------- 5702 5703:Capability: KVM_CAP_SREGS2 5704:Architectures: x86 5705:Type: vcpu ioctl 5706:Parameters: struct kvm_sregs2 (in) 5707:Returns: 0 on success, -1 on error 5708 5709Writes special registers into the vcpu. 5710See KVM_GET_SREGS2 for the data structures. 5711This ioctl (when supported) replaces the KVM_SET_SREGS. 5712 57134.133 KVM_GET_STATS_FD 5714---------------------- 5715 5716:Capability: KVM_CAP_STATS_BINARY_FD 5717:Architectures: all 5718:Type: vm ioctl, vcpu ioctl 5719:Parameters: none 5720:Returns: statistics file descriptor on success, < 0 on error 5721 5722Errors: 5723 5724 ====== ====================================================== 5725 ENOMEM if the fd could not be created due to lack of memory 5726 EMFILE if the number of opened files exceeds the limit 5727 ====== ====================================================== 5728 5729The returned file descriptor can be used to read VM/vCPU statistics data in 5730binary format. The data in the file descriptor consists of four blocks 5731organized as follows: 5732 5733+-------------+ 5734| Header | 5735+-------------+ 5736| id string | 5737+-------------+ 5738| Descriptors | 5739+-------------+ 5740| Stats Data | 5741+-------------+ 5742 5743Apart from the header starting at offset 0, please be aware that it is 5744not guaranteed that the four blocks are adjacent or in the above order; 5745the offsets of the id, descriptors and data blocks are found in the 5746header. However, all four blocks are aligned to 64 bit offsets in the 5747file and they do not overlap. 5748 5749All blocks except the data block are immutable. Userspace can read them 5750only one time after retrieving the file descriptor, and then use ``pread`` or 5751``lseek`` to read the statistics repeatedly. 5752 5753All data is in system endianness. 5754 5755The format of the header is as follows:: 5756 5757 struct kvm_stats_header { 5758 __u32 flags; 5759 __u32 name_size; 5760 __u32 num_desc; 5761 __u32 id_offset; 5762 __u32 desc_offset; 5763 __u32 data_offset; 5764 }; 5765 5766The ``flags`` field is not used at the moment. It is always read as 0. 5767 5768The ``name_size`` field is the size (in byte) of the statistics name string 5769(including trailing '\0') which is contained in the "id string" block and 5770appended at the end of every descriptor. 5771 5772The ``num_desc`` field is the number of descriptors that are included in the 5773descriptor block. (The actual number of values in the data block may be 5774larger, since each descriptor may comprise more than one value). 5775 5776The ``id_offset`` field is the offset of the id string from the start of the 5777file indicated by the file descriptor. It is a multiple of 8. 5778 5779The ``desc_offset`` field is the offset of the Descriptors block from the start 5780of the file indicated by the file descriptor. It is a multiple of 8. 5781 5782The ``data_offset`` field is the offset of the Stats Data block from the start 5783of the file indicated by the file descriptor. It is a multiple of 8. 5784 5785The id string block contains a string which identifies the file descriptor on 5786which KVM_GET_STATS_FD was invoked. The size of the block, including the 5787trailing ``'\0'``, is indicated by the ``name_size`` field in the header. 5788 5789The descriptors block is only needed to be read once for the lifetime of the 5790file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed 5791by a string of size ``name_size``. 5792:: 5793 5794 #define KVM_STATS_TYPE_SHIFT 0 5795 #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT) 5796 #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT) 5797 #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT) 5798 #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT) 5799 #define KVM_STATS_TYPE_LINEAR_HIST (0x3 << KVM_STATS_TYPE_SHIFT) 5800 #define KVM_STATS_TYPE_LOG_HIST (0x4 << KVM_STATS_TYPE_SHIFT) 5801 #define KVM_STATS_TYPE_MAX KVM_STATS_TYPE_LOG_HIST 5802 5803 #define KVM_STATS_UNIT_SHIFT 4 5804 #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT) 5805 #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT) 5806 #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) 5807 #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) 5808 #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) 5809 #define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT) 5810 #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_BOOLEAN 5811 5812 #define KVM_STATS_BASE_SHIFT 8 5813 #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT) 5814 #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT) 5815 #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT) 5816 #define KVM_STATS_BASE_MAX KVM_STATS_BASE_POW2 5817 5818 struct kvm_stats_desc { 5819 __u32 flags; 5820 __s16 exponent; 5821 __u16 size; 5822 __u32 offset; 5823 __u32 bucket_size; 5824 char name[]; 5825 }; 5826 5827The ``flags`` field contains the type and unit of the statistics data described 5828by this descriptor. Its endianness is CPU native. 5829The following flags are supported: 5830 5831Bits 0-3 of ``flags`` encode the type: 5832 5833 * ``KVM_STATS_TYPE_CUMULATIVE`` 5834 The statistics reports a cumulative count. The value of data can only be increased. 5835 Most of the counters used in KVM are of this type. 5836 The corresponding ``size`` field for this type is always 1. 5837 All cumulative statistics data are read/write. 5838 * ``KVM_STATS_TYPE_INSTANT`` 5839 The statistics reports an instantaneous value. Its value can be increased or 5840 decreased. This type is usually used as a measurement of some resources, 5841 like the number of dirty pages, the number of large pages, etc. 5842 All instant statistics are read only. 5843 The corresponding ``size`` field for this type is always 1. 5844 * ``KVM_STATS_TYPE_PEAK`` 5845 The statistics data reports a peak value, for example the maximum number 5846 of items in a hash table bucket, the longest time waited and so on. 5847 The value of data can only be increased. 5848 The corresponding ``size`` field for this type is always 1. 5849 * ``KVM_STATS_TYPE_LINEAR_HIST`` 5850 The statistic is reported as a linear histogram. The number of 5851 buckets is specified by the ``size`` field. The size of buckets is specified 5852 by the ``hist_param`` field. The range of the Nth bucket (1 <= N < ``size``) 5853 is [``hist_param``*(N-1), ``hist_param``*N), while the range of the last 5854 bucket is [``hist_param``*(``size``-1), +INF). (+INF means positive infinity 5855 value.) 5856 * ``KVM_STATS_TYPE_LOG_HIST`` 5857 The statistic is reported as a logarithmic histogram. The number of 5858 buckets is specified by the ``size`` field. The range of the first bucket is 5859 [0, 1), while the range of the last bucket is [pow(2, ``size``-2), +INF). 5860 Otherwise, The Nth bucket (1 < N < ``size``) covers 5861 [pow(2, N-2), pow(2, N-1)). 5862 5863Bits 4-7 of ``flags`` encode the unit: 5864 5865 * ``KVM_STATS_UNIT_NONE`` 5866 There is no unit for the value of statistics data. This usually means that 5867 the value is a simple counter of an event. 5868 * ``KVM_STATS_UNIT_BYTES`` 5869 It indicates that the statistics data is used to measure memory size, in the 5870 unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is 5871 determined by the ``exponent`` field in the descriptor. 5872 * ``KVM_STATS_UNIT_SECONDS`` 5873 It indicates that the statistics data is used to measure time or latency. 5874 * ``KVM_STATS_UNIT_CYCLES`` 5875 It indicates that the statistics data is used to measure CPU clock cycles. 5876 * ``KVM_STATS_UNIT_BOOLEAN`` 5877 It indicates that the statistic will always be either 0 or 1. Boolean 5878 statistics of "peak" type will never go back from 1 to 0. Boolean 5879 statistics can be linear histograms (with two buckets) but not logarithmic 5880 histograms. 5881 5882Note that, in the case of histograms, the unit applies to the bucket 5883ranges, while the bucket value indicates how many samples fell in the 5884bucket's range. 5885 5886Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the 5887unit: 5888 5889 * ``KVM_STATS_BASE_POW10`` 5890 The scale is based on power of 10. It is used for measurement of time and 5891 CPU clock cycles. For example, an exponent of -9 can be used with 5892 ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds. 5893 * ``KVM_STATS_BASE_POW2`` 5894 The scale is based on power of 2. It is used for measurement of memory size. 5895 For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to 5896 express that the unit is MiB. 5897 5898The ``size`` field is the number of values of this statistics data. Its 5899value is usually 1 for most of simple statistics. 1 means it contains an 5900unsigned 64bit data. 5901 5902The ``offset`` field is the offset from the start of Data Block to the start of 5903the corresponding statistics data. 5904 5905The ``bucket_size`` field is used as a parameter for histogram statistics data. 5906It is only used by linear histogram statistics data, specifying the size of a 5907bucket in the unit expressed by bits 4-11 of ``flags`` together with ``exponent``. 5908 5909The ``name`` field is the name string of the statistics data. The name string 5910starts at the end of ``struct kvm_stats_desc``. The maximum length including 5911the trailing ``'\0'``, is indicated by ``name_size`` in the header. 5912 5913The Stats Data block contains an array of 64-bit values in the same order 5914as the descriptors in Descriptors block. 5915 59164.134 KVM_GET_XSAVE2 5917-------------------- 5918 5919:Capability: KVM_CAP_XSAVE2 5920:Architectures: x86 5921:Type: vcpu ioctl 5922:Parameters: struct kvm_xsave (out) 5923:Returns: 0 on success, -1 on error 5924 5925 5926:: 5927 5928 struct kvm_xsave { 5929 __u32 region[1024]; 5930 __u32 extra[0]; 5931 }; 5932 5933This ioctl would copy current vcpu's xsave struct to the userspace. It 5934copies as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) 5935when invoked on the vm file descriptor. The size value returned by 5936KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 5937Currently, it is only greater than 4096 if a dynamic feature has been 5938enabled with ``arch_prctl()``, but this may change in the future. 5939 5940The offsets of the state save areas in struct kvm_xsave follow the contents 5941of CPUID leaf 0xD on the host. 5942 59434.135 KVM_XEN_HVM_EVTCHN_SEND 5944----------------------------- 5945 5946:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND 5947:Architectures: x86 5948:Type: vm ioctl 5949:Parameters: struct kvm_irq_routing_xen_evtchn 5950:Returns: 0 on success, < 0 on error 5951 5952 5953:: 5954 5955 struct kvm_irq_routing_xen_evtchn { 5956 __u32 port; 5957 __u32 vcpu; 5958 __u32 priority; 5959 }; 5960 5961This ioctl injects an event channel interrupt directly to the guest vCPU. 5962 59634.136 KVM_S390_PV_CPU_COMMAND 5964----------------------------- 5965 5966:Capability: KVM_CAP_S390_PROTECTED_DUMP 5967:Architectures: s390 5968:Type: vcpu ioctl 5969:Parameters: none 5970:Returns: 0 on success, < 0 on error 5971 5972This ioctl closely mirrors `KVM_S390_PV_COMMAND` but handles requests 5973for vcpus. It re-uses the kvm_s390_pv_dmp struct and hence also shares 5974the command ids. 5975 5976**command:** 5977 5978KVM_PV_DUMP 5979 Presents an API that provides calls which facilitate dumping a vcpu 5980 of a protected VM. 5981 5982**subcommand:** 5983 5984KVM_PV_DUMP_CPU 5985 Provides encrypted dump data like register values. 5986 The length of the returned data is provided by uv_info.guest_cpu_stor_len. 5987 59884.137 KVM_S390_ZPCI_OP 5989---------------------- 5990 5991:Capability: KVM_CAP_S390_ZPCI_OP 5992:Architectures: s390 5993:Type: vm ioctl 5994:Parameters: struct kvm_s390_zpci_op (in) 5995:Returns: 0 on success, <0 on error 5996 5997Used to manage hardware-assisted virtualization features for zPCI devices. 5998 5999Parameters are specified via the following structure:: 6000 6001 struct kvm_s390_zpci_op { 6002 /* in */ 6003 __u32 fh; /* target device */ 6004 __u8 op; /* operation to perform */ 6005 __u8 pad[3]; 6006 union { 6007 /* for KVM_S390_ZPCIOP_REG_AEN */ 6008 struct { 6009 __u64 ibv; /* Guest addr of interrupt bit vector */ 6010 __u64 sb; /* Guest addr of summary bit */ 6011 __u32 flags; 6012 __u32 noi; /* Number of interrupts */ 6013 __u8 isc; /* Guest interrupt subclass */ 6014 __u8 sbo; /* Offset of guest summary bit vector */ 6015 __u16 pad; 6016 } reg_aen; 6017 __u64 reserved[8]; 6018 } u; 6019 }; 6020 6021The type of operation is specified in the "op" field. 6022KVM_S390_ZPCIOP_REG_AEN is used to register the VM for adapter event 6023notification interpretation, which will allow firmware delivery of adapter 6024events directly to the vm, with KVM providing a backup delivery mechanism; 6025KVM_S390_ZPCIOP_DEREG_AEN is used to subsequently disable interpretation of 6026adapter event notifications. 6027 6028The target zPCI function must also be specified via the "fh" field. For the 6029KVM_S390_ZPCIOP_REG_AEN operation, additional information to establish firmware 6030delivery must be provided via the "reg_aen" struct. 6031 6032The "pad" and "reserved" fields may be used for future extensions and should be 6033set to 0s by userspace. 6034 60354.138 KVM_ARM_SET_COUNTER_OFFSET 6036-------------------------------- 6037 6038:Capability: KVM_CAP_COUNTER_OFFSET 6039:Architectures: arm64 6040:Type: vm ioctl 6041:Parameters: struct kvm_arm_counter_offset (in) 6042:Returns: 0 on success, < 0 on error 6043 6044This capability indicates that userspace is able to apply a single VM-wide 6045offset to both the virtual and physical counters as viewed by the guest 6046using the KVM_ARM_SET_CNT_OFFSET ioctl and the following data structure: 6047 6048:: 6049 6050 struct kvm_arm_counter_offset { 6051 __u64 counter_offset; 6052 __u64 reserved; 6053 }; 6054 6055The offset describes a number of counter cycles that are subtracted from 6056both virtual and physical counter views (similar to the effects of the 6057CNTVOFF_EL2 and CNTPOFF_EL2 system registers, but only global). The offset 6058always applies to all vcpus (already created or created after this ioctl) 6059for this VM. 6060 6061It is userspace's responsibility to compute the offset based, for example, 6062on previous values of the guest counters. 6063 6064Any value other than 0 for the "reserved" field may result in an error 6065(-EINVAL) being returned. This ioctl can also return -EBUSY if any vcpu 6066ioctl is issued concurrently. 6067 6068Note that using this ioctl results in KVM ignoring subsequent userspace 6069writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG 6070interface. No error will be returned, but the resulting offset will not be 6071applied. 6072 60735. The kvm_run structure 6074======================== 6075 6076Application code obtains a pointer to the kvm_run structure by 6077mmap()ing a vcpu fd. From that point, application code can control 6078execution by changing fields in kvm_run prior to calling the KVM_RUN 6079ioctl, and obtain information about the reason KVM_RUN returned by 6080looking up structure members. 6081 6082:: 6083 6084 struct kvm_run { 6085 /* in */ 6086 __u8 request_interrupt_window; 6087 6088Request that KVM_RUN return when it becomes possible to inject external 6089interrupts into the guest. Useful in conjunction with KVM_INTERRUPT. 6090 6091:: 6092 6093 __u8 immediate_exit; 6094 6095This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN 6096exits immediately, returning -EINTR. In the common scenario where a 6097signal is used to "kick" a VCPU out of KVM_RUN, this field can be used 6098to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability. 6099Rather than blocking the signal outside KVM_RUN, userspace can set up 6100a signal handler that sets run->immediate_exit to a non-zero value. 6101 6102This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available. 6103 6104:: 6105 6106 __u8 padding1[6]; 6107 6108 /* out */ 6109 __u32 exit_reason; 6110 6111When KVM_RUN has returned successfully (return value 0), this informs 6112application code why KVM_RUN has returned. Allowable values for this 6113field are detailed below. 6114 6115:: 6116 6117 __u8 ready_for_interrupt_injection; 6118 6119If request_interrupt_window has been specified, this field indicates 6120an interrupt can be injected now with KVM_INTERRUPT. 6121 6122:: 6123 6124 __u8 if_flag; 6125 6126The value of the current interrupt flag. Only valid if in-kernel 6127local APIC is not used. 6128 6129:: 6130 6131 __u16 flags; 6132 6133More architecture-specific flags detailing state of the VCPU that may 6134affect the device's behavior. Current defined flags:: 6135 6136 /* x86, set if the VCPU is in system management mode */ 6137 #define KVM_RUN_X86_SMM (1 << 0) 6138 /* x86, set if bus lock detected in VM */ 6139 #define KVM_RUN_BUS_LOCK (1 << 1) 6140 /* arm64, set for KVM_EXIT_DEBUG */ 6141 #define KVM_DEBUG_ARCH_HSR_HIGH_VALID (1 << 0) 6142 6143:: 6144 6145 /* in (pre_kvm_run), out (post_kvm_run) */ 6146 __u64 cr8; 6147 6148The value of the cr8 register. Only valid if in-kernel local APIC is 6149not used. Both input and output. 6150 6151:: 6152 6153 __u64 apic_base; 6154 6155The value of the APIC BASE msr. Only valid if in-kernel local 6156APIC is not used. Both input and output. 6157 6158:: 6159 6160 union { 6161 /* KVM_EXIT_UNKNOWN */ 6162 struct { 6163 __u64 hardware_exit_reason; 6164 } hw; 6165 6166If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown 6167reasons. Further architecture-specific information is available in 6168hardware_exit_reason. 6169 6170:: 6171 6172 /* KVM_EXIT_FAIL_ENTRY */ 6173 struct { 6174 __u64 hardware_entry_failure_reason; 6175 __u32 cpu; /* if KVM_LAST_CPU */ 6176 } fail_entry; 6177 6178If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due 6179to unknown reasons. Further architecture-specific information is 6180available in hardware_entry_failure_reason. 6181 6182:: 6183 6184 /* KVM_EXIT_EXCEPTION */ 6185 struct { 6186 __u32 exception; 6187 __u32 error_code; 6188 } ex; 6189 6190Unused. 6191 6192:: 6193 6194 /* KVM_EXIT_IO */ 6195 struct { 6196 #define KVM_EXIT_IO_IN 0 6197 #define KVM_EXIT_IO_OUT 1 6198 __u8 direction; 6199 __u8 size; /* bytes */ 6200 __u16 port; 6201 __u32 count; 6202 __u64 data_offset; /* relative to kvm_run start */ 6203 } io; 6204 6205If exit_reason is KVM_EXIT_IO, then the vcpu has 6206executed a port I/O instruction which could not be satisfied by kvm. 6207data_offset describes where the data is located (KVM_EXIT_IO_OUT) or 6208where kvm expects application code to place the data for the next 6209KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. 6210 6211:: 6212 6213 /* KVM_EXIT_DEBUG */ 6214 struct { 6215 struct kvm_debug_exit_arch arch; 6216 } debug; 6217 6218If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event 6219for which architecture specific information is returned. 6220 6221:: 6222 6223 /* KVM_EXIT_MMIO */ 6224 struct { 6225 __u64 phys_addr; 6226 __u8 data[8]; 6227 __u32 len; 6228 __u8 is_write; 6229 } mmio; 6230 6231If exit_reason is KVM_EXIT_MMIO, then the vcpu has 6232executed a memory-mapped I/O instruction which could not be satisfied 6233by kvm. The 'data' member contains the written data if 'is_write' is 6234true, and should be filled by application code otherwise. 6235 6236The 'data' member contains, in its first 'len' bytes, the value as it would 6237appear if the VCPU performed a load or store of the appropriate width directly 6238to the byte array. 6239 6240.. note:: 6241 6242 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN, 6243 KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding 6244 operations are complete (and guest state is consistent) only after userspace 6245 has re-entered the kernel with KVM_RUN. The kernel side will first finish 6246 incomplete operations and then check for pending signals. 6247 6248 The pending state of the operation is not preserved in state which is 6249 visible to userspace, thus userspace should ensure that the operation is 6250 completed before performing a live migration. Userspace can re-enter the 6251 guest with an unmasked signal pending or with the immediate_exit field set 6252 to complete pending operations without allowing any further instructions 6253 to be executed. 6254 6255:: 6256 6257 /* KVM_EXIT_HYPERCALL */ 6258 struct { 6259 __u64 nr; 6260 __u64 args[6]; 6261 __u64 ret; 6262 __u64 flags; 6263 } hypercall; 6264 6265 6266It is strongly recommended that userspace use ``KVM_EXIT_IO`` (x86) or 6267``KVM_EXIT_MMIO`` (all except s390) to implement functionality that 6268requires a guest to interact with host userspace. 6269 6270.. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO. 6271 6272For arm64: 6273---------- 6274 6275SMCCC exits can be enabled depending on the configuration of the SMCCC 6276filter. See the Documentation/virt/kvm/devices/vm.rst 6277``KVM_ARM_SMCCC_FILTER`` for more details. 6278 6279``nr`` contains the function ID of the guest's SMCCC call. Userspace is 6280expected to use the ``KVM_GET_ONE_REG`` ioctl to retrieve the call 6281parameters from the vCPU's GPRs. 6282 6283Definition of ``flags``: 6284 - ``KVM_HYPERCALL_EXIT_SMC``: Indicates that the guest used the SMC 6285 conduit to initiate the SMCCC call. If this bit is 0 then the guest 6286 used the HVC conduit for the SMCCC call. 6287 6288 - ``KVM_HYPERCALL_EXIT_16BIT``: Indicates that the guest used a 16bit 6289 instruction to initiate the SMCCC call. If this bit is 0 then the 6290 guest used a 32bit instruction. An AArch64 guest always has this 6291 bit set to 0. 6292 6293At the point of exit, PC points to the instruction immediately following 6294the trapping instruction. 6295 6296:: 6297 6298 /* KVM_EXIT_TPR_ACCESS */ 6299 struct { 6300 __u64 rip; 6301 __u32 is_write; 6302 __u32 pad; 6303 } tpr_access; 6304 6305To be documented (KVM_TPR_ACCESS_REPORTING). 6306 6307:: 6308 6309 /* KVM_EXIT_S390_SIEIC */ 6310 struct { 6311 __u8 icptcode; 6312 __u64 mask; /* psw upper half */ 6313 __u64 addr; /* psw lower half */ 6314 __u16 ipa; 6315 __u32 ipb; 6316 } s390_sieic; 6317 6318s390 specific. 6319 6320:: 6321 6322 /* KVM_EXIT_S390_RESET */ 6323 #define KVM_S390_RESET_POR 1 6324 #define KVM_S390_RESET_CLEAR 2 6325 #define KVM_S390_RESET_SUBSYSTEM 4 6326 #define KVM_S390_RESET_CPU_INIT 8 6327 #define KVM_S390_RESET_IPL 16 6328 __u64 s390_reset_flags; 6329 6330s390 specific. 6331 6332:: 6333 6334 /* KVM_EXIT_S390_UCONTROL */ 6335 struct { 6336 __u64 trans_exc_code; 6337 __u32 pgm_code; 6338 } s390_ucontrol; 6339 6340s390 specific. A page fault has occurred for a user controlled virtual 6341machine (KVM_VM_S390_UNCONTROL) on its host page table that cannot be 6342resolved by the kernel. 6343The program code and the translation exception code that were placed 6344in the cpu's lowcore are presented here as defined by the z Architecture 6345Principles of Operation Book in the Chapter for Dynamic Address Translation 6346(DAT) 6347 6348:: 6349 6350 /* KVM_EXIT_DCR */ 6351 struct { 6352 __u32 dcrn; 6353 __u32 data; 6354 __u8 is_write; 6355 } dcr; 6356 6357Deprecated - was used for 440 KVM. 6358 6359:: 6360 6361 /* KVM_EXIT_OSI */ 6362 struct { 6363 __u64 gprs[32]; 6364 } osi; 6365 6366MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch 6367hypercalls and exit with this exit struct that contains all the guest gprs. 6368 6369If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall. 6370Userspace can now handle the hypercall and when it's done modify the gprs as 6371necessary. Upon guest entry all guest GPRs will then be replaced by the values 6372in this struct. 6373 6374:: 6375 6376 /* KVM_EXIT_PAPR_HCALL */ 6377 struct { 6378 __u64 nr; 6379 __u64 ret; 6380 __u64 args[9]; 6381 } papr_hcall; 6382 6383This is used on 64-bit PowerPC when emulating a pSeries partition, 6384e.g. with the 'pseries' machine type in qemu. It occurs when the 6385guest does a hypercall using the 'sc 1' instruction. The 'nr' field 6386contains the hypercall number (from the guest R3), and 'args' contains 6387the arguments (from the guest R4 - R12). Userspace should put the 6388return code in 'ret' and any extra returned values in args[]. 6389The possible hypercalls are defined in the Power Architecture Platform 6390Requirements (PAPR) document available from www.power.org (free 6391developer registration required to access it). 6392 6393:: 6394 6395 /* KVM_EXIT_S390_TSCH */ 6396 struct { 6397 __u16 subchannel_id; 6398 __u16 subchannel_nr; 6399 __u32 io_int_parm; 6400 __u32 io_int_word; 6401 __u32 ipb; 6402 __u8 dequeued; 6403 } s390_tsch; 6404 6405s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled 6406and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O 6407interrupt for the target subchannel has been dequeued and subchannel_id, 6408subchannel_nr, io_int_parm and io_int_word contain the parameters for that 6409interrupt. ipb is needed for instruction parameter decoding. 6410 6411:: 6412 6413 /* KVM_EXIT_EPR */ 6414 struct { 6415 __u32 epr; 6416 } epr; 6417 6418On FSL BookE PowerPC chips, the interrupt controller has a fast patch 6419interrupt acknowledge path to the core. When the core successfully 6420delivers an interrupt, it automatically populates the EPR register with 6421the interrupt vector number and acknowledges the interrupt inside 6422the interrupt controller. 6423 6424In case the interrupt controller lives in user space, we need to do 6425the interrupt acknowledge cycle through it to fetch the next to be 6426delivered interrupt vector using this exit. 6427 6428It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an 6429external interrupt has just been delivered into the guest. User space 6430should put the acknowledged interrupt vector into the 'epr' field. 6431 6432:: 6433 6434 /* KVM_EXIT_SYSTEM_EVENT */ 6435 struct { 6436 #define KVM_SYSTEM_EVENT_SHUTDOWN 1 6437 #define KVM_SYSTEM_EVENT_RESET 2 6438 #define KVM_SYSTEM_EVENT_CRASH 3 6439 #define KVM_SYSTEM_EVENT_WAKEUP 4 6440 #define KVM_SYSTEM_EVENT_SUSPEND 5 6441 #define KVM_SYSTEM_EVENT_SEV_TERM 6 6442 __u32 type; 6443 __u32 ndata; 6444 __u64 data[16]; 6445 } system_event; 6446 6447If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered 6448a system-level event using some architecture specific mechanism (hypercall 6449or some special instruction). In case of ARM64, this is triggered using 6450HVC instruction based PSCI call from the vcpu. 6451 6452The 'type' field describes the system-level event type. 6453Valid values for 'type' are: 6454 6455 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the 6456 VM. Userspace is not obliged to honour this, and if it does honour 6457 this does not need to destroy the VM synchronously (ie it may call 6458 KVM_RUN again before shutdown finally occurs). 6459 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. 6460 As with SHUTDOWN, userspace can choose to ignore the request, or 6461 to schedule the reset to occur in the future and may call KVM_RUN again. 6462 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest 6463 has requested a crash condition maintenance. Userspace can choose 6464 to ignore the request, or to gather VM memory core dump and/or 6465 reset/shutdown of the VM. 6466 - KVM_SYSTEM_EVENT_SEV_TERM -- an AMD SEV guest requested termination. 6467 The guest physical address of the guest's GHCB is stored in `data[0]`. 6468 - KVM_SYSTEM_EVENT_WAKEUP -- the exiting vCPU is in a suspended state and 6469 KVM has recognized a wakeup event. Userspace may honor this event by 6470 marking the exiting vCPU as runnable, or deny it and call KVM_RUN again. 6471 - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of 6472 the VM. 6473 6474If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain 6475architecture specific information for the system-level event. Only 6476the first `ndata` items (possibly zero) of the data array are valid. 6477 6478 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if 6479 the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI 6480 specification. 6481 6482 - for RISC-V, data[0] is set to the value of the second argument of the 6483 ``sbi_system_reset`` call. 6484 6485Previous versions of Linux defined a `flags` member in this struct. The 6486field is now aliased to `data[0]`. Userspace can assume that it is only 6487written if ndata is greater than 0. 6488 6489For arm/arm64: 6490-------------- 6491 6492KVM_SYSTEM_EVENT_SUSPEND exits are enabled with the 6493KVM_CAP_ARM_SYSTEM_SUSPEND VM capability. If a guest invokes the PSCI 6494SYSTEM_SUSPEND function, KVM will exit to userspace with this event 6495type. 6496 6497It is the sole responsibility of userspace to implement the PSCI 6498SYSTEM_SUSPEND call according to ARM DEN0022D.b 5.19 "SYSTEM_SUSPEND". 6499KVM does not change the vCPU's state before exiting to userspace, so 6500the call parameters are left in-place in the vCPU registers. 6501 6502Userspace is _required_ to take action for such an exit. It must 6503either: 6504 6505 - Honor the guest request to suspend the VM. Userspace can request 6506 in-kernel emulation of suspension by setting the calling vCPU's 6507 state to KVM_MP_STATE_SUSPENDED. Userspace must configure the vCPU's 6508 state according to the parameters passed to the PSCI function when 6509 the calling vCPU is resumed. See ARM DEN0022D.b 5.19.1 "Intended use" 6510 for details on the function parameters. 6511 6512 - Deny the guest request to suspend the VM. See ARM DEN0022D.b 5.19.2 6513 "Caller responsibilities" for possible return values. 6514 6515:: 6516 6517 /* KVM_EXIT_IOAPIC_EOI */ 6518 struct { 6519 __u8 vector; 6520 } eoi; 6521 6522Indicates that the VCPU's in-kernel local APIC received an EOI for a 6523level-triggered IOAPIC interrupt. This exit only triggers when the 6524IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled); 6525the userspace IOAPIC should process the EOI and retrigger the interrupt if 6526it is still asserted. Vector is the LAPIC interrupt vector for which the 6527EOI was received. 6528 6529:: 6530 6531 struct kvm_hyperv_exit { 6532 #define KVM_EXIT_HYPERV_SYNIC 1 6533 #define KVM_EXIT_HYPERV_HCALL 2 6534 #define KVM_EXIT_HYPERV_SYNDBG 3 6535 __u32 type; 6536 __u32 pad1; 6537 union { 6538 struct { 6539 __u32 msr; 6540 __u32 pad2; 6541 __u64 control; 6542 __u64 evt_page; 6543 __u64 msg_page; 6544 } synic; 6545 struct { 6546 __u64 input; 6547 __u64 result; 6548 __u64 params[2]; 6549 } hcall; 6550 struct { 6551 __u32 msr; 6552 __u32 pad2; 6553 __u64 control; 6554 __u64 status; 6555 __u64 send_page; 6556 __u64 recv_page; 6557 __u64 pending_page; 6558 } syndbg; 6559 } u; 6560 }; 6561 /* KVM_EXIT_HYPERV */ 6562 struct kvm_hyperv_exit hyperv; 6563 6564Indicates that the VCPU exits into userspace to process some tasks 6565related to Hyper-V emulation. 6566 6567Valid values for 'type' are: 6568 6569 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about 6570 6571Hyper-V SynIC state change. Notification is used to remap SynIC 6572event/message pages and to enable/disable SynIC messages/events processing 6573in userspace. 6574 6575 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about 6576 6577Hyper-V Synthetic debugger state change. Notification is used to either update 6578the pending_page location or to send a control command (send the buffer located 6579in send_page or recv a buffer to recv_page). 6580 6581:: 6582 6583 /* KVM_EXIT_ARM_NISV */ 6584 struct { 6585 __u64 esr_iss; 6586 __u64 fault_ipa; 6587 } arm_nisv; 6588 6589Used on arm64 systems. If a guest accesses memory not in a memslot, 6590KVM will typically return to userspace and ask it to do MMIO emulation on its 6591behalf. However, for certain classes of instructions, no instruction decode 6592(direction, length of memory access) is provided, and fetching and decoding 6593the instruction from the VM is overly complicated to live in the kernel. 6594 6595Historically, when this situation occurred, KVM would print a warning and kill 6596the VM. KVM assumed that if the guest accessed non-memslot memory, it was 6597trying to do I/O, which just couldn't be emulated, and the warning message was 6598phrased accordingly. However, what happened more often was that a guest bug 6599caused access outside the guest memory areas which should lead to a more 6600meaningful warning message and an external abort in the guest, if the access 6601did not fall within an I/O window. 6602 6603Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable 6604this capability at VM creation. Once this is done, these types of errors will 6605instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from 6606the ESR_EL2 in the esr_iss field, and the faulting IPA in the fault_ipa field. 6607Userspace can either fix up the access if it's actually an I/O access by 6608decoding the instruction from guest memory (if it's very brave) and continue 6609executing the guest, or it can decide to suspend, dump, or restart the guest. 6610 6611Note that KVM does not skip the faulting instruction as it does for 6612KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state 6613if it decides to decode and emulate the instruction. 6614 6615:: 6616 6617 /* KVM_EXIT_X86_RDMSR / KVM_EXIT_X86_WRMSR */ 6618 struct { 6619 __u8 error; /* user -> kernel */ 6620 __u8 pad[7]; 6621 __u32 reason; /* kernel -> user */ 6622 __u32 index; /* kernel -> user */ 6623 __u64 data; /* kernel <-> user */ 6624 } msr; 6625 6626Used on x86 systems. When the VM capability KVM_CAP_X86_USER_SPACE_MSR is 6627enabled, MSR accesses to registers that would invoke a #GP by KVM kernel code 6628may instead trigger a KVM_EXIT_X86_RDMSR exit for reads and KVM_EXIT_X86_WRMSR 6629exit for writes. 6630 6631The "reason" field specifies why the MSR interception occurred. Userspace will 6632only receive MSR exits when a particular reason was requested during through 6633ENABLE_CAP. Currently valid exit reasons are: 6634 6635============================ ======================================== 6636 KVM_MSR_EXIT_REASON_UNKNOWN access to MSR that is unknown to KVM 6637 KVM_MSR_EXIT_REASON_INVAL access to invalid MSRs or reserved bits 6638 KVM_MSR_EXIT_REASON_FILTER access blocked by KVM_X86_SET_MSR_FILTER 6639============================ ======================================== 6640 6641For KVM_EXIT_X86_RDMSR, the "index" field tells userspace which MSR the guest 6642wants to read. To respond to this request with a successful read, userspace 6643writes the respective data into the "data" field and must continue guest 6644execution to ensure the read data is transferred into guest register state. 6645 6646If the RDMSR request was unsuccessful, userspace indicates that with a "1" in 6647the "error" field. This will inject a #GP into the guest when the VCPU is 6648executed again. 6649 6650For KVM_EXIT_X86_WRMSR, the "index" field tells userspace which MSR the guest 6651wants to write. Once finished processing the event, userspace must continue 6652vCPU execution. If the MSR write was unsuccessful, userspace also sets the 6653"error" field to "1". 6654 6655See KVM_X86_SET_MSR_FILTER for details on the interaction with MSR filtering. 6656 6657:: 6658 6659 6660 struct kvm_xen_exit { 6661 #define KVM_EXIT_XEN_HCALL 1 6662 __u32 type; 6663 union { 6664 struct { 6665 __u32 longmode; 6666 __u32 cpl; 6667 __u64 input; 6668 __u64 result; 6669 __u64 params[6]; 6670 } hcall; 6671 } u; 6672 }; 6673 /* KVM_EXIT_XEN */ 6674 struct kvm_hyperv_exit xen; 6675 6676Indicates that the VCPU exits into userspace to process some tasks 6677related to Xen emulation. 6678 6679Valid values for 'type' are: 6680 6681 - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall. 6682 Userspace is expected to place the hypercall result into the appropriate 6683 field before invoking KVM_RUN again. 6684 6685:: 6686 6687 /* KVM_EXIT_RISCV_SBI */ 6688 struct { 6689 unsigned long extension_id; 6690 unsigned long function_id; 6691 unsigned long args[6]; 6692 unsigned long ret[2]; 6693 } riscv_sbi; 6694 6695If exit reason is KVM_EXIT_RISCV_SBI then it indicates that the VCPU has 6696done a SBI call which is not handled by KVM RISC-V kernel module. The details 6697of the SBI call are available in 'riscv_sbi' member of kvm_run structure. The 6698'extension_id' field of 'riscv_sbi' represents SBI extension ID whereas the 6699'function_id' field represents function ID of given SBI extension. The 'args' 6700array field of 'riscv_sbi' represents parameters for the SBI call and 'ret' 6701array field represents return values. The userspace should update the return 6702values of SBI call before resuming the VCPU. For more details on RISC-V SBI 6703spec refer, https://github.com/riscv/riscv-sbi-doc. 6704 6705:: 6706 6707 /* KVM_EXIT_NOTIFY */ 6708 struct { 6709 #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) 6710 __u32 flags; 6711 } notify; 6712 6713Used on x86 systems. When the VM capability KVM_CAP_X86_NOTIFY_VMEXIT is 6714enabled, a VM exit generated if no event window occurs in VM non-root mode 6715for a specified amount of time. Once KVM_X86_NOTIFY_VMEXIT_USER is set when 6716enabling the cap, it would exit to userspace with the exit reason 6717KVM_EXIT_NOTIFY for further handling. The "flags" field contains more 6718detailed info. 6719 6720The valid value for 'flags' is: 6721 6722 - KVM_NOTIFY_CONTEXT_INVALID -- the VM context is corrupted and not valid 6723 in VMCS. It would run into unknown result if resume the target VM. 6724 6725:: 6726 6727 /* Fix the size of the union. */ 6728 char padding[256]; 6729 }; 6730 6731 /* 6732 * shared registers between kvm and userspace. 6733 * kvm_valid_regs specifies the register classes set by the host 6734 * kvm_dirty_regs specified the register classes dirtied by userspace 6735 * struct kvm_sync_regs is architecture specific, as well as the 6736 * bits for kvm_valid_regs and kvm_dirty_regs 6737 */ 6738 __u64 kvm_valid_regs; 6739 __u64 kvm_dirty_regs; 6740 union { 6741 struct kvm_sync_regs regs; 6742 char padding[SYNC_REGS_SIZE_BYTES]; 6743 } s; 6744 6745If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access 6746certain guest registers without having to call SET/GET_*REGS. Thus we can 6747avoid some system call overhead if userspace has to handle the exit. 6748Userspace can query the validity of the structure by checking 6749kvm_valid_regs for specific bits. These bits are architecture specific 6750and usually define the validity of a groups of registers. (e.g. one bit 6751for general purpose registers) 6752 6753Please note that the kernel is allowed to use the kvm_run structure as the 6754primary storage for certain register types. Therefore, the kernel may use the 6755values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set. 6756 6757 67586. Capabilities that can be enabled on vCPUs 6759============================================ 6760 6761There are certain capabilities that change the behavior of the virtual CPU or 6762the virtual machine when enabled. To enable them, please see section 4.37. 6763Below you can find a list of capabilities and what their effect on the vCPU or 6764the virtual machine is when enabling them. 6765 6766The following information is provided along with the description: 6767 6768 Architectures: 6769 which instruction set architectures provide this ioctl. 6770 x86 includes both i386 and x86_64. 6771 6772 Target: 6773 whether this is a per-vcpu or per-vm capability. 6774 6775 Parameters: 6776 what parameters are accepted by the capability. 6777 6778 Returns: 6779 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 6780 are not detailed, but errors with specific meanings are. 6781 6782 67836.1 KVM_CAP_PPC_OSI 6784------------------- 6785 6786:Architectures: ppc 6787:Target: vcpu 6788:Parameters: none 6789:Returns: 0 on success; -1 on error 6790 6791This capability enables interception of OSI hypercalls that otherwise would 6792be treated as normal system calls to be injected into the guest. OSI hypercalls 6793were invented by Mac-on-Linux to have a standardized communication mechanism 6794between the guest and the host. 6795 6796When this capability is enabled, KVM_EXIT_OSI can occur. 6797 6798 67996.2 KVM_CAP_PPC_PAPR 6800-------------------- 6801 6802:Architectures: ppc 6803:Target: vcpu 6804:Parameters: none 6805:Returns: 0 on success; -1 on error 6806 6807This capability enables interception of PAPR hypercalls. PAPR hypercalls are 6808done using the hypercall instruction "sc 1". 6809 6810It also sets the guest privilege level to "supervisor" mode. Usually the guest 6811runs in "hypervisor" privilege mode with a few missing features. 6812 6813In addition to the above, it changes the semantics of SDR1. In this mode, the 6814HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the 6815HTAB invisible to the guest. 6816 6817When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. 6818 6819 68206.3 KVM_CAP_SW_TLB 6821------------------ 6822 6823:Architectures: ppc 6824:Target: vcpu 6825:Parameters: args[0] is the address of a struct kvm_config_tlb 6826:Returns: 0 on success; -1 on error 6827 6828:: 6829 6830 struct kvm_config_tlb { 6831 __u64 params; 6832 __u64 array; 6833 __u32 mmu_type; 6834 __u32 array_len; 6835 }; 6836 6837Configures the virtual CPU's TLB array, establishing a shared memory area 6838between userspace and KVM. The "params" and "array" fields are userspace 6839addresses of mmu-type-specific data structures. The "array_len" field is an 6840safety mechanism, and should be set to the size in bytes of the memory that 6841userspace has reserved for the array. It must be at least the size dictated 6842by "mmu_type" and "params". 6843 6844While KVM_RUN is active, the shared region is under control of KVM. Its 6845contents are undefined, and any modification by userspace results in 6846boundedly undefined behavior. 6847 6848On return from KVM_RUN, the shared region will reflect the current state of 6849the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB 6850to tell KVM which entries have been changed, prior to calling KVM_RUN again 6851on this vcpu. 6852 6853For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV: 6854 6855 - The "params" field is of type "struct kvm_book3e_206_tlb_params". 6856 - The "array" field points to an array of type "struct 6857 kvm_book3e_206_tlb_entry". 6858 - The array consists of all entries in the first TLB, followed by all 6859 entries in the second TLB. 6860 - Within a TLB, entries are ordered first by increasing set number. Within a 6861 set, entries are ordered by way (increasing ESEL). 6862 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1) 6863 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value. 6864 - The tsize field of mas1 shall be set to 4K on TLB0, even though the 6865 hardware ignores this value for TLB0. 6866 68676.4 KVM_CAP_S390_CSS_SUPPORT 6868---------------------------- 6869 6870:Architectures: s390 6871:Target: vcpu 6872:Parameters: none 6873:Returns: 0 on success; -1 on error 6874 6875This capability enables support for handling of channel I/O instructions. 6876 6877TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are 6878handled in-kernel, while the other I/O instructions are passed to userspace. 6879 6880When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST 6881SUBCHANNEL intercepts. 6882 6883Note that even though this capability is enabled per-vcpu, the complete 6884virtual machine is affected. 6885 68866.5 KVM_CAP_PPC_EPR 6887------------------- 6888 6889:Architectures: ppc 6890:Target: vcpu 6891:Parameters: args[0] defines whether the proxy facility is active 6892:Returns: 0 on success; -1 on error 6893 6894This capability enables or disables the delivery of interrupts through the 6895external proxy facility. 6896 6897When enabled (args[0] != 0), every time the guest gets an external interrupt 6898delivered, it automatically exits into user space with a KVM_EXIT_EPR exit 6899to receive the topmost interrupt vector. 6900 6901When disabled (args[0] == 0), behavior is as if this facility is unsupported. 6902 6903When this capability is enabled, KVM_EXIT_EPR can occur. 6904 69056.6 KVM_CAP_IRQ_MPIC 6906-------------------- 6907 6908:Architectures: ppc 6909:Parameters: args[0] is the MPIC device fd; 6910 args[1] is the MPIC CPU number for this vcpu 6911 6912This capability connects the vcpu to an in-kernel MPIC device. 6913 69146.7 KVM_CAP_IRQ_XICS 6915-------------------- 6916 6917:Architectures: ppc 6918:Target: vcpu 6919:Parameters: args[0] is the XICS device fd; 6920 args[1] is the XICS CPU number (server ID) for this vcpu 6921 6922This capability connects the vcpu to an in-kernel XICS device. 6923 69246.8 KVM_CAP_S390_IRQCHIP 6925------------------------ 6926 6927:Architectures: s390 6928:Target: vm 6929:Parameters: none 6930 6931This capability enables the in-kernel irqchip for s390. Please refer to 6932"4.24 KVM_CREATE_IRQCHIP" for details. 6933 69346.9 KVM_CAP_MIPS_FPU 6935-------------------- 6936 6937:Architectures: mips 6938:Target: vcpu 6939:Parameters: args[0] is reserved for future use (should be 0). 6940 6941This capability allows the use of the host Floating Point Unit by the guest. It 6942allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is 6943done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be 6944accessed (depending on the current guest FPU register mode), and the Status.FR, 6945Config5.FRE bits are accessible via the KVM API and also from the guest, 6946depending on them being supported by the FPU. 6947 69486.10 KVM_CAP_MIPS_MSA 6949--------------------- 6950 6951:Architectures: mips 6952:Target: vcpu 6953:Parameters: args[0] is reserved for future use (should be 0). 6954 6955This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. 6956It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. 6957Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*`` 6958registers can be accessed, and the Config5.MSAEn bit is accessible via the 6959KVM API and also from the guest. 6960 69616.74 KVM_CAP_SYNC_REGS 6962---------------------- 6963 6964:Architectures: s390, x86 6965:Target: s390: always enabled, x86: vcpu 6966:Parameters: none 6967:Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register 6968 sets are supported 6969 (bitfields defined in arch/x86/include/uapi/asm/kvm.h). 6970 6971As described above in the kvm_sync_regs struct info in section 5 (kvm_run): 6972KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers 6973without having to call SET/GET_*REGS". This reduces overhead by eliminating 6974repeated ioctl calls for setting and/or getting register values. This is 6975particularly important when userspace is making synchronous guest state 6976modifications, e.g. when emulating and/or intercepting instructions in 6977userspace. 6978 6979For s390 specifics, please refer to the source code. 6980 6981For x86: 6982 6983- the register sets to be copied out to kvm_run are selectable 6984 by userspace (rather that all sets being copied out for every exit). 6985- vcpu_events are available in addition to regs and sregs. 6986 6987For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to 6988function as an input bit-array field set by userspace to indicate the 6989specific register sets to be copied out on the next exit. 6990 6991To indicate when userspace has modified values that should be copied into 6992the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set. 6993This is done using the same bitflags as for the 'kvm_valid_regs' field. 6994If the dirty bit is not set, then the register set values will not be copied 6995into the vCPU even if they've been modified. 6996 6997Unused bitfields in the bitarrays must be set to zero. 6998 6999:: 7000 7001 struct kvm_sync_regs { 7002 struct kvm_regs regs; 7003 struct kvm_sregs sregs; 7004 struct kvm_vcpu_events events; 7005 }; 7006 70076.75 KVM_CAP_PPC_IRQ_XIVE 7008------------------------- 7009 7010:Architectures: ppc 7011:Target: vcpu 7012:Parameters: args[0] is the XIVE device fd; 7013 args[1] is the XIVE CPU number (server ID) for this vcpu 7014 7015This capability connects the vcpu to an in-kernel XIVE device. 7016 70177. Capabilities that can be enabled on VMs 7018========================================== 7019 7020There are certain capabilities that change the behavior of the virtual 7021machine when enabled. To enable them, please see section 4.37. Below 7022you can find a list of capabilities and what their effect on the VM 7023is when enabling them. 7024 7025The following information is provided along with the description: 7026 7027 Architectures: 7028 which instruction set architectures provide this ioctl. 7029 x86 includes both i386 and x86_64. 7030 7031 Parameters: 7032 what parameters are accepted by the capability. 7033 7034 Returns: 7035 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 7036 are not detailed, but errors with specific meanings are. 7037 7038 70397.1 KVM_CAP_PPC_ENABLE_HCALL 7040---------------------------- 7041 7042:Architectures: ppc 7043:Parameters: args[0] is the sPAPR hcall number; 7044 args[1] is 0 to disable, 1 to enable in-kernel handling 7045 7046This capability controls whether individual sPAPR hypercalls (hcalls) 7047get handled by the kernel or not. Enabling or disabling in-kernel 7048handling of an hcall is effective across the VM. On creation, an 7049initial set of hcalls are enabled for in-kernel handling, which 7050consists of those hcalls for which in-kernel handlers were implemented 7051before this capability was implemented. If disabled, the kernel will 7052not to attempt to handle the hcall, but will always exit to userspace 7053to handle it. Note that it may not make sense to enable some and 7054disable others of a group of related hcalls, but KVM does not prevent 7055userspace from doing that. 7056 7057If the hcall number specified is not one that has an in-kernel 7058implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL 7059error. 7060 70617.2 KVM_CAP_S390_USER_SIGP 7062-------------------------- 7063 7064:Architectures: s390 7065:Parameters: none 7066 7067This capability controls which SIGP orders will be handled completely in user 7068space. With this capability enabled, all fast orders will be handled completely 7069in the kernel: 7070 7071- SENSE 7072- SENSE RUNNING 7073- EXTERNAL CALL 7074- EMERGENCY SIGNAL 7075- CONDITIONAL EMERGENCY SIGNAL 7076 7077All other orders will be handled completely in user space. 7078 7079Only privileged operation exceptions will be checked for in the kernel (or even 7080in the hardware prior to interception). If this capability is not enabled, the 7081old way of handling SIGP orders is used (partially in kernel and user space). 7082 70837.3 KVM_CAP_S390_VECTOR_REGISTERS 7084--------------------------------- 7085 7086:Architectures: s390 7087:Parameters: none 7088:Returns: 0 on success, negative value on error 7089 7090Allows use of the vector registers introduced with z13 processor, and 7091provides for the synchronization between host and user space. Will 7092return -EINVAL if the machine does not support vectors. 7093 70947.4 KVM_CAP_S390_USER_STSI 7095-------------------------- 7096 7097:Architectures: s390 7098:Parameters: none 7099 7100This capability allows post-handlers for the STSI instruction. After 7101initial handling in the kernel, KVM exits to user space with 7102KVM_EXIT_S390_STSI to allow user space to insert further data. 7103 7104Before exiting to userspace, kvm handlers should fill in s390_stsi field of 7105vcpu->run:: 7106 7107 struct { 7108 __u64 addr; 7109 __u8 ar; 7110 __u8 reserved; 7111 __u8 fc; 7112 __u8 sel1; 7113 __u16 sel2; 7114 } s390_stsi; 7115 7116 @addr - guest address of STSI SYSIB 7117 @fc - function code 7118 @sel1 - selector 1 7119 @sel2 - selector 2 7120 @ar - access register number 7121 7122KVM handlers should exit to userspace with rc = -EREMOTE. 7123 71247.5 KVM_CAP_SPLIT_IRQCHIP 7125------------------------- 7126 7127:Architectures: x86 7128:Parameters: args[0] - number of routes reserved for userspace IOAPICs 7129:Returns: 0 on success, -1 on error 7130 7131Create a local apic for each processor in the kernel. This can be used 7132instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the 7133IOAPIC and PIC (and also the PIT, even though this has to be enabled 7134separately). 7135 7136This capability also enables in kernel routing of interrupt requests; 7137when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are 7138used in the IRQ routing table. The first args[0] MSI routes are reserved 7139for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes, 7140a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace. 7141 7142Fails if VCPU has already been created, or if the irqchip is already in the 7143kernel (i.e. KVM_CREATE_IRQCHIP has already been called). 7144 71457.6 KVM_CAP_S390_RI 7146------------------- 7147 7148:Architectures: s390 7149:Parameters: none 7150 7151Allows use of runtime-instrumentation introduced with zEC12 processor. 7152Will return -EINVAL if the machine does not support runtime-instrumentation. 7153Will return -EBUSY if a VCPU has already been created. 7154 71557.7 KVM_CAP_X2APIC_API 7156---------------------- 7157 7158:Architectures: x86 7159:Parameters: args[0] - features that should be enabled 7160:Returns: 0 on success, -EINVAL when args[0] contains invalid features 7161 7162Valid feature flags in args[0] are:: 7163 7164 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) 7165 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) 7166 7167Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of 7168KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, 7169allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their 7170respective sections. 7171 7172KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work 7173in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff 7174as a broadcast even in x2APIC mode in order to support physical x2APIC 7175without interrupt remapping. This is undesirable in logical mode, 7176where 0xff represents CPUs 0-7 in cluster 0. 7177 71787.8 KVM_CAP_S390_USER_INSTR0 7179---------------------------- 7180 7181:Architectures: s390 7182:Parameters: none 7183 7184With this capability enabled, all illegal instructions 0x0000 (2 bytes) will 7185be intercepted and forwarded to user space. User space can use this 7186mechanism e.g. to realize 2-byte software breakpoints. The kernel will 7187not inject an operating exception for these instructions, user space has 7188to take care of that. 7189 7190This capability can be enabled dynamically even if VCPUs were already 7191created and are running. 7192 71937.9 KVM_CAP_S390_GS 7194------------------- 7195 7196:Architectures: s390 7197:Parameters: none 7198:Returns: 0 on success; -EINVAL if the machine does not support 7199 guarded storage; -EBUSY if a VCPU has already been created. 7200 7201Allows use of guarded storage for the KVM guest. 7202 72037.10 KVM_CAP_S390_AIS 7204--------------------- 7205 7206:Architectures: s390 7207:Parameters: none 7208 7209Allow use of adapter-interruption suppression. 7210:Returns: 0 on success; -EBUSY if a VCPU has already been created. 7211 72127.11 KVM_CAP_PPC_SMT 7213-------------------- 7214 7215:Architectures: ppc 7216:Parameters: vsmt_mode, flags 7217 7218Enabling this capability on a VM provides userspace with a way to set 7219the desired virtual SMT mode (i.e. the number of virtual CPUs per 7220virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2 7221between 1 and 8. On POWER8, vsmt_mode must also be no greater than 7222the number of threads per subcore for the host. Currently flags must 7223be 0. A successful call to enable this capability will result in 7224vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is 7225subsequently queried for the VM. This capability is only supported by 7226HV KVM, and can only be set before any VCPUs have been created. 7227The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT 7228modes are available. 7229 72307.12 KVM_CAP_PPC_FWNMI 7231---------------------- 7232 7233:Architectures: ppc 7234:Parameters: none 7235 7236With this capability a machine check exception in the guest address 7237space will cause KVM to exit the guest with NMI exit reason. This 7238enables QEMU to build error log and branch to guest kernel registered 7239machine check handling routine. Without this capability KVM will 7240branch to guests' 0x200 interrupt vector. 7241 72427.13 KVM_CAP_X86_DISABLE_EXITS 7243------------------------------ 7244 7245:Architectures: x86 7246:Parameters: args[0] defines which exits are disabled 7247:Returns: 0 on success, -EINVAL when args[0] contains invalid exits 7248 7249Valid bits in args[0] are:: 7250 7251 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) 7252 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1) 7253 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) 7254 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3) 7255 7256Enabling this capability on a VM provides userspace with a way to no 7257longer intercept some instructions for improved latency in some 7258workloads, and is suggested when vCPUs are associated to dedicated 7259physical CPUs. More bits can be added in the future; userspace can 7260just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable 7261all such vmexits. 7262 7263Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. 7264 72657.14 KVM_CAP_S390_HPAGE_1M 7266-------------------------- 7267 7268:Architectures: s390 7269:Parameters: none 7270:Returns: 0 on success, -EINVAL if hpage module parameter was not set 7271 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL 7272 flag set 7273 7274With this capability the KVM support for memory backing with 1m pages 7275through hugetlbfs can be enabled for a VM. After the capability is 7276enabled, cmma can't be enabled anymore and pfmfi and the storage key 7277interpretation are disabled. If cmma has already been enabled or the 7278hpage module parameter is not set to 1, -EINVAL is returned. 7279 7280While it is generally possible to create a huge page backed VM without 7281this capability, the VM will not be able to run. 7282 72837.15 KVM_CAP_MSR_PLATFORM_INFO 7284------------------------------ 7285 7286:Architectures: x86 7287:Parameters: args[0] whether feature should be enabled or not 7288 7289With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise, 7290a #GP would be raised when the guest tries to access. Currently, this 7291capability does not enable write permissions of this MSR for the guest. 7292 72937.16 KVM_CAP_PPC_NESTED_HV 7294-------------------------- 7295 7296:Architectures: ppc 7297:Parameters: none 7298:Returns: 0 on success, -EINVAL when the implementation doesn't support 7299 nested-HV virtualization. 7300 7301HV-KVM on POWER9 and later systems allows for "nested-HV" 7302virtualization, which provides a way for a guest VM to run guests that 7303can run using the CPU's supervisor mode (privileged non-hypervisor 7304state). Enabling this capability on a VM depends on the CPU having 7305the necessary functionality and on the facility being enabled with a 7306kvm-hv module parameter. 7307 73087.17 KVM_CAP_EXCEPTION_PAYLOAD 7309------------------------------ 7310 7311:Architectures: x86 7312:Parameters: args[0] whether feature should be enabled or not 7313 7314With this capability enabled, CR2 will not be modified prior to the 7315emulated VM-exit when L1 intercepts a #PF exception that occurs in 7316L2. Similarly, for kvm-intel only, DR6 will not be modified prior to 7317the emulated VM-exit when L1 intercepts a #DB exception that occurs in 7318L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or 7319#DB) exception for L2, exception.has_payload will be set and the 7320faulting address (or the new DR6 bits*) will be reported in the 7321exception_payload field. Similarly, when userspace injects a #PF (or 7322#DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set 7323exception.has_payload and to put the faulting address - or the new DR6 7324bits\ [#]_ - in the exception_payload field. 7325 7326This capability also enables exception.pending in struct 7327kvm_vcpu_events, which allows userspace to distinguish between pending 7328and injected exceptions. 7329 7330 7331.. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception 7332 will clear DR6.RTM. 7333 73347.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 7335-------------------------------------- 7336 7337:Architectures: x86, arm64, mips 7338:Parameters: args[0] whether feature should be enabled or not 7339 7340Valid flags are:: 7341 7342 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0) 7343 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) 7344 7345With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not 7346automatically clear and write-protect all pages that are returned as dirty. 7347Rather, userspace will have to do this operation separately using 7348KVM_CLEAR_DIRTY_LOG. 7349 7350At the cost of a slightly more complicated operation, this provides better 7351scalability and responsiveness for two reasons. First, 7352KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather 7353than requiring to sync a full memslot; this ensures that KVM does not 7354take spinlocks for an extended period of time. Second, in some cases a 7355large amount of time can pass between a call to KVM_GET_DIRTY_LOG and 7356userspace actually using the data in the page. Pages can be modified 7357during this time, which is inefficient for both the guest and userspace: 7358the guest will incur a higher penalty due to write protection faults, 7359while userspace can see false reports of dirty pages. Manual reprotection 7360helps reducing this time, improving guest performance and reducing the 7361number of dirty log false positives. 7362 7363With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap 7364will be initialized to 1 when created. This also improves performance because 7365dirty logging can be enabled gradually in small chunks on the first call 7366to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on 7367KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on 7368x86 and arm64 for now). 7369 7370KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name 7371KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make 7372it hard or impossible to use it correctly. The availability of 7373KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed. 7374Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT. 7375 73767.19 KVM_CAP_PPC_SECURE_GUEST 7377------------------------------ 7378 7379:Architectures: ppc 7380 7381This capability indicates that KVM is running on a host that has 7382ultravisor firmware and thus can support a secure guest. On such a 7383system, a guest can ask the ultravisor to make it a secure guest, 7384one whose memory is inaccessible to the host except for pages which 7385are explicitly requested to be shared with the host. The ultravisor 7386notifies KVM when a guest requests to become a secure guest, and KVM 7387has the opportunity to veto the transition. 7388 7389If present, this capability can be enabled for a VM, meaning that KVM 7390will allow the transition to secure guest mode. Otherwise KVM will 7391veto the transition. 7392 73937.20 KVM_CAP_HALT_POLL 7394---------------------- 7395 7396:Architectures: all 7397:Target: VM 7398:Parameters: args[0] is the maximum poll time in nanoseconds 7399:Returns: 0 on success; -1 on error 7400 7401KVM_CAP_HALT_POLL overrides the kvm.halt_poll_ns module parameter to set the 7402maximum halt-polling time for all vCPUs in the target VM. This capability can 7403be invoked at any time and any number of times to dynamically change the 7404maximum halt-polling time. 7405 7406See Documentation/virt/kvm/halt-polling.rst for more information on halt 7407polling. 7408 74097.21 KVM_CAP_X86_USER_SPACE_MSR 7410------------------------------- 7411 7412:Architectures: x86 7413:Target: VM 7414:Parameters: args[0] contains the mask of KVM_MSR_EXIT_REASON_* events to report 7415:Returns: 0 on success; -1 on error 7416 7417This capability allows userspace to intercept RDMSR and WRMSR instructions if 7418access to an MSR is denied. By default, KVM injects #GP on denied accesses. 7419 7420When a guest requests to read or write an MSR, KVM may not implement all MSRs 7421that are relevant to a respective system. It also does not differentiate by 7422CPU type. 7423 7424To allow more fine grained control over MSR handling, userspace may enable 7425this capability. With it enabled, MSR accesses that match the mask specified in 7426args[0] and would trigger a #GP inside the guest will instead trigger 7427KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications. Userspace 7428can then implement model specific MSR handling and/or user notifications 7429to inform a user that an MSR was not emulated/virtualized by KVM. 7430 7431The valid mask flags are: 7432 7433============================ =============================================== 7434 KVM_MSR_EXIT_REASON_UNKNOWN intercept accesses to unknown (to KVM) MSRs 7435 KVM_MSR_EXIT_REASON_INVAL intercept accesses that are architecturally 7436 invalid according to the vCPU model and/or mode 7437 KVM_MSR_EXIT_REASON_FILTER intercept accesses that are denied by userspace 7438 via KVM_X86_SET_MSR_FILTER 7439============================ =============================================== 7440 74417.22 KVM_CAP_X86_BUS_LOCK_EXIT 7442------------------------------- 7443 7444:Architectures: x86 7445:Target: VM 7446:Parameters: args[0] defines the policy used when bus locks detected in guest 7447:Returns: 0 on success, -EINVAL when args[0] contains invalid bits 7448 7449Valid bits in args[0] are:: 7450 7451 #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) 7452 #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) 7453 7454Enabling this capability on a VM provides userspace with a way to select 7455a policy to handle the bus locks detected in guest. Userspace can obtain 7456the supported modes from the result of KVM_CHECK_EXTENSION and define it 7457through the KVM_ENABLE_CAP. 7458 7459KVM_BUS_LOCK_DETECTION_OFF and KVM_BUS_LOCK_DETECTION_EXIT are supported 7460currently and mutually exclusive with each other. More bits can be added in 7461the future. 7462 7463With KVM_BUS_LOCK_DETECTION_OFF set, bus locks in guest will not cause vm exits 7464so that no additional actions are needed. This is the default mode. 7465 7466With KVM_BUS_LOCK_DETECTION_EXIT set, vm exits happen when bus lock detected 7467in VM. KVM just exits to userspace when handling them. Userspace can enforce 7468its own throttling or other policy based mitigations. 7469 7470This capability is aimed to address the thread that VM can exploit bus locks to 7471degree the performance of the whole system. Once the userspace enable this 7472capability and select the KVM_BUS_LOCK_DETECTION_EXIT mode, KVM will set the 7473KVM_RUN_BUS_LOCK flag in vcpu-run->flags field and exit to userspace. Concerning 7474the bus lock vm exit can be preempted by a higher priority VM exit, the exit 7475notifications to userspace can be KVM_EXIT_BUS_LOCK or other reasons. 7476KVM_RUN_BUS_LOCK flag is used to distinguish between them. 7477 74787.23 KVM_CAP_PPC_DAWR1 7479---------------------- 7480 7481:Architectures: ppc 7482:Parameters: none 7483:Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR 7484 7485This capability can be used to check / enable 2nd DAWR feature provided 7486by POWER10 processor. 7487 7488 74897.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 7490------------------------------------- 7491 7492Architectures: x86 SEV enabled 7493Type: vm 7494Parameters: args[0] is the fd of the source vm 7495Returns: 0 on success; ENOTTY on error 7496 7497This capability enables userspace to copy encryption context from the vm 7498indicated by the fd to the vm this is called on. 7499 7500This is intended to support in-guest workloads scheduled by the host. This 7501allows the in-guest workload to maintain its own NPTs and keeps the two vms 7502from accidentally clobbering each other with interrupts and the like (separate 7503APIC/MSRs/etc). 7504 75057.25 KVM_CAP_SGX_ATTRIBUTE 7506-------------------------- 7507 7508:Architectures: x86 7509:Target: VM 7510:Parameters: args[0] is a file handle of a SGX attribute file in securityfs 7511:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested 7512 attribute is not supported by KVM. 7513 7514KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or 7515more privileged enclave attributes. args[0] must hold a file handle to a valid 7516SGX attribute file corresponding to an attribute that is supported/restricted 7517by KVM (currently only PROVISIONKEY). 7518 7519The SGX subsystem restricts access to a subset of enclave attributes to provide 7520additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY 7521is restricted to deter malware from using the PROVISIONKEY to obtain a stable 7522system fingerprint. To prevent userspace from circumventing such restrictions 7523by running an enclave in a VM, KVM prevents access to privileged attributes by 7524default. 7525 7526See Documentation/arch/x86/sgx.rst for more details. 7527 75287.26 KVM_CAP_PPC_RPT_INVALIDATE 7529------------------------------- 7530 7531:Capability: KVM_CAP_PPC_RPT_INVALIDATE 7532:Architectures: ppc 7533:Type: vm 7534 7535This capability indicates that the kernel is capable of handling 7536H_RPT_INVALIDATE hcall. 7537 7538In order to enable the use of H_RPT_INVALIDATE in the guest, 7539user space might have to advertise it for the guest. For example, 7540IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is 7541present in the "ibm,hypertas-functions" device-tree property. 7542 7543This capability is enabled for hypervisors on platforms like POWER9 7544that support radix MMU. 7545 75467.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE 7547-------------------------------------- 7548 7549:Architectures: x86 7550:Parameters: args[0] whether the feature should be enabled or not 7551 7552When this capability is enabled, an emulation failure will result in an exit 7553to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked 7554to handle a VMware backdoor instruction). Furthermore, KVM will now provide up 7555to 15 instruction bytes for any exit to userspace resulting from an emulation 7556failure. When these exits to userspace occur use the emulation_failure struct 7557instead of the internal struct. They both have the same layout, but the 7558emulation_failure struct matches the content better. It also explicitly 7559defines the 'flags' field which is used to describe the fields in the struct 7560that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is 7561set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data 7562in them.) 7563 75647.28 KVM_CAP_ARM_MTE 7565-------------------- 7566 7567:Architectures: arm64 7568:Parameters: none 7569 7570This capability indicates that KVM (and the hardware) supports exposing the 7571Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the 7572VMM before creating any VCPUs to allow the guest access. Note that MTE is only 7573available to a guest running in AArch64 mode and enabling this capability will 7574cause attempts to create AArch32 VCPUs to fail. 7575 7576When enabled the guest is able to access tags associated with any memory given 7577to the guest. KVM will ensure that the tags are maintained during swap or 7578hibernation of the host; however the VMM needs to manually save/restore the 7579tags as appropriate if the VM is migrated. 7580 7581When this capability is enabled all memory in memslots must be mapped as 7582``MAP_ANONYMOUS`` or with a RAM-based file mapping (``tmpfs``, ``memfd``), 7583attempts to create a memslot with an invalid mmap will result in an 7584-EINVAL return. 7585 7586When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to 7587perform a bulk copy of tags to/from the guest. 7588 75897.29 KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 7590------------------------------------- 7591 7592Architectures: x86 SEV enabled 7593Type: vm 7594Parameters: args[0] is the fd of the source vm 7595Returns: 0 on success 7596 7597This capability enables userspace to migrate the encryption context from the VM 7598indicated by the fd to the VM this is called on. 7599 7600This is intended to support intra-host migration of VMs between userspace VMMs, 7601upgrading the VMM process without interrupting the guest. 7602 76037.30 KVM_CAP_PPC_AIL_MODE_3 7604------------------------------- 7605 7606:Capability: KVM_CAP_PPC_AIL_MODE_3 7607:Architectures: ppc 7608:Type: vm 7609 7610This capability indicates that the kernel supports the mode 3 setting for the 7611"Address Translation Mode on Interrupt" aka "Alternate Interrupt Location" 7612resource that is controlled with the H_SET_MODE hypercall. 7613 7614This capability allows a guest kernel to use a better-performance mode for 7615handling interrupts and system calls. 7616 76177.31 KVM_CAP_DISABLE_QUIRKS2 7618---------------------------- 7619 7620:Capability: KVM_CAP_DISABLE_QUIRKS2 7621:Parameters: args[0] - set of KVM quirks to disable 7622:Architectures: x86 7623:Type: vm 7624 7625This capability, if enabled, will cause KVM to disable some behavior 7626quirks. 7627 7628Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 7629quirks that can be disabled in KVM. 7630 7631The argument to KVM_ENABLE_CAP for this capability is a bitmask of 7632quirks to disable, and must be a subset of the bitmask returned by 7633KVM_CHECK_EXTENSION. 7634 7635The valid bits in cap.args[0] are: 7636 7637=================================== ============================================ 7638 KVM_X86_QUIRK_LINT0_REENABLED By default, the reset value for the LVT 7639 LINT0 register is 0x700 (APIC_MODE_EXTINT). 7640 When this quirk is disabled, the reset value 7641 is 0x10000 (APIC_LVT_MASKED). 7642 7643 KVM_X86_QUIRK_CD_NW_CLEARED By default, KVM clears CR0.CD and CR0.NW. 7644 When this quirk is disabled, KVM does not 7645 change the value of CR0.CD and CR0.NW. 7646 7647 KVM_X86_QUIRK_LAPIC_MMIO_HOLE By default, the MMIO LAPIC interface is 7648 available even when configured for x2APIC 7649 mode. When this quirk is disabled, KVM 7650 disables the MMIO LAPIC interface if the 7651 LAPIC is in x2APIC mode. 7652 7653 KVM_X86_QUIRK_OUT_7E_INC_RIP By default, KVM pre-increments %rip before 7654 exiting to userspace for an OUT instruction 7655 to port 0x7e. When this quirk is disabled, 7656 KVM does not pre-increment %rip before 7657 exiting to userspace. 7658 7659 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT When this quirk is disabled, KVM sets 7660 CPUID.01H:ECX[bit 3] (MONITOR/MWAIT) if 7661 IA32_MISC_ENABLE[bit 18] (MWAIT) is set. 7662 Additionally, when this quirk is disabled, 7663 KVM clears CPUID.01H:ECX[bit 3] if 7664 IA32_MISC_ENABLE[bit 18] is cleared. 7665 7666 KVM_X86_QUIRK_FIX_HYPERCALL_INSN By default, KVM rewrites guest 7667 VMMCALL/VMCALL instructions to match the 7668 vendor's hypercall instruction for the 7669 system. When this quirk is disabled, KVM 7670 will no longer rewrite invalid guest 7671 hypercall instructions. Executing the 7672 incorrect hypercall instruction will 7673 generate a #UD within the guest. 7674 7675KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if 7676 they are intercepted) as NOPs regardless of 7677 whether or not MONITOR/MWAIT are supported 7678 according to guest CPUID. When this quirk 7679 is disabled and KVM_X86_DISABLE_EXITS_MWAIT 7680 is not set (MONITOR/MWAIT are intercepted), 7681 KVM will inject a #UD on MONITOR/MWAIT if 7682 they're unsupported per guest CPUID. Note, 7683 KVM will modify MONITOR/MWAIT support in 7684 guest CPUID on writes to MISC_ENABLE if 7685 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is 7686 disabled. 7687=================================== ============================================ 7688 76897.32 KVM_CAP_MAX_VCPU_ID 7690------------------------ 7691 7692:Architectures: x86 7693:Target: VM 7694:Parameters: args[0] - maximum APIC ID value set for current VM 7695:Returns: 0 on success, -EINVAL if args[0] is beyond KVM_MAX_VCPU_IDS 7696 supported in KVM or if it has been set. 7697 7698This capability allows userspace to specify maximum possible APIC ID 7699assigned for current VM session prior to the creation of vCPUs, saving 7700memory for data structures indexed by the APIC ID. Userspace is able 7701to calculate the limit to APIC ID values from designated 7702CPU topology. 7703 7704The value can be changed only until KVM_ENABLE_CAP is set to a nonzero 7705value or until a vCPU is created. Upon creation of the first vCPU, 7706if the value was set to zero or KVM_ENABLE_CAP was not invoked, KVM 7707uses the return value of KVM_CHECK_EXTENSION(KVM_CAP_MAX_VCPU_ID) as 7708the maximum APIC ID. 7709 77107.33 KVM_CAP_X86_NOTIFY_VMEXIT 7711------------------------------ 7712 7713:Architectures: x86 7714:Target: VM 7715:Parameters: args[0] is the value of notify window as well as some flags 7716:Returns: 0 on success, -EINVAL if args[0] contains invalid flags or notify 7717 VM exit is unsupported. 7718 7719Bits 63:32 of args[0] are used for notify window. 7720Bits 31:0 of args[0] are for some flags. Valid bits are:: 7721 7722 #define KVM_X86_NOTIFY_VMEXIT_ENABLED (1 << 0) 7723 #define KVM_X86_NOTIFY_VMEXIT_USER (1 << 1) 7724 7725This capability allows userspace to configure the notify VM exit on/off 7726in per-VM scope during VM creation. Notify VM exit is disabled by default. 7727When userspace sets KVM_X86_NOTIFY_VMEXIT_ENABLED bit in args[0], VMM will 7728enable this feature with the notify window provided, which will generate 7729a VM exit if no event window occurs in VM non-root mode for a specified of 7730time (notify window). 7731 7732If KVM_X86_NOTIFY_VMEXIT_USER is set in args[0], upon notify VM exits happen, 7733KVM would exit to userspace for handling. 7734 7735This capability is aimed to mitigate the threat that malicious VMs can 7736cause CPU stuck (due to event windows don't open up) and make the CPU 7737unavailable to host or other VMs. 7738 77398. Other capabilities. 7740====================== 7741 7742This section lists capabilities that give information about other 7743features of the KVM implementation. 7744 77458.1 KVM_CAP_PPC_HWRNG 7746--------------------- 7747 7748:Architectures: ppc 7749 7750This capability, if KVM_CHECK_EXTENSION indicates that it is 7751available, means that the kernel has an implementation of the 7752H_RANDOM hypercall backed by a hardware random-number generator. 7753If present, the kernel H_RANDOM handler can be enabled for guest use 7754with the KVM_CAP_PPC_ENABLE_HCALL capability. 7755 77568.2 KVM_CAP_HYPERV_SYNIC 7757------------------------ 7758 7759:Architectures: x86 7760 7761This capability, if KVM_CHECK_EXTENSION indicates that it is 7762available, means that the kernel has an implementation of the 7763Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is 7764used to support Windows Hyper-V based guest paravirt drivers(VMBus). 7765 7766In order to use SynIC, it has to be activated by setting this 7767capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this 7768will disable the use of APIC hardware virtualization even if supported 7769by the CPU, as it's incompatible with SynIC auto-EOI behavior. 7770 77718.3 KVM_CAP_PPC_RADIX_MMU 7772------------------------- 7773 7774:Architectures: ppc 7775 7776This capability, if KVM_CHECK_EXTENSION indicates that it is 7777available, means that the kernel can support guests using the 7778radix MMU defined in Power ISA V3.00 (as implemented in the POWER9 7779processor). 7780 77818.4 KVM_CAP_PPC_HASH_MMU_V3 7782--------------------------- 7783 7784:Architectures: ppc 7785 7786This capability, if KVM_CHECK_EXTENSION indicates that it is 7787available, means that the kernel can support guests using the 7788hashed page table MMU defined in Power ISA V3.00 (as implemented in 7789the POWER9 processor), including in-memory segment tables. 7790 77918.5 KVM_CAP_MIPS_VZ 7792------------------- 7793 7794:Architectures: mips 7795 7796This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 7797it is available, means that full hardware assisted virtualization capabilities 7798of the hardware are available for use through KVM. An appropriate 7799KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which 7800utilises it. 7801 7802If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 7803available, it means that the VM is using full hardware assisted virtualization 7804capabilities of the hardware. This is useful to check after creating a VM with 7805KVM_VM_MIPS_DEFAULT. 7806 7807The value returned by KVM_CHECK_EXTENSION should be compared against known 7808values (see below). All other values are reserved. This is to allow for the 7809possibility of other hardware assisted virtualization implementations which 7810may be incompatible with the MIPS VZ ASE. 7811 7812== ========================================================================== 7813 0 The trap & emulate implementation is in use to run guest code in user 7814 mode. Guest virtual memory segments are rearranged to fit the guest in the 7815 user mode address space. 7816 7817 1 The MIPS VZ ASE is in use, providing full hardware assisted 7818 virtualization, including standard guest virtual memory segments. 7819== ========================================================================== 7820 78218.6 KVM_CAP_MIPS_TE 7822------------------- 7823 7824:Architectures: mips 7825 7826This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 7827it is available, means that the trap & emulate implementation is available to 7828run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware 7829assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed 7830to KVM_CREATE_VM to create a VM which utilises it. 7831 7832If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 7833available, it means that the VM is using trap & emulate. 7834 78358.7 KVM_CAP_MIPS_64BIT 7836---------------------- 7837 7838:Architectures: mips 7839 7840This capability indicates the supported architecture type of the guest, i.e. the 7841supported register and address width. 7842 7843The values returned when this capability is checked by KVM_CHECK_EXTENSION on a 7844kvm VM handle correspond roughly to the CP0_Config.AT register field, and should 7845be checked specifically against known values (see below). All other values are 7846reserved. 7847 7848== ======================================================================== 7849 0 MIPS32 or microMIPS32. 7850 Both registers and addresses are 32-bits wide. 7851 It will only be possible to run 32-bit guest code. 7852 7853 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments. 7854 Registers are 64-bits wide, but addresses are 32-bits wide. 7855 64-bit guest code may run but cannot access MIPS64 memory segments. 7856 It will also be possible to run 32-bit guest code. 7857 7858 2 MIPS64 or microMIPS64 with access to all address segments. 7859 Both registers and addresses are 64-bits wide. 7860 It will be possible to run 64-bit or 32-bit guest code. 7861== ======================================================================== 7862 78638.9 KVM_CAP_ARM_USER_IRQ 7864------------------------ 7865 7866:Architectures: arm64 7867 7868This capability, if KVM_CHECK_EXTENSION indicates that it is available, means 7869that if userspace creates a VM without an in-kernel interrupt controller, it 7870will be notified of changes to the output level of in-kernel emulated devices, 7871which can generate virtual interrupts, presented to the VM. 7872For such VMs, on every return to userspace, the kernel 7873updates the vcpu's run->s.regs.device_irq_level field to represent the actual 7874output level of the device. 7875 7876Whenever kvm detects a change in the device output level, kvm guarantees at 7877least one return to userspace before running the VM. This exit could either 7878be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way, 7879userspace can always sample the device output level and re-compute the state of 7880the userspace interrupt controller. Userspace should always check the state 7881of run->s.regs.device_irq_level on every kvm exit. 7882The value in run->s.regs.device_irq_level can represent both level and edge 7883triggered interrupt signals, depending on the device. Edge triggered interrupt 7884signals will exit to userspace with the bit in run->s.regs.device_irq_level 7885set exactly once per edge signal. 7886 7887The field run->s.regs.device_irq_level is available independent of 7888run->kvm_valid_regs or run->kvm_dirty_regs bits. 7889 7890If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a 7891number larger than 0 indicating the version of this capability is implemented 7892and thereby which bits in run->s.regs.device_irq_level can signal values. 7893 7894Currently the following bits are defined for the device_irq_level bitmap:: 7895 7896 KVM_CAP_ARM_USER_IRQ >= 1: 7897 7898 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer 7899 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer 7900 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal 7901 7902Future versions of kvm may implement additional events. These will get 7903indicated by returning a higher number from KVM_CHECK_EXTENSION and will be 7904listed above. 7905 79068.10 KVM_CAP_PPC_SMT_POSSIBLE 7907----------------------------- 7908 7909:Architectures: ppc 7910 7911Querying this capability returns a bitmap indicating the possible 7912virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N 7913(counting from the right) is set, then a virtual SMT mode of 2^N is 7914available. 7915 79168.11 KVM_CAP_HYPERV_SYNIC2 7917-------------------------- 7918 7919:Architectures: x86 7920 7921This capability enables a newer version of Hyper-V Synthetic interrupt 7922controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM 7923doesn't clear SynIC message and event flags pages when they are enabled by 7924writing to the respective MSRs. 7925 79268.12 KVM_CAP_HYPERV_VP_INDEX 7927---------------------------- 7928 7929:Architectures: x86 7930 7931This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its 7932value is used to denote the target vcpu for a SynIC interrupt. For 7933compatibility, KVM initializes this msr to KVM's internal vcpu index. When this 7934capability is absent, userspace can still query this msr's value. 7935 79368.13 KVM_CAP_S390_AIS_MIGRATION 7937------------------------------- 7938 7939:Architectures: s390 7940:Parameters: none 7941 7942This capability indicates if the flic device will be able to get/set the 7943AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows 7944to discover this without having to create a flic device. 7945 79468.14 KVM_CAP_S390_PSW 7947--------------------- 7948 7949:Architectures: s390 7950 7951This capability indicates that the PSW is exposed via the kvm_run structure. 7952 79538.15 KVM_CAP_S390_GMAP 7954---------------------- 7955 7956:Architectures: s390 7957 7958This capability indicates that the user space memory used as guest mapping can 7959be anywhere in the user memory address space, as long as the memory slots are 7960aligned and sized to a segment (1MB) boundary. 7961 79628.16 KVM_CAP_S390_COW 7963--------------------- 7964 7965:Architectures: s390 7966 7967This capability indicates that the user space memory used as guest mapping can 7968use copy-on-write semantics as well as dirty pages tracking via read-only page 7969tables. 7970 79718.17 KVM_CAP_S390_BPB 7972--------------------- 7973 7974:Architectures: s390 7975 7976This capability indicates that kvm will implement the interfaces to handle 7977reset, migration and nested KVM for branch prediction blocking. The stfle 7978facility 82 should not be provided to the guest without this capability. 7979 79808.18 KVM_CAP_HYPERV_TLBFLUSH 7981---------------------------- 7982 7983:Architectures: x86 7984 7985This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush 7986hypercalls: 7987HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, 7988HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. 7989 79908.19 KVM_CAP_ARM_INJECT_SERROR_ESR 7991---------------------------------- 7992 7993:Architectures: arm64 7994 7995This capability indicates that userspace can specify (via the 7996KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it 7997takes a virtual SError interrupt exception. 7998If KVM advertises this capability, userspace can only specify the ISS field for 7999the ESR syndrome. Other parts of the ESR, such as the EC are generated by the 8000CPU when the exception is taken. If this virtual SError is taken to EL1 using 8001AArch64, this value will be reported in the ISS field of ESR_ELx. 8002 8003See KVM_CAP_VCPU_EVENTS for more details. 8004 80058.20 KVM_CAP_HYPERV_SEND_IPI 8006---------------------------- 8007 8008:Architectures: x86 8009 8010This capability indicates that KVM supports paravirtualized Hyper-V IPI send 8011hypercalls: 8012HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. 8013 80148.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH 8015----------------------------------- 8016 8017:Architectures: x86 8018 8019This capability indicates that KVM running on top of Hyper-V hypervisor 8020enables Direct TLB flush for its guests meaning that TLB flush 8021hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM. 8022Due to the different ABI for hypercall parameters between Hyper-V and 8023KVM, enabling this capability effectively disables all hypercall 8024handling by KVM (as some KVM hypercall may be mistakenly treated as TLB 8025flush hypercalls by Hyper-V) so userspace should disable KVM identification 8026in CPUID and only exposes Hyper-V identification. In this case, guest 8027thinks it's running on Hyper-V and only use Hyper-V hypercalls. 8028 80298.22 KVM_CAP_S390_VCPU_RESETS 8030----------------------------- 8031 8032:Architectures: s390 8033 8034This capability indicates that the KVM_S390_NORMAL_RESET and 8035KVM_S390_CLEAR_RESET ioctls are available. 8036 80378.23 KVM_CAP_S390_PROTECTED 8038--------------------------- 8039 8040:Architectures: s390 8041 8042This capability indicates that the Ultravisor has been initialized and 8043KVM can therefore start protected VMs. 8044This capability governs the KVM_S390_PV_COMMAND ioctl and the 8045KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected 8046guests when the state change is invalid. 8047 80488.24 KVM_CAP_STEAL_TIME 8049----------------------- 8050 8051:Architectures: arm64, x86 8052 8053This capability indicates that KVM supports steal time accounting. 8054When steal time accounting is supported it may be enabled with 8055architecture-specific interfaces. This capability and the architecture- 8056specific interfaces must be consistent, i.e. if one says the feature 8057is supported, than the other should as well and vice versa. For arm64 8058see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". 8059For x86 see Documentation/virt/kvm/x86/msr.rst "MSR_KVM_STEAL_TIME". 8060 80618.25 KVM_CAP_S390_DIAG318 8062------------------------- 8063 8064:Architectures: s390 8065 8066This capability enables a guest to set information about its control program 8067(i.e. guest kernel type and version). The information is helpful during 8068system/firmware service events, providing additional data about the guest 8069environments running on the machine. 8070 8071The information is associated with the DIAGNOSE 0x318 instruction, which sets 8072an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and 8073a 7-byte Control Program Version Code (CPVC). The CPNC determines what 8074environment the control program is running in (e.g. Linux, z/VM...), and the 8075CPVC is used for information specific to OS (e.g. Linux version, Linux 8076distribution...) 8077 8078If this capability is available, then the CPNC and CPVC can be synchronized 8079between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318). 8080 80818.26 KVM_CAP_X86_USER_SPACE_MSR 8082------------------------------- 8083 8084:Architectures: x86 8085 8086This capability indicates that KVM supports deflection of MSR reads and 8087writes to user space. It can be enabled on a VM level. If enabled, MSR 8088accesses that would usually trigger a #GP by KVM into the guest will 8089instead get bounced to user space through the KVM_EXIT_X86_RDMSR and 8090KVM_EXIT_X86_WRMSR exit notifications. 8091 80928.27 KVM_CAP_X86_MSR_FILTER 8093--------------------------- 8094 8095:Architectures: x86 8096 8097This capability indicates that KVM supports that accesses to user defined MSRs 8098may be rejected. With this capability exposed, KVM exports new VM ioctl 8099KVM_X86_SET_MSR_FILTER which user space can call to specify bitmaps of MSR 8100ranges that KVM should deny access to. 8101 8102In combination with KVM_CAP_X86_USER_SPACE_MSR, this allows user space to 8103trap and emulate MSRs that are outside of the scope of KVM as well as 8104limit the attack surface on KVM's MSR emulation code. 8105 81068.28 KVM_CAP_ENFORCE_PV_FEATURE_CPUID 8107------------------------------------- 8108 8109Architectures: x86 8110 8111When enabled, KVM will disable paravirtual features provided to the 8112guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf 8113(0x40000001). Otherwise, a guest may use the paravirtual features 8114regardless of what has actually been exposed through the CPUID leaf. 8115 81168.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8117---------------------------------------------------------- 8118 8119:Architectures: x86, arm64 8120:Parameters: args[0] - size of the dirty log ring 8121 8122KVM is capable of tracking dirty memory using ring buffers that are 8123mmapped into userspace; there is one dirty ring per vcpu. 8124 8125The dirty ring is available to userspace as an array of 8126``struct kvm_dirty_gfn``. Each dirty entry is defined as:: 8127 8128 struct kvm_dirty_gfn { 8129 __u32 flags; 8130 __u32 slot; /* as_id | slot_id */ 8131 __u64 offset; 8132 }; 8133 8134The following values are defined for the flags field to define the 8135current state of the entry:: 8136 8137 #define KVM_DIRTY_GFN_F_DIRTY BIT(0) 8138 #define KVM_DIRTY_GFN_F_RESET BIT(1) 8139 #define KVM_DIRTY_GFN_F_MASK 0x3 8140 8141Userspace should call KVM_ENABLE_CAP ioctl right after KVM_CREATE_VM 8142ioctl to enable this capability for the new guest and set the size of 8143the rings. Enabling the capability is only allowed before creating any 8144vCPU, and the size of the ring must be a power of two. The larger the 8145ring buffer, the less likely the ring is full and the VM is forced to 8146exit to userspace. The optimal size depends on the workload, but it is 8147recommended that it be at least 64 KiB (4096 entries). 8148 8149Just like for dirty page bitmaps, the buffer tracks writes to 8150all user memory regions for which the KVM_MEM_LOG_DIRTY_PAGES flag was 8151set in KVM_SET_USER_MEMORY_REGION. Once a memory region is registered 8152with the flag set, userspace can start harvesting dirty pages from the 8153ring buffer. 8154 8155An entry in the ring buffer can be unused (flag bits ``00``), 8156dirty (flag bits ``01``) or harvested (flag bits ``1X``). The 8157state machine for the entry is as follows:: 8158 8159 dirtied harvested reset 8160 00 -----------> 01 -------------> 1X -------+ 8161 ^ | 8162 | | 8163 +------------------------------------------+ 8164 8165To harvest the dirty pages, userspace accesses the mmapped ring buffer 8166to read the dirty GFNs. If the flags has the DIRTY bit set (at this stage 8167the RESET bit must be cleared), then it means this GFN is a dirty GFN. 8168The userspace should harvest this GFN and mark the flags from state 8169``01b`` to ``1Xb`` (bit 0 will be ignored by KVM, but bit 1 must be set 8170to show that this GFN is harvested and waiting for a reset), and move 8171on to the next GFN. The userspace should continue to do this until the 8172flags of a GFN have the DIRTY bit cleared, meaning that it has harvested 8173all the dirty GFNs that were available. 8174 8175Note that on weakly ordered architectures, userspace accesses to the 8176ring buffer (and more specifically the 'flags' field) must be ordered, 8177using load-acquire/store-release accessors when available, or any 8178other memory barrier that will ensure this ordering. 8179 8180It's not necessary for userspace to harvest the all dirty GFNs at once. 8181However it must collect the dirty GFNs in sequence, i.e., the userspace 8182program cannot skip one dirty GFN to collect the one next to it. 8183 8184After processing one or more entries in the ring buffer, userspace 8185calls the VM ioctl KVM_RESET_DIRTY_RINGS to notify the kernel about 8186it, so that the kernel will reprotect those collected GFNs. 8187Therefore, the ioctl must be called *before* reading the content of 8188the dirty pages. 8189 8190The dirty ring can get full. When it happens, the KVM_RUN of the 8191vcpu will return with exit reason KVM_EXIT_DIRTY_LOG_FULL. 8192 8193The dirty ring interface has a major difference comparing to the 8194KVM_GET_DIRTY_LOG interface in that, when reading the dirty ring from 8195userspace, it's still possible that the kernel has not yet flushed the 8196processor's dirty page buffers into the kernel buffer (with dirty bitmaps, the 8197flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one 8198needs to kick the vcpu out of KVM_RUN using a signal. The resulting 8199vmexit ensures that all dirty GFNs are flushed to the dirty rings. 8200 8201NOTE: KVM_CAP_DIRTY_LOG_RING_ACQ_REL is the only capability that 8202should be exposed by weakly ordered architecture, in order to indicate 8203the additional memory ordering requirements imposed on userspace when 8204reading the state of an entry and mutating it from DIRTY to HARVESTED. 8205Architecture with TSO-like ordering (such as x86) are allowed to 8206expose both KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8207to userspace. 8208 8209After enabling the dirty rings, the userspace needs to detect the 8210capability of KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP to see whether the 8211ring structures can be backed by per-slot bitmaps. With this capability 8212advertised, it means the architecture can dirty guest pages without 8213vcpu/ring context, so that some of the dirty information will still be 8214maintained in the bitmap structure. KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 8215can't be enabled if the capability of KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8216hasn't been enabled, or any memslot has been existing. 8217 8218Note that the bitmap here is only a backup of the ring structure. The 8219use of the ring and bitmap combination is only beneficial if there is 8220only a very small amount of memory that is dirtied out of vcpu/ring 8221context. Otherwise, the stand-alone per-slot bitmap mechanism needs to 8222be considered. 8223 8224To collect dirty bits in the backup bitmap, userspace can use the same 8225KVM_GET_DIRTY_LOG ioctl. KVM_CLEAR_DIRTY_LOG isn't needed as long as all 8226the generation of the dirty bits is done in a single pass. Collecting 8227the dirty bitmap should be the very last thing that the VMM does before 8228considering the state as complete. VMM needs to ensure that the dirty 8229state is final and avoid missing dirty pages from another ioctl ordered 8230after the bitmap collection. 8231 8232NOTE: Multiple examples of using the backup bitmap: (1) save vgic/its 8233tables through command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} on 8234KVM device "kvm-arm-vgic-its". (2) restore vgic/its tables through 8235command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM device 8236"kvm-arm-vgic-its". VGICv3 LPI pending status is restored. (3) save 8237vgic3 pending table through KVM_DEV_ARM_VGIC_{GRP_CTRL, SAVE_PENDING_TABLES} 8238command on KVM device "kvm-arm-vgic-v3". 8239 82408.30 KVM_CAP_XEN_HVM 8241-------------------- 8242 8243:Architectures: x86 8244 8245This capability indicates the features that Xen supports for hosting Xen 8246PVHVM guests. Valid flags are:: 8247 8248 #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0) 8249 #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1) 8250 #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2) 8251 #define KVM_XEN_HVM_CONFIG_RUNSTATE (1 << 3) 8252 #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 4) 8253 #define KVM_XEN_HVM_CONFIG_EVTCHN_SEND (1 << 5) 8254 #define KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG (1 << 6) 8255 8256The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG 8257ioctl is available, for the guest to set its hypercall page. 8258 8259If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be 8260provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page 8261contents, to request that KVM generate hypercall page content automatically 8262and also enable interception of guest hypercalls with KVM_EXIT_XEN. 8263 8264The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the 8265KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and 8266KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors 8267for event channel upcalls when the evtchn_upcall_pending field of a vcpu's 8268vcpu_info is set. 8269 8270The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related 8271features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are 8272supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls. 8273 8274The KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL flag indicates that IRQ routing entries 8275of the type KVM_IRQ_ROUTING_XEN_EVTCHN are supported, with the priority 8276field set to indicate 2 level event channel delivery. 8277 8278The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates that KVM supports 8279injecting event channel events directly into the guest with the 8280KVM_XEN_HVM_EVTCHN_SEND ioctl. It also indicates support for the 8281KVM_XEN_ATTR_TYPE_EVTCHN/XEN_VERSION HVM attributes and the 8282KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID/TIMER/UPCALL_VECTOR vCPU attributes. 8283related to event channel delivery, timers, and the XENVER_version 8284interception. 8285 8286The KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG flag indicates that KVM supports 8287the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute in the KVM_XEN_SET_ATTR 8288and KVM_XEN_GET_ATTR ioctls. This controls whether KVM will set the 8289XEN_RUNSTATE_UPDATE flag in guest memory mapped vcpu_runstate_info during 8290updates of the runstate information. Note that versions of KVM which support 8291the RUNSTATE feature above, but not the RUNSTATE_UPDATE_FLAG feature, will 8292always set the XEN_RUNSTATE_UPDATE flag when updating the guest structure, 8293which is perhaps counterintuitive. When this flag is advertised, KVM will 8294behave more correctly, not using the XEN_RUNSTATE_UPDATE flag until/unless 8295specifically enabled (by the guest making the hypercall, causing the VMM 8296to enable the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute). 8297 82988.31 KVM_CAP_PPC_MULTITCE 8299------------------------- 8300 8301:Capability: KVM_CAP_PPC_MULTITCE 8302:Architectures: ppc 8303:Type: vm 8304 8305This capability means the kernel is capable of handling hypercalls 8306H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user 8307space. This significantly accelerates DMA operations for PPC KVM guests. 8308User space should expect that its handlers for these hypercalls 8309are not going to be called if user space previously registered LIOBN 8310in KVM (via KVM_CREATE_SPAPR_TCE or similar calls). 8311 8312In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest, 8313user space might have to advertise it for the guest. For example, 8314IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is 8315present in the "ibm,hypertas-functions" device-tree property. 8316 8317The hypercalls mentioned above may or may not be processed successfully 8318in the kernel based fast path. If they can not be handled by the kernel, 8319they will get passed on to user space. So user space still has to have 8320an implementation for these despite the in kernel acceleration. 8321 8322This capability is always enabled. 8323 83248.32 KVM_CAP_PTP_KVM 8325-------------------- 8326 8327:Architectures: arm64 8328 8329This capability indicates that the KVM virtual PTP service is 8330supported in the host. A VMM can check whether the service is 8331available to the guest on migration. 8332 83338.33 KVM_CAP_HYPERV_ENFORCE_CPUID 8334--------------------------------- 8335 8336Architectures: x86 8337 8338When enabled, KVM will disable emulated Hyper-V features provided to the 8339guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all 8340currently implemented Hyper-V features are provided unconditionally when 8341Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001) 8342leaf. 8343 83448.34 KVM_CAP_EXIT_HYPERCALL 8345--------------------------- 8346 8347:Capability: KVM_CAP_EXIT_HYPERCALL 8348:Architectures: x86 8349:Type: vm 8350 8351This capability, if enabled, will cause KVM to exit to userspace 8352with KVM_EXIT_HYPERCALL exit reason to process some hypercalls. 8353 8354Calling KVM_CHECK_EXTENSION for this capability will return a bitmask 8355of hypercalls that can be configured to exit to userspace. 8356Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE. 8357 8358The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset 8359of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace 8360the hypercalls whose corresponding bit is in the argument, and return 8361ENOSYS for the others. 8362 83638.35 KVM_CAP_PMU_CAPABILITY 8364--------------------------- 8365 8366:Capability: KVM_CAP_PMU_CAPABILITY 8367:Architectures: x86 8368:Type: vm 8369:Parameters: arg[0] is bitmask of PMU virtualization capabilities. 8370:Returns: 0 on success, -EINVAL when arg[0] contains invalid bits 8371 8372This capability alters PMU virtualization in KVM. 8373 8374Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 8375PMU virtualization capabilities that can be adjusted on a VM. 8376 8377The argument to KVM_ENABLE_CAP is also a bitmask and selects specific 8378PMU virtualization capabilities to be applied to the VM. This can 8379only be invoked on a VM prior to the creation of VCPUs. 8380 8381At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting 8382this capability will disable PMU virtualization for that VM. Usermode 8383should adjust CPUID leaf 0xA to reflect that the PMU is disabled. 8384 83858.36 KVM_CAP_ARM_SYSTEM_SUSPEND 8386------------------------------- 8387 8388:Capability: KVM_CAP_ARM_SYSTEM_SUSPEND 8389:Architectures: arm64 8390:Type: vm 8391 8392When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of 8393type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. 8394 83958.37 KVM_CAP_S390_PROTECTED_DUMP 8396-------------------------------- 8397 8398:Capability: KVM_CAP_S390_PROTECTED_DUMP 8399:Architectures: s390 8400:Type: vm 8401 8402This capability indicates that KVM and the Ultravisor support dumping 8403PV guests. The `KVM_PV_DUMP` command is available for the 8404`KVM_S390_PV_COMMAND` ioctl and the `KVM_PV_INFO` command provides 8405dump related UV data. Also the vcpu ioctl `KVM_S390_PV_CPU_COMMAND` is 8406available and supports the `KVM_PV_DUMP_CPU` subcommand. 8407 84088.38 KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8409------------------------------------- 8410 8411:Capability: KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8412:Architectures: x86 8413:Type: vm 8414:Parameters: arg[0] must be 0. 8415:Returns: 0 on success, -EPERM if the userspace process does not 8416 have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been 8417 created. 8418 8419This capability disables the NX huge pages mitigation for iTLB MULTIHIT. 8420 8421The capability has no effect if the nx_huge_pages module parameter is not set. 8422 8423This capability may only be set before any vCPUs are created. 8424 84258.39 KVM_CAP_S390_CPU_TOPOLOGY 8426------------------------------ 8427 8428:Capability: KVM_CAP_S390_CPU_TOPOLOGY 8429:Architectures: s390 8430:Type: vm 8431 8432This capability indicates that KVM will provide the S390 CPU Topology 8433facility which consist of the interpretation of the PTF instruction for 8434the function code 2 along with interception and forwarding of both the 8435PTF instruction with function codes 0 or 1 and the STSI(15,1,x) 8436instruction to the userland hypervisor. 8437 8438The stfle facility 11, CPU Topology facility, should not be indicated 8439to the guest without this capability. 8440 8441When this capability is present, KVM provides a new attribute group 8442on vm fd, KVM_S390_VM_CPU_TOPOLOGY. 8443This new attribute allows to get, set or clear the Modified Change 8444Topology Report (MTCR) bit of the SCA through the kvm_device_attr 8445structure. 8446 8447When getting the Modified Change Topology Report value, the attr->addr 8448must point to a byte where the value will be stored or retrieved from. 8449 84508.40 KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 8451--------------------------------------- 8452 8453:Capability: KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 8454:Architectures: arm64 8455:Type: vm 8456:Parameters: arg[0] is the new split chunk size. 8457:Returns: 0 on success, -EINVAL if any memslot was already created. 8458 8459This capability sets the chunk size used in Eager Page Splitting. 8460 8461Eager Page Splitting improves the performance of dirty-logging (used 8462in live migrations) when guest memory is backed by huge-pages. It 8463avoids splitting huge-pages (into PAGE_SIZE pages) on fault, by doing 8464it eagerly when enabling dirty logging (with the 8465KVM_MEM_LOG_DIRTY_PAGES flag for a memory region), or when using 8466KVM_CLEAR_DIRTY_LOG. 8467 8468The chunk size specifies how many pages to break at a time, using a 8469single allocation for each chunk. Bigger the chunk size, more pages 8470need to be allocated ahead of time. 8471 8472The chunk size needs to be a valid block size. The list of acceptable 8473block sizes is exposed in KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES as a 847464-bit bitmap (each bit describing a block size). The default value is 84750, to disable the eager page splitting. 8476 84779. Known KVM API problems 8478========================= 8479 8480In some cases, KVM's API has some inconsistencies or common pitfalls 8481that userspace need to be aware of. This section details some of 8482these issues. 8483 8484Most of them are architecture specific, so the section is split by 8485architecture. 8486 84879.1. x86 8488-------- 8489 8490``KVM_GET_SUPPORTED_CPUID`` issues 8491^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 8492 8493In general, ``KVM_GET_SUPPORTED_CPUID`` is designed so that it is possible 8494to take its result and pass it directly to ``KVM_SET_CPUID2``. This section 8495documents some cases in which that requires some care. 8496 8497Local APIC features 8498~~~~~~~~~~~~~~~~~~~ 8499 8500CPU[EAX=1]:ECX[21] (X2APIC) is reported by ``KVM_GET_SUPPORTED_CPUID``, 8501but it can only be enabled if ``KVM_CREATE_IRQCHIP`` or 8502``KVM_ENABLE_CAP(KVM_CAP_IRQCHIP_SPLIT)`` are used to enable in-kernel emulation of 8503the local APIC. 8504 8505The same is true for the ``KVM_FEATURE_PV_UNHALT`` paravirtualized feature. 8506 8507CPU[EAX=1]:ECX[24] (TSC_DEADLINE) is not reported by ``KVM_GET_SUPPORTED_CPUID``. 8508It can be enabled if ``KVM_CAP_TSC_DEADLINE_TIMER`` is present and the kernel 8509has enabled in-kernel emulation of the local APIC. 8510 8511CPU topology 8512~~~~~~~~~~~~ 8513 8514Several CPUID values include topology information for the host CPU: 85150x0b and 0x1f for Intel systems, 0x8000001e for AMD systems. Different 8516versions of KVM return different values for this information and userspace 8517should not rely on it. Currently they return all zeroes. 8518 8519If userspace wishes to set up a guest topology, it should be careful that 8520the values of these three leaves differ for each CPU. In particular, 8521the APIC ID is found in EDX for all subleaves of 0x0b and 0x1f, and in EAX 8522for 0x8000001e; the latter also encodes the core id and node id in bits 85237:0 of EBX and ECX respectively. 8524 8525Obsolete ioctls and capabilities 8526^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 8527 8528KVM_CAP_DISABLE_QUIRKS does not let userspace know which quirks are actually 8529available. Use ``KVM_CHECK_EXTENSION(KVM_CAP_DISABLE_QUIRKS2)`` instead if 8530available. 8531 8532Ordering of KVM_GET_*/KVM_SET_* ioctls 8533^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 8534 8535TBD 8536