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 virutal 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 ====== ============================================================ 2263 2264(These error codes are indicative only: do not rely on a specific error 2265code being returned in a specific situation.) 2266 2267:: 2268 2269 struct kvm_one_reg { 2270 __u64 id; 2271 __u64 addr; 2272 }; 2273 2274Using this ioctl, a single vcpu register can be set to a specific value 2275defined by user space with the passed in struct kvm_one_reg, where id 2276refers to the register identifier as described below and addr is a pointer 2277to a variable with the respective size. There can be architecture agnostic 2278and architecture specific registers. Each have their own range of operation 2279and their own constants and width. To keep track of the implemented 2280registers, find a list below: 2281 2282 ======= =============================== ============ 2283 Arch Register Width (bits) 2284 ======= =============================== ============ 2285 PPC KVM_REG_PPC_HIOR 64 2286 PPC KVM_REG_PPC_IAC1 64 2287 PPC KVM_REG_PPC_IAC2 64 2288 PPC KVM_REG_PPC_IAC3 64 2289 PPC KVM_REG_PPC_IAC4 64 2290 PPC KVM_REG_PPC_DAC1 64 2291 PPC KVM_REG_PPC_DAC2 64 2292 PPC KVM_REG_PPC_DABR 64 2293 PPC KVM_REG_PPC_DSCR 64 2294 PPC KVM_REG_PPC_PURR 64 2295 PPC KVM_REG_PPC_SPURR 64 2296 PPC KVM_REG_PPC_DAR 64 2297 PPC KVM_REG_PPC_DSISR 32 2298 PPC KVM_REG_PPC_AMR 64 2299 PPC KVM_REG_PPC_UAMOR 64 2300 PPC KVM_REG_PPC_MMCR0 64 2301 PPC KVM_REG_PPC_MMCR1 64 2302 PPC KVM_REG_PPC_MMCRA 64 2303 PPC KVM_REG_PPC_MMCR2 64 2304 PPC KVM_REG_PPC_MMCRS 64 2305 PPC KVM_REG_PPC_MMCR3 64 2306 PPC KVM_REG_PPC_SIAR 64 2307 PPC KVM_REG_PPC_SDAR 64 2308 PPC KVM_REG_PPC_SIER 64 2309 PPC KVM_REG_PPC_SIER2 64 2310 PPC KVM_REG_PPC_SIER3 64 2311 PPC KVM_REG_PPC_PMC1 32 2312 PPC KVM_REG_PPC_PMC2 32 2313 PPC KVM_REG_PPC_PMC3 32 2314 PPC KVM_REG_PPC_PMC4 32 2315 PPC KVM_REG_PPC_PMC5 32 2316 PPC KVM_REG_PPC_PMC6 32 2317 PPC KVM_REG_PPC_PMC7 32 2318 PPC KVM_REG_PPC_PMC8 32 2319 PPC KVM_REG_PPC_FPR0 64 2320 ... 2321 PPC KVM_REG_PPC_FPR31 64 2322 PPC KVM_REG_PPC_VR0 128 2323 ... 2324 PPC KVM_REG_PPC_VR31 128 2325 PPC KVM_REG_PPC_VSR0 128 2326 ... 2327 PPC KVM_REG_PPC_VSR31 128 2328 PPC KVM_REG_PPC_FPSCR 64 2329 PPC KVM_REG_PPC_VSCR 32 2330 PPC KVM_REG_PPC_VPA_ADDR 64 2331 PPC KVM_REG_PPC_VPA_SLB 128 2332 PPC KVM_REG_PPC_VPA_DTL 128 2333 PPC KVM_REG_PPC_EPCR 32 2334 PPC KVM_REG_PPC_EPR 32 2335 PPC KVM_REG_PPC_TCR 32 2336 PPC KVM_REG_PPC_TSR 32 2337 PPC KVM_REG_PPC_OR_TSR 32 2338 PPC KVM_REG_PPC_CLEAR_TSR 32 2339 PPC KVM_REG_PPC_MAS0 32 2340 PPC KVM_REG_PPC_MAS1 32 2341 PPC KVM_REG_PPC_MAS2 64 2342 PPC KVM_REG_PPC_MAS7_3 64 2343 PPC KVM_REG_PPC_MAS4 32 2344 PPC KVM_REG_PPC_MAS6 32 2345 PPC KVM_REG_PPC_MMUCFG 32 2346 PPC KVM_REG_PPC_TLB0CFG 32 2347 PPC KVM_REG_PPC_TLB1CFG 32 2348 PPC KVM_REG_PPC_TLB2CFG 32 2349 PPC KVM_REG_PPC_TLB3CFG 32 2350 PPC KVM_REG_PPC_TLB0PS 32 2351 PPC KVM_REG_PPC_TLB1PS 32 2352 PPC KVM_REG_PPC_TLB2PS 32 2353 PPC KVM_REG_PPC_TLB3PS 32 2354 PPC KVM_REG_PPC_EPTCFG 32 2355 PPC KVM_REG_PPC_ICP_STATE 64 2356 PPC KVM_REG_PPC_VP_STATE 128 2357 PPC KVM_REG_PPC_TB_OFFSET 64 2358 PPC KVM_REG_PPC_SPMC1 32 2359 PPC KVM_REG_PPC_SPMC2 32 2360 PPC KVM_REG_PPC_IAMR 64 2361 PPC KVM_REG_PPC_TFHAR 64 2362 PPC KVM_REG_PPC_TFIAR 64 2363 PPC KVM_REG_PPC_TEXASR 64 2364 PPC KVM_REG_PPC_FSCR 64 2365 PPC KVM_REG_PPC_PSPB 32 2366 PPC KVM_REG_PPC_EBBHR 64 2367 PPC KVM_REG_PPC_EBBRR 64 2368 PPC KVM_REG_PPC_BESCR 64 2369 PPC KVM_REG_PPC_TAR 64 2370 PPC KVM_REG_PPC_DPDES 64 2371 PPC KVM_REG_PPC_DAWR 64 2372 PPC KVM_REG_PPC_DAWRX 64 2373 PPC KVM_REG_PPC_CIABR 64 2374 PPC KVM_REG_PPC_IC 64 2375 PPC KVM_REG_PPC_VTB 64 2376 PPC KVM_REG_PPC_CSIGR 64 2377 PPC KVM_REG_PPC_TACR 64 2378 PPC KVM_REG_PPC_TCSCR 64 2379 PPC KVM_REG_PPC_PID 64 2380 PPC KVM_REG_PPC_ACOP 64 2381 PPC KVM_REG_PPC_VRSAVE 32 2382 PPC KVM_REG_PPC_LPCR 32 2383 PPC KVM_REG_PPC_LPCR_64 64 2384 PPC KVM_REG_PPC_PPR 64 2385 PPC KVM_REG_PPC_ARCH_COMPAT 32 2386 PPC KVM_REG_PPC_DABRX 32 2387 PPC KVM_REG_PPC_WORT 64 2388 PPC KVM_REG_PPC_SPRG9 64 2389 PPC KVM_REG_PPC_DBSR 32 2390 PPC KVM_REG_PPC_TIDR 64 2391 PPC KVM_REG_PPC_PSSCR 64 2392 PPC KVM_REG_PPC_DEC_EXPIRY 64 2393 PPC KVM_REG_PPC_PTCR 64 2394 PPC KVM_REG_PPC_DAWR1 64 2395 PPC KVM_REG_PPC_DAWRX1 64 2396 PPC KVM_REG_PPC_TM_GPR0 64 2397 ... 2398 PPC KVM_REG_PPC_TM_GPR31 64 2399 PPC KVM_REG_PPC_TM_VSR0 128 2400 ... 2401 PPC KVM_REG_PPC_TM_VSR63 128 2402 PPC KVM_REG_PPC_TM_CR 64 2403 PPC KVM_REG_PPC_TM_LR 64 2404 PPC KVM_REG_PPC_TM_CTR 64 2405 PPC KVM_REG_PPC_TM_FPSCR 64 2406 PPC KVM_REG_PPC_TM_AMR 64 2407 PPC KVM_REG_PPC_TM_PPR 64 2408 PPC KVM_REG_PPC_TM_VRSAVE 64 2409 PPC KVM_REG_PPC_TM_VSCR 32 2410 PPC KVM_REG_PPC_TM_DSCR 64 2411 PPC KVM_REG_PPC_TM_TAR 64 2412 PPC KVM_REG_PPC_TM_XER 64 2413 2414 MIPS KVM_REG_MIPS_R0 64 2415 ... 2416 MIPS KVM_REG_MIPS_R31 64 2417 MIPS KVM_REG_MIPS_HI 64 2418 MIPS KVM_REG_MIPS_LO 64 2419 MIPS KVM_REG_MIPS_PC 64 2420 MIPS KVM_REG_MIPS_CP0_INDEX 32 2421 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64 2422 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64 2423 MIPS KVM_REG_MIPS_CP0_CONTEXT 64 2424 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32 2425 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64 2426 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64 2427 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32 2428 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32 2429 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64 2430 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64 2431 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64 2432 MIPS KVM_REG_MIPS_CP0_PWBASE 64 2433 MIPS KVM_REG_MIPS_CP0_PWFIELD 64 2434 MIPS KVM_REG_MIPS_CP0_PWSIZE 64 2435 MIPS KVM_REG_MIPS_CP0_WIRED 32 2436 MIPS KVM_REG_MIPS_CP0_PWCTL 32 2437 MIPS KVM_REG_MIPS_CP0_HWRENA 32 2438 MIPS KVM_REG_MIPS_CP0_BADVADDR 64 2439 MIPS KVM_REG_MIPS_CP0_BADINSTR 32 2440 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32 2441 MIPS KVM_REG_MIPS_CP0_COUNT 32 2442 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64 2443 MIPS KVM_REG_MIPS_CP0_COMPARE 32 2444 MIPS KVM_REG_MIPS_CP0_STATUS 32 2445 MIPS KVM_REG_MIPS_CP0_INTCTL 32 2446 MIPS KVM_REG_MIPS_CP0_CAUSE 32 2447 MIPS KVM_REG_MIPS_CP0_EPC 64 2448 MIPS KVM_REG_MIPS_CP0_PRID 32 2449 MIPS KVM_REG_MIPS_CP0_EBASE 64 2450 MIPS KVM_REG_MIPS_CP0_CONFIG 32 2451 MIPS KVM_REG_MIPS_CP0_CONFIG1 32 2452 MIPS KVM_REG_MIPS_CP0_CONFIG2 32 2453 MIPS KVM_REG_MIPS_CP0_CONFIG3 32 2454 MIPS KVM_REG_MIPS_CP0_CONFIG4 32 2455 MIPS KVM_REG_MIPS_CP0_CONFIG5 32 2456 MIPS KVM_REG_MIPS_CP0_CONFIG7 32 2457 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64 2458 MIPS KVM_REG_MIPS_CP0_ERROREPC 64 2459 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64 2460 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64 2461 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64 2462 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64 2463 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64 2464 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64 2465 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64 2466 MIPS KVM_REG_MIPS_COUNT_CTL 64 2467 MIPS KVM_REG_MIPS_COUNT_RESUME 64 2468 MIPS KVM_REG_MIPS_COUNT_HZ 64 2469 MIPS KVM_REG_MIPS_FPR_32(0..31) 32 2470 MIPS KVM_REG_MIPS_FPR_64(0..31) 64 2471 MIPS KVM_REG_MIPS_VEC_128(0..31) 128 2472 MIPS KVM_REG_MIPS_FCR_IR 32 2473 MIPS KVM_REG_MIPS_FCR_CSR 32 2474 MIPS KVM_REG_MIPS_MSA_IR 32 2475 MIPS KVM_REG_MIPS_MSA_CSR 32 2476 ======= =============================== ============ 2477 2478ARM registers are mapped using the lower 32 bits. The upper 16 of that 2479is the register group type, or coprocessor number: 2480 2481ARM core registers have the following id bit patterns:: 2482 2483 0x4020 0000 0010 <index into the kvm_regs struct:16> 2484 2485ARM 32-bit CP15 registers have the following id bit patterns:: 2486 2487 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3> 2488 2489ARM 64-bit CP15 registers have the following id bit patterns:: 2490 2491 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3> 2492 2493ARM CCSIDR registers are demultiplexed by CSSELR value:: 2494 2495 0x4020 0000 0011 00 <csselr:8> 2496 2497ARM 32-bit VFP control registers have the following id bit patterns:: 2498 2499 0x4020 0000 0012 1 <regno:12> 2500 2501ARM 64-bit FP registers have the following id bit patterns:: 2502 2503 0x4030 0000 0012 0 <regno:12> 2504 2505ARM firmware pseudo-registers have the following bit pattern:: 2506 2507 0x4030 0000 0014 <regno:16> 2508 2509 2510arm64 registers are mapped using the lower 32 bits. The upper 16 of 2511that is the register group type, or coprocessor number: 2512 2513arm64 core/FP-SIMD registers have the following id bit patterns. Note 2514that the size of the access is variable, as the kvm_regs structure 2515contains elements ranging from 32 to 128 bits. The index is a 32bit 2516value in the kvm_regs structure seen as a 32bit array:: 2517 2518 0x60x0 0000 0010 <index into the kvm_regs struct:16> 2519 2520Specifically: 2521 2522======================= ========= ===== ======================================= 2523 Encoding Register Bits kvm_regs member 2524======================= ========= ===== ======================================= 2525 0x6030 0000 0010 0000 X0 64 regs.regs[0] 2526 0x6030 0000 0010 0002 X1 64 regs.regs[1] 2527 ... 2528 0x6030 0000 0010 003c X30 64 regs.regs[30] 2529 0x6030 0000 0010 003e SP 64 regs.sp 2530 0x6030 0000 0010 0040 PC 64 regs.pc 2531 0x6030 0000 0010 0042 PSTATE 64 regs.pstate 2532 0x6030 0000 0010 0044 SP_EL1 64 sp_el1 2533 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1 2534 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC) 2535 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT] 2536 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND] 2537 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ] 2538 0x6060 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ] 2539 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_ 2540 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_ 2541 ... 2542 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_ 2543 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr 2544 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr 2545======================= ========= ===== ======================================= 2546 2547.. [1] These encodings are not accepted for SVE-enabled vcpus. See 2548 KVM_ARM_VCPU_INIT. 2549 2550 The equivalent register content can be accessed via bits [127:0] of 2551 the corresponding SVE Zn registers instead for vcpus that have SVE 2552 enabled (see below). 2553 2554arm64 CCSIDR registers are demultiplexed by CSSELR value:: 2555 2556 0x6020 0000 0011 00 <csselr:8> 2557 2558arm64 system registers have the following id bit patterns:: 2559 2560 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3> 2561 2562.. warning:: 2563 2564 Two system register IDs do not follow the specified pattern. These 2565 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to 2566 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These 2567 two had their values accidentally swapped, which means TIMER_CVAL is 2568 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is 2569 derived from the register encoding for CNTV_CVAL_EL0. As this is 2570 API, it must remain this way. 2571 2572arm64 firmware pseudo-registers have the following bit pattern:: 2573 2574 0x6030 0000 0014 <regno:16> 2575 2576arm64 SVE registers have the following bit patterns:: 2577 2578 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice] 2579 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice] 2580 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice] 2581 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register 2582 2583Access to register IDs where 2048 * slice >= 128 * max_vq will fail with 2584ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit 2585quadwords: see [2]_ below. 2586 2587These registers are only accessible on vcpus for which SVE is enabled. 2588See KVM_ARM_VCPU_INIT for details. 2589 2590In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not 2591accessible until the vcpu's SVE configuration has been finalized 2592using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT 2593and KVM_ARM_VCPU_FINALIZE for more information about this procedure. 2594 2595KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector 2596lengths supported by the vcpu to be discovered and configured by 2597userspace. When transferred to or from user memory via KVM_GET_ONE_REG 2598or KVM_SET_ONE_REG, the value of this register is of type 2599__u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as 2600follows:: 2601 2602 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS]; 2603 2604 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX && 2605 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >> 2606 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1)) 2607 /* Vector length vq * 16 bytes supported */ 2608 else 2609 /* Vector length vq * 16 bytes not supported */ 2610 2611.. [2] The maximum value vq for which the above condition is true is 2612 max_vq. This is the maximum vector length available to the guest on 2613 this vcpu, and determines which register slices are visible through 2614 this ioctl interface. 2615 2616(See Documentation/arm64/sve.rst for an explanation of the "vq" 2617nomenclature.) 2618 2619KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT. 2620KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that 2621the host supports. 2622 2623Userspace may subsequently modify it if desired until the vcpu's SVE 2624configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). 2625 2626Apart from simply removing all vector lengths from the host set that 2627exceed some value, support for arbitrarily chosen sets of vector lengths 2628is hardware-dependent and may not be available. Attempting to configure 2629an invalid set of vector lengths via KVM_SET_ONE_REG will fail with 2630EINVAL. 2631 2632After the vcpu's SVE configuration is finalized, further attempts to 2633write this register will fail with EPERM. 2634 2635arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: 2636 2637 0x6030 0000 0016 <regno:16> 2638 2639The bitmap feature firmware registers exposes the hypercall services that 2640are available for userspace to configure. The set bits corresponds to the 2641services that are available for the guests to access. By default, KVM 2642sets all the supported bits during VM initialization. The userspace can 2643discover the available services via KVM_GET_ONE_REG, and write back the 2644bitmap corresponding to the features that it wishes guests to see via 2645KVM_SET_ONE_REG. 2646 2647Note: These registers are immutable once any of the vCPUs of the VM has 2648run at least once. A KVM_SET_ONE_REG in such a scenario will return 2649a -EBUSY to userspace. 2650 2651(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) 2652 2653 2654MIPS registers are mapped using the lower 32 bits. The upper 16 of that is 2655the register group type: 2656 2657MIPS core registers (see above) have the following id bit patterns:: 2658 2659 0x7030 0000 0000 <reg:16> 2660 2661MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit 2662patterns depending on whether they're 32-bit or 64-bit registers:: 2663 2664 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit) 2665 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2666 2667Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64 2668versions of the EntryLo registers regardless of the word size of the host 2669hardware, host kernel, guest, and whether XPA is present in the guest, i.e. 2670with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and 2671the PFNX field starting at bit 30. 2672 2673MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit 2674patterns:: 2675 2676 0x7030 0000 0001 01 <reg:8> 2677 2678MIPS KVM control registers (see above) have the following id bit patterns:: 2679 2680 0x7030 0000 0002 <reg:16> 2681 2682MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following 2683id bit patterns depending on the size of the register being accessed. They are 2684always accessed according to the current guest FPU mode (Status.FR and 2685Config5.FRE), i.e. as the guest would see them, and they become unpredictable 2686if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector 2687registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they 2688overlap the FPU registers:: 2689 2690 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers) 2691 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers) 2692 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers) 2693 2694MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the 2695following id bit patterns:: 2696 2697 0x7020 0000 0003 01 <0:3> <reg:5> 2698 2699MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the 2700following id bit patterns:: 2701 2702 0x7020 0000 0003 02 <0:3> <reg:5> 2703 2704RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of 2705that is the register group type. 2706 2707RISC-V config registers are meant for configuring a Guest VCPU and it has 2708the following id bit patterns:: 2709 2710 0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host) 2711 0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host) 2712 2713Following are the RISC-V config registers: 2714 2715======================= ========= ============================================= 2716 Encoding Register Description 2717======================= ========= ============================================= 2718 0x80x0 0000 0100 0000 isa ISA feature bitmap of Guest VCPU 2719======================= ========= ============================================= 2720 2721The isa config register can be read anytime but can only be written before 2722a Guest VCPU runs. It will have ISA feature bits matching underlying host 2723set by default. 2724 2725RISC-V core registers represent the general excution state of a Guest VCPU 2726and it has the following id bit patterns:: 2727 2728 0x8020 0000 02 <index into the kvm_riscv_core struct:24> (32bit Host) 2729 0x8030 0000 02 <index into the kvm_riscv_core struct:24> (64bit Host) 2730 2731Following are the RISC-V core registers: 2732 2733======================= ========= ============================================= 2734 Encoding Register Description 2735======================= ========= ============================================= 2736 0x80x0 0000 0200 0000 regs.pc Program counter 2737 0x80x0 0000 0200 0001 regs.ra Return address 2738 0x80x0 0000 0200 0002 regs.sp Stack pointer 2739 0x80x0 0000 0200 0003 regs.gp Global pointer 2740 0x80x0 0000 0200 0004 regs.tp Task pointer 2741 0x80x0 0000 0200 0005 regs.t0 Caller saved register 0 2742 0x80x0 0000 0200 0006 regs.t1 Caller saved register 1 2743 0x80x0 0000 0200 0007 regs.t2 Caller saved register 2 2744 0x80x0 0000 0200 0008 regs.s0 Callee saved register 0 2745 0x80x0 0000 0200 0009 regs.s1 Callee saved register 1 2746 0x80x0 0000 0200 000a regs.a0 Function argument (or return value) 0 2747 0x80x0 0000 0200 000b regs.a1 Function argument (or return value) 1 2748 0x80x0 0000 0200 000c regs.a2 Function argument 2 2749 0x80x0 0000 0200 000d regs.a3 Function argument 3 2750 0x80x0 0000 0200 000e regs.a4 Function argument 4 2751 0x80x0 0000 0200 000f regs.a5 Function argument 5 2752 0x80x0 0000 0200 0010 regs.a6 Function argument 6 2753 0x80x0 0000 0200 0011 regs.a7 Function argument 7 2754 0x80x0 0000 0200 0012 regs.s2 Callee saved register 2 2755 0x80x0 0000 0200 0013 regs.s3 Callee saved register 3 2756 0x80x0 0000 0200 0014 regs.s4 Callee saved register 4 2757 0x80x0 0000 0200 0015 regs.s5 Callee saved register 5 2758 0x80x0 0000 0200 0016 regs.s6 Callee saved register 6 2759 0x80x0 0000 0200 0017 regs.s7 Callee saved register 7 2760 0x80x0 0000 0200 0018 regs.s8 Callee saved register 8 2761 0x80x0 0000 0200 0019 regs.s9 Callee saved register 9 2762 0x80x0 0000 0200 001a regs.s10 Callee saved register 10 2763 0x80x0 0000 0200 001b regs.s11 Callee saved register 11 2764 0x80x0 0000 0200 001c regs.t3 Caller saved register 3 2765 0x80x0 0000 0200 001d regs.t4 Caller saved register 4 2766 0x80x0 0000 0200 001e regs.t5 Caller saved register 5 2767 0x80x0 0000 0200 001f regs.t6 Caller saved register 6 2768 0x80x0 0000 0200 0020 mode Privilege mode (1 = S-mode or 0 = U-mode) 2769======================= ========= ============================================= 2770 2771RISC-V csr registers represent the supervisor mode control/status registers 2772of a Guest VCPU and it has the following id bit patterns:: 2773 2774 0x8020 0000 03 <index into the kvm_riscv_csr struct:24> (32bit Host) 2775 0x8030 0000 03 <index into the kvm_riscv_csr struct:24> (64bit Host) 2776 2777Following are the RISC-V csr registers: 2778 2779======================= ========= ============================================= 2780 Encoding Register Description 2781======================= ========= ============================================= 2782 0x80x0 0000 0300 0000 sstatus Supervisor status 2783 0x80x0 0000 0300 0001 sie Supervisor interrupt enable 2784 0x80x0 0000 0300 0002 stvec Supervisor trap vector base 2785 0x80x0 0000 0300 0003 sscratch Supervisor scratch register 2786 0x80x0 0000 0300 0004 sepc Supervisor exception program counter 2787 0x80x0 0000 0300 0005 scause Supervisor trap cause 2788 0x80x0 0000 0300 0006 stval Supervisor bad address or instruction 2789 0x80x0 0000 0300 0007 sip Supervisor interrupt pending 2790 0x80x0 0000 0300 0008 satp Supervisor address translation and protection 2791======================= ========= ============================================= 2792 2793RISC-V timer registers represent the timer state of a Guest VCPU and it has 2794the following id bit patterns:: 2795 2796 0x8030 0000 04 <index into the kvm_riscv_timer struct:24> 2797 2798Following are the RISC-V timer registers: 2799 2800======================= ========= ============================================= 2801 Encoding Register Description 2802======================= ========= ============================================= 2803 0x8030 0000 0400 0000 frequency Time base frequency (read-only) 2804 0x8030 0000 0400 0001 time Time value visible to Guest 2805 0x8030 0000 0400 0002 compare Time compare programmed by Guest 2806 0x8030 0000 0400 0003 state Time compare state (1 = ON or 0 = OFF) 2807======================= ========= ============================================= 2808 2809RISC-V F-extension registers represent the single precision floating point 2810state of a Guest VCPU and it has the following id bit patterns:: 2811 2812 0x8020 0000 05 <index into the __riscv_f_ext_state struct:24> 2813 2814Following are the RISC-V F-extension registers: 2815 2816======================= ========= ============================================= 2817 Encoding Register Description 2818======================= ========= ============================================= 2819 0x8020 0000 0500 0000 f[0] Floating point register 0 2820 ... 2821 0x8020 0000 0500 001f f[31] Floating point register 31 2822 0x8020 0000 0500 0020 fcsr Floating point control and status register 2823======================= ========= ============================================= 2824 2825RISC-V D-extension registers represent the double precision floating point 2826state of a Guest VCPU and it has the following id bit patterns:: 2827 2828 0x8020 0000 06 <index into the __riscv_d_ext_state struct:24> (fcsr) 2829 0x8030 0000 06 <index into the __riscv_d_ext_state struct:24> (non-fcsr) 2830 2831Following are the RISC-V D-extension registers: 2832 2833======================= ========= ============================================= 2834 Encoding Register Description 2835======================= ========= ============================================= 2836 0x8030 0000 0600 0000 f[0] Floating point register 0 2837 ... 2838 0x8030 0000 0600 001f f[31] Floating point register 31 2839 0x8020 0000 0600 0020 fcsr Floating point control and status register 2840======================= ========= ============================================= 2841 2842 28434.69 KVM_GET_ONE_REG 2844-------------------- 2845 2846:Capability: KVM_CAP_ONE_REG 2847:Architectures: all 2848:Type: vcpu ioctl 2849:Parameters: struct kvm_one_reg (in and out) 2850:Returns: 0 on success, negative value on failure 2851 2852Errors include: 2853 2854 ======== ============================================================ 2855 ENOENT no such register 2856 EINVAL invalid register ID, or no such register or used with VMs in 2857 protected virtualization mode on s390 2858 EPERM (arm64) register access not allowed before vcpu finalization 2859 ======== ============================================================ 2860 2861(These error codes are indicative only: do not rely on a specific error 2862code being returned in a specific situation.) 2863 2864This ioctl allows to receive the value of a single register implemented 2865in a vcpu. The register to read is indicated by the "id" field of the 2866kvm_one_reg struct passed in. On success, the register value can be found 2867at the memory location pointed to by "addr". 2868 2869The list of registers accessible using this interface is identical to the 2870list in 4.68. 2871 2872 28734.70 KVM_KVMCLOCK_CTRL 2874---------------------- 2875 2876:Capability: KVM_CAP_KVMCLOCK_CTRL 2877:Architectures: Any that implement pvclocks (currently x86 only) 2878:Type: vcpu ioctl 2879:Parameters: None 2880:Returns: 0 on success, -1 on error 2881 2882This ioctl sets a flag accessible to the guest indicating that the specified 2883vCPU has been paused by the host userspace. 2884 2885The host will set a flag in the pvclock structure that is checked from the 2886soft lockup watchdog. The flag is part of the pvclock structure that is 2887shared between guest and host, specifically the second bit of the flags 2888field of the pvclock_vcpu_time_info structure. It will be set exclusively by 2889the host and read/cleared exclusively by the guest. The guest operation of 2890checking and clearing the flag must be an atomic operation so 2891load-link/store-conditional, or equivalent must be used. There are two cases 2892where the guest will clear the flag: when the soft lockup watchdog timer resets 2893itself or when a soft lockup is detected. This ioctl can be called any time 2894after pausing the vcpu, but before it is resumed. 2895 2896 28974.71 KVM_SIGNAL_MSI 2898------------------- 2899 2900:Capability: KVM_CAP_SIGNAL_MSI 2901:Architectures: x86 arm64 2902:Type: vm ioctl 2903:Parameters: struct kvm_msi (in) 2904:Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error 2905 2906Directly inject a MSI message. Only valid with in-kernel irqchip that handles 2907MSI messages. 2908 2909:: 2910 2911 struct kvm_msi { 2912 __u32 address_lo; 2913 __u32 address_hi; 2914 __u32 data; 2915 __u32 flags; 2916 __u32 devid; 2917 __u8 pad[12]; 2918 }; 2919 2920flags: 2921 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM 2922 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 2923 the device ID. If this capability is not available, userspace 2924 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 2925 2926If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 2927for the device that wrote the MSI message. For PCI, this is usually a 2928BFD identifier in the lower 16 bits. 2929 2930On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 2931feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 2932address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 2933address_hi must be zero. 2934 2935 29364.71 KVM_CREATE_PIT2 2937-------------------- 2938 2939:Capability: KVM_CAP_PIT2 2940:Architectures: x86 2941:Type: vm ioctl 2942:Parameters: struct kvm_pit_config (in) 2943:Returns: 0 on success, -1 on error 2944 2945Creates an in-kernel device model for the i8254 PIT. This call is only valid 2946after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following 2947parameters have to be passed:: 2948 2949 struct kvm_pit_config { 2950 __u32 flags; 2951 __u32 pad[15]; 2952 }; 2953 2954Valid flags are:: 2955 2956 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */ 2957 2958PIT timer interrupts may use a per-VM kernel thread for injection. If it 2959exists, this thread will have a name of the following pattern:: 2960 2961 kvm-pit/<owner-process-pid> 2962 2963When running a guest with elevated priorities, the scheduling parameters of 2964this thread may have to be adjusted accordingly. 2965 2966This IOCTL replaces the obsolete KVM_CREATE_PIT. 2967 2968 29694.72 KVM_GET_PIT2 2970----------------- 2971 2972:Capability: KVM_CAP_PIT_STATE2 2973:Architectures: x86 2974:Type: vm ioctl 2975:Parameters: struct kvm_pit_state2 (out) 2976:Returns: 0 on success, -1 on error 2977 2978Retrieves the state of the in-kernel PIT model. Only valid after 2979KVM_CREATE_PIT2. The state is returned in the following structure:: 2980 2981 struct kvm_pit_state2 { 2982 struct kvm_pit_channel_state channels[3]; 2983 __u32 flags; 2984 __u32 reserved[9]; 2985 }; 2986 2987Valid flags are:: 2988 2989 /* disable PIT in HPET legacy mode */ 2990 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 2991 /* speaker port data bit enabled */ 2992 #define KVM_PIT_FLAGS_SPEAKER_DATA_ON 0x00000002 2993 2994This IOCTL replaces the obsolete KVM_GET_PIT. 2995 2996 29974.73 KVM_SET_PIT2 2998----------------- 2999 3000:Capability: KVM_CAP_PIT_STATE2 3001:Architectures: x86 3002:Type: vm ioctl 3003:Parameters: struct kvm_pit_state2 (in) 3004:Returns: 0 on success, -1 on error 3005 3006Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. 3007See KVM_GET_PIT2 for details on struct kvm_pit_state2. 3008 3009This IOCTL replaces the obsolete KVM_SET_PIT. 3010 3011 30124.74 KVM_PPC_GET_SMMU_INFO 3013-------------------------- 3014 3015:Capability: KVM_CAP_PPC_GET_SMMU_INFO 3016:Architectures: powerpc 3017:Type: vm ioctl 3018:Parameters: None 3019:Returns: 0 on success, -1 on error 3020 3021This populates and returns a structure describing the features of 3022the "Server" class MMU emulation supported by KVM. 3023This can in turn be used by userspace to generate the appropriate 3024device-tree properties for the guest operating system. 3025 3026The structure contains some global information, followed by an 3027array of supported segment page sizes:: 3028 3029 struct kvm_ppc_smmu_info { 3030 __u64 flags; 3031 __u32 slb_size; 3032 __u32 pad; 3033 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3034 }; 3035 3036The supported flags are: 3037 3038 - KVM_PPC_PAGE_SIZES_REAL: 3039 When that flag is set, guest page sizes must "fit" the backing 3040 store page sizes. When not set, any page size in the list can 3041 be used regardless of how they are backed by userspace. 3042 3043 - KVM_PPC_1T_SEGMENTS 3044 The emulated MMU supports 1T segments in addition to the 3045 standard 256M ones. 3046 3047 - KVM_PPC_NO_HASH 3048 This flag indicates that HPT guests are not supported by KVM, 3049 thus all guests must use radix MMU mode. 3050 3051The "slb_size" field indicates how many SLB entries are supported 3052 3053The "sps" array contains 8 entries indicating the supported base 3054page sizes for a segment in increasing order. Each entry is defined 3055as follow:: 3056 3057 struct kvm_ppc_one_seg_page_size { 3058 __u32 page_shift; /* Base page shift of segment (or 0) */ 3059 __u32 slb_enc; /* SLB encoding for BookS */ 3060 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3061 }; 3062 3063An entry with a "page_shift" of 0 is unused. Because the array is 3064organized in increasing order, a lookup can stop when encoutering 3065such an entry. 3066 3067The "slb_enc" field provides the encoding to use in the SLB for the 3068page size. The bits are in positions such as the value can directly 3069be OR'ed into the "vsid" argument of the slbmte instruction. 3070 3071The "enc" array is a list which for each of those segment base page 3072size provides the list of supported actual page sizes (which can be 3073only larger or equal to the base page size), along with the 3074corresponding encoding in the hash PTE. Similarly, the array is 30758 entries sorted by increasing sizes and an entry with a "0" shift 3076is an empty entry and a terminator:: 3077 3078 struct kvm_ppc_one_page_size { 3079 __u32 page_shift; /* Page shift (or 0) */ 3080 __u32 pte_enc; /* Encoding in the HPTE (>>12) */ 3081 }; 3082 3083The "pte_enc" field provides a value that can OR'ed into the hash 3084PTE's RPN field (ie, it needs to be shifted left by 12 to OR it 3085into the hash PTE second double word). 3086 30874.75 KVM_IRQFD 3088-------------- 3089 3090:Capability: KVM_CAP_IRQFD 3091:Architectures: x86 s390 arm64 3092:Type: vm ioctl 3093:Parameters: struct kvm_irqfd (in) 3094:Returns: 0 on success, -1 on error 3095 3096Allows setting an eventfd to directly trigger a guest interrupt. 3097kvm_irqfd.fd specifies the file descriptor to use as the eventfd and 3098kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When 3099an event is triggered on the eventfd, an interrupt is injected into 3100the guest using the specified gsi pin. The irqfd is removed using 3101the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd 3102and kvm_irqfd.gsi. 3103 3104With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify 3105mechanism allowing emulation of level-triggered, irqfd-based 3106interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an 3107additional eventfd in the kvm_irqfd.resamplefd field. When operating 3108in resample mode, posting of an interrupt through kvm_irq.fd asserts 3109the specified gsi in the irqchip. When the irqchip is resampled, such 3110as from an EOI, the gsi is de-asserted and the user is notified via 3111kvm_irqfd.resamplefd. It is the user's responsibility to re-queue 3112the interrupt if the device making use of it still requires service. 3113Note that closing the resamplefd is not sufficient to disable the 3114irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment 3115and need not be specified with KVM_IRQFD_FLAG_DEASSIGN. 3116 3117On arm64, gsi routing being supported, the following can happen: 3118 3119- in case no routing entry is associated to this gsi, injection fails 3120- in case the gsi is associated to an irqchip routing entry, 3121 irqchip.pin + 32 corresponds to the injected SPI ID. 3122- in case the gsi is associated to an MSI routing entry, the MSI 3123 message and device ID are translated into an LPI (support restricted 3124 to GICv3 ITS in-kernel emulation). 3125 31264.76 KVM_PPC_ALLOCATE_HTAB 3127-------------------------- 3128 3129:Capability: KVM_CAP_PPC_ALLOC_HTAB 3130:Architectures: powerpc 3131:Type: vm ioctl 3132:Parameters: Pointer to u32 containing hash table order (in/out) 3133:Returns: 0 on success, -1 on error 3134 3135This requests the host kernel to allocate an MMU hash table for a 3136guest using the PAPR paravirtualization interface. This only does 3137anything if the kernel is configured to use the Book 3S HV style of 3138virtualization. Otherwise the capability doesn't exist and the ioctl 3139returns an ENOTTY error. The rest of this description assumes Book 3S 3140HV. 3141 3142There must be no vcpus running when this ioctl is called; if there 3143are, it will do nothing and return an EBUSY error. 3144 3145The parameter is a pointer to a 32-bit unsigned integer variable 3146containing the order (log base 2) of the desired size of the hash 3147table, which must be between 18 and 46. On successful return from the 3148ioctl, the value will not be changed by the kernel. 3149 3150If no hash table has been allocated when any vcpu is asked to run 3151(with the KVM_RUN ioctl), the host kernel will allocate a 3152default-sized hash table (16 MB). 3153 3154If this ioctl is called when a hash table has already been allocated, 3155with a different order from the existing hash table, the existing hash 3156table will be freed and a new one allocated. If this is ioctl is 3157called when a hash table has already been allocated of the same order 3158as specified, the kernel will clear out the existing hash table (zero 3159all HPTEs). In either case, if the guest is using the virtualized 3160real-mode area (VRMA) facility, the kernel will re-create the VMRA 3161HPTEs on the next KVM_RUN of any vcpu. 3162 31634.77 KVM_S390_INTERRUPT 3164----------------------- 3165 3166:Capability: basic 3167:Architectures: s390 3168:Type: vm ioctl, vcpu ioctl 3169:Parameters: struct kvm_s390_interrupt (in) 3170:Returns: 0 on success, -1 on error 3171 3172Allows to inject an interrupt to the guest. Interrupts can be floating 3173(vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type. 3174 3175Interrupt parameters are passed via kvm_s390_interrupt:: 3176 3177 struct kvm_s390_interrupt { 3178 __u32 type; 3179 __u32 parm; 3180 __u64 parm64; 3181 }; 3182 3183type can be one of the following: 3184 3185KVM_S390_SIGP_STOP (vcpu) 3186 - sigp stop; optional flags in parm 3187KVM_S390_PROGRAM_INT (vcpu) 3188 - program check; code in parm 3189KVM_S390_SIGP_SET_PREFIX (vcpu) 3190 - sigp set prefix; prefix address in parm 3191KVM_S390_RESTART (vcpu) 3192 - restart 3193KVM_S390_INT_CLOCK_COMP (vcpu) 3194 - clock comparator interrupt 3195KVM_S390_INT_CPU_TIMER (vcpu) 3196 - CPU timer interrupt 3197KVM_S390_INT_VIRTIO (vm) 3198 - virtio external interrupt; external interrupt 3199 parameters in parm and parm64 3200KVM_S390_INT_SERVICE (vm) 3201 - sclp external interrupt; sclp parameter in parm 3202KVM_S390_INT_EMERGENCY (vcpu) 3203 - sigp emergency; source cpu in parm 3204KVM_S390_INT_EXTERNAL_CALL (vcpu) 3205 - sigp external call; source cpu in parm 3206KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) 3207 - compound value to indicate an 3208 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel); 3209 I/O interruption parameters in parm (subchannel) and parm64 (intparm, 3210 interruption subclass) 3211KVM_S390_MCHK (vm, vcpu) 3212 - machine check interrupt; cr 14 bits in parm, machine check interrupt 3213 code in parm64 (note that machine checks needing further payload are not 3214 supported by this ioctl) 3215 3216This is an asynchronous vcpu ioctl and can be invoked from any thread. 3217 32184.78 KVM_PPC_GET_HTAB_FD 3219------------------------ 3220 3221:Capability: KVM_CAP_PPC_HTAB_FD 3222:Architectures: powerpc 3223:Type: vm ioctl 3224:Parameters: Pointer to struct kvm_get_htab_fd (in) 3225:Returns: file descriptor number (>= 0) on success, -1 on error 3226 3227This returns a file descriptor that can be used either to read out the 3228entries in the guest's hashed page table (HPT), or to write entries to 3229initialize the HPT. The returned fd can only be written to if the 3230KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and 3231can only be read if that bit is clear. The argument struct looks like 3232this:: 3233 3234 /* For KVM_PPC_GET_HTAB_FD */ 3235 struct kvm_get_htab_fd { 3236 __u64 flags; 3237 __u64 start_index; 3238 __u64 reserved[2]; 3239 }; 3240 3241 /* Values for kvm_get_htab_fd.flags */ 3242 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1) 3243 #define KVM_GET_HTAB_WRITE ((__u64)0x2) 3244 3245The 'start_index' field gives the index in the HPT of the entry at 3246which to start reading. It is ignored when writing. 3247 3248Reads on the fd will initially supply information about all 3249"interesting" HPT entries. Interesting entries are those with the 3250bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise 3251all entries. When the end of the HPT is reached, the read() will 3252return. If read() is called again on the fd, it will start again from 3253the beginning of the HPT, but will only return HPT entries that have 3254changed since they were last read. 3255 3256Data read or written is structured as a header (8 bytes) followed by a 3257series of valid HPT entries (16 bytes) each. The header indicates how 3258many valid HPT entries there are and how many invalid entries follow 3259the valid entries. The invalid entries are not represented explicitly 3260in the stream. The header format is:: 3261 3262 struct kvm_get_htab_header { 3263 __u32 index; 3264 __u16 n_valid; 3265 __u16 n_invalid; 3266 }; 3267 3268Writes to the fd create HPT entries starting at the index given in the 3269header; first 'n_valid' valid entries with contents from the data 3270written, then 'n_invalid' invalid entries, invalidating any previously 3271valid entries found. 3272 32734.79 KVM_CREATE_DEVICE 3274---------------------- 3275 3276:Capability: KVM_CAP_DEVICE_CTRL 3277:Architectures: all 3278:Type: vm ioctl 3279:Parameters: struct kvm_create_device (in/out) 3280:Returns: 0 on success, -1 on error 3281 3282Errors: 3283 3284 ====== ======================================================= 3285 ENODEV The device type is unknown or unsupported 3286 EEXIST Device already created, and this type of device may not 3287 be instantiated multiple times 3288 ====== ======================================================= 3289 3290 Other error conditions may be defined by individual device types or 3291 have their standard meanings. 3292 3293Creates an emulated device in the kernel. The file descriptor returned 3294in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR. 3295 3296If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the 3297device type is supported (not necessarily whether it can be created 3298in the current vm). 3299 3300Individual devices should not define flags. Attributes should be used 3301for specifying any behavior that is not implied by the device type 3302number. 3303 3304:: 3305 3306 struct kvm_create_device { 3307 __u32 type; /* in: KVM_DEV_TYPE_xxx */ 3308 __u32 fd; /* out: device handle */ 3309 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ 3310 }; 3311 33124.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR 3313-------------------------------------------- 3314 3315:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3316 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3317 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device (no set) 3318:Architectures: x86, arm64, s390 3319:Type: device ioctl, vm ioctl, vcpu ioctl 3320:Parameters: struct kvm_device_attr 3321:Returns: 0 on success, -1 on error 3322 3323Errors: 3324 3325 ===== ============================================================= 3326 ENXIO The group or attribute is unknown/unsupported for this device 3327 or hardware support is missing. 3328 EPERM The attribute cannot (currently) be accessed this way 3329 (e.g. read-only attribute, or attribute that only makes 3330 sense when the device is in a different state) 3331 ===== ============================================================= 3332 3333 Other error conditions may be defined by individual device types. 3334 3335Gets/sets a specified piece of device configuration and/or state. The 3336semantics are device-specific. See individual device documentation in 3337the "devices" directory. As with ONE_REG, the size of the data 3338transferred is defined by the particular attribute. 3339 3340:: 3341 3342 struct kvm_device_attr { 3343 __u32 flags; /* no flags currently defined */ 3344 __u32 group; /* device-defined */ 3345 __u64 attr; /* group-defined */ 3346 __u64 addr; /* userspace address of attr data */ 3347 }; 3348 33494.81 KVM_HAS_DEVICE_ATTR 3350------------------------ 3351 3352:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3353 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3354 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device 3355:Type: device ioctl, vm ioctl, vcpu ioctl 3356:Parameters: struct kvm_device_attr 3357:Returns: 0 on success, -1 on error 3358 3359Errors: 3360 3361 ===== ============================================================= 3362 ENXIO The group or attribute is unknown/unsupported for this device 3363 or hardware support is missing. 3364 ===== ============================================================= 3365 3366Tests whether a device supports a particular attribute. A successful 3367return indicates the attribute is implemented. It does not necessarily 3368indicate that the attribute can be read or written in the device's 3369current state. "addr" is ignored. 3370 33714.82 KVM_ARM_VCPU_INIT 3372---------------------- 3373 3374:Capability: basic 3375:Architectures: arm64 3376:Type: vcpu ioctl 3377:Parameters: struct kvm_vcpu_init (in) 3378:Returns: 0 on success; -1 on error 3379 3380Errors: 3381 3382 ====== ================================================================= 3383 EINVAL the target is unknown, or the combination of features is invalid. 3384 ENOENT a features bit specified is unknown. 3385 ====== ================================================================= 3386 3387This tells KVM what type of CPU to present to the guest, and what 3388optional features it should have. This will cause a reset of the cpu 3389registers to their initial values. If this is not called, KVM_RUN will 3390return ENOEXEC for that vcpu. 3391 3392The initial values are defined as: 3393 - Processor state: 3394 * AArch64: EL1h, D, A, I and F bits set. All other bits 3395 are cleared. 3396 * AArch32: SVC, A, I and F bits set. All other bits are 3397 cleared. 3398 - General Purpose registers, including PC and SP: set to 0 3399 - FPSIMD/NEON registers: set to 0 3400 - SVE registers: set to 0 3401 - System registers: Reset to their architecturally defined 3402 values as for a warm reset to EL1 (resp. SVC) 3403 3404Note that because some registers reflect machine topology, all vcpus 3405should be created before this ioctl is invoked. 3406 3407Userspace can call this function multiple times for a given vcpu, including 3408after the vcpu has been run. This will reset the vcpu to its initial 3409state. All calls to this function after the initial call must use the same 3410target and same set of feature flags, otherwise EINVAL will be returned. 3411 3412Possible features: 3413 3414 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. 3415 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on 3416 and execute guest code when KVM_RUN is called. 3417 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. 3418 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). 3419 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision 3420 backward compatible with v0.2) for the CPU. 3421 Depends on KVM_CAP_ARM_PSCI_0_2. 3422 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. 3423 Depends on KVM_CAP_ARM_PMU_V3. 3424 3425 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication 3426 for arm64 only. 3427 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. 3428 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3429 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3430 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3431 requested. 3432 3433 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication 3434 for arm64 only. 3435 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. 3436 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3437 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3438 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3439 requested. 3440 3441 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). 3442 Depends on KVM_CAP_ARM_SVE. 3443 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3444 3445 * After KVM_ARM_VCPU_INIT: 3446 3447 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the 3448 initial value of this pseudo-register indicates the best set of 3449 vector lengths possible for a vcpu on this host. 3450 3451 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3452 3453 - KVM_RUN and KVM_GET_REG_LIST are not available; 3454 3455 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access 3456 the scalable archietctural SVE registers 3457 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or 3458 KVM_REG_ARM64_SVE_FFR; 3459 3460 - KVM_REG_ARM64_SVE_VLS may optionally be written using 3461 KVM_SET_ONE_REG, to modify the set of vector lengths available 3462 for the vcpu. 3463 3464 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3465 3466 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can 3467 no longer be written using KVM_SET_ONE_REG. 3468 34694.83 KVM_ARM_PREFERRED_TARGET 3470----------------------------- 3471 3472:Capability: basic 3473:Architectures: arm64 3474:Type: vm ioctl 3475:Parameters: struct kvm_vcpu_init (out) 3476:Returns: 0 on success; -1 on error 3477 3478Errors: 3479 3480 ====== ========================================== 3481 ENODEV no preferred target available for the host 3482 ====== ========================================== 3483 3484This queries KVM for preferred CPU target type which can be emulated 3485by KVM on underlying host. 3486 3487The ioctl returns struct kvm_vcpu_init instance containing information 3488about preferred CPU target type and recommended features for it. The 3489kvm_vcpu_init->features bitmap returned will have feature bits set if 3490the preferred target recommends setting these features, but this is 3491not mandatory. 3492 3493The information returned by this ioctl can be used to prepare an instance 3494of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in 3495VCPU matching underlying host. 3496 3497 34984.84 KVM_GET_REG_LIST 3499--------------------- 3500 3501:Capability: basic 3502:Architectures: arm64, mips 3503:Type: vcpu ioctl 3504:Parameters: struct kvm_reg_list (in/out) 3505:Returns: 0 on success; -1 on error 3506 3507Errors: 3508 3509 ===== ============================================================== 3510 E2BIG the reg index list is too big to fit in the array specified by 3511 the user (the number required will be written into n). 3512 ===== ============================================================== 3513 3514:: 3515 3516 struct kvm_reg_list { 3517 __u64 n; /* number of registers in reg[] */ 3518 __u64 reg[0]; 3519 }; 3520 3521This ioctl returns the guest registers that are supported for the 3522KVM_GET_ONE_REG/KVM_SET_ONE_REG calls. 3523 3524 35254.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) 3526----------------------------------------- 3527 3528:Capability: KVM_CAP_ARM_SET_DEVICE_ADDR 3529:Architectures: arm64 3530:Type: vm ioctl 3531:Parameters: struct kvm_arm_device_address (in) 3532:Returns: 0 on success, -1 on error 3533 3534Errors: 3535 3536 ====== ============================================ 3537 ENODEV The device id is unknown 3538 ENXIO Device not supported on current system 3539 EEXIST Address already set 3540 E2BIG Address outside guest physical address space 3541 EBUSY Address overlaps with other device range 3542 ====== ============================================ 3543 3544:: 3545 3546 struct kvm_arm_device_addr { 3547 __u64 id; 3548 __u64 addr; 3549 }; 3550 3551Specify a device address in the guest's physical address space where guests 3552can access emulated or directly exposed devices, which the host kernel needs 3553to know about. The id field is an architecture specific identifier for a 3554specific device. 3555 3556arm64 divides the id field into two parts, a device id and an 3557address type id specific to the individual device:: 3558 3559 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 | 3560 field: | 0x00000000 | device id | addr type id | 3561 3562arm64 currently only require this when using the in-kernel GIC 3563support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 3564as the device id. When setting the base address for the guest's 3565mapping of the VGIC virtual CPU and distributor interface, the ioctl 3566must be called after calling KVM_CREATE_IRQCHIP, but before calling 3567KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the 3568base addresses will return -EEXIST. 3569 3570Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API 3571should be used instead. 3572 3573 35744.86 KVM_PPC_RTAS_DEFINE_TOKEN 3575------------------------------ 3576 3577:Capability: KVM_CAP_PPC_RTAS 3578:Architectures: ppc 3579:Type: vm ioctl 3580:Parameters: struct kvm_rtas_token_args 3581:Returns: 0 on success, -1 on error 3582 3583Defines a token value for a RTAS (Run Time Abstraction Services) 3584service in order to allow it to be handled in the kernel. The 3585argument struct gives the name of the service, which must be the name 3586of a service that has a kernel-side implementation. If the token 3587value is non-zero, it will be associated with that service, and 3588subsequent RTAS calls by the guest specifying that token will be 3589handled by the kernel. If the token value is 0, then any token 3590associated with the service will be forgotten, and subsequent RTAS 3591calls by the guest for that service will be passed to userspace to be 3592handled. 3593 35944.87 KVM_SET_GUEST_DEBUG 3595------------------------ 3596 3597:Capability: KVM_CAP_SET_GUEST_DEBUG 3598:Architectures: x86, s390, ppc, arm64 3599:Type: vcpu ioctl 3600:Parameters: struct kvm_guest_debug (in) 3601:Returns: 0 on success; -1 on error 3602 3603:: 3604 3605 struct kvm_guest_debug { 3606 __u32 control; 3607 __u32 pad; 3608 struct kvm_guest_debug_arch arch; 3609 }; 3610 3611Set up the processor specific debug registers and configure vcpu for 3612handling guest debug events. There are two parts to the structure, the 3613first a control bitfield indicates the type of debug events to handle 3614when running. Common control bits are: 3615 3616 - KVM_GUESTDBG_ENABLE: guest debugging is enabled 3617 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step 3618 3619The top 16 bits of the control field are architecture specific control 3620flags which can include the following: 3621 3622 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] 3623 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] 3624 - KVM_GUESTDBG_USE_HW: using hardware debug events [arm64] 3625 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] 3626 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] 3627 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] 3628 - KVM_GUESTDBG_BLOCKIRQ: avoid injecting interrupts/NMI/SMI [x86] 3629 3630For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints 3631are enabled in memory so we need to ensure breakpoint exceptions are 3632correctly trapped and the KVM run loop exits at the breakpoint and not 3633running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP 3634we need to ensure the guest vCPUs architecture specific registers are 3635updated to the correct (supplied) values. 3636 3637The second part of the structure is architecture specific and 3638typically contains a set of debug registers. 3639 3640For arm64 the number of debug registers is implementation defined and 3641can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and 3642KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number 3643indicating the number of supported registers. 3644 3645For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether 3646the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported. 3647 3648Also when supported, KVM_CAP_SET_GUEST_DEBUG2 capability indicates the 3649supported KVM_GUESTDBG_* bits in the control field. 3650 3651When debug events exit the main run loop with the reason 3652KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run 3653structure containing architecture specific debug information. 3654 36554.88 KVM_GET_EMULATED_CPUID 3656--------------------------- 3657 3658:Capability: KVM_CAP_EXT_EMUL_CPUID 3659:Architectures: x86 3660:Type: system ioctl 3661:Parameters: struct kvm_cpuid2 (in/out) 3662:Returns: 0 on success, -1 on error 3663 3664:: 3665 3666 struct kvm_cpuid2 { 3667 __u32 nent; 3668 __u32 flags; 3669 struct kvm_cpuid_entry2 entries[0]; 3670 }; 3671 3672The member 'flags' is used for passing flags from userspace. 3673 3674:: 3675 3676 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 3677 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 3678 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 3679 3680 struct kvm_cpuid_entry2 { 3681 __u32 function; 3682 __u32 index; 3683 __u32 flags; 3684 __u32 eax; 3685 __u32 ebx; 3686 __u32 ecx; 3687 __u32 edx; 3688 __u32 padding[3]; 3689 }; 3690 3691This ioctl returns x86 cpuid features which are emulated by 3692kvm.Userspace can use the information returned by this ioctl to query 3693which features are emulated by kvm instead of being present natively. 3694 3695Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2 3696structure with the 'nent' field indicating the number of entries in 3697the variable-size array 'entries'. If the number of entries is too low 3698to describe the cpu capabilities, an error (E2BIG) is returned. If the 3699number is too high, the 'nent' field is adjusted and an error (ENOMEM) 3700is returned. If the number is just right, the 'nent' field is adjusted 3701to the number of valid entries in the 'entries' array, which is then 3702filled. 3703 3704The entries returned are the set CPUID bits of the respective features 3705which kvm emulates, as returned by the CPUID instruction, with unknown 3706or unsupported feature bits cleared. 3707 3708Features like x2apic, for example, may not be present in the host cpu 3709but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be 3710emulated efficiently and thus not included here. 3711 3712The fields in each entry are defined as follows: 3713 3714 function: 3715 the eax value used to obtain the entry 3716 index: 3717 the ecx value used to obtain the entry (for entries that are 3718 affected by ecx) 3719 flags: 3720 an OR of zero or more of the following: 3721 3722 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 3723 if the index field is valid 3724 3725 eax, ebx, ecx, edx: 3726 3727 the values returned by the cpuid instruction for 3728 this function/index combination 3729 37304.89 KVM_S390_MEM_OP 3731-------------------- 3732 3733:Capability: KVM_CAP_S390_MEM_OP, KVM_CAP_S390_PROTECTED, KVM_CAP_S390_MEM_OP_EXTENSION 3734:Architectures: s390 3735:Type: vm ioctl, vcpu ioctl 3736:Parameters: struct kvm_s390_mem_op (in) 3737:Returns: = 0 on success, 3738 < 0 on generic error (e.g. -EFAULT or -ENOMEM), 3739 > 0 if an exception occurred while walking the page tables 3740 3741Read or write data from/to the VM's memory. 3742The KVM_CAP_S390_MEM_OP_EXTENSION capability specifies what functionality is 3743supported. 3744 3745Parameters are specified via the following structure:: 3746 3747 struct kvm_s390_mem_op { 3748 __u64 gaddr; /* the guest address */ 3749 __u64 flags; /* flags */ 3750 __u32 size; /* amount of bytes */ 3751 __u32 op; /* type of operation */ 3752 __u64 buf; /* buffer in userspace */ 3753 union { 3754 struct { 3755 __u8 ar; /* the access register number */ 3756 __u8 key; /* access key, ignored if flag unset */ 3757 }; 3758 __u32 sida_offset; /* offset into the sida */ 3759 __u8 reserved[32]; /* ignored */ 3760 }; 3761 }; 3762 3763The start address of the memory region has to be specified in the "gaddr" 3764field, and the length of the region in the "size" field (which must not 3765be 0). The maximum value for "size" can be obtained by checking the 3766KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the 3767userspace application where the read data should be written to for 3768a read access, or where the data that should be written is stored for 3769a write access. The "reserved" field is meant for future extensions. 3770Reserved and unused values are ignored. Future extension that add members must 3771introduce new flags. 3772 3773The type of operation is specified in the "op" field. Flags modifying 3774their behavior can be set in the "flags" field. Undefined flag bits must 3775be set to 0. 3776 3777Possible operations are: 3778 * ``KVM_S390_MEMOP_LOGICAL_READ`` 3779 * ``KVM_S390_MEMOP_LOGICAL_WRITE`` 3780 * ``KVM_S390_MEMOP_ABSOLUTE_READ`` 3781 * ``KVM_S390_MEMOP_ABSOLUTE_WRITE`` 3782 * ``KVM_S390_MEMOP_SIDA_READ`` 3783 * ``KVM_S390_MEMOP_SIDA_WRITE`` 3784 3785Logical read/write: 3786^^^^^^^^^^^^^^^^^^^ 3787 3788Access logical memory, i.e. translate the given guest address to an absolute 3789address given the state of the VCPU and use the absolute address as target of 3790the access. "ar" designates the access register number to be used; the valid 3791range is 0..15. 3792Logical accesses are permitted for the VCPU ioctl only. 3793Logical accesses are permitted for non-protected guests only. 3794 3795Supported flags: 3796 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3797 * ``KVM_S390_MEMOP_F_INJECT_EXCEPTION`` 3798 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3799 3800The KVM_S390_MEMOP_F_CHECK_ONLY flag can be set to check whether the 3801corresponding memory access would cause an access exception; however, 3802no actual access to the data in memory at the destination is performed. 3803In this case, "buf" is unused and can be NULL. 3804 3805In case an access exception occurred during the access (or would occur 3806in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive 3807error number indicating the type of exception. This exception is also 3808raised directly at the corresponding VCPU if the flag 3809KVM_S390_MEMOP_F_INJECT_EXCEPTION is set. 3810On protection exceptions, unless specified otherwise, the injected 3811translation-exception identifier (TEID) indicates suppression. 3812 3813If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key 3814protection is also in effect and may cause exceptions if accesses are 3815prohibited given the access key designated by "key"; the valid range is 0..15. 3816KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION 3817is > 0. 3818Since the accessed memory may span multiple pages and those pages might have 3819different storage keys, it is possible that a protection exception occurs 3820after memory has been modified. In this case, if the exception is injected, 3821the TEID does not indicate suppression. 3822 3823Absolute read/write: 3824^^^^^^^^^^^^^^^^^^^^ 3825 3826Access absolute memory. This operation is intended to be used with the 3827KVM_S390_MEMOP_F_SKEY_PROTECTION flag, to allow accessing memory and performing 3828the checks required for storage key protection as one operation (as opposed to 3829user space getting the storage keys, performing the checks, and accessing 3830memory thereafter, which could lead to a delay between check and access). 3831Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION 3832is > 0. 3833Currently absolute accesses are not permitted for VCPU ioctls. 3834Absolute accesses are permitted for non-protected guests only. 3835 3836Supported flags: 3837 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3838 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3839 3840The semantics of the flags are as for logical accesses. 3841 3842SIDA read/write: 3843^^^^^^^^^^^^^^^^ 3844 3845Access the secure instruction data area which contains memory operands necessary 3846for instruction emulation for protected guests. 3847SIDA accesses are available if the KVM_CAP_S390_PROTECTED capability is available. 3848SIDA accesses are permitted for the VCPU ioctl only. 3849SIDA accesses are permitted for protected guests only. 3850 3851No flags are supported. 3852 38534.90 KVM_S390_GET_SKEYS 3854----------------------- 3855 3856:Capability: KVM_CAP_S390_SKEYS 3857:Architectures: s390 3858:Type: vm ioctl 3859:Parameters: struct kvm_s390_skeys 3860:Returns: 0 on success, KVM_S390_GET_SKEYS_NONE if guest is not using storage 3861 keys, negative value on error 3862 3863This ioctl is used to get guest storage key values on the s390 3864architecture. The ioctl takes parameters via the kvm_s390_skeys struct:: 3865 3866 struct kvm_s390_skeys { 3867 __u64 start_gfn; 3868 __u64 count; 3869 __u64 skeydata_addr; 3870 __u32 flags; 3871 __u32 reserved[9]; 3872 }; 3873 3874The start_gfn field is the number of the first guest frame whose storage keys 3875you want to get. 3876 3877The count field is the number of consecutive frames (starting from start_gfn) 3878whose storage keys to get. The count field must be at least 1 and the maximum 3879allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3880will cause the ioctl to return -EINVAL. 3881 3882The skeydata_addr field is the address to a buffer large enough to hold count 3883bytes. This buffer will be filled with storage key data by the ioctl. 3884 38854.91 KVM_S390_SET_SKEYS 3886----------------------- 3887 3888:Capability: KVM_CAP_S390_SKEYS 3889:Architectures: s390 3890:Type: vm ioctl 3891:Parameters: struct kvm_s390_skeys 3892:Returns: 0 on success, negative value on error 3893 3894This ioctl is used to set guest storage key values on the s390 3895architecture. The ioctl takes parameters via the kvm_s390_skeys struct. 3896See section on KVM_S390_GET_SKEYS for struct definition. 3897 3898The start_gfn field is the number of the first guest frame whose storage keys 3899you want to set. 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 containing count bytes of 3907storage keys. Each byte in the buffer will be set as the storage key for a 3908single frame starting at start_gfn for count frames. 3909 3910Note: If any architecturally invalid key value is found in the given data then 3911the ioctl will return -EINVAL. 3912 39134.92 KVM_S390_IRQ 3914----------------- 3915 3916:Capability: KVM_CAP_S390_INJECT_IRQ 3917:Architectures: s390 3918:Type: vcpu ioctl 3919:Parameters: struct kvm_s390_irq (in) 3920:Returns: 0 on success, -1 on error 3921 3922Errors: 3923 3924 3925 ====== ================================================================= 3926 EINVAL interrupt type is invalid 3927 type is KVM_S390_SIGP_STOP and flag parameter is invalid value, 3928 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger 3929 than the maximum of VCPUs 3930 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped, 3931 type is KVM_S390_SIGP_STOP and a stop irq is already pending, 3932 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt 3933 is already pending 3934 ====== ================================================================= 3935 3936Allows to inject an interrupt to the guest. 3937 3938Using struct kvm_s390_irq as a parameter allows 3939to inject additional payload which is not 3940possible via KVM_S390_INTERRUPT. 3941 3942Interrupt parameters are passed via kvm_s390_irq:: 3943 3944 struct kvm_s390_irq { 3945 __u64 type; 3946 union { 3947 struct kvm_s390_io_info io; 3948 struct kvm_s390_ext_info ext; 3949 struct kvm_s390_pgm_info pgm; 3950 struct kvm_s390_emerg_info emerg; 3951 struct kvm_s390_extcall_info extcall; 3952 struct kvm_s390_prefix_info prefix; 3953 struct kvm_s390_stop_info stop; 3954 struct kvm_s390_mchk_info mchk; 3955 char reserved[64]; 3956 } u; 3957 }; 3958 3959type can be one of the following: 3960 3961- KVM_S390_SIGP_STOP - sigp stop; parameter in .stop 3962- KVM_S390_PROGRAM_INT - program check; parameters in .pgm 3963- KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix 3964- KVM_S390_RESTART - restart; no parameters 3965- KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters 3966- KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters 3967- KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg 3968- KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall 3969- KVM_S390_MCHK - machine check interrupt; parameters in .mchk 3970 3971This is an asynchronous vcpu ioctl and can be invoked from any thread. 3972 39734.94 KVM_S390_GET_IRQ_STATE 3974--------------------------- 3975 3976:Capability: KVM_CAP_S390_IRQ_STATE 3977:Architectures: s390 3978:Type: vcpu ioctl 3979:Parameters: struct kvm_s390_irq_state (out) 3980:Returns: >= number of bytes copied into buffer, 3981 -EINVAL if buffer size is 0, 3982 -ENOBUFS if buffer size is too small to fit all pending interrupts, 3983 -EFAULT if the buffer address was invalid 3984 3985This ioctl allows userspace to retrieve the complete state of all currently 3986pending interrupts in a single buffer. Use cases include migration 3987and introspection. The parameter structure contains the address of a 3988userspace buffer and its length:: 3989 3990 struct kvm_s390_irq_state { 3991 __u64 buf; 3992 __u32 flags; /* will stay unused for compatibility reasons */ 3993 __u32 len; 3994 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 3995 }; 3996 3997Userspace passes in the above struct and for each pending interrupt a 3998struct kvm_s390_irq is copied to the provided buffer. 3999 4000The structure contains a flags and a reserved field for future extensions. As 4001the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and 4002reserved, these fields can not be used in the future without breaking 4003compatibility. 4004 4005If -ENOBUFS is returned the buffer provided was too small and userspace 4006may retry with a bigger buffer. 4007 40084.95 KVM_S390_SET_IRQ_STATE 4009--------------------------- 4010 4011:Capability: KVM_CAP_S390_IRQ_STATE 4012:Architectures: s390 4013:Type: vcpu ioctl 4014:Parameters: struct kvm_s390_irq_state (in) 4015:Returns: 0 on success, 4016 -EFAULT if the buffer address was invalid, 4017 -EINVAL for an invalid buffer length (see below), 4018 -EBUSY if there were already interrupts pending, 4019 errors occurring when actually injecting the 4020 interrupt. See KVM_S390_IRQ. 4021 4022This ioctl allows userspace to set the complete state of all cpu-local 4023interrupts currently pending for the vcpu. It is intended for restoring 4024interrupt state after a migration. The input parameter is a userspace buffer 4025containing a struct kvm_s390_irq_state:: 4026 4027 struct kvm_s390_irq_state { 4028 __u64 buf; 4029 __u32 flags; /* will stay unused for compatibility reasons */ 4030 __u32 len; 4031 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4032 }; 4033 4034The restrictions for flags and reserved apply as well. 4035(see KVM_S390_GET_IRQ_STATE) 4036 4037The userspace memory referenced by buf contains a struct kvm_s390_irq 4038for each interrupt to be injected into the guest. 4039If one of the interrupts could not be injected for some reason the 4040ioctl aborts. 4041 4042len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0 4043and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq), 4044which is the maximum number of possibly pending cpu-local interrupts. 4045 40464.96 KVM_SMI 4047------------ 4048 4049:Capability: KVM_CAP_X86_SMM 4050:Architectures: x86 4051:Type: vcpu ioctl 4052:Parameters: none 4053:Returns: 0 on success, -1 on error 4054 4055Queues an SMI on the thread's vcpu. 4056 40574.97 KVM_X86_SET_MSR_FILTER 4058---------------------------- 4059 4060:Capability: KVM_CAP_X86_MSR_FILTER 4061:Architectures: x86 4062:Type: vm ioctl 4063:Parameters: struct kvm_msr_filter 4064:Returns: 0 on success, < 0 on error 4065 4066:: 4067 4068 struct kvm_msr_filter_range { 4069 #define KVM_MSR_FILTER_READ (1 << 0) 4070 #define KVM_MSR_FILTER_WRITE (1 << 1) 4071 __u32 flags; 4072 __u32 nmsrs; /* number of msrs in bitmap */ 4073 __u32 base; /* MSR index the bitmap starts at */ 4074 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ 4075 }; 4076 4077 #define KVM_MSR_FILTER_MAX_RANGES 16 4078 struct kvm_msr_filter { 4079 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) 4080 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) 4081 __u32 flags; 4082 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; 4083 }; 4084 4085flags values for ``struct kvm_msr_filter_range``: 4086 4087``KVM_MSR_FILTER_READ`` 4088 4089 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap 4090 indicates that read accesses should be denied, while a 1 indicates that 4091 a read for a particular MSR should be allowed regardless of the default 4092 filter action. 4093 4094``KVM_MSR_FILTER_WRITE`` 4095 4096 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap 4097 indicates that write accesses should be denied, while a 1 indicates that 4098 a write for a particular MSR should be allowed regardless of the default 4099 filter action. 4100 4101flags values for ``struct kvm_msr_filter``: 4102 4103``KVM_MSR_FILTER_DEFAULT_ALLOW`` 4104 4105 If no filter range matches an MSR index that is getting accessed, KVM will 4106 allow accesses to all MSRs by default. 4107 4108``KVM_MSR_FILTER_DEFAULT_DENY`` 4109 4110 If no filter range matches an MSR index that is getting accessed, KVM will 4111 deny accesses to all MSRs by default. 4112 4113This ioctl allows userspace to define up to 16 bitmaps of MSR ranges to deny 4114guest MSR accesses that would normally be allowed by KVM. If an MSR is not 4115covered by a specific range, the "default" filtering behavior applies. Each 4116bitmap range covers MSRs from [base .. base+nmsrs). 4117 4118If an MSR access is denied by userspace, the resulting KVM behavior depends on 4119whether or not KVM_CAP_X86_USER_SPACE_MSR's KVM_MSR_EXIT_REASON_FILTER is 4120enabled. If KVM_MSR_EXIT_REASON_FILTER is enabled, KVM will exit to userspace 4121on denied accesses, i.e. userspace effectively intercepts the MSR access. If 4122KVM_MSR_EXIT_REASON_FILTER is not enabled, KVM will inject a #GP into the guest 4123on denied accesses. 4124 4125If an MSR access is allowed by userspace, KVM will emulate and/or virtualize 4126the access in accordance with the vCPU model. Note, KVM may still ultimately 4127inject a #GP if an access is allowed by userspace, e.g. if KVM doesn't support 4128the MSR, or to follow architectural behavior for the MSR. 4129 4130By default, KVM operates in KVM_MSR_FILTER_DEFAULT_ALLOW mode with no MSR range 4131filters. 4132 4133Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR 4134filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes 4135an error. 4136 4137.. warning:: 4138 MSR accesses as part of nested VM-Enter/VM-Exit are not filtered. 4139 This includes both writes to individual VMCS fields and reads/writes 4140 through the MSR lists pointed to by the VMCS. 4141 4142 x2APIC MSR accesses cannot be filtered (KVM silently ignores filters that 4143 cover any x2APIC MSRs). 4144 4145Note, invoking this ioctl while a vCPU is running is inherently racy. However, 4146KVM does guarantee that vCPUs will see either the previous filter or the new 4147filter, e.g. MSRs with identical settings in both the old and new filter will 4148have deterministic behavior. 4149 4150Similarly, if userspace wishes to intercept on denied accesses, 4151KVM_MSR_EXIT_REASON_FILTER must be enabled before activating any filters, and 4152left enabled until after all filters are deactivated. Failure to do so may 4153result in KVM injecting a #GP instead of exiting to userspace. 4154 41554.98 KVM_CREATE_SPAPR_TCE_64 4156---------------------------- 4157 4158:Capability: KVM_CAP_SPAPR_TCE_64 4159:Architectures: powerpc 4160:Type: vm ioctl 4161:Parameters: struct kvm_create_spapr_tce_64 (in) 4162:Returns: file descriptor for manipulating the created TCE table 4163 4164This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit 4165windows, described in 4.62 KVM_CREATE_SPAPR_TCE 4166 4167This capability uses extended struct in ioctl interface:: 4168 4169 /* for KVM_CAP_SPAPR_TCE_64 */ 4170 struct kvm_create_spapr_tce_64 { 4171 __u64 liobn; 4172 __u32 page_shift; 4173 __u32 flags; 4174 __u64 offset; /* in pages */ 4175 __u64 size; /* in pages */ 4176 }; 4177 4178The aim of extension is to support an additional bigger DMA window with 4179a variable page size. 4180KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and 4181a bus offset of the corresponding DMA window, @size and @offset are numbers 4182of IOMMU pages. 4183 4184@flags are not used at the moment. 4185 4186The rest of functionality is identical to KVM_CREATE_SPAPR_TCE. 4187 41884.99 KVM_REINJECT_CONTROL 4189------------------------- 4190 4191:Capability: KVM_CAP_REINJECT_CONTROL 4192:Architectures: x86 4193:Type: vm ioctl 4194:Parameters: struct kvm_reinject_control (in) 4195:Returns: 0 on success, 4196 -EFAULT if struct kvm_reinject_control cannot be read, 4197 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier. 4198 4199i8254 (PIT) has two modes, reinject and !reinject. The default is reinject, 4200where KVM queues elapsed i8254 ticks and monitors completion of interrupt from 4201vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its 4202interrupt whenever there isn't a pending interrupt from i8254. 4203!reinject mode injects an interrupt as soon as a tick arrives. 4204 4205:: 4206 4207 struct kvm_reinject_control { 4208 __u8 pit_reinject; 4209 __u8 reserved[31]; 4210 }; 4211 4212pit_reinject = 0 (!reinject mode) is recommended, unless running an old 4213operating system that uses the PIT for timing (e.g. Linux 2.4.x). 4214 42154.100 KVM_PPC_CONFIGURE_V3_MMU 4216------------------------------ 4217 4218:Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3 4219:Architectures: ppc 4220:Type: vm ioctl 4221:Parameters: struct kvm_ppc_mmuv3_cfg (in) 4222:Returns: 0 on success, 4223 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read, 4224 -EINVAL if the configuration is invalid 4225 4226This ioctl controls whether the guest will use radix or HPT (hashed 4227page table) translation, and sets the pointer to the process table for 4228the guest. 4229 4230:: 4231 4232 struct kvm_ppc_mmuv3_cfg { 4233 __u64 flags; 4234 __u64 process_table; 4235 }; 4236 4237There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and 4238KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest 4239to use radix tree translation, and if clear, to use HPT translation. 4240KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest 4241to be able to use the global TLB and SLB invalidation instructions; 4242if clear, the guest may not use these instructions. 4243 4244The process_table field specifies the address and size of the guest 4245process table, which is in the guest's space. This field is formatted 4246as the second doubleword of the partition table entry, as defined in 4247the Power ISA V3.00, Book III section 5.7.6.1. 4248 42494.101 KVM_PPC_GET_RMMU_INFO 4250--------------------------- 4251 4252:Capability: KVM_CAP_PPC_RADIX_MMU 4253:Architectures: ppc 4254:Type: vm ioctl 4255:Parameters: struct kvm_ppc_rmmu_info (out) 4256:Returns: 0 on success, 4257 -EFAULT if struct kvm_ppc_rmmu_info cannot be written, 4258 -EINVAL if no useful information can be returned 4259 4260This ioctl returns a structure containing two things: (a) a list 4261containing supported radix tree geometries, and (b) a list that maps 4262page sizes to put in the "AP" (actual page size) field for the tlbie 4263(TLB invalidate entry) instruction. 4264 4265:: 4266 4267 struct kvm_ppc_rmmu_info { 4268 struct kvm_ppc_radix_geom { 4269 __u8 page_shift; 4270 __u8 level_bits[4]; 4271 __u8 pad[3]; 4272 } geometries[8]; 4273 __u32 ap_encodings[8]; 4274 }; 4275 4276The geometries[] field gives up to 8 supported geometries for the 4277radix page table, in terms of the log base 2 of the smallest page 4278size, and the number of bits indexed at each level of the tree, from 4279the PTE level up to the PGD level in that order. Any unused entries 4280will have 0 in the page_shift field. 4281 4282The ap_encodings gives the supported page sizes and their AP field 4283encodings, encoded with the AP value in the top 3 bits and the log 4284base 2 of the page size in the bottom 6 bits. 4285 42864.102 KVM_PPC_RESIZE_HPT_PREPARE 4287-------------------------------- 4288 4289:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4290:Architectures: powerpc 4291:Type: vm ioctl 4292:Parameters: struct kvm_ppc_resize_hpt (in) 4293:Returns: 0 on successful completion, 4294 >0 if a new HPT is being prepared, the value is an estimated 4295 number of milliseconds until preparation is complete, 4296 -EFAULT if struct kvm_reinject_control cannot be read, 4297 -EINVAL if the supplied shift or flags are invalid, 4298 -ENOMEM if unable to allocate the new HPT, 4299 4300Used to implement the PAPR extension for runtime resizing of a guest's 4301Hashed Page Table (HPT). Specifically this starts, stops or monitors 4302the preparation of a new potential HPT for the guest, essentially 4303implementing the H_RESIZE_HPT_PREPARE hypercall. 4304 4305:: 4306 4307 struct kvm_ppc_resize_hpt { 4308 __u64 flags; 4309 __u32 shift; 4310 __u32 pad; 4311 }; 4312 4313If called with shift > 0 when there is no pending HPT for the guest, 4314this begins preparation of a new pending HPT of size 2^(shift) bytes. 4315It then returns a positive integer with the estimated number of 4316milliseconds until preparation is complete. 4317 4318If called when there is a pending HPT whose size does not match that 4319requested in the parameters, discards the existing pending HPT and 4320creates a new one as above. 4321 4322If called when there is a pending HPT of the size requested, will: 4323 4324 * If preparation of the pending HPT is already complete, return 0 4325 * If preparation of the pending HPT has failed, return an error 4326 code, then discard the pending HPT. 4327 * If preparation of the pending HPT is still in progress, return an 4328 estimated number of milliseconds until preparation is complete. 4329 4330If called with shift == 0, discards any currently pending HPT and 4331returns 0 (i.e. cancels any in-progress preparation). 4332 4333flags is reserved for future expansion, currently setting any bits in 4334flags will result in an -EINVAL. 4335 4336Normally this will be called repeatedly with the same parameters until 4337it returns <= 0. The first call will initiate preparation, subsequent 4338ones will monitor preparation until it completes or fails. 4339 43404.103 KVM_PPC_RESIZE_HPT_COMMIT 4341------------------------------- 4342 4343:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4344:Architectures: powerpc 4345:Type: vm ioctl 4346:Parameters: struct kvm_ppc_resize_hpt (in) 4347:Returns: 0 on successful completion, 4348 -EFAULT if struct kvm_reinject_control cannot be read, 4349 -EINVAL if the supplied shift or flags are invalid, 4350 -ENXIO is there is no pending HPT, or the pending HPT doesn't 4351 have the requested size, 4352 -EBUSY if the pending HPT is not fully prepared, 4353 -ENOSPC if there was a hash collision when moving existing 4354 HPT entries to the new HPT, 4355 -EIO on other error conditions 4356 4357Used to implement the PAPR extension for runtime resizing of a guest's 4358Hashed Page Table (HPT). Specifically this requests that the guest be 4359transferred to working with the new HPT, essentially implementing the 4360H_RESIZE_HPT_COMMIT hypercall. 4361 4362:: 4363 4364 struct kvm_ppc_resize_hpt { 4365 __u64 flags; 4366 __u32 shift; 4367 __u32 pad; 4368 }; 4369 4370This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has 4371returned 0 with the same parameters. In other cases 4372KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or 4373-EBUSY, though others may be possible if the preparation was started, 4374but failed). 4375 4376This will have undefined effects on the guest if it has not already 4377placed itself in a quiescent state where no vcpu will make MMU enabled 4378memory accesses. 4379 4380On succsful completion, the pending HPT will become the guest's active 4381HPT and the previous HPT will be discarded. 4382 4383On failure, the guest will still be operating on its previous HPT. 4384 43854.104 KVM_X86_GET_MCE_CAP_SUPPORTED 4386----------------------------------- 4387 4388:Capability: KVM_CAP_MCE 4389:Architectures: x86 4390:Type: system ioctl 4391:Parameters: u64 mce_cap (out) 4392:Returns: 0 on success, -1 on error 4393 4394Returns supported MCE capabilities. The u64 mce_cap parameter 4395has the same format as the MSR_IA32_MCG_CAP register. Supported 4396capabilities will have the corresponding bits set. 4397 43984.105 KVM_X86_SETUP_MCE 4399----------------------- 4400 4401:Capability: KVM_CAP_MCE 4402:Architectures: x86 4403:Type: vcpu ioctl 4404:Parameters: u64 mcg_cap (in) 4405:Returns: 0 on success, 4406 -EFAULT if u64 mcg_cap cannot be read, 4407 -EINVAL if the requested number of banks is invalid, 4408 -EINVAL if requested MCE capability is not supported. 4409 4410Initializes MCE support for use. The u64 mcg_cap parameter 4411has the same format as the MSR_IA32_MCG_CAP register and 4412specifies which capabilities should be enabled. The maximum 4413supported number of error-reporting banks can be retrieved when 4414checking for KVM_CAP_MCE. The supported capabilities can be 4415retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED. 4416 44174.106 KVM_X86_SET_MCE 4418--------------------- 4419 4420:Capability: KVM_CAP_MCE 4421:Architectures: x86 4422:Type: vcpu ioctl 4423:Parameters: struct kvm_x86_mce (in) 4424:Returns: 0 on success, 4425 -EFAULT if struct kvm_x86_mce cannot be read, 4426 -EINVAL if the bank number is invalid, 4427 -EINVAL if VAL bit is not set in status field. 4428 4429Inject a machine check error (MCE) into the guest. The input 4430parameter is:: 4431 4432 struct kvm_x86_mce { 4433 __u64 status; 4434 __u64 addr; 4435 __u64 misc; 4436 __u64 mcg_status; 4437 __u8 bank; 4438 __u8 pad1[7]; 4439 __u64 pad2[3]; 4440 }; 4441 4442If the MCE being reported is an uncorrected error, KVM will 4443inject it as an MCE exception into the guest. If the guest 4444MCG_STATUS register reports that an MCE is in progress, KVM 4445causes an KVM_EXIT_SHUTDOWN vmexit. 4446 4447Otherwise, if the MCE is a corrected error, KVM will just 4448store it in the corresponding bank (provided this bank is 4449not holding a previously reported uncorrected error). 4450 44514.107 KVM_S390_GET_CMMA_BITS 4452---------------------------- 4453 4454:Capability: KVM_CAP_S390_CMMA_MIGRATION 4455:Architectures: s390 4456:Type: vm ioctl 4457:Parameters: struct kvm_s390_cmma_log (in, out) 4458:Returns: 0 on success, a negative value on error 4459 4460This ioctl is used to get the values of the CMMA bits on the s390 4461architecture. It is meant to be used in two scenarios: 4462 4463- During live migration to save the CMMA values. Live migration needs 4464 to be enabled via the KVM_REQ_START_MIGRATION VM property. 4465- To non-destructively peek at the CMMA values, with the flag 4466 KVM_S390_CMMA_PEEK set. 4467 4468The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired 4469values are written to a buffer whose location is indicated via the "values" 4470member in the kvm_s390_cmma_log struct. The values in the input struct are 4471also updated as needed. 4472 4473Each CMMA value takes up one byte. 4474 4475:: 4476 4477 struct kvm_s390_cmma_log { 4478 __u64 start_gfn; 4479 __u32 count; 4480 __u32 flags; 4481 union { 4482 __u64 remaining; 4483 __u64 mask; 4484 }; 4485 __u64 values; 4486 }; 4487 4488start_gfn is the number of the first guest frame whose CMMA values are 4489to be retrieved, 4490 4491count is the length of the buffer in bytes, 4492 4493values points to the buffer where the result will be written to. 4494 4495If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be 4496KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with 4497other ioctls. 4498 4499The result is written in the buffer pointed to by the field values, and 4500the values of the input parameter are updated as follows. 4501 4502Depending on the flags, different actions are performed. The only 4503supported flag so far is KVM_S390_CMMA_PEEK. 4504 4505The default behaviour if KVM_S390_CMMA_PEEK is not set is: 4506start_gfn will indicate the first page frame whose CMMA bits were dirty. 4507It is not necessarily the same as the one passed as input, as clean pages 4508are skipped. 4509 4510count will indicate the number of bytes actually written in the buffer. 4511It can (and very often will) be smaller than the input value, since the 4512buffer is only filled until 16 bytes of clean values are found (which 4513are then not copied in the buffer). Since a CMMA migration block needs 4514the base address and the length, for a total of 16 bytes, we will send 4515back some clean data if there is some dirty data afterwards, as long as 4516the size of the clean data does not exceed the size of the header. This 4517allows to minimize the amount of data to be saved or transferred over 4518the network at the expense of more roundtrips to userspace. The next 4519invocation of the ioctl will skip over all the clean values, saving 4520potentially more than just the 16 bytes we found. 4521 4522If KVM_S390_CMMA_PEEK is set: 4523the existing storage attributes are read even when not in migration 4524mode, and no other action is performed; 4525 4526the output start_gfn will be equal to the input start_gfn, 4527 4528the output count will be equal to the input count, except if the end of 4529memory has been reached. 4530 4531In both cases: 4532the field "remaining" will indicate the total number of dirty CMMA values 4533still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is 4534not enabled. 4535 4536mask is unused. 4537 4538values points to the userspace buffer where the result will be stored. 4539 4540This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4541complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4542KVM_S390_CMMA_PEEK is not set but migration mode was not enabled, with 4543-EFAULT if the userspace address is invalid or if no page table is 4544present for the addresses (e.g. when using hugepages). 4545 45464.108 KVM_S390_SET_CMMA_BITS 4547---------------------------- 4548 4549:Capability: KVM_CAP_S390_CMMA_MIGRATION 4550:Architectures: s390 4551:Type: vm ioctl 4552:Parameters: struct kvm_s390_cmma_log (in) 4553:Returns: 0 on success, a negative value on error 4554 4555This ioctl is used to set the values of the CMMA bits on the s390 4556architecture. It is meant to be used during live migration to restore 4557the CMMA values, but there are no restrictions on its use. 4558The ioctl takes parameters via the kvm_s390_cmma_values struct. 4559Each CMMA value takes up one byte. 4560 4561:: 4562 4563 struct kvm_s390_cmma_log { 4564 __u64 start_gfn; 4565 __u32 count; 4566 __u32 flags; 4567 union { 4568 __u64 remaining; 4569 __u64 mask; 4570 }; 4571 __u64 values; 4572 }; 4573 4574start_gfn indicates the starting guest frame number, 4575 4576count indicates how many values are to be considered in the buffer, 4577 4578flags is not used and must be 0. 4579 4580mask indicates which PGSTE bits are to be considered. 4581 4582remaining is not used. 4583 4584values points to the buffer in userspace where to store the values. 4585 4586This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4587complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4588the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or 4589if the flags field was not 0, with -EFAULT if the userspace address is 4590invalid, if invalid pages are written to (e.g. after the end of memory) 4591or if no page table is present for the addresses (e.g. when using 4592hugepages). 4593 45944.109 KVM_PPC_GET_CPU_CHAR 4595-------------------------- 4596 4597:Capability: KVM_CAP_PPC_GET_CPU_CHAR 4598:Architectures: powerpc 4599:Type: vm ioctl 4600:Parameters: struct kvm_ppc_cpu_char (out) 4601:Returns: 0 on successful completion, 4602 -EFAULT if struct kvm_ppc_cpu_char cannot be written 4603 4604This ioctl gives userspace information about certain characteristics 4605of the CPU relating to speculative execution of instructions and 4606possible information leakage resulting from speculative execution (see 4607CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is 4608returned in struct kvm_ppc_cpu_char, which looks like this:: 4609 4610 struct kvm_ppc_cpu_char { 4611 __u64 character; /* characteristics of the CPU */ 4612 __u64 behaviour; /* recommended software behaviour */ 4613 __u64 character_mask; /* valid bits in character */ 4614 __u64 behaviour_mask; /* valid bits in behaviour */ 4615 }; 4616 4617For extensibility, the character_mask and behaviour_mask fields 4618indicate which bits of character and behaviour have been filled in by 4619the kernel. If the set of defined bits is extended in future then 4620userspace will be able to tell whether it is running on a kernel that 4621knows about the new bits. 4622 4623The character field describes attributes of the CPU which can help 4624with preventing inadvertent information disclosure - specifically, 4625whether there is an instruction to flash-invalidate the L1 data cache 4626(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set 4627to a mode where entries can only be used by the thread that created 4628them, whether the bcctr[l] instruction prevents speculation, and 4629whether a speculation barrier instruction (ori 31,31,0) is provided. 4630 4631The behaviour field describes actions that software should take to 4632prevent inadvertent information disclosure, and thus describes which 4633vulnerabilities the hardware is subject to; specifically whether the 4634L1 data cache should be flushed when returning to user mode from the 4635kernel, and whether a speculation barrier should be placed between an 4636array bounds check and the array access. 4637 4638These fields use the same bit definitions as the new 4639H_GET_CPU_CHARACTERISTICS hypercall. 4640 46414.110 KVM_MEMORY_ENCRYPT_OP 4642--------------------------- 4643 4644:Capability: basic 4645:Architectures: x86 4646:Type: vm 4647:Parameters: an opaque platform specific structure (in/out) 4648:Returns: 0 on success; -1 on error 4649 4650If the platform supports creating encrypted VMs then this ioctl can be used 4651for issuing platform-specific memory encryption commands to manage those 4652encrypted VMs. 4653 4654Currently, this ioctl is used for issuing Secure Encrypted Virtualization 4655(SEV) commands on AMD Processors. The SEV commands are defined in 4656Documentation/virt/kvm/x86/amd-memory-encryption.rst. 4657 46584.111 KVM_MEMORY_ENCRYPT_REG_REGION 4659----------------------------------- 4660 4661:Capability: basic 4662:Architectures: x86 4663:Type: system 4664:Parameters: struct kvm_enc_region (in) 4665:Returns: 0 on success; -1 on error 4666 4667This ioctl can be used to register a guest memory region which may 4668contain encrypted data (e.g. guest RAM, SMRAM etc). 4669 4670It is used in the SEV-enabled guest. When encryption is enabled, a guest 4671memory region may contain encrypted data. The SEV memory encryption 4672engine uses a tweak such that two identical plaintext pages, each at 4673different locations will have differing ciphertexts. So swapping or 4674moving ciphertext of those pages will not result in plaintext being 4675swapped. So relocating (or migrating) physical backing pages for the SEV 4676guest will require some additional steps. 4677 4678Note: The current SEV key management spec does not provide commands to 4679swap or migrate (move) ciphertext pages. Hence, for now we pin the guest 4680memory region registered with the ioctl. 4681 46824.112 KVM_MEMORY_ENCRYPT_UNREG_REGION 4683------------------------------------- 4684 4685:Capability: basic 4686:Architectures: x86 4687:Type: system 4688:Parameters: struct kvm_enc_region (in) 4689:Returns: 0 on success; -1 on error 4690 4691This ioctl can be used to unregister the guest memory region registered 4692with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above. 4693 46944.113 KVM_HYPERV_EVENTFD 4695------------------------ 4696 4697:Capability: KVM_CAP_HYPERV_EVENTFD 4698:Architectures: x86 4699:Type: vm ioctl 4700:Parameters: struct kvm_hyperv_eventfd (in) 4701 4702This ioctl (un)registers an eventfd to receive notifications from the guest on 4703the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without 4704causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number 4705(bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit. 4706 4707:: 4708 4709 struct kvm_hyperv_eventfd { 4710 __u32 conn_id; 4711 __s32 fd; 4712 __u32 flags; 4713 __u32 padding[3]; 4714 }; 4715 4716The conn_id field should fit within 24 bits:: 4717 4718 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff 4719 4720The acceptable values for the flags field are:: 4721 4722 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) 4723 4724:Returns: 0 on success, 4725 -EINVAL if conn_id or flags is outside the allowed range, 4726 -ENOENT on deassign if the conn_id isn't registered, 4727 -EEXIST on assign if the conn_id is already registered 4728 47294.114 KVM_GET_NESTED_STATE 4730-------------------------- 4731 4732:Capability: KVM_CAP_NESTED_STATE 4733:Architectures: x86 4734:Type: vcpu ioctl 4735:Parameters: struct kvm_nested_state (in/out) 4736:Returns: 0 on success, -1 on error 4737 4738Errors: 4739 4740 ===== ============================================================= 4741 E2BIG the total state size exceeds the value of 'size' specified by 4742 the user; the size required will be written into size. 4743 ===== ============================================================= 4744 4745:: 4746 4747 struct kvm_nested_state { 4748 __u16 flags; 4749 __u16 format; 4750 __u32 size; 4751 4752 union { 4753 struct kvm_vmx_nested_state_hdr vmx; 4754 struct kvm_svm_nested_state_hdr svm; 4755 4756 /* Pad the header to 128 bytes. */ 4757 __u8 pad[120]; 4758 } hdr; 4759 4760 union { 4761 struct kvm_vmx_nested_state_data vmx[0]; 4762 struct kvm_svm_nested_state_data svm[0]; 4763 } data; 4764 }; 4765 4766 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001 4767 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002 4768 #define KVM_STATE_NESTED_EVMCS 0x00000004 4769 4770 #define KVM_STATE_NESTED_FORMAT_VMX 0 4771 #define KVM_STATE_NESTED_FORMAT_SVM 1 4772 4773 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000 4774 4775 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001 4776 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002 4777 4778 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001 4779 4780 struct kvm_vmx_nested_state_hdr { 4781 __u64 vmxon_pa; 4782 __u64 vmcs12_pa; 4783 4784 struct { 4785 __u16 flags; 4786 } smm; 4787 4788 __u32 flags; 4789 __u64 preemption_timer_deadline; 4790 }; 4791 4792 struct kvm_vmx_nested_state_data { 4793 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4794 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4795 }; 4796 4797This ioctl copies the vcpu's nested virtualization state from the kernel to 4798userspace. 4799 4800The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE 4801to the KVM_CHECK_EXTENSION ioctl(). 4802 48034.115 KVM_SET_NESTED_STATE 4804-------------------------- 4805 4806:Capability: KVM_CAP_NESTED_STATE 4807:Architectures: x86 4808:Type: vcpu ioctl 4809:Parameters: struct kvm_nested_state (in) 4810:Returns: 0 on success, -1 on error 4811 4812This copies the vcpu's kvm_nested_state struct from userspace to the kernel. 4813For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE. 4814 48154.116 KVM_(UN)REGISTER_COALESCED_MMIO 4816------------------------------------- 4817 4818:Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio) 4819 KVM_CAP_COALESCED_PIO (for coalesced pio) 4820:Architectures: all 4821:Type: vm ioctl 4822:Parameters: struct kvm_coalesced_mmio_zone 4823:Returns: 0 on success, < 0 on error 4824 4825Coalesced I/O is a performance optimization that defers hardware 4826register write emulation so that userspace exits are avoided. It is 4827typically used to reduce the overhead of emulating frequently accessed 4828hardware registers. 4829 4830When a hardware register is configured for coalesced I/O, write accesses 4831do not exit to userspace and their value is recorded in a ring buffer 4832that is shared between kernel and userspace. 4833 4834Coalesced I/O is used if one or more write accesses to a hardware 4835register can be deferred until a read or a write to another hardware 4836register on the same device. This last access will cause a vmexit and 4837userspace will process accesses from the ring buffer before emulating 4838it. That will avoid exiting to userspace on repeated writes. 4839 4840Coalesced pio is based on coalesced mmio. There is little difference 4841between coalesced mmio and pio except that coalesced pio records accesses 4842to I/O ports. 4843 48444.117 KVM_CLEAR_DIRTY_LOG (vm ioctl) 4845------------------------------------ 4846 4847:Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4848:Architectures: x86, arm64, mips 4849:Type: vm ioctl 4850:Parameters: struct kvm_clear_dirty_log (in) 4851:Returns: 0 on success, -1 on error 4852 4853:: 4854 4855 /* for KVM_CLEAR_DIRTY_LOG */ 4856 struct kvm_clear_dirty_log { 4857 __u32 slot; 4858 __u32 num_pages; 4859 __u64 first_page; 4860 union { 4861 void __user *dirty_bitmap; /* one bit per page */ 4862 __u64 padding; 4863 }; 4864 }; 4865 4866The ioctl clears the dirty status of pages in a memory slot, according to 4867the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap 4868field. Bit 0 of the bitmap corresponds to page "first_page" in the 4869memory slot, and num_pages is the size in bits of the input bitmap. 4870first_page must be a multiple of 64; num_pages must also be a multiple of 487164 unless first_page + num_pages is the size of the memory slot. For each 4872bit that is set in the input bitmap, the corresponding page is marked "clean" 4873in KVM's dirty bitmap, and dirty tracking is re-enabled for that page 4874(for example via write-protection, or by clearing the dirty bit in 4875a page table entry). 4876 4877If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 4878the address space for which you want to clear the dirty status. See 4879KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 4880 4881This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4882is enabled; for more information, see the description of the capability. 4883However, it can always be used as long as KVM_CHECK_EXTENSION confirms 4884that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. 4885 48864.118 KVM_GET_SUPPORTED_HV_CPUID 4887-------------------------------- 4888 4889:Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system) 4890:Architectures: x86 4891:Type: system ioctl, vcpu ioctl 4892:Parameters: struct kvm_cpuid2 (in/out) 4893:Returns: 0 on success, -1 on error 4894 4895:: 4896 4897 struct kvm_cpuid2 { 4898 __u32 nent; 4899 __u32 padding; 4900 struct kvm_cpuid_entry2 entries[0]; 4901 }; 4902 4903 struct kvm_cpuid_entry2 { 4904 __u32 function; 4905 __u32 index; 4906 __u32 flags; 4907 __u32 eax; 4908 __u32 ebx; 4909 __u32 ecx; 4910 __u32 edx; 4911 __u32 padding[3]; 4912 }; 4913 4914This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in 4915KVM. Userspace can use the information returned by this ioctl to construct 4916cpuid information presented to guests consuming Hyper-V enlightenments (e.g. 4917Windows or Hyper-V guests). 4918 4919CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level 4920Functional Specification (TLFS). These leaves can't be obtained with 4921KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature 4922leaves (0x40000000, 0x40000001). 4923 4924Currently, the following list of CPUID leaves are returned: 4925 4926 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS 4927 - HYPERV_CPUID_INTERFACE 4928 - HYPERV_CPUID_VERSION 4929 - HYPERV_CPUID_FEATURES 4930 - HYPERV_CPUID_ENLIGHTMENT_INFO 4931 - HYPERV_CPUID_IMPLEMENT_LIMITS 4932 - HYPERV_CPUID_NESTED_FEATURES 4933 - HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS 4934 - HYPERV_CPUID_SYNDBG_INTERFACE 4935 - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES 4936 4937Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure 4938with the 'nent' field indicating the number of entries in the variable-size 4939array 'entries'. If the number of entries is too low to describe all Hyper-V 4940feature leaves, an error (E2BIG) is returned. If the number is more or equal 4941to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the 4942number of valid entries in the 'entries' array, which is then filled. 4943 4944'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, 4945userspace should not expect to get any particular value there. 4946 4947Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike 4948system ioctl which exposes all supported feature bits unconditionally, vcpu 4949version has the following quirks: 4950 4951- HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED 4952 feature bit are only exposed when Enlightened VMCS was previously enabled 4953 on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). 4954- HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC. 4955 (presumes KVM_CREATE_IRQCHIP has already been called). 4956 49574.119 KVM_ARM_VCPU_FINALIZE 4958--------------------------- 4959 4960:Architectures: arm64 4961:Type: vcpu ioctl 4962:Parameters: int feature (in) 4963:Returns: 0 on success, -1 on error 4964 4965Errors: 4966 4967 ====== ============================================================== 4968 EPERM feature not enabled, needs configuration, or already finalized 4969 EINVAL feature unknown or not present 4970 ====== ============================================================== 4971 4972Recognised values for feature: 4973 4974 ===== =========================================== 4975 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE) 4976 ===== =========================================== 4977 4978Finalizes the configuration of the specified vcpu feature. 4979 4980The vcpu must already have been initialised, enabling the affected feature, by 4981means of a successful KVM_ARM_VCPU_INIT call with the appropriate flag set in 4982features[]. 4983 4984For affected vcpu features, this is a mandatory step that must be performed 4985before the vcpu is fully usable. 4986 4987Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be 4988configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration 4989that should be performaned and how to do it are feature-dependent. 4990 4991Other calls that depend on a particular feature being finalized, such as 4992KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with 4993-EPERM unless the feature has already been finalized by means of a 4994KVM_ARM_VCPU_FINALIZE call. 4995 4996See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization 4997using this ioctl. 4998 49994.120 KVM_SET_PMU_EVENT_FILTER 5000------------------------------ 5001 5002:Capability: KVM_CAP_PMU_EVENT_FILTER 5003:Architectures: x86 5004:Type: vm ioctl 5005:Parameters: struct kvm_pmu_event_filter (in) 5006:Returns: 0 on success, -1 on error 5007 5008:: 5009 5010 struct kvm_pmu_event_filter { 5011 __u32 action; 5012 __u32 nevents; 5013 __u32 fixed_counter_bitmap; 5014 __u32 flags; 5015 __u32 pad[4]; 5016 __u64 events[0]; 5017 }; 5018 5019This ioctl restricts the set of PMU events that the guest can program. 5020The argument holds a list of events which will be allowed or denied. 5021The eventsel+umask of each event the guest attempts to program is compared 5022against the events field to determine whether the guest should have access. 5023The events field only controls general purpose counters; fixed purpose 5024counters are controlled by the fixed_counter_bitmap. 5025 5026No flags are defined yet, the field must be zero. 5027 5028Valid values for 'action':: 5029 5030 #define KVM_PMU_EVENT_ALLOW 0 5031 #define KVM_PMU_EVENT_DENY 1 5032 50334.121 KVM_PPC_SVM_OFF 5034--------------------- 5035 5036:Capability: basic 5037:Architectures: powerpc 5038:Type: vm ioctl 5039:Parameters: none 5040:Returns: 0 on successful completion, 5041 5042Errors: 5043 5044 ====== ================================================================ 5045 EINVAL if ultravisor failed to terminate the secure guest 5046 ENOMEM if hypervisor failed to allocate new radix page tables for guest 5047 ====== ================================================================ 5048 5049This ioctl is used to turn off the secure mode of the guest or transition 5050the guest from secure mode to normal mode. This is invoked when the guest 5051is reset. This has no effect if called for a normal guest. 5052 5053This ioctl issues an ultravisor call to terminate the secure guest, 5054unpins the VPA pages and releases all the device pages that are used to 5055track the secure pages by hypervisor. 5056 50574.122 KVM_S390_NORMAL_RESET 5058--------------------------- 5059 5060:Capability: KVM_CAP_S390_VCPU_RESETS 5061:Architectures: s390 5062:Type: vcpu ioctl 5063:Parameters: none 5064:Returns: 0 5065 5066This ioctl resets VCPU registers and control structures according to 5067the cpu reset definition in the POP (Principles Of Operation). 5068 50694.123 KVM_S390_INITIAL_RESET 5070---------------------------- 5071 5072:Capability: none 5073:Architectures: s390 5074:Type: vcpu ioctl 5075:Parameters: none 5076:Returns: 0 5077 5078This ioctl resets VCPU registers and control structures according to 5079the initial cpu reset definition in the POP. However, the cpu is not 5080put into ESA mode. This reset is a superset of the normal reset. 5081 50824.124 KVM_S390_CLEAR_RESET 5083-------------------------- 5084 5085:Capability: KVM_CAP_S390_VCPU_RESETS 5086:Architectures: s390 5087:Type: vcpu ioctl 5088:Parameters: none 5089:Returns: 0 5090 5091This ioctl resets VCPU registers and control structures according to 5092the clear cpu reset definition in the POP. However, the cpu is not put 5093into ESA mode. This reset is a superset of the initial reset. 5094 5095 50964.125 KVM_S390_PV_COMMAND 5097------------------------- 5098 5099:Capability: KVM_CAP_S390_PROTECTED 5100:Architectures: s390 5101:Type: vm ioctl 5102:Parameters: struct kvm_pv_cmd 5103:Returns: 0 on success, < 0 on error 5104 5105:: 5106 5107 struct kvm_pv_cmd { 5108 __u32 cmd; /* Command to be executed */ 5109 __u16 rc; /* Ultravisor return code */ 5110 __u16 rrc; /* Ultravisor return reason code */ 5111 __u64 data; /* Data or address */ 5112 __u32 flags; /* flags for future extensions. Must be 0 for now */ 5113 __u32 reserved[3]; 5114 }; 5115 5116**Ultravisor return codes** 5117The Ultravisor return (reason) codes are provided by the kernel if a 5118Ultravisor call has been executed to achieve the results expected by 5119the command. Therefore they are independent of the IOCTL return 5120code. If KVM changes `rc`, its value will always be greater than 0 5121hence setting it to 0 before issuing a PV command is advised to be 5122able to detect a change of `rc`. 5123 5124**cmd values:** 5125 5126KVM_PV_ENABLE 5127 Allocate memory and register the VM with the Ultravisor, thereby 5128 donating memory to the Ultravisor that will become inaccessible to 5129 KVM. All existing CPUs are converted to protected ones. After this 5130 command has succeeded, any CPU added via hotplug will become 5131 protected during its creation as well. 5132 5133 Errors: 5134 5135 ===== ============================= 5136 EINTR an unmasked signal is pending 5137 ===== ============================= 5138 5139KVM_PV_DISABLE 5140 Deregister the VM from the Ultravisor and reclaim the memory that had 5141 been donated to the Ultravisor, making it usable by the kernel again. 5142 All registered VCPUs are converted back to non-protected ones. If a 5143 previous protected VM had been prepared for asynchonous teardown with 5144 KVM_PV_ASYNC_CLEANUP_PREPARE and not subsequently torn down with 5145 KVM_PV_ASYNC_CLEANUP_PERFORM, it will be torn down in this call 5146 together with the current protected VM. 5147 5148KVM_PV_VM_SET_SEC_PARMS 5149 Pass the image header from VM memory to the Ultravisor in 5150 preparation of image unpacking and verification. 5151 5152KVM_PV_VM_UNPACK 5153 Unpack (protect and decrypt) a page of the encrypted boot image. 5154 5155KVM_PV_VM_VERIFY 5156 Verify the integrity of the unpacked image. Only if this succeeds, 5157 KVM is allowed to start protected VCPUs. 5158 5159KVM_PV_INFO 5160 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5161 5162 Presents an API that provides Ultravisor related data to userspace 5163 via subcommands. len_max is the size of the user space buffer, 5164 len_written is KVM's indication of how much bytes of that buffer 5165 were actually written to. len_written can be used to determine the 5166 valid fields if more response fields are added in the future. 5167 5168 :: 5169 5170 enum pv_cmd_info_id { 5171 KVM_PV_INFO_VM, 5172 KVM_PV_INFO_DUMP, 5173 }; 5174 5175 struct kvm_s390_pv_info_header { 5176 __u32 id; 5177 __u32 len_max; 5178 __u32 len_written; 5179 __u32 reserved; 5180 }; 5181 5182 struct kvm_s390_pv_info { 5183 struct kvm_s390_pv_info_header header; 5184 struct kvm_s390_pv_info_dump dump; 5185 struct kvm_s390_pv_info_vm vm; 5186 }; 5187 5188**subcommands:** 5189 5190 KVM_PV_INFO_VM 5191 This subcommand provides basic Ultravisor information for PV 5192 hosts. These values are likely also exported as files in the sysfs 5193 firmware UV query interface but they are more easily available to 5194 programs in this API. 5195 5196 The installed calls and feature_indication members provide the 5197 installed UV calls and the UV's other feature indications. 5198 5199 The max_* members provide information about the maximum number of PV 5200 vcpus, PV guests and PV guest memory size. 5201 5202 :: 5203 5204 struct kvm_s390_pv_info_vm { 5205 __u64 inst_calls_list[4]; 5206 __u64 max_cpus; 5207 __u64 max_guests; 5208 __u64 max_guest_addr; 5209 __u64 feature_indication; 5210 }; 5211 5212 5213 KVM_PV_INFO_DUMP 5214 This subcommand provides information related to dumping PV guests. 5215 5216 :: 5217 5218 struct kvm_s390_pv_info_dump { 5219 __u64 dump_cpu_buffer_len; 5220 __u64 dump_config_mem_buffer_per_1m; 5221 __u64 dump_config_finalize_len; 5222 }; 5223 5224KVM_PV_DUMP 5225 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5226 5227 Presents an API that provides calls which facilitate dumping a 5228 protected VM. 5229 5230 :: 5231 5232 struct kvm_s390_pv_dmp { 5233 __u64 subcmd; 5234 __u64 buff_addr; 5235 __u64 buff_len; 5236 __u64 gaddr; /* For dump storage state */ 5237 }; 5238 5239 **subcommands:** 5240 5241 KVM_PV_DUMP_INIT 5242 Initializes the dump process of a protected VM. If this call does 5243 not succeed all other subcommands will fail with -EINVAL. This 5244 subcommand will return -EINVAL if a dump process has not yet been 5245 completed. 5246 5247 Not all PV vms can be dumped, the owner needs to set `dump 5248 allowed` PCF bit 34 in the SE header to allow dumping. 5249 5250 KVM_PV_DUMP_CONFIG_STOR_STATE 5251 Stores `buff_len` bytes of tweak component values starting with 5252 the 1MB block specified by the absolute guest address 5253 (`gaddr`). `buff_len` needs to be `conf_dump_storage_state_len` 5254 aligned and at least >= the `conf_dump_storage_state_len` value 5255 provided by the dump uv_info data. buff_user might be written to 5256 even if an error rc is returned. For instance if we encounter a 5257 fault after writing the first page of data. 5258 5259 KVM_PV_DUMP_COMPLETE 5260 If the subcommand succeeds it completes the dump process and lets 5261 KVM_PV_DUMP_INIT be called again. 5262 5263 On success `conf_dump_finalize_len` bytes of completion data will be 5264 stored to the `buff_addr`. The completion data contains a key 5265 derivation seed, IV, tweak nonce and encryption keys as well as an 5266 authentication tag all of which are needed to decrypt the dump at a 5267 later time. 5268 5269KVM_PV_ASYNC_CLEANUP_PREPARE 5270 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5271 5272 Prepare the current protected VM for asynchronous teardown. Most 5273 resources used by the current protected VM will be set aside for a 5274 subsequent asynchronous teardown. The current protected VM will then 5275 resume execution immediately as non-protected. There can be at most 5276 one protected VM prepared for asynchronous teardown at any time. If 5277 a protected VM had already been prepared for teardown without 5278 subsequently calling KVM_PV_ASYNC_CLEANUP_PERFORM, this call will 5279 fail. In that case, the userspace process should issue a normal 5280 KVM_PV_DISABLE. The resources set aside with this call will need to 5281 be cleaned up with a subsequent call to KVM_PV_ASYNC_CLEANUP_PERFORM 5282 or KVM_PV_DISABLE, otherwise they will be cleaned up when KVM 5283 terminates. KVM_PV_ASYNC_CLEANUP_PREPARE can be called again as soon 5284 as cleanup starts, i.e. before KVM_PV_ASYNC_CLEANUP_PERFORM finishes. 5285 5286KVM_PV_ASYNC_CLEANUP_PERFORM 5287 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5288 5289 Tear down the protected VM previously prepared for teardown with 5290 KVM_PV_ASYNC_CLEANUP_PREPARE. The resources that had been set aside 5291 will be freed during the execution of this command. This PV command 5292 should ideally be issued by userspace from a separate thread. If a 5293 fatal signal is received (or the process terminates naturally), the 5294 command will terminate immediately without completing, and the normal 5295 KVM shutdown procedure will take care of cleaning up all remaining 5296 protected VMs, including the ones whose teardown was interrupted by 5297 process termination. 5298 52994.126 KVM_XEN_HVM_SET_ATTR 5300-------------------------- 5301 5302:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5303:Architectures: x86 5304:Type: vm ioctl 5305:Parameters: struct kvm_xen_hvm_attr 5306:Returns: 0 on success, < 0 on error 5307 5308:: 5309 5310 struct kvm_xen_hvm_attr { 5311 __u16 type; 5312 __u16 pad[3]; 5313 union { 5314 __u8 long_mode; 5315 __u8 vector; 5316 __u8 runstate_update_flag; 5317 struct { 5318 __u64 gfn; 5319 } shared_info; 5320 struct { 5321 __u32 send_port; 5322 __u32 type; /* EVTCHNSTAT_ipi / EVTCHNSTAT_interdomain */ 5323 __u32 flags; 5324 union { 5325 struct { 5326 __u32 port; 5327 __u32 vcpu; 5328 __u32 priority; 5329 } port; 5330 struct { 5331 __u32 port; /* Zero for eventfd */ 5332 __s32 fd; 5333 } eventfd; 5334 __u32 padding[4]; 5335 } deliver; 5336 } evtchn; 5337 __u32 xen_version; 5338 __u64 pad[8]; 5339 } u; 5340 }; 5341 5342type values: 5343 5344KVM_XEN_ATTR_TYPE_LONG_MODE 5345 Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This 5346 determines the layout of the shared info pages exposed to the VM. 5347 5348KVM_XEN_ATTR_TYPE_SHARED_INFO 5349 Sets the guest physical frame number at which the Xen "shared info" 5350 page resides. Note that although Xen places vcpu_info for the first 5351 32 vCPUs in the shared_info page, KVM does not automatically do so 5352 and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO be used 5353 explicitly even when the vcpu_info for a given vCPU resides at the 5354 "default" location in the shared_info page. This is because KVM may 5355 not be aware of the Xen CPU id which is used as the index into the 5356 vcpu_info[] array, so may know the correct default location. 5357 5358 Note that the shared info page may be constantly written to by KVM; 5359 it contains the event channel bitmap used to deliver interrupts to 5360 a Xen guest, amongst other things. It is exempt from dirty tracking 5361 mechanisms — KVM will not explicitly mark the page as dirty each 5362 time an event channel interrupt is delivered to the guest! Thus, 5363 userspace should always assume that the designated GFN is dirty if 5364 any vCPU has been running or any event channel interrupts can be 5365 routed to the guest. 5366 5367 Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared info 5368 page. 5369 5370KVM_XEN_ATTR_TYPE_UPCALL_VECTOR 5371 Sets the exception vector used to deliver Xen event channel upcalls. 5372 This is the HVM-wide vector injected directly by the hypervisor 5373 (not through the local APIC), typically configured by a guest via 5374 HVM_PARAM_CALLBACK_IRQ. This can be disabled again (e.g. for guest 5375 SHUTDOWN_soft_reset) by setting it to zero. 5376 5377KVM_XEN_ATTR_TYPE_EVTCHN 5378 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5379 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5380 an outbound port number for interception of EVTCHNOP_send requests 5381 from the guest. A given sending port number may be directed back to 5382 a specified vCPU (by APIC ID) / port / priority on the guest, or to 5383 trigger events on an eventfd. The vCPU and priority can be changed 5384 by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but but other 5385 fields cannot change for a given sending port. A port mapping is 5386 removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing 5387 KVM_XEN_EVTCHN_RESET in the flags field removes all interception of 5388 outbound event channels. The values of the flags field are mutually 5389 exclusive and cannot be combined as a bitmask. 5390 5391KVM_XEN_ATTR_TYPE_XEN_VERSION 5392 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5393 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5394 the 32-bit version code returned to the guest when it invokes the 5395 XENVER_version call; typically (XEN_MAJOR << 16 | XEN_MINOR). PV 5396 Xen guests will often use this to as a dummy hypercall to trigger 5397 event channel delivery, so responding within the kernel without 5398 exiting to userspace is beneficial. 5399 5400KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG 5401 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5402 support for KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG. It enables the 5403 XEN_RUNSTATE_UPDATE flag which allows guest vCPUs to safely read 5404 other vCPUs' vcpu_runstate_info. Xen guests enable this feature via 5405 the VMASST_TYPE_runstate_update_flag of the HYPERVISOR_vm_assist 5406 hypercall. 5407 54084.127 KVM_XEN_HVM_GET_ATTR 5409-------------------------- 5410 5411:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5412:Architectures: x86 5413:Type: vm ioctl 5414:Parameters: struct kvm_xen_hvm_attr 5415:Returns: 0 on success, < 0 on error 5416 5417Allows Xen VM attributes to be read. For the structure and types, 5418see KVM_XEN_HVM_SET_ATTR above. The KVM_XEN_ATTR_TYPE_EVTCHN 5419attribute cannot be read. 5420 54214.128 KVM_XEN_VCPU_SET_ATTR 5422--------------------------- 5423 5424:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5425:Architectures: x86 5426:Type: vcpu ioctl 5427:Parameters: struct kvm_xen_vcpu_attr 5428:Returns: 0 on success, < 0 on error 5429 5430:: 5431 5432 struct kvm_xen_vcpu_attr { 5433 __u16 type; 5434 __u16 pad[3]; 5435 union { 5436 __u64 gpa; 5437 __u64 pad[4]; 5438 struct { 5439 __u64 state; 5440 __u64 state_entry_time; 5441 __u64 time_running; 5442 __u64 time_runnable; 5443 __u64 time_blocked; 5444 __u64 time_offline; 5445 } runstate; 5446 __u32 vcpu_id; 5447 struct { 5448 __u32 port; 5449 __u32 priority; 5450 __u64 expires_ns; 5451 } timer; 5452 __u8 vector; 5453 } u; 5454 }; 5455 5456type values: 5457 5458KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO 5459 Sets the guest physical address of the vcpu_info for a given vCPU. 5460 As with the shared_info page for the VM, the corresponding page may be 5461 dirtied at any time if event channel interrupt delivery is enabled, so 5462 userspace should always assume that the page is dirty without relying 5463 on dirty logging. Setting the gpa to KVM_XEN_INVALID_GPA will disable 5464 the vcpu_info. 5465 5466KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO 5467 Sets the guest physical address of an additional pvclock structure 5468 for a given vCPU. This is typically used for guest vsyscall support. 5469 Setting the gpa to KVM_XEN_INVALID_GPA will disable the structure. 5470 5471KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR 5472 Sets the guest physical address of the vcpu_runstate_info for a given 5473 vCPU. This is how a Xen guest tracks CPU state such as steal time. 5474 Setting the gpa to KVM_XEN_INVALID_GPA will disable the runstate area. 5475 5476KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT 5477 Sets the runstate (RUNSTATE_running/_runnable/_blocked/_offline) of 5478 the given vCPU from the .u.runstate.state member of the structure. 5479 KVM automatically accounts running and runnable time but blocked 5480 and offline states are only entered explicitly. 5481 5482KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA 5483 Sets all fields of the vCPU runstate data from the .u.runstate member 5484 of the structure, including the current runstate. The state_entry_time 5485 must equal the sum of the other four times. 5486 5487KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST 5488 This *adds* the contents of the .u.runstate members of the structure 5489 to the corresponding members of the given vCPU's runstate data, thus 5490 permitting atomic adjustments to the runstate times. The adjustment 5491 to the state_entry_time must equal the sum of the adjustments to the 5492 other four times. The state field must be set to -1, or to a valid 5493 runstate value (RUNSTATE_running, RUNSTATE_runnable, RUNSTATE_blocked 5494 or RUNSTATE_offline) to set the current accounted state as of the 5495 adjusted state_entry_time. 5496 5497KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID 5498 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5499 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the Xen 5500 vCPU ID of the given vCPU, to allow timer-related VCPU operations to 5501 be intercepted by KVM. 5502 5503KVM_XEN_VCPU_ATTR_TYPE_TIMER 5504 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5505 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5506 event channel port/priority for the VIRQ_TIMER of the vCPU, as well 5507 as allowing a pending timer to be saved/restored. Setting the timer 5508 port to zero disables kernel handling of the singleshot timer. 5509 5510KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR 5511 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5512 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5513 per-vCPU local APIC upcall vector, configured by a Xen guest with 5514 the HVMOP_set_evtchn_upcall_vector hypercall. This is typically 5515 used by Windows guests, and is distinct from the HVM-wide upcall 5516 vector configured with HVM_PARAM_CALLBACK_IRQ. It is disabled by 5517 setting the vector to zero. 5518 5519 55204.129 KVM_XEN_VCPU_GET_ATTR 5521--------------------------- 5522 5523:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5524:Architectures: x86 5525:Type: vcpu ioctl 5526:Parameters: struct kvm_xen_vcpu_attr 5527:Returns: 0 on success, < 0 on error 5528 5529Allows Xen vCPU attributes to be read. For the structure and types, 5530see KVM_XEN_VCPU_SET_ATTR above. 5531 5532The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used 5533with the KVM_XEN_VCPU_GET_ATTR ioctl. 5534 55354.130 KVM_ARM_MTE_COPY_TAGS 5536--------------------------- 5537 5538:Capability: KVM_CAP_ARM_MTE 5539:Architectures: arm64 5540:Type: vm ioctl 5541:Parameters: struct kvm_arm_copy_mte_tags 5542:Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect 5543 arguments, -EFAULT if memory cannot be accessed). 5544 5545:: 5546 5547 struct kvm_arm_copy_mte_tags { 5548 __u64 guest_ipa; 5549 __u64 length; 5550 void __user *addr; 5551 __u64 flags; 5552 __u64 reserved[2]; 5553 }; 5554 5555Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The 5556``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. The ``addr`` 5557field must point to a buffer which the tags will be copied to or from. 5558 5559``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or 5560``KVM_ARM_TAGS_FROM_GUEST``. 5561 5562The size of the buffer to store the tags is ``(length / 16)`` bytes 5563(granules in MTE are 16 bytes long). Each byte contains a single tag 5564value. This matches the format of ``PTRACE_PEEKMTETAGS`` and 5565``PTRACE_POKEMTETAGS``. 5566 5567If an error occurs before any data is copied then a negative error code is 5568returned. If some tags have been copied before an error occurs then the number 5569of bytes successfully copied is returned. If the call completes successfully 5570then ``length`` is returned. 5571 55724.131 KVM_GET_SREGS2 5573-------------------- 5574 5575:Capability: KVM_CAP_SREGS2 5576:Architectures: x86 5577:Type: vcpu ioctl 5578:Parameters: struct kvm_sregs2 (out) 5579:Returns: 0 on success, -1 on error 5580 5581Reads special registers from the vcpu. 5582This ioctl (when supported) replaces the KVM_GET_SREGS. 5583 5584:: 5585 5586 struct kvm_sregs2 { 5587 /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ 5588 struct kvm_segment cs, ds, es, fs, gs, ss; 5589 struct kvm_segment tr, ldt; 5590 struct kvm_dtable gdt, idt; 5591 __u64 cr0, cr2, cr3, cr4, cr8; 5592 __u64 efer; 5593 __u64 apic_base; 5594 __u64 flags; 5595 __u64 pdptrs[4]; 5596 }; 5597 5598flags values for ``kvm_sregs2``: 5599 5600``KVM_SREGS2_FLAGS_PDPTRS_VALID`` 5601 5602 Indicates thats the struct contain valid PDPTR values. 5603 5604 56054.132 KVM_SET_SREGS2 5606-------------------- 5607 5608:Capability: KVM_CAP_SREGS2 5609:Architectures: x86 5610:Type: vcpu ioctl 5611:Parameters: struct kvm_sregs2 (in) 5612:Returns: 0 on success, -1 on error 5613 5614Writes special registers into the vcpu. 5615See KVM_GET_SREGS2 for the data structures. 5616This ioctl (when supported) replaces the KVM_SET_SREGS. 5617 56184.133 KVM_GET_STATS_FD 5619---------------------- 5620 5621:Capability: KVM_CAP_STATS_BINARY_FD 5622:Architectures: all 5623:Type: vm ioctl, vcpu ioctl 5624:Parameters: none 5625:Returns: statistics file descriptor on success, < 0 on error 5626 5627Errors: 5628 5629 ====== ====================================================== 5630 ENOMEM if the fd could not be created due to lack of memory 5631 EMFILE if the number of opened files exceeds the limit 5632 ====== ====================================================== 5633 5634The returned file descriptor can be used to read VM/vCPU statistics data in 5635binary format. The data in the file descriptor consists of four blocks 5636organized as follows: 5637 5638+-------------+ 5639| Header | 5640+-------------+ 5641| id string | 5642+-------------+ 5643| Descriptors | 5644+-------------+ 5645| Stats Data | 5646+-------------+ 5647 5648Apart from the header starting at offset 0, please be aware that it is 5649not guaranteed that the four blocks are adjacent or in the above order; 5650the offsets of the id, descriptors and data blocks are found in the 5651header. However, all four blocks are aligned to 64 bit offsets in the 5652file and they do not overlap. 5653 5654All blocks except the data block are immutable. Userspace can read them 5655only one time after retrieving the file descriptor, and then use ``pread`` or 5656``lseek`` to read the statistics repeatedly. 5657 5658All data is in system endianness. 5659 5660The format of the header is as follows:: 5661 5662 struct kvm_stats_header { 5663 __u32 flags; 5664 __u32 name_size; 5665 __u32 num_desc; 5666 __u32 id_offset; 5667 __u32 desc_offset; 5668 __u32 data_offset; 5669 }; 5670 5671The ``flags`` field is not used at the moment. It is always read as 0. 5672 5673The ``name_size`` field is the size (in byte) of the statistics name string 5674(including trailing '\0') which is contained in the "id string" block and 5675appended at the end of every descriptor. 5676 5677The ``num_desc`` field is the number of descriptors that are included in the 5678descriptor block. (The actual number of values in the data block may be 5679larger, since each descriptor may comprise more than one value). 5680 5681The ``id_offset`` field is the offset of the id string from the start of the 5682file indicated by the file descriptor. It is a multiple of 8. 5683 5684The ``desc_offset`` field is the offset of the Descriptors block from the start 5685of the file indicated by the file descriptor. It is a multiple of 8. 5686 5687The ``data_offset`` field is the offset of the Stats Data block from the start 5688of the file indicated by the file descriptor. It is a multiple of 8. 5689 5690The id string block contains a string which identifies the file descriptor on 5691which KVM_GET_STATS_FD was invoked. The size of the block, including the 5692trailing ``'\0'``, is indicated by the ``name_size`` field in the header. 5693 5694The descriptors block is only needed to be read once for the lifetime of the 5695file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed 5696by a string of size ``name_size``. 5697:: 5698 5699 #define KVM_STATS_TYPE_SHIFT 0 5700 #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT) 5701 #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT) 5702 #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT) 5703 #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT) 5704 #define KVM_STATS_TYPE_LINEAR_HIST (0x3 << KVM_STATS_TYPE_SHIFT) 5705 #define KVM_STATS_TYPE_LOG_HIST (0x4 << KVM_STATS_TYPE_SHIFT) 5706 #define KVM_STATS_TYPE_MAX KVM_STATS_TYPE_LOG_HIST 5707 5708 #define KVM_STATS_UNIT_SHIFT 4 5709 #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT) 5710 #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT) 5711 #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) 5712 #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) 5713 #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) 5714 #define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT) 5715 #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_BOOLEAN 5716 5717 #define KVM_STATS_BASE_SHIFT 8 5718 #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT) 5719 #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT) 5720 #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT) 5721 #define KVM_STATS_BASE_MAX KVM_STATS_BASE_POW2 5722 5723 struct kvm_stats_desc { 5724 __u32 flags; 5725 __s16 exponent; 5726 __u16 size; 5727 __u32 offset; 5728 __u32 bucket_size; 5729 char name[]; 5730 }; 5731 5732The ``flags`` field contains the type and unit of the statistics data described 5733by this descriptor. Its endianness is CPU native. 5734The following flags are supported: 5735 5736Bits 0-3 of ``flags`` encode the type: 5737 5738 * ``KVM_STATS_TYPE_CUMULATIVE`` 5739 The statistics reports a cumulative count. The value of data can only be increased. 5740 Most of the counters used in KVM are of this type. 5741 The corresponding ``size`` field for this type is always 1. 5742 All cumulative statistics data are read/write. 5743 * ``KVM_STATS_TYPE_INSTANT`` 5744 The statistics reports an instantaneous value. Its value can be increased or 5745 decreased. This type is usually used as a measurement of some resources, 5746 like the number of dirty pages, the number of large pages, etc. 5747 All instant statistics are read only. 5748 The corresponding ``size`` field for this type is always 1. 5749 * ``KVM_STATS_TYPE_PEAK`` 5750 The statistics data reports a peak value, for example the maximum number 5751 of items in a hash table bucket, the longest time waited and so on. 5752 The value of data can only be increased. 5753 The corresponding ``size`` field for this type is always 1. 5754 * ``KVM_STATS_TYPE_LINEAR_HIST`` 5755 The statistic is reported as a linear histogram. The number of 5756 buckets is specified by the ``size`` field. The size of buckets is specified 5757 by the ``hist_param`` field. The range of the Nth bucket (1 <= N < ``size``) 5758 is [``hist_param``*(N-1), ``hist_param``*N), while the range of the last 5759 bucket is [``hist_param``*(``size``-1), +INF). (+INF means positive infinity 5760 value.) 5761 * ``KVM_STATS_TYPE_LOG_HIST`` 5762 The statistic is reported as a logarithmic histogram. The number of 5763 buckets is specified by the ``size`` field. The range of the first bucket is 5764 [0, 1), while the range of the last bucket is [pow(2, ``size``-2), +INF). 5765 Otherwise, The Nth bucket (1 < N < ``size``) covers 5766 [pow(2, N-2), pow(2, N-1)). 5767 5768Bits 4-7 of ``flags`` encode the unit: 5769 5770 * ``KVM_STATS_UNIT_NONE`` 5771 There is no unit for the value of statistics data. This usually means that 5772 the value is a simple counter of an event. 5773 * ``KVM_STATS_UNIT_BYTES`` 5774 It indicates that the statistics data is used to measure memory size, in the 5775 unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is 5776 determined by the ``exponent`` field in the descriptor. 5777 * ``KVM_STATS_UNIT_SECONDS`` 5778 It indicates that the statistics data is used to measure time or latency. 5779 * ``KVM_STATS_UNIT_CYCLES`` 5780 It indicates that the statistics data is used to measure CPU clock cycles. 5781 * ``KVM_STATS_UNIT_BOOLEAN`` 5782 It indicates that the statistic will always be either 0 or 1. Boolean 5783 statistics of "peak" type will never go back from 1 to 0. Boolean 5784 statistics can be linear histograms (with two buckets) but not logarithmic 5785 histograms. 5786 5787Note that, in the case of histograms, the unit applies to the bucket 5788ranges, while the bucket value indicates how many samples fell in the 5789bucket's range. 5790 5791Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the 5792unit: 5793 5794 * ``KVM_STATS_BASE_POW10`` 5795 The scale is based on power of 10. It is used for measurement of time and 5796 CPU clock cycles. For example, an exponent of -9 can be used with 5797 ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds. 5798 * ``KVM_STATS_BASE_POW2`` 5799 The scale is based on power of 2. It is used for measurement of memory size. 5800 For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to 5801 express that the unit is MiB. 5802 5803The ``size`` field is the number of values of this statistics data. Its 5804value is usually 1 for most of simple statistics. 1 means it contains an 5805unsigned 64bit data. 5806 5807The ``offset`` field is the offset from the start of Data Block to the start of 5808the corresponding statistics data. 5809 5810The ``bucket_size`` field is used as a parameter for histogram statistics data. 5811It is only used by linear histogram statistics data, specifying the size of a 5812bucket in the unit expressed by bits 4-11 of ``flags`` together with ``exponent``. 5813 5814The ``name`` field is the name string of the statistics data. The name string 5815starts at the end of ``struct kvm_stats_desc``. The maximum length including 5816the trailing ``'\0'``, is indicated by ``name_size`` in the header. 5817 5818The Stats Data block contains an array of 64-bit values in the same order 5819as the descriptors in Descriptors block. 5820 58214.134 KVM_GET_XSAVE2 5822-------------------- 5823 5824:Capability: KVM_CAP_XSAVE2 5825:Architectures: x86 5826:Type: vcpu ioctl 5827:Parameters: struct kvm_xsave (out) 5828:Returns: 0 on success, -1 on error 5829 5830 5831:: 5832 5833 struct kvm_xsave { 5834 __u32 region[1024]; 5835 __u32 extra[0]; 5836 }; 5837 5838This ioctl would copy current vcpu's xsave struct to the userspace. It 5839copies as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) 5840when invoked on the vm file descriptor. The size value returned by 5841KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 5842Currently, it is only greater than 4096 if a dynamic feature has been 5843enabled with ``arch_prctl()``, but this may change in the future. 5844 5845The offsets of the state save areas in struct kvm_xsave follow the contents 5846of CPUID leaf 0xD on the host. 5847 58484.135 KVM_XEN_HVM_EVTCHN_SEND 5849----------------------------- 5850 5851:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND 5852:Architectures: x86 5853:Type: vm ioctl 5854:Parameters: struct kvm_irq_routing_xen_evtchn 5855:Returns: 0 on success, < 0 on error 5856 5857 5858:: 5859 5860 struct kvm_irq_routing_xen_evtchn { 5861 __u32 port; 5862 __u32 vcpu; 5863 __u32 priority; 5864 }; 5865 5866This ioctl injects an event channel interrupt directly to the guest vCPU. 5867 58684.136 KVM_S390_PV_CPU_COMMAND 5869----------------------------- 5870 5871:Capability: KVM_CAP_S390_PROTECTED_DUMP 5872:Architectures: s390 5873:Type: vcpu ioctl 5874:Parameters: none 5875:Returns: 0 on success, < 0 on error 5876 5877This ioctl closely mirrors `KVM_S390_PV_COMMAND` but handles requests 5878for vcpus. It re-uses the kvm_s390_pv_dmp struct and hence also shares 5879the command ids. 5880 5881**command:** 5882 5883KVM_PV_DUMP 5884 Presents an API that provides calls which facilitate dumping a vcpu 5885 of a protected VM. 5886 5887**subcommand:** 5888 5889KVM_PV_DUMP_CPU 5890 Provides encrypted dump data like register values. 5891 The length of the returned data is provided by uv_info.guest_cpu_stor_len. 5892 58934.137 KVM_S390_ZPCI_OP 5894---------------------- 5895 5896:Capability: KVM_CAP_S390_ZPCI_OP 5897:Architectures: s390 5898:Type: vm ioctl 5899:Parameters: struct kvm_s390_zpci_op (in) 5900:Returns: 0 on success, <0 on error 5901 5902Used to manage hardware-assisted virtualization features for zPCI devices. 5903 5904Parameters are specified via the following structure:: 5905 5906 struct kvm_s390_zpci_op { 5907 /* in */ 5908 __u32 fh; /* target device */ 5909 __u8 op; /* operation to perform */ 5910 __u8 pad[3]; 5911 union { 5912 /* for KVM_S390_ZPCIOP_REG_AEN */ 5913 struct { 5914 __u64 ibv; /* Guest addr of interrupt bit vector */ 5915 __u64 sb; /* Guest addr of summary bit */ 5916 __u32 flags; 5917 __u32 noi; /* Number of interrupts */ 5918 __u8 isc; /* Guest interrupt subclass */ 5919 __u8 sbo; /* Offset of guest summary bit vector */ 5920 __u16 pad; 5921 } reg_aen; 5922 __u64 reserved[8]; 5923 } u; 5924 }; 5925 5926The type of operation is specified in the "op" field. 5927KVM_S390_ZPCIOP_REG_AEN is used to register the VM for adapter event 5928notification interpretation, which will allow firmware delivery of adapter 5929events directly to the vm, with KVM providing a backup delivery mechanism; 5930KVM_S390_ZPCIOP_DEREG_AEN is used to subsequently disable interpretation of 5931adapter event notifications. 5932 5933The target zPCI function must also be specified via the "fh" field. For the 5934KVM_S390_ZPCIOP_REG_AEN operation, additional information to establish firmware 5935delivery must be provided via the "reg_aen" struct. 5936 5937The "pad" and "reserved" fields may be used for future extensions and should be 5938set to 0s by userspace. 5939 59405. The kvm_run structure 5941======================== 5942 5943Application code obtains a pointer to the kvm_run structure by 5944mmap()ing a vcpu fd. From that point, application code can control 5945execution by changing fields in kvm_run prior to calling the KVM_RUN 5946ioctl, and obtain information about the reason KVM_RUN returned by 5947looking up structure members. 5948 5949:: 5950 5951 struct kvm_run { 5952 /* in */ 5953 __u8 request_interrupt_window; 5954 5955Request that KVM_RUN return when it becomes possible to inject external 5956interrupts into the guest. Useful in conjunction with KVM_INTERRUPT. 5957 5958:: 5959 5960 __u8 immediate_exit; 5961 5962This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN 5963exits immediately, returning -EINTR. In the common scenario where a 5964signal is used to "kick" a VCPU out of KVM_RUN, this field can be used 5965to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability. 5966Rather than blocking the signal outside KVM_RUN, userspace can set up 5967a signal handler that sets run->immediate_exit to a non-zero value. 5968 5969This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available. 5970 5971:: 5972 5973 __u8 padding1[6]; 5974 5975 /* out */ 5976 __u32 exit_reason; 5977 5978When KVM_RUN has returned successfully (return value 0), this informs 5979application code why KVM_RUN has returned. Allowable values for this 5980field are detailed below. 5981 5982:: 5983 5984 __u8 ready_for_interrupt_injection; 5985 5986If request_interrupt_window has been specified, this field indicates 5987an interrupt can be injected now with KVM_INTERRUPT. 5988 5989:: 5990 5991 __u8 if_flag; 5992 5993The value of the current interrupt flag. Only valid if in-kernel 5994local APIC is not used. 5995 5996:: 5997 5998 __u16 flags; 5999 6000More architecture-specific flags detailing state of the VCPU that may 6001affect the device's behavior. Current defined flags:: 6002 6003 /* x86, set if the VCPU is in system management mode */ 6004 #define KVM_RUN_X86_SMM (1 << 0) 6005 /* x86, set if bus lock detected in VM */ 6006 #define KVM_RUN_BUS_LOCK (1 << 1) 6007 /* arm64, set for KVM_EXIT_DEBUG */ 6008 #define KVM_DEBUG_ARCH_HSR_HIGH_VALID (1 << 0) 6009 6010:: 6011 6012 /* in (pre_kvm_run), out (post_kvm_run) */ 6013 __u64 cr8; 6014 6015The value of the cr8 register. Only valid if in-kernel local APIC is 6016not used. Both input and output. 6017 6018:: 6019 6020 __u64 apic_base; 6021 6022The value of the APIC BASE msr. Only valid if in-kernel local 6023APIC is not used. Both input and output. 6024 6025:: 6026 6027 union { 6028 /* KVM_EXIT_UNKNOWN */ 6029 struct { 6030 __u64 hardware_exit_reason; 6031 } hw; 6032 6033If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown 6034reasons. Further architecture-specific information is available in 6035hardware_exit_reason. 6036 6037:: 6038 6039 /* KVM_EXIT_FAIL_ENTRY */ 6040 struct { 6041 __u64 hardware_entry_failure_reason; 6042 __u32 cpu; /* if KVM_LAST_CPU */ 6043 } fail_entry; 6044 6045If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due 6046to unknown reasons. Further architecture-specific information is 6047available in hardware_entry_failure_reason. 6048 6049:: 6050 6051 /* KVM_EXIT_EXCEPTION */ 6052 struct { 6053 __u32 exception; 6054 __u32 error_code; 6055 } ex; 6056 6057Unused. 6058 6059:: 6060 6061 /* KVM_EXIT_IO */ 6062 struct { 6063 #define KVM_EXIT_IO_IN 0 6064 #define KVM_EXIT_IO_OUT 1 6065 __u8 direction; 6066 __u8 size; /* bytes */ 6067 __u16 port; 6068 __u32 count; 6069 __u64 data_offset; /* relative to kvm_run start */ 6070 } io; 6071 6072If exit_reason is KVM_EXIT_IO, then the vcpu has 6073executed a port I/O instruction which could not be satisfied by kvm. 6074data_offset describes where the data is located (KVM_EXIT_IO_OUT) or 6075where kvm expects application code to place the data for the next 6076KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. 6077 6078:: 6079 6080 /* KVM_EXIT_DEBUG */ 6081 struct { 6082 struct kvm_debug_exit_arch arch; 6083 } debug; 6084 6085If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event 6086for which architecture specific information is returned. 6087 6088:: 6089 6090 /* KVM_EXIT_MMIO */ 6091 struct { 6092 __u64 phys_addr; 6093 __u8 data[8]; 6094 __u32 len; 6095 __u8 is_write; 6096 } mmio; 6097 6098If exit_reason is KVM_EXIT_MMIO, then the vcpu has 6099executed a memory-mapped I/O instruction which could not be satisfied 6100by kvm. The 'data' member contains the written data if 'is_write' is 6101true, and should be filled by application code otherwise. 6102 6103The 'data' member contains, in its first 'len' bytes, the value as it would 6104appear if the VCPU performed a load or store of the appropriate width directly 6105to the byte array. 6106 6107.. note:: 6108 6109 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN, 6110 KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding 6111 operations are complete (and guest state is consistent) only after userspace 6112 has re-entered the kernel with KVM_RUN. The kernel side will first finish 6113 incomplete operations and then check for pending signals. 6114 6115 The pending state of the operation is not preserved in state which is 6116 visible to userspace, thus userspace should ensure that the operation is 6117 completed before performing a live migration. Userspace can re-enter the 6118 guest with an unmasked signal pending or with the immediate_exit field set 6119 to complete pending operations without allowing any further instructions 6120 to be executed. 6121 6122:: 6123 6124 /* KVM_EXIT_HYPERCALL */ 6125 struct { 6126 __u64 nr; 6127 __u64 args[6]; 6128 __u64 ret; 6129 __u32 longmode; 6130 __u32 pad; 6131 } hypercall; 6132 6133Unused. This was once used for 'hypercall to userspace'. To implement 6134such functionality, use KVM_EXIT_IO (x86) or KVM_EXIT_MMIO (all except s390). 6135 6136.. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO. 6137 6138:: 6139 6140 /* KVM_EXIT_TPR_ACCESS */ 6141 struct { 6142 __u64 rip; 6143 __u32 is_write; 6144 __u32 pad; 6145 } tpr_access; 6146 6147To be documented (KVM_TPR_ACCESS_REPORTING). 6148 6149:: 6150 6151 /* KVM_EXIT_S390_SIEIC */ 6152 struct { 6153 __u8 icptcode; 6154 __u64 mask; /* psw upper half */ 6155 __u64 addr; /* psw lower half */ 6156 __u16 ipa; 6157 __u32 ipb; 6158 } s390_sieic; 6159 6160s390 specific. 6161 6162:: 6163 6164 /* KVM_EXIT_S390_RESET */ 6165 #define KVM_S390_RESET_POR 1 6166 #define KVM_S390_RESET_CLEAR 2 6167 #define KVM_S390_RESET_SUBSYSTEM 4 6168 #define KVM_S390_RESET_CPU_INIT 8 6169 #define KVM_S390_RESET_IPL 16 6170 __u64 s390_reset_flags; 6171 6172s390 specific. 6173 6174:: 6175 6176 /* KVM_EXIT_S390_UCONTROL */ 6177 struct { 6178 __u64 trans_exc_code; 6179 __u32 pgm_code; 6180 } s390_ucontrol; 6181 6182s390 specific. A page fault has occurred for a user controlled virtual 6183machine (KVM_VM_S390_UNCONTROL) on it's host page table that cannot be 6184resolved by the kernel. 6185The program code and the translation exception code that were placed 6186in the cpu's lowcore are presented here as defined by the z Architecture 6187Principles of Operation Book in the Chapter for Dynamic Address Translation 6188(DAT) 6189 6190:: 6191 6192 /* KVM_EXIT_DCR */ 6193 struct { 6194 __u32 dcrn; 6195 __u32 data; 6196 __u8 is_write; 6197 } dcr; 6198 6199Deprecated - was used for 440 KVM. 6200 6201:: 6202 6203 /* KVM_EXIT_OSI */ 6204 struct { 6205 __u64 gprs[32]; 6206 } osi; 6207 6208MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch 6209hypercalls and exit with this exit struct that contains all the guest gprs. 6210 6211If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall. 6212Userspace can now handle the hypercall and when it's done modify the gprs as 6213necessary. Upon guest entry all guest GPRs will then be replaced by the values 6214in this struct. 6215 6216:: 6217 6218 /* KVM_EXIT_PAPR_HCALL */ 6219 struct { 6220 __u64 nr; 6221 __u64 ret; 6222 __u64 args[9]; 6223 } papr_hcall; 6224 6225This is used on 64-bit PowerPC when emulating a pSeries partition, 6226e.g. with the 'pseries' machine type in qemu. It occurs when the 6227guest does a hypercall using the 'sc 1' instruction. The 'nr' field 6228contains the hypercall number (from the guest R3), and 'args' contains 6229the arguments (from the guest R4 - R12). Userspace should put the 6230return code in 'ret' and any extra returned values in args[]. 6231The possible hypercalls are defined in the Power Architecture Platform 6232Requirements (PAPR) document available from www.power.org (free 6233developer registration required to access it). 6234 6235:: 6236 6237 /* KVM_EXIT_S390_TSCH */ 6238 struct { 6239 __u16 subchannel_id; 6240 __u16 subchannel_nr; 6241 __u32 io_int_parm; 6242 __u32 io_int_word; 6243 __u32 ipb; 6244 __u8 dequeued; 6245 } s390_tsch; 6246 6247s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled 6248and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O 6249interrupt for the target subchannel has been dequeued and subchannel_id, 6250subchannel_nr, io_int_parm and io_int_word contain the parameters for that 6251interrupt. ipb is needed for instruction parameter decoding. 6252 6253:: 6254 6255 /* KVM_EXIT_EPR */ 6256 struct { 6257 __u32 epr; 6258 } epr; 6259 6260On FSL BookE PowerPC chips, the interrupt controller has a fast patch 6261interrupt acknowledge path to the core. When the core successfully 6262delivers an interrupt, it automatically populates the EPR register with 6263the interrupt vector number and acknowledges the interrupt inside 6264the interrupt controller. 6265 6266In case the interrupt controller lives in user space, we need to do 6267the interrupt acknowledge cycle through it to fetch the next to be 6268delivered interrupt vector using this exit. 6269 6270It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an 6271external interrupt has just been delivered into the guest. User space 6272should put the acknowledged interrupt vector into the 'epr' field. 6273 6274:: 6275 6276 /* KVM_EXIT_SYSTEM_EVENT */ 6277 struct { 6278 #define KVM_SYSTEM_EVENT_SHUTDOWN 1 6279 #define KVM_SYSTEM_EVENT_RESET 2 6280 #define KVM_SYSTEM_EVENT_CRASH 3 6281 #define KVM_SYSTEM_EVENT_WAKEUP 4 6282 #define KVM_SYSTEM_EVENT_SUSPEND 5 6283 #define KVM_SYSTEM_EVENT_SEV_TERM 6 6284 __u32 type; 6285 __u32 ndata; 6286 __u64 data[16]; 6287 } system_event; 6288 6289If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered 6290a system-level event using some architecture specific mechanism (hypercall 6291or some special instruction). In case of ARM64, this is triggered using 6292HVC instruction based PSCI call from the vcpu. 6293 6294The 'type' field describes the system-level event type. 6295Valid values for 'type' are: 6296 6297 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the 6298 VM. Userspace is not obliged to honour this, and if it does honour 6299 this does not need to destroy the VM synchronously (ie it may call 6300 KVM_RUN again before shutdown finally occurs). 6301 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. 6302 As with SHUTDOWN, userspace can choose to ignore the request, or 6303 to schedule the reset to occur in the future and may call KVM_RUN again. 6304 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest 6305 has requested a crash condition maintenance. Userspace can choose 6306 to ignore the request, or to gather VM memory core dump and/or 6307 reset/shutdown of the VM. 6308 - KVM_SYSTEM_EVENT_SEV_TERM -- an AMD SEV guest requested termination. 6309 The guest physical address of the guest's GHCB is stored in `data[0]`. 6310 - KVM_SYSTEM_EVENT_WAKEUP -- the exiting vCPU is in a suspended state and 6311 KVM has recognized a wakeup event. Userspace may honor this event by 6312 marking the exiting vCPU as runnable, or deny it and call KVM_RUN again. 6313 - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of 6314 the VM. 6315 6316If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain 6317architecture specific information for the system-level event. Only 6318the first `ndata` items (possibly zero) of the data array are valid. 6319 6320 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if 6321 the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI 6322 specification. 6323 6324 - for RISC-V, data[0] is set to the value of the second argument of the 6325 ``sbi_system_reset`` call. 6326 6327Previous versions of Linux defined a `flags` member in this struct. The 6328field is now aliased to `data[0]`. Userspace can assume that it is only 6329written if ndata is greater than 0. 6330 6331For arm/arm64: 6332-------------- 6333 6334KVM_SYSTEM_EVENT_SUSPEND exits are enabled with the 6335KVM_CAP_ARM_SYSTEM_SUSPEND VM capability. If a guest invokes the PSCI 6336SYSTEM_SUSPEND function, KVM will exit to userspace with this event 6337type. 6338 6339It is the sole responsibility of userspace to implement the PSCI 6340SYSTEM_SUSPEND call according to ARM DEN0022D.b 5.19 "SYSTEM_SUSPEND". 6341KVM does not change the vCPU's state before exiting to userspace, so 6342the call parameters are left in-place in the vCPU registers. 6343 6344Userspace is _required_ to take action for such an exit. It must 6345either: 6346 6347 - Honor the guest request to suspend the VM. Userspace can request 6348 in-kernel emulation of suspension by setting the calling vCPU's 6349 state to KVM_MP_STATE_SUSPENDED. Userspace must configure the vCPU's 6350 state according to the parameters passed to the PSCI function when 6351 the calling vCPU is resumed. See ARM DEN0022D.b 5.19.1 "Intended use" 6352 for details on the function parameters. 6353 6354 - Deny the guest request to suspend the VM. See ARM DEN0022D.b 5.19.2 6355 "Caller responsibilities" for possible return values. 6356 6357:: 6358 6359 /* KVM_EXIT_IOAPIC_EOI */ 6360 struct { 6361 __u8 vector; 6362 } eoi; 6363 6364Indicates that the VCPU's in-kernel local APIC received an EOI for a 6365level-triggered IOAPIC interrupt. This exit only triggers when the 6366IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled); 6367the userspace IOAPIC should process the EOI and retrigger the interrupt if 6368it is still asserted. Vector is the LAPIC interrupt vector for which the 6369EOI was received. 6370 6371:: 6372 6373 struct kvm_hyperv_exit { 6374 #define KVM_EXIT_HYPERV_SYNIC 1 6375 #define KVM_EXIT_HYPERV_HCALL 2 6376 #define KVM_EXIT_HYPERV_SYNDBG 3 6377 __u32 type; 6378 __u32 pad1; 6379 union { 6380 struct { 6381 __u32 msr; 6382 __u32 pad2; 6383 __u64 control; 6384 __u64 evt_page; 6385 __u64 msg_page; 6386 } synic; 6387 struct { 6388 __u64 input; 6389 __u64 result; 6390 __u64 params[2]; 6391 } hcall; 6392 struct { 6393 __u32 msr; 6394 __u32 pad2; 6395 __u64 control; 6396 __u64 status; 6397 __u64 send_page; 6398 __u64 recv_page; 6399 __u64 pending_page; 6400 } syndbg; 6401 } u; 6402 }; 6403 /* KVM_EXIT_HYPERV */ 6404 struct kvm_hyperv_exit hyperv; 6405 6406Indicates that the VCPU exits into userspace to process some tasks 6407related to Hyper-V emulation. 6408 6409Valid values for 'type' are: 6410 6411 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about 6412 6413Hyper-V SynIC state change. Notification is used to remap SynIC 6414event/message pages and to enable/disable SynIC messages/events processing 6415in userspace. 6416 6417 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about 6418 6419Hyper-V Synthetic debugger state change. Notification is used to either update 6420the pending_page location or to send a control command (send the buffer located 6421in send_page or recv a buffer to recv_page). 6422 6423:: 6424 6425 /* KVM_EXIT_ARM_NISV */ 6426 struct { 6427 __u64 esr_iss; 6428 __u64 fault_ipa; 6429 } arm_nisv; 6430 6431Used on arm64 systems. If a guest accesses memory not in a memslot, 6432KVM will typically return to userspace and ask it to do MMIO emulation on its 6433behalf. However, for certain classes of instructions, no instruction decode 6434(direction, length of memory access) is provided, and fetching and decoding 6435the instruction from the VM is overly complicated to live in the kernel. 6436 6437Historically, when this situation occurred, KVM would print a warning and kill 6438the VM. KVM assumed that if the guest accessed non-memslot memory, it was 6439trying to do I/O, which just couldn't be emulated, and the warning message was 6440phrased accordingly. However, what happened more often was that a guest bug 6441caused access outside the guest memory areas which should lead to a more 6442meaningful warning message and an external abort in the guest, if the access 6443did not fall within an I/O window. 6444 6445Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable 6446this capability at VM creation. Once this is done, these types of errors will 6447instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from 6448the ESR_EL2 in the esr_iss field, and the faulting IPA in the fault_ipa field. 6449Userspace can either fix up the access if it's actually an I/O access by 6450decoding the instruction from guest memory (if it's very brave) and continue 6451executing the guest, or it can decide to suspend, dump, or restart the guest. 6452 6453Note that KVM does not skip the faulting instruction as it does for 6454KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state 6455if it decides to decode and emulate the instruction. 6456 6457:: 6458 6459 /* KVM_EXIT_X86_RDMSR / KVM_EXIT_X86_WRMSR */ 6460 struct { 6461 __u8 error; /* user -> kernel */ 6462 __u8 pad[7]; 6463 __u32 reason; /* kernel -> user */ 6464 __u32 index; /* kernel -> user */ 6465 __u64 data; /* kernel <-> user */ 6466 } msr; 6467 6468Used on x86 systems. When the VM capability KVM_CAP_X86_USER_SPACE_MSR is 6469enabled, MSR accesses to registers that would invoke a #GP by KVM kernel code 6470may instead trigger a KVM_EXIT_X86_RDMSR exit for reads and KVM_EXIT_X86_WRMSR 6471exit for writes. 6472 6473The "reason" field specifies why the MSR interception occurred. Userspace will 6474only receive MSR exits when a particular reason was requested during through 6475ENABLE_CAP. Currently valid exit reasons are: 6476 6477============================ ======================================== 6478 KVM_MSR_EXIT_REASON_UNKNOWN access to MSR that is unknown to KVM 6479 KVM_MSR_EXIT_REASON_INVAL access to invalid MSRs or reserved bits 6480 KVM_MSR_EXIT_REASON_FILTER access blocked by KVM_X86_SET_MSR_FILTER 6481============================ ======================================== 6482 6483For KVM_EXIT_X86_RDMSR, the "index" field tells userspace which MSR the guest 6484wants to read. To respond to this request with a successful read, userspace 6485writes the respective data into the "data" field and must continue guest 6486execution to ensure the read data is transferred into guest register state. 6487 6488If the RDMSR request was unsuccessful, userspace indicates that with a "1" in 6489the "error" field. This will inject a #GP into the guest when the VCPU is 6490executed again. 6491 6492For KVM_EXIT_X86_WRMSR, the "index" field tells userspace which MSR the guest 6493wants to write. Once finished processing the event, userspace must continue 6494vCPU execution. If the MSR write was unsuccessful, userspace also sets the 6495"error" field to "1". 6496 6497See KVM_X86_SET_MSR_FILTER for details on the interaction with MSR filtering. 6498 6499:: 6500 6501 6502 struct kvm_xen_exit { 6503 #define KVM_EXIT_XEN_HCALL 1 6504 __u32 type; 6505 union { 6506 struct { 6507 __u32 longmode; 6508 __u32 cpl; 6509 __u64 input; 6510 __u64 result; 6511 __u64 params[6]; 6512 } hcall; 6513 } u; 6514 }; 6515 /* KVM_EXIT_XEN */ 6516 struct kvm_hyperv_exit xen; 6517 6518Indicates that the VCPU exits into userspace to process some tasks 6519related to Xen emulation. 6520 6521Valid values for 'type' are: 6522 6523 - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall. 6524 Userspace is expected to place the hypercall result into the appropriate 6525 field before invoking KVM_RUN again. 6526 6527:: 6528 6529 /* KVM_EXIT_RISCV_SBI */ 6530 struct { 6531 unsigned long extension_id; 6532 unsigned long function_id; 6533 unsigned long args[6]; 6534 unsigned long ret[2]; 6535 } riscv_sbi; 6536 6537If exit reason is KVM_EXIT_RISCV_SBI then it indicates that the VCPU has 6538done a SBI call which is not handled by KVM RISC-V kernel module. The details 6539of the SBI call are available in 'riscv_sbi' member of kvm_run structure. The 6540'extension_id' field of 'riscv_sbi' represents SBI extension ID whereas the 6541'function_id' field represents function ID of given SBI extension. The 'args' 6542array field of 'riscv_sbi' represents parameters for the SBI call and 'ret' 6543array field represents return values. The userspace should update the return 6544values of SBI call before resuming the VCPU. For more details on RISC-V SBI 6545spec refer, https://github.com/riscv/riscv-sbi-doc. 6546 6547:: 6548 6549 /* KVM_EXIT_NOTIFY */ 6550 struct { 6551 #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) 6552 __u32 flags; 6553 } notify; 6554 6555Used on x86 systems. When the VM capability KVM_CAP_X86_NOTIFY_VMEXIT is 6556enabled, a VM exit generated if no event window occurs in VM non-root mode 6557for a specified amount of time. Once KVM_X86_NOTIFY_VMEXIT_USER is set when 6558enabling the cap, it would exit to userspace with the exit reason 6559KVM_EXIT_NOTIFY for further handling. The "flags" field contains more 6560detailed info. 6561 6562The valid value for 'flags' is: 6563 6564 - KVM_NOTIFY_CONTEXT_INVALID -- the VM context is corrupted and not valid 6565 in VMCS. It would run into unknown result if resume the target VM. 6566 6567:: 6568 6569 /* Fix the size of the union. */ 6570 char padding[256]; 6571 }; 6572 6573 /* 6574 * shared registers between kvm and userspace. 6575 * kvm_valid_regs specifies the register classes set by the host 6576 * kvm_dirty_regs specified the register classes dirtied by userspace 6577 * struct kvm_sync_regs is architecture specific, as well as the 6578 * bits for kvm_valid_regs and kvm_dirty_regs 6579 */ 6580 __u64 kvm_valid_regs; 6581 __u64 kvm_dirty_regs; 6582 union { 6583 struct kvm_sync_regs regs; 6584 char padding[SYNC_REGS_SIZE_BYTES]; 6585 } s; 6586 6587If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access 6588certain guest registers without having to call SET/GET_*REGS. Thus we can 6589avoid some system call overhead if userspace has to handle the exit. 6590Userspace can query the validity of the structure by checking 6591kvm_valid_regs for specific bits. These bits are architecture specific 6592and usually define the validity of a groups of registers. (e.g. one bit 6593for general purpose registers) 6594 6595Please note that the kernel is allowed to use the kvm_run structure as the 6596primary storage for certain register types. Therefore, the kernel may use the 6597values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set. 6598 6599 66006. Capabilities that can be enabled on vCPUs 6601============================================ 6602 6603There are certain capabilities that change the behavior of the virtual CPU or 6604the virtual machine when enabled. To enable them, please see section 4.37. 6605Below you can find a list of capabilities and what their effect on the vCPU or 6606the virtual machine is when enabling them. 6607 6608The following information is provided along with the description: 6609 6610 Architectures: 6611 which instruction set architectures provide this ioctl. 6612 x86 includes both i386 and x86_64. 6613 6614 Target: 6615 whether this is a per-vcpu or per-vm capability. 6616 6617 Parameters: 6618 what parameters are accepted by the capability. 6619 6620 Returns: 6621 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 6622 are not detailed, but errors with specific meanings are. 6623 6624 66256.1 KVM_CAP_PPC_OSI 6626------------------- 6627 6628:Architectures: ppc 6629:Target: vcpu 6630:Parameters: none 6631:Returns: 0 on success; -1 on error 6632 6633This capability enables interception of OSI hypercalls that otherwise would 6634be treated as normal system calls to be injected into the guest. OSI hypercalls 6635were invented by Mac-on-Linux to have a standardized communication mechanism 6636between the guest and the host. 6637 6638When this capability is enabled, KVM_EXIT_OSI can occur. 6639 6640 66416.2 KVM_CAP_PPC_PAPR 6642-------------------- 6643 6644:Architectures: ppc 6645:Target: vcpu 6646:Parameters: none 6647:Returns: 0 on success; -1 on error 6648 6649This capability enables interception of PAPR hypercalls. PAPR hypercalls are 6650done using the hypercall instruction "sc 1". 6651 6652It also sets the guest privilege level to "supervisor" mode. Usually the guest 6653runs in "hypervisor" privilege mode with a few missing features. 6654 6655In addition to the above, it changes the semantics of SDR1. In this mode, the 6656HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the 6657HTAB invisible to the guest. 6658 6659When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. 6660 6661 66626.3 KVM_CAP_SW_TLB 6663------------------ 6664 6665:Architectures: ppc 6666:Target: vcpu 6667:Parameters: args[0] is the address of a struct kvm_config_tlb 6668:Returns: 0 on success; -1 on error 6669 6670:: 6671 6672 struct kvm_config_tlb { 6673 __u64 params; 6674 __u64 array; 6675 __u32 mmu_type; 6676 __u32 array_len; 6677 }; 6678 6679Configures the virtual CPU's TLB array, establishing a shared memory area 6680between userspace and KVM. The "params" and "array" fields are userspace 6681addresses of mmu-type-specific data structures. The "array_len" field is an 6682safety mechanism, and should be set to the size in bytes of the memory that 6683userspace has reserved for the array. It must be at least the size dictated 6684by "mmu_type" and "params". 6685 6686While KVM_RUN is active, the shared region is under control of KVM. Its 6687contents are undefined, and any modification by userspace results in 6688boundedly undefined behavior. 6689 6690On return from KVM_RUN, the shared region will reflect the current state of 6691the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB 6692to tell KVM which entries have been changed, prior to calling KVM_RUN again 6693on this vcpu. 6694 6695For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV: 6696 6697 - The "params" field is of type "struct kvm_book3e_206_tlb_params". 6698 - The "array" field points to an array of type "struct 6699 kvm_book3e_206_tlb_entry". 6700 - The array consists of all entries in the first TLB, followed by all 6701 entries in the second TLB. 6702 - Within a TLB, entries are ordered first by increasing set number. Within a 6703 set, entries are ordered by way (increasing ESEL). 6704 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1) 6705 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value. 6706 - The tsize field of mas1 shall be set to 4K on TLB0, even though the 6707 hardware ignores this value for TLB0. 6708 67096.4 KVM_CAP_S390_CSS_SUPPORT 6710---------------------------- 6711 6712:Architectures: s390 6713:Target: vcpu 6714:Parameters: none 6715:Returns: 0 on success; -1 on error 6716 6717This capability enables support for handling of channel I/O instructions. 6718 6719TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are 6720handled in-kernel, while the other I/O instructions are passed to userspace. 6721 6722When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST 6723SUBCHANNEL intercepts. 6724 6725Note that even though this capability is enabled per-vcpu, the complete 6726virtual machine is affected. 6727 67286.5 KVM_CAP_PPC_EPR 6729------------------- 6730 6731:Architectures: ppc 6732:Target: vcpu 6733:Parameters: args[0] defines whether the proxy facility is active 6734:Returns: 0 on success; -1 on error 6735 6736This capability enables or disables the delivery of interrupts through the 6737external proxy facility. 6738 6739When enabled (args[0] != 0), every time the guest gets an external interrupt 6740delivered, it automatically exits into user space with a KVM_EXIT_EPR exit 6741to receive the topmost interrupt vector. 6742 6743When disabled (args[0] == 0), behavior is as if this facility is unsupported. 6744 6745When this capability is enabled, KVM_EXIT_EPR can occur. 6746 67476.6 KVM_CAP_IRQ_MPIC 6748-------------------- 6749 6750:Architectures: ppc 6751:Parameters: args[0] is the MPIC device fd; 6752 args[1] is the MPIC CPU number for this vcpu 6753 6754This capability connects the vcpu to an in-kernel MPIC device. 6755 67566.7 KVM_CAP_IRQ_XICS 6757-------------------- 6758 6759:Architectures: ppc 6760:Target: vcpu 6761:Parameters: args[0] is the XICS device fd; 6762 args[1] is the XICS CPU number (server ID) for this vcpu 6763 6764This capability connects the vcpu to an in-kernel XICS device. 6765 67666.8 KVM_CAP_S390_IRQCHIP 6767------------------------ 6768 6769:Architectures: s390 6770:Target: vm 6771:Parameters: none 6772 6773This capability enables the in-kernel irqchip for s390. Please refer to 6774"4.24 KVM_CREATE_IRQCHIP" for details. 6775 67766.9 KVM_CAP_MIPS_FPU 6777-------------------- 6778 6779:Architectures: mips 6780:Target: vcpu 6781:Parameters: args[0] is reserved for future use (should be 0). 6782 6783This capability allows the use of the host Floating Point Unit by the guest. It 6784allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is 6785done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be 6786accessed (depending on the current guest FPU register mode), and the Status.FR, 6787Config5.FRE bits are accessible via the KVM API and also from the guest, 6788depending on them being supported by the FPU. 6789 67906.10 KVM_CAP_MIPS_MSA 6791--------------------- 6792 6793:Architectures: mips 6794:Target: vcpu 6795:Parameters: args[0] is reserved for future use (should be 0). 6796 6797This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. 6798It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. 6799Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*`` 6800registers can be accessed, and the Config5.MSAEn bit is accessible via the 6801KVM API and also from the guest. 6802 68036.74 KVM_CAP_SYNC_REGS 6804---------------------- 6805 6806:Architectures: s390, x86 6807:Target: s390: always enabled, x86: vcpu 6808:Parameters: none 6809:Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register 6810 sets are supported 6811 (bitfields defined in arch/x86/include/uapi/asm/kvm.h). 6812 6813As described above in the kvm_sync_regs struct info in section 5 (kvm_run): 6814KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers 6815without having to call SET/GET_*REGS". This reduces overhead by eliminating 6816repeated ioctl calls for setting and/or getting register values. This is 6817particularly important when userspace is making synchronous guest state 6818modifications, e.g. when emulating and/or intercepting instructions in 6819userspace. 6820 6821For s390 specifics, please refer to the source code. 6822 6823For x86: 6824 6825- the register sets to be copied out to kvm_run are selectable 6826 by userspace (rather that all sets being copied out for every exit). 6827- vcpu_events are available in addition to regs and sregs. 6828 6829For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to 6830function as an input bit-array field set by userspace to indicate the 6831specific register sets to be copied out on the next exit. 6832 6833To indicate when userspace has modified values that should be copied into 6834the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set. 6835This is done using the same bitflags as for the 'kvm_valid_regs' field. 6836If the dirty bit is not set, then the register set values will not be copied 6837into the vCPU even if they've been modified. 6838 6839Unused bitfields in the bitarrays must be set to zero. 6840 6841:: 6842 6843 struct kvm_sync_regs { 6844 struct kvm_regs regs; 6845 struct kvm_sregs sregs; 6846 struct kvm_vcpu_events events; 6847 }; 6848 68496.75 KVM_CAP_PPC_IRQ_XIVE 6850------------------------- 6851 6852:Architectures: ppc 6853:Target: vcpu 6854:Parameters: args[0] is the XIVE device fd; 6855 args[1] is the XIVE CPU number (server ID) for this vcpu 6856 6857This capability connects the vcpu to an in-kernel XIVE device. 6858 68597. Capabilities that can be enabled on VMs 6860========================================== 6861 6862There are certain capabilities that change the behavior of the virtual 6863machine when enabled. To enable them, please see section 4.37. Below 6864you can find a list of capabilities and what their effect on the VM 6865is when enabling them. 6866 6867The following information is provided along with the description: 6868 6869 Architectures: 6870 which instruction set architectures provide this ioctl. 6871 x86 includes both i386 and x86_64. 6872 6873 Parameters: 6874 what parameters are accepted by the capability. 6875 6876 Returns: 6877 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 6878 are not detailed, but errors with specific meanings are. 6879 6880 68817.1 KVM_CAP_PPC_ENABLE_HCALL 6882---------------------------- 6883 6884:Architectures: ppc 6885:Parameters: args[0] is the sPAPR hcall number; 6886 args[1] is 0 to disable, 1 to enable in-kernel handling 6887 6888This capability controls whether individual sPAPR hypercalls (hcalls) 6889get handled by the kernel or not. Enabling or disabling in-kernel 6890handling of an hcall is effective across the VM. On creation, an 6891initial set of hcalls are enabled for in-kernel handling, which 6892consists of those hcalls for which in-kernel handlers were implemented 6893before this capability was implemented. If disabled, the kernel will 6894not to attempt to handle the hcall, but will always exit to userspace 6895to handle it. Note that it may not make sense to enable some and 6896disable others of a group of related hcalls, but KVM does not prevent 6897userspace from doing that. 6898 6899If the hcall number specified is not one that has an in-kernel 6900implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL 6901error. 6902 69037.2 KVM_CAP_S390_USER_SIGP 6904-------------------------- 6905 6906:Architectures: s390 6907:Parameters: none 6908 6909This capability controls which SIGP orders will be handled completely in user 6910space. With this capability enabled, all fast orders will be handled completely 6911in the kernel: 6912 6913- SENSE 6914- SENSE RUNNING 6915- EXTERNAL CALL 6916- EMERGENCY SIGNAL 6917- CONDITIONAL EMERGENCY SIGNAL 6918 6919All other orders will be handled completely in user space. 6920 6921Only privileged operation exceptions will be checked for in the kernel (or even 6922in the hardware prior to interception). If this capability is not enabled, the 6923old way of handling SIGP orders is used (partially in kernel and user space). 6924 69257.3 KVM_CAP_S390_VECTOR_REGISTERS 6926--------------------------------- 6927 6928:Architectures: s390 6929:Parameters: none 6930:Returns: 0 on success, negative value on error 6931 6932Allows use of the vector registers introduced with z13 processor, and 6933provides for the synchronization between host and user space. Will 6934return -EINVAL if the machine does not support vectors. 6935 69367.4 KVM_CAP_S390_USER_STSI 6937-------------------------- 6938 6939:Architectures: s390 6940:Parameters: none 6941 6942This capability allows post-handlers for the STSI instruction. After 6943initial handling in the kernel, KVM exits to user space with 6944KVM_EXIT_S390_STSI to allow user space to insert further data. 6945 6946Before exiting to userspace, kvm handlers should fill in s390_stsi field of 6947vcpu->run:: 6948 6949 struct { 6950 __u64 addr; 6951 __u8 ar; 6952 __u8 reserved; 6953 __u8 fc; 6954 __u8 sel1; 6955 __u16 sel2; 6956 } s390_stsi; 6957 6958 @addr - guest address of STSI SYSIB 6959 @fc - function code 6960 @sel1 - selector 1 6961 @sel2 - selector 2 6962 @ar - access register number 6963 6964KVM handlers should exit to userspace with rc = -EREMOTE. 6965 69667.5 KVM_CAP_SPLIT_IRQCHIP 6967------------------------- 6968 6969:Architectures: x86 6970:Parameters: args[0] - number of routes reserved for userspace IOAPICs 6971:Returns: 0 on success, -1 on error 6972 6973Create a local apic for each processor in the kernel. This can be used 6974instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the 6975IOAPIC and PIC (and also the PIT, even though this has to be enabled 6976separately). 6977 6978This capability also enables in kernel routing of interrupt requests; 6979when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are 6980used in the IRQ routing table. The first args[0] MSI routes are reserved 6981for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes, 6982a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace. 6983 6984Fails if VCPU has already been created, or if the irqchip is already in the 6985kernel (i.e. KVM_CREATE_IRQCHIP has already been called). 6986 69877.6 KVM_CAP_S390_RI 6988------------------- 6989 6990:Architectures: s390 6991:Parameters: none 6992 6993Allows use of runtime-instrumentation introduced with zEC12 processor. 6994Will return -EINVAL if the machine does not support runtime-instrumentation. 6995Will return -EBUSY if a VCPU has already been created. 6996 69977.7 KVM_CAP_X2APIC_API 6998---------------------- 6999 7000:Architectures: x86 7001:Parameters: args[0] - features that should be enabled 7002:Returns: 0 on success, -EINVAL when args[0] contains invalid features 7003 7004Valid feature flags in args[0] are:: 7005 7006 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) 7007 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) 7008 7009Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of 7010KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, 7011allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their 7012respective sections. 7013 7014KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work 7015in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff 7016as a broadcast even in x2APIC mode in order to support physical x2APIC 7017without interrupt remapping. This is undesirable in logical mode, 7018where 0xff represents CPUs 0-7 in cluster 0. 7019 70207.8 KVM_CAP_S390_USER_INSTR0 7021---------------------------- 7022 7023:Architectures: s390 7024:Parameters: none 7025 7026With this capability enabled, all illegal instructions 0x0000 (2 bytes) will 7027be intercepted and forwarded to user space. User space can use this 7028mechanism e.g. to realize 2-byte software breakpoints. The kernel will 7029not inject an operating exception for these instructions, user space has 7030to take care of that. 7031 7032This capability can be enabled dynamically even if VCPUs were already 7033created and are running. 7034 70357.9 KVM_CAP_S390_GS 7036------------------- 7037 7038:Architectures: s390 7039:Parameters: none 7040:Returns: 0 on success; -EINVAL if the machine does not support 7041 guarded storage; -EBUSY if a VCPU has already been created. 7042 7043Allows use of guarded storage for the KVM guest. 7044 70457.10 KVM_CAP_S390_AIS 7046--------------------- 7047 7048:Architectures: s390 7049:Parameters: none 7050 7051Allow use of adapter-interruption suppression. 7052:Returns: 0 on success; -EBUSY if a VCPU has already been created. 7053 70547.11 KVM_CAP_PPC_SMT 7055-------------------- 7056 7057:Architectures: ppc 7058:Parameters: vsmt_mode, flags 7059 7060Enabling this capability on a VM provides userspace with a way to set 7061the desired virtual SMT mode (i.e. the number of virtual CPUs per 7062virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2 7063between 1 and 8. On POWER8, vsmt_mode must also be no greater than 7064the number of threads per subcore for the host. Currently flags must 7065be 0. A successful call to enable this capability will result in 7066vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is 7067subsequently queried for the VM. This capability is only supported by 7068HV KVM, and can only be set before any VCPUs have been created. 7069The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT 7070modes are available. 7071 70727.12 KVM_CAP_PPC_FWNMI 7073---------------------- 7074 7075:Architectures: ppc 7076:Parameters: none 7077 7078With this capability a machine check exception in the guest address 7079space will cause KVM to exit the guest with NMI exit reason. This 7080enables QEMU to build error log and branch to guest kernel registered 7081machine check handling routine. Without this capability KVM will 7082branch to guests' 0x200 interrupt vector. 7083 70847.13 KVM_CAP_X86_DISABLE_EXITS 7085------------------------------ 7086 7087:Architectures: x86 7088:Parameters: args[0] defines which exits are disabled 7089:Returns: 0 on success, -EINVAL when args[0] contains invalid exits 7090 7091Valid bits in args[0] are:: 7092 7093 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) 7094 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1) 7095 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) 7096 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3) 7097 7098Enabling this capability on a VM provides userspace with a way to no 7099longer intercept some instructions for improved latency in some 7100workloads, and is suggested when vCPUs are associated to dedicated 7101physical CPUs. More bits can be added in the future; userspace can 7102just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable 7103all such vmexits. 7104 7105Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. 7106 71077.14 KVM_CAP_S390_HPAGE_1M 7108-------------------------- 7109 7110:Architectures: s390 7111:Parameters: none 7112:Returns: 0 on success, -EINVAL if hpage module parameter was not set 7113 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL 7114 flag set 7115 7116With this capability the KVM support for memory backing with 1m pages 7117through hugetlbfs can be enabled for a VM. After the capability is 7118enabled, cmma can't be enabled anymore and pfmfi and the storage key 7119interpretation are disabled. If cmma has already been enabled or the 7120hpage module parameter is not set to 1, -EINVAL is returned. 7121 7122While it is generally possible to create a huge page backed VM without 7123this capability, the VM will not be able to run. 7124 71257.15 KVM_CAP_MSR_PLATFORM_INFO 7126------------------------------ 7127 7128:Architectures: x86 7129:Parameters: args[0] whether feature should be enabled or not 7130 7131With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise, 7132a #GP would be raised when the guest tries to access. Currently, this 7133capability does not enable write permissions of this MSR for the guest. 7134 71357.16 KVM_CAP_PPC_NESTED_HV 7136-------------------------- 7137 7138:Architectures: ppc 7139:Parameters: none 7140:Returns: 0 on success, -EINVAL when the implementation doesn't support 7141 nested-HV virtualization. 7142 7143HV-KVM on POWER9 and later systems allows for "nested-HV" 7144virtualization, which provides a way for a guest VM to run guests that 7145can run using the CPU's supervisor mode (privileged non-hypervisor 7146state). Enabling this capability on a VM depends on the CPU having 7147the necessary functionality and on the facility being enabled with a 7148kvm-hv module parameter. 7149 71507.17 KVM_CAP_EXCEPTION_PAYLOAD 7151------------------------------ 7152 7153:Architectures: x86 7154:Parameters: args[0] whether feature should be enabled or not 7155 7156With this capability enabled, CR2 will not be modified prior to the 7157emulated VM-exit when L1 intercepts a #PF exception that occurs in 7158L2. Similarly, for kvm-intel only, DR6 will not be modified prior to 7159the emulated VM-exit when L1 intercepts a #DB exception that occurs in 7160L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or 7161#DB) exception for L2, exception.has_payload will be set and the 7162faulting address (or the new DR6 bits*) will be reported in the 7163exception_payload field. Similarly, when userspace injects a #PF (or 7164#DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set 7165exception.has_payload and to put the faulting address - or the new DR6 7166bits\ [#]_ - in the exception_payload field. 7167 7168This capability also enables exception.pending in struct 7169kvm_vcpu_events, which allows userspace to distinguish between pending 7170and injected exceptions. 7171 7172 7173.. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception 7174 will clear DR6.RTM. 7175 71767.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 7177 7178:Architectures: x86, arm64, mips 7179:Parameters: args[0] whether feature should be enabled or not 7180 7181Valid flags are:: 7182 7183 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0) 7184 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) 7185 7186With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not 7187automatically clear and write-protect all pages that are returned as dirty. 7188Rather, userspace will have to do this operation separately using 7189KVM_CLEAR_DIRTY_LOG. 7190 7191At the cost of a slightly more complicated operation, this provides better 7192scalability and responsiveness for two reasons. First, 7193KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather 7194than requiring to sync a full memslot; this ensures that KVM does not 7195take spinlocks for an extended period of time. Second, in some cases a 7196large amount of time can pass between a call to KVM_GET_DIRTY_LOG and 7197userspace actually using the data in the page. Pages can be modified 7198during this time, which is inefficient for both the guest and userspace: 7199the guest will incur a higher penalty due to write protection faults, 7200while userspace can see false reports of dirty pages. Manual reprotection 7201helps reducing this time, improving guest performance and reducing the 7202number of dirty log false positives. 7203 7204With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap 7205will be initialized to 1 when created. This also improves performance because 7206dirty logging can be enabled gradually in small chunks on the first call 7207to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on 7208KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on 7209x86 and arm64 for now). 7210 7211KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name 7212KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make 7213it hard or impossible to use it correctly. The availability of 7214KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed. 7215Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT. 7216 72177.19 KVM_CAP_PPC_SECURE_GUEST 7218------------------------------ 7219 7220:Architectures: ppc 7221 7222This capability indicates that KVM is running on a host that has 7223ultravisor firmware and thus can support a secure guest. On such a 7224system, a guest can ask the ultravisor to make it a secure guest, 7225one whose memory is inaccessible to the host except for pages which 7226are explicitly requested to be shared with the host. The ultravisor 7227notifies KVM when a guest requests to become a secure guest, and KVM 7228has the opportunity to veto the transition. 7229 7230If present, this capability can be enabled for a VM, meaning that KVM 7231will allow the transition to secure guest mode. Otherwise KVM will 7232veto the transition. 7233 72347.20 KVM_CAP_HALT_POLL 7235---------------------- 7236 7237:Architectures: all 7238:Target: VM 7239:Parameters: args[0] is the maximum poll time in nanoseconds 7240:Returns: 0 on success; -1 on error 7241 7242KVM_CAP_HALT_POLL overrides the kvm.halt_poll_ns module parameter to set the 7243maximum halt-polling time for all vCPUs in the target VM. This capability can 7244be invoked at any time and any number of times to dynamically change the 7245maximum halt-polling time. 7246 7247See Documentation/virt/kvm/halt-polling.rst for more information on halt 7248polling. 7249 72507.21 KVM_CAP_X86_USER_SPACE_MSR 7251------------------------------- 7252 7253:Architectures: x86 7254:Target: VM 7255:Parameters: args[0] contains the mask of KVM_MSR_EXIT_REASON_* events to report 7256:Returns: 0 on success; -1 on error 7257 7258This capability allows userspace to intercept RDMSR and WRMSR instructions if 7259access to an MSR is denied. By default, KVM injects #GP on denied accesses. 7260 7261When a guest requests to read or write an MSR, KVM may not implement all MSRs 7262that are relevant to a respective system. It also does not differentiate by 7263CPU type. 7264 7265To allow more fine grained control over MSR handling, userspace may enable 7266this capability. With it enabled, MSR accesses that match the mask specified in 7267args[0] and would trigger a #GP inside the guest will instead trigger 7268KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications. Userspace 7269can then implement model specific MSR handling and/or user notifications 7270to inform a user that an MSR was not emulated/virtualized by KVM. 7271 7272The valid mask flags are: 7273 7274============================ =============================================== 7275 KVM_MSR_EXIT_REASON_UNKNOWN intercept accesses to unknown (to KVM) MSRs 7276 KVM_MSR_EXIT_REASON_INVAL intercept accesses that are architecturally 7277 invalid according to the vCPU model and/or mode 7278 KVM_MSR_EXIT_REASON_FILTER intercept accesses that are denied by userspace 7279 via KVM_X86_SET_MSR_FILTER 7280============================ =============================================== 7281 72827.22 KVM_CAP_X86_BUS_LOCK_EXIT 7283------------------------------- 7284 7285:Architectures: x86 7286:Target: VM 7287:Parameters: args[0] defines the policy used when bus locks detected in guest 7288:Returns: 0 on success, -EINVAL when args[0] contains invalid bits 7289 7290Valid bits in args[0] are:: 7291 7292 #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) 7293 #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) 7294 7295Enabling this capability on a VM provides userspace with a way to select 7296a policy to handle the bus locks detected in guest. Userspace can obtain 7297the supported modes from the result of KVM_CHECK_EXTENSION and define it 7298through the KVM_ENABLE_CAP. 7299 7300KVM_BUS_LOCK_DETECTION_OFF and KVM_BUS_LOCK_DETECTION_EXIT are supported 7301currently and mutually exclusive with each other. More bits can be added in 7302the future. 7303 7304With KVM_BUS_LOCK_DETECTION_OFF set, bus locks in guest will not cause vm exits 7305so that no additional actions are needed. This is the default mode. 7306 7307With KVM_BUS_LOCK_DETECTION_EXIT set, vm exits happen when bus lock detected 7308in VM. KVM just exits to userspace when handling them. Userspace can enforce 7309its own throttling or other policy based mitigations. 7310 7311This capability is aimed to address the thread that VM can exploit bus locks to 7312degree the performance of the whole system. Once the userspace enable this 7313capability and select the KVM_BUS_LOCK_DETECTION_EXIT mode, KVM will set the 7314KVM_RUN_BUS_LOCK flag in vcpu-run->flags field and exit to userspace. Concerning 7315the bus lock vm exit can be preempted by a higher priority VM exit, the exit 7316notifications to userspace can be KVM_EXIT_BUS_LOCK or other reasons. 7317KVM_RUN_BUS_LOCK flag is used to distinguish between them. 7318 73197.23 KVM_CAP_PPC_DAWR1 7320---------------------- 7321 7322:Architectures: ppc 7323:Parameters: none 7324:Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR 7325 7326This capability can be used to check / enable 2nd DAWR feature provided 7327by POWER10 processor. 7328 7329 73307.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 7331------------------------------------- 7332 7333Architectures: x86 SEV enabled 7334Type: vm 7335Parameters: args[0] is the fd of the source vm 7336Returns: 0 on success; ENOTTY on error 7337 7338This capability enables userspace to copy encryption context from the vm 7339indicated by the fd to the vm this is called on. 7340 7341This is intended to support in-guest workloads scheduled by the host. This 7342allows the in-guest workload to maintain its own NPTs and keeps the two vms 7343from accidentally clobbering each other with interrupts and the like (separate 7344APIC/MSRs/etc). 7345 73467.25 KVM_CAP_SGX_ATTRIBUTE 7347-------------------------- 7348 7349:Architectures: x86 7350:Target: VM 7351:Parameters: args[0] is a file handle of a SGX attribute file in securityfs 7352:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested 7353 attribute is not supported by KVM. 7354 7355KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or 7356more priveleged enclave attributes. args[0] must hold a file handle to a valid 7357SGX attribute file corresponding to an attribute that is supported/restricted 7358by KVM (currently only PROVISIONKEY). 7359 7360The SGX subsystem restricts access to a subset of enclave attributes to provide 7361additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY 7362is restricted to deter malware from using the PROVISIONKEY to obtain a stable 7363system fingerprint. To prevent userspace from circumventing such restrictions 7364by running an enclave in a VM, KVM prevents access to privileged attributes by 7365default. 7366 7367See Documentation/x86/sgx.rst for more details. 7368 73697.26 KVM_CAP_PPC_RPT_INVALIDATE 7370------------------------------- 7371 7372:Capability: KVM_CAP_PPC_RPT_INVALIDATE 7373:Architectures: ppc 7374:Type: vm 7375 7376This capability indicates that the kernel is capable of handling 7377H_RPT_INVALIDATE hcall. 7378 7379In order to enable the use of H_RPT_INVALIDATE in the guest, 7380user space might have to advertise it for the guest. For example, 7381IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is 7382present in the "ibm,hypertas-functions" device-tree property. 7383 7384This capability is enabled for hypervisors on platforms like POWER9 7385that support radix MMU. 7386 73877.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE 7388-------------------------------------- 7389 7390:Architectures: x86 7391:Parameters: args[0] whether the feature should be enabled or not 7392 7393When this capability is enabled, an emulation failure will result in an exit 7394to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked 7395to handle a VMware backdoor instruction). Furthermore, KVM will now provide up 7396to 15 instruction bytes for any exit to userspace resulting from an emulation 7397failure. When these exits to userspace occur use the emulation_failure struct 7398instead of the internal struct. They both have the same layout, but the 7399emulation_failure struct matches the content better. It also explicitly 7400defines the 'flags' field which is used to describe the fields in the struct 7401that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is 7402set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data 7403in them.) 7404 74057.28 KVM_CAP_ARM_MTE 7406-------------------- 7407 7408:Architectures: arm64 7409:Parameters: none 7410 7411This capability indicates that KVM (and the hardware) supports exposing the 7412Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the 7413VMM before creating any VCPUs to allow the guest access. Note that MTE is only 7414available to a guest running in AArch64 mode and enabling this capability will 7415cause attempts to create AArch32 VCPUs to fail. 7416 7417When enabled the guest is able to access tags associated with any memory given 7418to the guest. KVM will ensure that the tags are maintained during swap or 7419hibernation of the host; however the VMM needs to manually save/restore the 7420tags as appropriate if the VM is migrated. 7421 7422When this capability is enabled all memory in memslots must be mapped as 7423``MAP_ANONYMOUS`` or with a RAM-based file mapping (``tmpfs``, ``memfd``), 7424attempts to create a memslot with an invalid mmap will result in an 7425-EINVAL return. 7426 7427When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to 7428perform a bulk copy of tags to/from the guest. 7429 74307.29 KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 7431------------------------------------- 7432 7433Architectures: x86 SEV enabled 7434Type: vm 7435Parameters: args[0] is the fd of the source vm 7436Returns: 0 on success 7437 7438This capability enables userspace to migrate the encryption context from the VM 7439indicated by the fd to the VM this is called on. 7440 7441This is intended to support intra-host migration of VMs between userspace VMMs, 7442upgrading the VMM process without interrupting the guest. 7443 74447.30 KVM_CAP_PPC_AIL_MODE_3 7445------------------------------- 7446 7447:Capability: KVM_CAP_PPC_AIL_MODE_3 7448:Architectures: ppc 7449:Type: vm 7450 7451This capability indicates that the kernel supports the mode 3 setting for the 7452"Address Translation Mode on Interrupt" aka "Alternate Interrupt Location" 7453resource that is controlled with the H_SET_MODE hypercall. 7454 7455This capability allows a guest kernel to use a better-performance mode for 7456handling interrupts and system calls. 7457 74587.31 KVM_CAP_DISABLE_QUIRKS2 7459---------------------------- 7460 7461:Capability: KVM_CAP_DISABLE_QUIRKS2 7462:Parameters: args[0] - set of KVM quirks to disable 7463:Architectures: x86 7464:Type: vm 7465 7466This capability, if enabled, will cause KVM to disable some behavior 7467quirks. 7468 7469Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 7470quirks that can be disabled in KVM. 7471 7472The argument to KVM_ENABLE_CAP for this capability is a bitmask of 7473quirks to disable, and must be a subset of the bitmask returned by 7474KVM_CHECK_EXTENSION. 7475 7476The valid bits in cap.args[0] are: 7477 7478=================================== ============================================ 7479 KVM_X86_QUIRK_LINT0_REENABLED By default, the reset value for the LVT 7480 LINT0 register is 0x700 (APIC_MODE_EXTINT). 7481 When this quirk is disabled, the reset value 7482 is 0x10000 (APIC_LVT_MASKED). 7483 7484 KVM_X86_QUIRK_CD_NW_CLEARED By default, KVM clears CR0.CD and CR0.NW. 7485 When this quirk is disabled, KVM does not 7486 change the value of CR0.CD and CR0.NW. 7487 7488 KVM_X86_QUIRK_LAPIC_MMIO_HOLE By default, the MMIO LAPIC interface is 7489 available even when configured for x2APIC 7490 mode. When this quirk is disabled, KVM 7491 disables the MMIO LAPIC interface if the 7492 LAPIC is in x2APIC mode. 7493 7494 KVM_X86_QUIRK_OUT_7E_INC_RIP By default, KVM pre-increments %rip before 7495 exiting to userspace for an OUT instruction 7496 to port 0x7e. When this quirk is disabled, 7497 KVM does not pre-increment %rip before 7498 exiting to userspace. 7499 7500 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT When this quirk is disabled, KVM sets 7501 CPUID.01H:ECX[bit 3] (MONITOR/MWAIT) if 7502 IA32_MISC_ENABLE[bit 18] (MWAIT) is set. 7503 Additionally, when this quirk is disabled, 7504 KVM clears CPUID.01H:ECX[bit 3] if 7505 IA32_MISC_ENABLE[bit 18] is cleared. 7506 7507 KVM_X86_QUIRK_FIX_HYPERCALL_INSN By default, KVM rewrites guest 7508 VMMCALL/VMCALL instructions to match the 7509 vendor's hypercall instruction for the 7510 system. When this quirk is disabled, KVM 7511 will no longer rewrite invalid guest 7512 hypercall instructions. Executing the 7513 incorrect hypercall instruction will 7514 generate a #UD within the guest. 7515 7516KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if 7517 they are intercepted) as NOPs regardless of 7518 whether or not MONITOR/MWAIT are supported 7519 according to guest CPUID. When this quirk 7520 is disabled and KVM_X86_DISABLE_EXITS_MWAIT 7521 is not set (MONITOR/MWAIT are intercepted), 7522 KVM will inject a #UD on MONITOR/MWAIT if 7523 they're unsupported per guest CPUID. Note, 7524 KVM will modify MONITOR/MWAIT support in 7525 guest CPUID on writes to MISC_ENABLE if 7526 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is 7527 disabled. 7528=================================== ============================================ 7529 75307.32 KVM_CAP_MAX_VCPU_ID 7531------------------------ 7532 7533:Architectures: x86 7534:Target: VM 7535:Parameters: args[0] - maximum APIC ID value set for current VM 7536:Returns: 0 on success, -EINVAL if args[0] is beyond KVM_MAX_VCPU_IDS 7537 supported in KVM or if it has been set. 7538 7539This capability allows userspace to specify maximum possible APIC ID 7540assigned for current VM session prior to the creation of vCPUs, saving 7541memory for data structures indexed by the APIC ID. Userspace is able 7542to calculate the limit to APIC ID values from designated 7543CPU topology. 7544 7545The value can be changed only until KVM_ENABLE_CAP is set to a nonzero 7546value or until a vCPU is created. Upon creation of the first vCPU, 7547if the value was set to zero or KVM_ENABLE_CAP was not invoked, KVM 7548uses the return value of KVM_CHECK_EXTENSION(KVM_CAP_MAX_VCPU_ID) as 7549the maximum APIC ID. 7550 75517.33 KVM_CAP_X86_NOTIFY_VMEXIT 7552------------------------------ 7553 7554:Architectures: x86 7555:Target: VM 7556:Parameters: args[0] is the value of notify window as well as some flags 7557:Returns: 0 on success, -EINVAL if args[0] contains invalid flags or notify 7558 VM exit is unsupported. 7559 7560Bits 63:32 of args[0] are used for notify window. 7561Bits 31:0 of args[0] are for some flags. Valid bits are:: 7562 7563 #define KVM_X86_NOTIFY_VMEXIT_ENABLED (1 << 0) 7564 #define KVM_X86_NOTIFY_VMEXIT_USER (1 << 1) 7565 7566This capability allows userspace to configure the notify VM exit on/off 7567in per-VM scope during VM creation. Notify VM exit is disabled by default. 7568When userspace sets KVM_X86_NOTIFY_VMEXIT_ENABLED bit in args[0], VMM will 7569enable this feature with the notify window provided, which will generate 7570a VM exit if no event window occurs in VM non-root mode for a specified of 7571time (notify window). 7572 7573If KVM_X86_NOTIFY_VMEXIT_USER is set in args[0], upon notify VM exits happen, 7574KVM would exit to userspace for handling. 7575 7576This capability is aimed to mitigate the threat that malicious VMs can 7577cause CPU stuck (due to event windows don't open up) and make the CPU 7578unavailable to host or other VMs. 7579 75808. Other capabilities. 7581====================== 7582 7583This section lists capabilities that give information about other 7584features of the KVM implementation. 7585 75868.1 KVM_CAP_PPC_HWRNG 7587--------------------- 7588 7589:Architectures: ppc 7590 7591This capability, if KVM_CHECK_EXTENSION indicates that it is 7592available, means that the kernel has an implementation of the 7593H_RANDOM hypercall backed by a hardware random-number generator. 7594If present, the kernel H_RANDOM handler can be enabled for guest use 7595with the KVM_CAP_PPC_ENABLE_HCALL capability. 7596 75978.2 KVM_CAP_HYPERV_SYNIC 7598------------------------ 7599 7600:Architectures: x86 7601 7602This capability, if KVM_CHECK_EXTENSION indicates that it is 7603available, means that the kernel has an implementation of the 7604Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is 7605used to support Windows Hyper-V based guest paravirt drivers(VMBus). 7606 7607In order to use SynIC, it has to be activated by setting this 7608capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this 7609will disable the use of APIC hardware virtualization even if supported 7610by the CPU, as it's incompatible with SynIC auto-EOI behavior. 7611 76128.3 KVM_CAP_PPC_RADIX_MMU 7613------------------------- 7614 7615:Architectures: ppc 7616 7617This capability, if KVM_CHECK_EXTENSION indicates that it is 7618available, means that the kernel can support guests using the 7619radix MMU defined in Power ISA V3.00 (as implemented in the POWER9 7620processor). 7621 76228.4 KVM_CAP_PPC_HASH_MMU_V3 7623--------------------------- 7624 7625:Architectures: ppc 7626 7627This capability, if KVM_CHECK_EXTENSION indicates that it is 7628available, means that the kernel can support guests using the 7629hashed page table MMU defined in Power ISA V3.00 (as implemented in 7630the POWER9 processor), including in-memory segment tables. 7631 76328.5 KVM_CAP_MIPS_VZ 7633------------------- 7634 7635:Architectures: mips 7636 7637This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 7638it is available, means that full hardware assisted virtualization capabilities 7639of the hardware are available for use through KVM. An appropriate 7640KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which 7641utilises it. 7642 7643If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 7644available, it means that the VM is using full hardware assisted virtualization 7645capabilities of the hardware. This is useful to check after creating a VM with 7646KVM_VM_MIPS_DEFAULT. 7647 7648The value returned by KVM_CHECK_EXTENSION should be compared against known 7649values (see below). All other values are reserved. This is to allow for the 7650possibility of other hardware assisted virtualization implementations which 7651may be incompatible with the MIPS VZ ASE. 7652 7653== ========================================================================== 7654 0 The trap & emulate implementation is in use to run guest code in user 7655 mode. Guest virtual memory segments are rearranged to fit the guest in the 7656 user mode address space. 7657 7658 1 The MIPS VZ ASE is in use, providing full hardware assisted 7659 virtualization, including standard guest virtual memory segments. 7660== ========================================================================== 7661 76628.6 KVM_CAP_MIPS_TE 7663------------------- 7664 7665:Architectures: mips 7666 7667This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 7668it is available, means that the trap & emulate implementation is available to 7669run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware 7670assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed 7671to KVM_CREATE_VM to create a VM which utilises it. 7672 7673If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 7674available, it means that the VM is using trap & emulate. 7675 76768.7 KVM_CAP_MIPS_64BIT 7677---------------------- 7678 7679:Architectures: mips 7680 7681This capability indicates the supported architecture type of the guest, i.e. the 7682supported register and address width. 7683 7684The values returned when this capability is checked by KVM_CHECK_EXTENSION on a 7685kvm VM handle correspond roughly to the CP0_Config.AT register field, and should 7686be checked specifically against known values (see below). All other values are 7687reserved. 7688 7689== ======================================================================== 7690 0 MIPS32 or microMIPS32. 7691 Both registers and addresses are 32-bits wide. 7692 It will only be possible to run 32-bit guest code. 7693 7694 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments. 7695 Registers are 64-bits wide, but addresses are 32-bits wide. 7696 64-bit guest code may run but cannot access MIPS64 memory segments. 7697 It will also be possible to run 32-bit guest code. 7698 7699 2 MIPS64 or microMIPS64 with access to all address segments. 7700 Both registers and addresses are 64-bits wide. 7701 It will be possible to run 64-bit or 32-bit guest code. 7702== ======================================================================== 7703 77048.9 KVM_CAP_ARM_USER_IRQ 7705------------------------ 7706 7707:Architectures: arm64 7708 7709This capability, if KVM_CHECK_EXTENSION indicates that it is available, means 7710that if userspace creates a VM without an in-kernel interrupt controller, it 7711will be notified of changes to the output level of in-kernel emulated devices, 7712which can generate virtual interrupts, presented to the VM. 7713For such VMs, on every return to userspace, the kernel 7714updates the vcpu's run->s.regs.device_irq_level field to represent the actual 7715output level of the device. 7716 7717Whenever kvm detects a change in the device output level, kvm guarantees at 7718least one return to userspace before running the VM. This exit could either 7719be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way, 7720userspace can always sample the device output level and re-compute the state of 7721the userspace interrupt controller. Userspace should always check the state 7722of run->s.regs.device_irq_level on every kvm exit. 7723The value in run->s.regs.device_irq_level can represent both level and edge 7724triggered interrupt signals, depending on the device. Edge triggered interrupt 7725signals will exit to userspace with the bit in run->s.regs.device_irq_level 7726set exactly once per edge signal. 7727 7728The field run->s.regs.device_irq_level is available independent of 7729run->kvm_valid_regs or run->kvm_dirty_regs bits. 7730 7731If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a 7732number larger than 0 indicating the version of this capability is implemented 7733and thereby which bits in run->s.regs.device_irq_level can signal values. 7734 7735Currently the following bits are defined for the device_irq_level bitmap:: 7736 7737 KVM_CAP_ARM_USER_IRQ >= 1: 7738 7739 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer 7740 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer 7741 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal 7742 7743Future versions of kvm may implement additional events. These will get 7744indicated by returning a higher number from KVM_CHECK_EXTENSION and will be 7745listed above. 7746 77478.10 KVM_CAP_PPC_SMT_POSSIBLE 7748----------------------------- 7749 7750:Architectures: ppc 7751 7752Querying this capability returns a bitmap indicating the possible 7753virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N 7754(counting from the right) is set, then a virtual SMT mode of 2^N is 7755available. 7756 77578.11 KVM_CAP_HYPERV_SYNIC2 7758-------------------------- 7759 7760:Architectures: x86 7761 7762This capability enables a newer version of Hyper-V Synthetic interrupt 7763controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM 7764doesn't clear SynIC message and event flags pages when they are enabled by 7765writing to the respective MSRs. 7766 77678.12 KVM_CAP_HYPERV_VP_INDEX 7768---------------------------- 7769 7770:Architectures: x86 7771 7772This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its 7773value is used to denote the target vcpu for a SynIC interrupt. For 7774compatibilty, KVM initializes this msr to KVM's internal vcpu index. When this 7775capability is absent, userspace can still query this msr's value. 7776 77778.13 KVM_CAP_S390_AIS_MIGRATION 7778------------------------------- 7779 7780:Architectures: s390 7781:Parameters: none 7782 7783This capability indicates if the flic device will be able to get/set the 7784AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows 7785to discover this without having to create a flic device. 7786 77878.14 KVM_CAP_S390_PSW 7788--------------------- 7789 7790:Architectures: s390 7791 7792This capability indicates that the PSW is exposed via the kvm_run structure. 7793 77948.15 KVM_CAP_S390_GMAP 7795---------------------- 7796 7797:Architectures: s390 7798 7799This capability indicates that the user space memory used as guest mapping can 7800be anywhere in the user memory address space, as long as the memory slots are 7801aligned and sized to a segment (1MB) boundary. 7802 78038.16 KVM_CAP_S390_COW 7804--------------------- 7805 7806:Architectures: s390 7807 7808This capability indicates that the user space memory used as guest mapping can 7809use copy-on-write semantics as well as dirty pages tracking via read-only page 7810tables. 7811 78128.17 KVM_CAP_S390_BPB 7813--------------------- 7814 7815:Architectures: s390 7816 7817This capability indicates that kvm will implement the interfaces to handle 7818reset, migration and nested KVM for branch prediction blocking. The stfle 7819facility 82 should not be provided to the guest without this capability. 7820 78218.18 KVM_CAP_HYPERV_TLBFLUSH 7822---------------------------- 7823 7824:Architectures: x86 7825 7826This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush 7827hypercalls: 7828HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, 7829HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. 7830 78318.19 KVM_CAP_ARM_INJECT_SERROR_ESR 7832---------------------------------- 7833 7834:Architectures: arm64 7835 7836This capability indicates that userspace can specify (via the 7837KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it 7838takes a virtual SError interrupt exception. 7839If KVM advertises this capability, userspace can only specify the ISS field for 7840the ESR syndrome. Other parts of the ESR, such as the EC are generated by the 7841CPU when the exception is taken. If this virtual SError is taken to EL1 using 7842AArch64, this value will be reported in the ISS field of ESR_ELx. 7843 7844See KVM_CAP_VCPU_EVENTS for more details. 7845 78468.20 KVM_CAP_HYPERV_SEND_IPI 7847---------------------------- 7848 7849:Architectures: x86 7850 7851This capability indicates that KVM supports paravirtualized Hyper-V IPI send 7852hypercalls: 7853HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. 7854 78558.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH 7856----------------------------------- 7857 7858:Architectures: x86 7859 7860This capability indicates that KVM running on top of Hyper-V hypervisor 7861enables Direct TLB flush for its guests meaning that TLB flush 7862hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM. 7863Due to the different ABI for hypercall parameters between Hyper-V and 7864KVM, enabling this capability effectively disables all hypercall 7865handling by KVM (as some KVM hypercall may be mistakenly treated as TLB 7866flush hypercalls by Hyper-V) so userspace should disable KVM identification 7867in CPUID and only exposes Hyper-V identification. In this case, guest 7868thinks it's running on Hyper-V and only use Hyper-V hypercalls. 7869 78708.22 KVM_CAP_S390_VCPU_RESETS 7871----------------------------- 7872 7873:Architectures: s390 7874 7875This capability indicates that the KVM_S390_NORMAL_RESET and 7876KVM_S390_CLEAR_RESET ioctls are available. 7877 78788.23 KVM_CAP_S390_PROTECTED 7879--------------------------- 7880 7881:Architectures: s390 7882 7883This capability indicates that the Ultravisor has been initialized and 7884KVM can therefore start protected VMs. 7885This capability governs the KVM_S390_PV_COMMAND ioctl and the 7886KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected 7887guests when the state change is invalid. 7888 78898.24 KVM_CAP_STEAL_TIME 7890----------------------- 7891 7892:Architectures: arm64, x86 7893 7894This capability indicates that KVM supports steal time accounting. 7895When steal time accounting is supported it may be enabled with 7896architecture-specific interfaces. This capability and the architecture- 7897specific interfaces must be consistent, i.e. if one says the feature 7898is supported, than the other should as well and vice versa. For arm64 7899see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". 7900For x86 see Documentation/virt/kvm/x86/msr.rst "MSR_KVM_STEAL_TIME". 7901 79028.25 KVM_CAP_S390_DIAG318 7903------------------------- 7904 7905:Architectures: s390 7906 7907This capability enables a guest to set information about its control program 7908(i.e. guest kernel type and version). The information is helpful during 7909system/firmware service events, providing additional data about the guest 7910environments running on the machine. 7911 7912The information is associated with the DIAGNOSE 0x318 instruction, which sets 7913an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and 7914a 7-byte Control Program Version Code (CPVC). The CPNC determines what 7915environment the control program is running in (e.g. Linux, z/VM...), and the 7916CPVC is used for information specific to OS (e.g. Linux version, Linux 7917distribution...) 7918 7919If this capability is available, then the CPNC and CPVC can be synchronized 7920between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318). 7921 79228.26 KVM_CAP_X86_USER_SPACE_MSR 7923------------------------------- 7924 7925:Architectures: x86 7926 7927This capability indicates that KVM supports deflection of MSR reads and 7928writes to user space. It can be enabled on a VM level. If enabled, MSR 7929accesses that would usually trigger a #GP by KVM into the guest will 7930instead get bounced to user space through the KVM_EXIT_X86_RDMSR and 7931KVM_EXIT_X86_WRMSR exit notifications. 7932 79338.27 KVM_CAP_X86_MSR_FILTER 7934--------------------------- 7935 7936:Architectures: x86 7937 7938This capability indicates that KVM supports that accesses to user defined MSRs 7939may be rejected. With this capability exposed, KVM exports new VM ioctl 7940KVM_X86_SET_MSR_FILTER which user space can call to specify bitmaps of MSR 7941ranges that KVM should deny access to. 7942 7943In combination with KVM_CAP_X86_USER_SPACE_MSR, this allows user space to 7944trap and emulate MSRs that are outside of the scope of KVM as well as 7945limit the attack surface on KVM's MSR emulation code. 7946 79478.28 KVM_CAP_ENFORCE_PV_FEATURE_CPUID 7948------------------------------------- 7949 7950Architectures: x86 7951 7952When enabled, KVM will disable paravirtual features provided to the 7953guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf 7954(0x40000001). Otherwise, a guest may use the paravirtual features 7955regardless of what has actually been exposed through the CPUID leaf. 7956 79578.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL 7958---------------------------------------------------------- 7959 7960:Architectures: x86, arm64 7961:Parameters: args[0] - size of the dirty log ring 7962 7963KVM is capable of tracking dirty memory using ring buffers that are 7964mmaped into userspace; there is one dirty ring per vcpu. 7965 7966The dirty ring is available to userspace as an array of 7967``struct kvm_dirty_gfn``. Each dirty entry it's defined as:: 7968 7969 struct kvm_dirty_gfn { 7970 __u32 flags; 7971 __u32 slot; /* as_id | slot_id */ 7972 __u64 offset; 7973 }; 7974 7975The following values are defined for the flags field to define the 7976current state of the entry:: 7977 7978 #define KVM_DIRTY_GFN_F_DIRTY BIT(0) 7979 #define KVM_DIRTY_GFN_F_RESET BIT(1) 7980 #define KVM_DIRTY_GFN_F_MASK 0x3 7981 7982Userspace should call KVM_ENABLE_CAP ioctl right after KVM_CREATE_VM 7983ioctl to enable this capability for the new guest and set the size of 7984the rings. Enabling the capability is only allowed before creating any 7985vCPU, and the size of the ring must be a power of two. The larger the 7986ring buffer, the less likely the ring is full and the VM is forced to 7987exit to userspace. The optimal size depends on the workload, but it is 7988recommended that it be at least 64 KiB (4096 entries). 7989 7990Just like for dirty page bitmaps, the buffer tracks writes to 7991all user memory regions for which the KVM_MEM_LOG_DIRTY_PAGES flag was 7992set in KVM_SET_USER_MEMORY_REGION. Once a memory region is registered 7993with the flag set, userspace can start harvesting dirty pages from the 7994ring buffer. 7995 7996An entry in the ring buffer can be unused (flag bits ``00``), 7997dirty (flag bits ``01``) or harvested (flag bits ``1X``). The 7998state machine for the entry is as follows:: 7999 8000 dirtied harvested reset 8001 00 -----------> 01 -------------> 1X -------+ 8002 ^ | 8003 | | 8004 +------------------------------------------+ 8005 8006To harvest the dirty pages, userspace accesses the mmaped ring buffer 8007to read the dirty GFNs. If the flags has the DIRTY bit set (at this stage 8008the RESET bit must be cleared), then it means this GFN is a dirty GFN. 8009The userspace should harvest this GFN and mark the flags from state 8010``01b`` to ``1Xb`` (bit 0 will be ignored by KVM, but bit 1 must be set 8011to show that this GFN is harvested and waiting for a reset), and move 8012on to the next GFN. The userspace should continue to do this until the 8013flags of a GFN have the DIRTY bit cleared, meaning that it has harvested 8014all the dirty GFNs that were available. 8015 8016Note that on weakly ordered architectures, userspace accesses to the 8017ring buffer (and more specifically the 'flags' field) must be ordered, 8018using load-acquire/store-release accessors when available, or any 8019other memory barrier that will ensure this ordering. 8020 8021It's not necessary for userspace to harvest the all dirty GFNs at once. 8022However it must collect the dirty GFNs in sequence, i.e., the userspace 8023program cannot skip one dirty GFN to collect the one next to it. 8024 8025After processing one or more entries in the ring buffer, userspace 8026calls the VM ioctl KVM_RESET_DIRTY_RINGS to notify the kernel about 8027it, so that the kernel will reprotect those collected GFNs. 8028Therefore, the ioctl must be called *before* reading the content of 8029the dirty pages. 8030 8031The dirty ring can get full. When it happens, the KVM_RUN of the 8032vcpu will return with exit reason KVM_EXIT_DIRTY_LOG_FULL. 8033 8034The dirty ring interface has a major difference comparing to the 8035KVM_GET_DIRTY_LOG interface in that, when reading the dirty ring from 8036userspace, it's still possible that the kernel has not yet flushed the 8037processor's dirty page buffers into the kernel buffer (with dirty bitmaps, the 8038flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one 8039needs to kick the vcpu out of KVM_RUN using a signal. The resulting 8040vmexit ensures that all dirty GFNs are flushed to the dirty rings. 8041 8042NOTE: KVM_CAP_DIRTY_LOG_RING_ACQ_REL is the only capability that 8043should be exposed by weakly ordered architecture, in order to indicate 8044the additional memory ordering requirements imposed on userspace when 8045reading the state of an entry and mutating it from DIRTY to HARVESTED. 8046Architecture with TSO-like ordering (such as x86) are allowed to 8047expose both KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8048to userspace. 8049 8050After enabling the dirty rings, the userspace needs to detect the 8051capability of KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP to see whether the 8052ring structures can be backed by per-slot bitmaps. With this capability 8053advertised, it means the architecture can dirty guest pages without 8054vcpu/ring context, so that some of the dirty information will still be 8055maintained in the bitmap structure. KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 8056can't be enabled if the capability of KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8057hasn't been enabled, or any memslot has been existing. 8058 8059Note that the bitmap here is only a backup of the ring structure. The 8060use of the ring and bitmap combination is only beneficial if there is 8061only a very small amount of memory that is dirtied out of vcpu/ring 8062context. Otherwise, the stand-alone per-slot bitmap mechanism needs to 8063be considered. 8064 8065To collect dirty bits in the backup bitmap, userspace can use the same 8066KVM_GET_DIRTY_LOG ioctl. KVM_CLEAR_DIRTY_LOG isn't needed as long as all 8067the generation of the dirty bits is done in a single pass. Collecting 8068the dirty bitmap should be the very last thing that the VMM does before 8069considering the state as complete. VMM needs to ensure that the dirty 8070state is final and avoid missing dirty pages from another ioctl ordered 8071after the bitmap collection. 8072 8073NOTE: One example of using the backup bitmap is saving arm64 vgic/its 8074tables through KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} command on 8075KVM device "kvm-arm-vgic-its" when dirty ring is enabled. 8076 80778.30 KVM_CAP_XEN_HVM 8078-------------------- 8079 8080:Architectures: x86 8081 8082This capability indicates the features that Xen supports for hosting Xen 8083PVHVM guests. Valid flags are:: 8084 8085 #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0) 8086 #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1) 8087 #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2) 8088 #define KVM_XEN_HVM_CONFIG_RUNSTATE (1 << 3) 8089 #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 4) 8090 #define KVM_XEN_HVM_CONFIG_EVTCHN_SEND (1 << 5) 8091 #define KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG (1 << 6) 8092 8093The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG 8094ioctl is available, for the guest to set its hypercall page. 8095 8096If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be 8097provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page 8098contents, to request that KVM generate hypercall page content automatically 8099and also enable interception of guest hypercalls with KVM_EXIT_XEN. 8100 8101The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the 8102KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and 8103KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors 8104for event channel upcalls when the evtchn_upcall_pending field of a vcpu's 8105vcpu_info is set. 8106 8107The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related 8108features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are 8109supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls. 8110 8111The KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL flag indicates that IRQ routing entries 8112of the type KVM_IRQ_ROUTING_XEN_EVTCHN are supported, with the priority 8113field set to indicate 2 level event channel delivery. 8114 8115The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates that KVM supports 8116injecting event channel events directly into the guest with the 8117KVM_XEN_HVM_EVTCHN_SEND ioctl. It also indicates support for the 8118KVM_XEN_ATTR_TYPE_EVTCHN/XEN_VERSION HVM attributes and the 8119KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID/TIMER/UPCALL_VECTOR vCPU attributes. 8120related to event channel delivery, timers, and the XENVER_version 8121interception. 8122 8123The KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG flag indicates that KVM supports 8124the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute in the KVM_XEN_SET_ATTR 8125and KVM_XEN_GET_ATTR ioctls. This controls whether KVM will set the 8126XEN_RUNSTATE_UPDATE flag in guest memory mapped vcpu_runstate_info during 8127updates of the runstate information. Note that versions of KVM which support 8128the RUNSTATE feature above, but not thie RUNSTATE_UPDATE_FLAG feature, will 8129always set the XEN_RUNSTATE_UPDATE flag when updating the guest structure, 8130which is perhaps counterintuitive. When this flag is advertised, KVM will 8131behave more correctly, not using the XEN_RUNSTATE_UPDATE flag until/unless 8132specifically enabled (by the guest making the hypercall, causing the VMM 8133to enable the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute). 8134 81358.31 KVM_CAP_PPC_MULTITCE 8136------------------------- 8137 8138:Capability: KVM_CAP_PPC_MULTITCE 8139:Architectures: ppc 8140:Type: vm 8141 8142This capability means the kernel is capable of handling hypercalls 8143H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user 8144space. This significantly accelerates DMA operations for PPC KVM guests. 8145User space should expect that its handlers for these hypercalls 8146are not going to be called if user space previously registered LIOBN 8147in KVM (via KVM_CREATE_SPAPR_TCE or similar calls). 8148 8149In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest, 8150user space might have to advertise it for the guest. For example, 8151IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is 8152present in the "ibm,hypertas-functions" device-tree property. 8153 8154The hypercalls mentioned above may or may not be processed successfully 8155in the kernel based fast path. If they can not be handled by the kernel, 8156they will get passed on to user space. So user space still has to have 8157an implementation for these despite the in kernel acceleration. 8158 8159This capability is always enabled. 8160 81618.32 KVM_CAP_PTP_KVM 8162-------------------- 8163 8164:Architectures: arm64 8165 8166This capability indicates that the KVM virtual PTP service is 8167supported in the host. A VMM can check whether the service is 8168available to the guest on migration. 8169 81708.33 KVM_CAP_HYPERV_ENFORCE_CPUID 8171--------------------------------- 8172 8173Architectures: x86 8174 8175When enabled, KVM will disable emulated Hyper-V features provided to the 8176guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all 8177currently implmented Hyper-V features are provided unconditionally when 8178Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001) 8179leaf. 8180 81818.34 KVM_CAP_EXIT_HYPERCALL 8182--------------------------- 8183 8184:Capability: KVM_CAP_EXIT_HYPERCALL 8185:Architectures: x86 8186:Type: vm 8187 8188This capability, if enabled, will cause KVM to exit to userspace 8189with KVM_EXIT_HYPERCALL exit reason to process some hypercalls. 8190 8191Calling KVM_CHECK_EXTENSION for this capability will return a bitmask 8192of hypercalls that can be configured to exit to userspace. 8193Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE. 8194 8195The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset 8196of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace 8197the hypercalls whose corresponding bit is in the argument, and return 8198ENOSYS for the others. 8199 82008.35 KVM_CAP_PMU_CAPABILITY 8201--------------------------- 8202 8203:Capability KVM_CAP_PMU_CAPABILITY 8204:Architectures: x86 8205:Type: vm 8206:Parameters: arg[0] is bitmask of PMU virtualization capabilities. 8207:Returns 0 on success, -EINVAL when arg[0] contains invalid bits 8208 8209This capability alters PMU virtualization in KVM. 8210 8211Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 8212PMU virtualization capabilities that can be adjusted on a VM. 8213 8214The argument to KVM_ENABLE_CAP is also a bitmask and selects specific 8215PMU virtualization capabilities to be applied to the VM. This can 8216only be invoked on a VM prior to the creation of VCPUs. 8217 8218At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting 8219this capability will disable PMU virtualization for that VM. Usermode 8220should adjust CPUID leaf 0xA to reflect that the PMU is disabled. 8221 82228.36 KVM_CAP_ARM_SYSTEM_SUSPEND 8223------------------------------- 8224 8225:Capability: KVM_CAP_ARM_SYSTEM_SUSPEND 8226:Architectures: arm64 8227:Type: vm 8228 8229When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of 8230type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. 8231 82328.37 KVM_CAP_S390_PROTECTED_DUMP 8233-------------------------------- 8234 8235:Capability: KVM_CAP_S390_PROTECTED_DUMP 8236:Architectures: s390 8237:Type: vm 8238 8239This capability indicates that KVM and the Ultravisor support dumping 8240PV guests. The `KVM_PV_DUMP` command is available for the 8241`KVM_S390_PV_COMMAND` ioctl and the `KVM_PV_INFO` command provides 8242dump related UV data. Also the vcpu ioctl `KVM_S390_PV_CPU_COMMAND` is 8243available and supports the `KVM_PV_DUMP_CPU` subcommand. 8244 82458.38 KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8246------------------------------------- 8247 8248:Capability: KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8249:Architectures: x86 8250:Type: vm 8251:Parameters: arg[0] must be 0. 8252:Returns: 0 on success, -EPERM if the userspace process does not 8253 have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been 8254 created. 8255 8256This capability disables the NX huge pages mitigation for iTLB MULTIHIT. 8257 8258The capability has no effect if the nx_huge_pages module parameter is not set. 8259 8260This capability may only be set before any vCPUs are created. 8261 82628.39 KVM_CAP_S390_CPU_TOPOLOGY 8263------------------------------ 8264 8265:Capability: KVM_CAP_S390_CPU_TOPOLOGY 8266:Architectures: s390 8267:Type: vm 8268 8269This capability indicates that KVM will provide the S390 CPU Topology 8270facility which consist of the interpretation of the PTF instruction for 8271the function code 2 along with interception and forwarding of both the 8272PTF instruction with function codes 0 or 1 and the STSI(15,1,x) 8273instruction to the userland hypervisor. 8274 8275The stfle facility 11, CPU Topology facility, should not be indicated 8276to the guest without this capability. 8277 8278When this capability is present, KVM provides a new attribute group 8279on vm fd, KVM_S390_VM_CPU_TOPOLOGY. 8280This new attribute allows to get, set or clear the Modified Change 8281Topology Report (MTCR) bit of the SCA through the kvm_device_attr 8282structure. 8283 8284When getting the Modified Change Topology Report value, the attr->addr 8285must point to a byte where the value will be stored or retrieved from. 8286 82879. Known KVM API problems 8288========================= 8289 8290In some cases, KVM's API has some inconsistencies or common pitfalls 8291that userspace need to be aware of. This section details some of 8292these issues. 8293 8294Most of them are architecture specific, so the section is split by 8295architecture. 8296 82979.1. x86 8298-------- 8299 8300``KVM_GET_SUPPORTED_CPUID`` issues 8301^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 8302 8303In general, ``KVM_GET_SUPPORTED_CPUID`` is designed so that it is possible 8304to take its result and pass it directly to ``KVM_SET_CPUID2``. This section 8305documents some cases in which that requires some care. 8306 8307Local APIC features 8308~~~~~~~~~~~~~~~~~~~ 8309 8310CPU[EAX=1]:ECX[21] (X2APIC) is reported by ``KVM_GET_SUPPORTED_CPUID``, 8311but it can only be enabled if ``KVM_CREATE_IRQCHIP`` or 8312``KVM_ENABLE_CAP(KVM_CAP_IRQCHIP_SPLIT)`` are used to enable in-kernel emulation of 8313the local APIC. 8314 8315The same is true for the ``KVM_FEATURE_PV_UNHALT`` paravirtualized feature. 8316 8317CPU[EAX=1]:ECX[24] (TSC_DEADLINE) is not reported by ``KVM_GET_SUPPORTED_CPUID``. 8318It can be enabled if ``KVM_CAP_TSC_DEADLINE_TIMER`` is present and the kernel 8319has enabled in-kernel emulation of the local APIC. 8320 8321CPU topology 8322~~~~~~~~~~~~ 8323 8324Several CPUID values include topology information for the host CPU: 83250x0b and 0x1f for Intel systems, 0x8000001e for AMD systems. Different 8326versions of KVM return different values for this information and userspace 8327should not rely on it. Currently they return all zeroes. 8328 8329If userspace wishes to set up a guest topology, it should be careful that 8330the values of these three leaves differ for each CPU. In particular, 8331the APIC ID is found in EDX for all subleaves of 0x0b and 0x1f, and in EAX 8332for 0x8000001e; the latter also encodes the core id and node id in bits 83337:0 of EBX and ECX respectively. 8334 8335Obsolete ioctls and capabilities 8336^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 8337 8338KVM_CAP_DISABLE_QUIRKS does not let userspace know which quirks are actually 8339available. Use ``KVM_CHECK_EXTENSION(KVM_CAP_DISABLE_QUIRKS2)`` instead if 8340available. 8341 8342Ordering of KVM_GET_*/KVM_SET_* ioctls 8343^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 8344 8345TBD 8346