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 154To use hardware assisted virtualization on MIPS (VZ ASE) rather than 155the default trap & emulate implementation (which changes the virtual 156memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the 157flag KVM_VM_MIPS_VZ. 158 159 160On arm64, the physical address size for a VM (IPA Size limit) is limited 161to 40bits by default. The limit can be configured if the host supports the 162extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use 163KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type 164identifier, where IPA_Bits is the maximum width of any physical 165address used by the VM. The IPA_Bits is encoded in bits[7-0] of the 166machine type identifier. 167 168e.g, to configure a guest to use 48bit physical address size:: 169 170 vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48)); 171 172The requested size (IPA_Bits) must be: 173 174 == ========================================================= 175 0 Implies default size, 40bits (for backward compatibility) 176 N Implies N bits, where N is a positive integer such that, 177 32 <= N <= Host_IPA_Limit 178 == ========================================================= 179 180Host_IPA_Limit is the maximum possible value for IPA_Bits on the host and 181is dependent on the CPU capability and the kernel configuration. The limit can 182be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the KVM_CHECK_EXTENSION 183ioctl() at run-time. 184 185Creation of the VM will fail if the requested IPA size (whether it is 186implicit or explicit) is unsupported on the host. 187 188Please note that configuring the IPA size does not affect the capability 189exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects 190size of the address translated by the stage2 level (guest physical to 191host physical address translations). 192 193 1944.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST 195---------------------------------------------------------- 196 197:Capability: basic, KVM_CAP_GET_MSR_FEATURES for KVM_GET_MSR_FEATURE_INDEX_LIST 198:Architectures: x86 199:Type: system ioctl 200:Parameters: struct kvm_msr_list (in/out) 201:Returns: 0 on success; -1 on error 202 203Errors: 204 205 ====== ============================================================ 206 EFAULT the msr index list cannot be read from or written to 207 E2BIG the msr index list is too big to fit in the array specified by 208 the user. 209 ====== ============================================================ 210 211:: 212 213 struct kvm_msr_list { 214 __u32 nmsrs; /* number of msrs in entries */ 215 __u32 indices[0]; 216 }; 217 218The user fills in the size of the indices array in nmsrs, and in return 219kvm adjusts nmsrs to reflect the actual number of msrs and fills in the 220indices array with their numbers. 221 222KVM_GET_MSR_INDEX_LIST returns the guest msrs that are supported. The list 223varies by kvm version and host processor, but does not change otherwise. 224 225Note: if kvm indicates supports MCE (KVM_CAP_MCE), then the MCE bank MSRs are 226not returned in the MSR list, as different vcpus can have a different number 227of banks, as set via the KVM_X86_SETUP_MCE ioctl. 228 229KVM_GET_MSR_FEATURE_INDEX_LIST returns the list of MSRs that can be passed 230to the KVM_GET_MSRS system ioctl. This lets userspace probe host capabilities 231and processor features that are exposed via MSRs (e.g., VMX capabilities). 232This list also varies by kvm version and host processor, but does not change 233otherwise. 234 235 2364.4 KVM_CHECK_EXTENSION 237----------------------- 238 239:Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl 240:Architectures: all 241:Type: system ioctl, vm ioctl 242:Parameters: extension identifier (KVM_CAP_*) 243:Returns: 0 if unsupported; 1 (or some other positive integer) if supported 244 245The API allows the application to query about extensions to the core 246kvm API. Userspace passes an extension identifier (an integer) and 247receives an integer that describes the extension availability. 248Generally 0 means no and 1 means yes, but some extensions may report 249additional information in the integer return value. 250 251Based on their initialization different VMs may have different capabilities. 252It is thus encouraged to use the vm ioctl to query for capabilities (available 253with KVM_CAP_CHECK_EXTENSION_VM on the vm fd) 254 2554.5 KVM_GET_VCPU_MMAP_SIZE 256-------------------------- 257 258:Capability: basic 259:Architectures: all 260:Type: system ioctl 261:Parameters: none 262:Returns: size of vcpu mmap area, in bytes 263 264The KVM_RUN ioctl (cf.) communicates with userspace via a shared 265memory region. This ioctl returns the size of that region. See the 266KVM_RUN documentation for details. 267 268Besides the size of the KVM_RUN communication region, other areas of 269the VCPU file descriptor can be mmap-ed, including: 270 271- if KVM_CAP_COALESCED_MMIO is available, a page at 272 KVM_COALESCED_MMIO_PAGE_OFFSET * PAGE_SIZE; for historical reasons, 273 this page is included in the result of KVM_GET_VCPU_MMAP_SIZE. 274 KVM_CAP_COALESCED_MMIO is not documented yet. 275 276- if KVM_CAP_DIRTY_LOG_RING is available, a number of pages at 277 KVM_DIRTY_LOG_PAGE_OFFSET * PAGE_SIZE. For more information on 278 KVM_CAP_DIRTY_LOG_RING, see section 8.3. 279 280 2814.6 KVM_SET_MEMORY_REGION 282------------------------- 283 284:Capability: basic 285:Architectures: all 286:Type: vm ioctl 287:Parameters: struct kvm_memory_region (in) 288:Returns: 0 on success, -1 on error 289 290This ioctl is obsolete and has been removed. 291 292 2934.7 KVM_CREATE_VCPU 294------------------- 295 296:Capability: basic 297:Architectures: all 298:Type: vm ioctl 299:Parameters: vcpu id (apic id on x86) 300:Returns: vcpu fd on success, -1 on error 301 302This API adds a vcpu to a virtual machine. No more than max_vcpus may be added. 303The vcpu id is an integer in the range [0, max_vcpu_id). 304 305The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of 306the KVM_CHECK_EXTENSION ioctl() at run-time. 307The maximum possible value for max_vcpus can be retrieved using the 308KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. 309 310If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 311cpus max. 312If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is 313same as the value returned from KVM_CAP_NR_VCPUS. 314 315The maximum possible value for max_vcpu_id can be retrieved using the 316KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time. 317 318If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that max_vcpu_id 319is the same as the value returned from KVM_CAP_MAX_VCPUS. 320 321On powerpc using book3s_hv mode, the vcpus are mapped onto virtual 322threads in one or more virtual CPU cores. (This is because the 323hardware requires all the hardware threads in a CPU core to be in the 324same partition.) The KVM_CAP_PPC_SMT capability indicates the number 325of vcpus per virtual core (vcore). The vcore id is obtained by 326dividing the vcpu id by the number of vcpus per vcore. The vcpus in a 327given vcore will always be in the same physical core as each other 328(though that might be a different physical core from time to time). 329Userspace can control the threading (SMT) mode of the guest by its 330allocation of vcpu ids. For example, if userspace wants 331single-threaded guest vcpus, it should make all vcpu ids be a multiple 332of the number of vcpus per vcore. 333 334For virtual cpus that have been created with S390 user controlled virtual 335machines, the resulting vcpu fd can be memory mapped at page offset 336KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of the virtual 337cpu's hardware control block. 338 339 3404.8 KVM_GET_DIRTY_LOG (vm ioctl) 341-------------------------------- 342 343:Capability: basic 344:Architectures: all 345:Type: vm ioctl 346:Parameters: struct kvm_dirty_log (in/out) 347:Returns: 0 on success, -1 on error 348 349:: 350 351 /* for KVM_GET_DIRTY_LOG */ 352 struct kvm_dirty_log { 353 __u32 slot; 354 __u32 padding; 355 union { 356 void __user *dirty_bitmap; /* one bit per page */ 357 __u64 padding; 358 }; 359 }; 360 361Given a memory slot, return a bitmap containing any pages dirtied 362since the last call to this ioctl. Bit 0 is the first page in the 363memory slot. Ensure the entire structure is cleared to avoid padding 364issues. 365 366If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 367the address space for which you want to return the dirty bitmap. See 368KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 369 370The bits in the dirty bitmap are cleared before the ioctl returns, unless 371KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information, 372see the description of the capability. 373 374Note that the Xen shared info page, if configured, shall always be assumed 375to be dirty. KVM will not explicitly mark it such. 376 3774.9 KVM_SET_MEMORY_ALIAS 378------------------------ 379 380:Capability: basic 381:Architectures: x86 382:Type: vm ioctl 383:Parameters: struct kvm_memory_alias (in) 384:Returns: 0 (success), -1 (error) 385 386This ioctl is obsolete and has been removed. 387 388 3894.10 KVM_RUN 390------------ 391 392:Capability: basic 393:Architectures: all 394:Type: vcpu ioctl 395:Parameters: none 396:Returns: 0 on success, -1 on error 397 398Errors: 399 400 ======= ============================================================== 401 EINTR an unmasked signal is pending 402 ENOEXEC the vcpu hasn't been initialized or the guest tried to execute 403 instructions from device memory (arm64) 404 ENOSYS data abort outside memslots with no syndrome info and 405 KVM_CAP_ARM_NISV_TO_USER not enabled (arm64) 406 EPERM SVE feature set but not finalized (arm64) 407 ======= ============================================================== 408 409This ioctl is used to run a guest virtual cpu. While there are no 410explicit parameters, there is an implicit parameter block that can be 411obtained by mmap()ing the vcpu fd at offset 0, with the size given by 412KVM_GET_VCPU_MMAP_SIZE. The parameter block is formatted as a 'struct 413kvm_run' (see below). 414 415 4164.11 KVM_GET_REGS 417----------------- 418 419:Capability: basic 420:Architectures: all except arm64 421:Type: vcpu ioctl 422:Parameters: struct kvm_regs (out) 423:Returns: 0 on success, -1 on error 424 425Reads the general purpose registers from the vcpu. 426 427:: 428 429 /* x86 */ 430 struct kvm_regs { 431 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 432 __u64 rax, rbx, rcx, rdx; 433 __u64 rsi, rdi, rsp, rbp; 434 __u64 r8, r9, r10, r11; 435 __u64 r12, r13, r14, r15; 436 __u64 rip, rflags; 437 }; 438 439 /* mips */ 440 struct kvm_regs { 441 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 442 __u64 gpr[32]; 443 __u64 hi; 444 __u64 lo; 445 __u64 pc; 446 }; 447 448 4494.12 KVM_SET_REGS 450----------------- 451 452:Capability: basic 453:Architectures: all except arm64 454:Type: vcpu ioctl 455:Parameters: struct kvm_regs (in) 456:Returns: 0 on success, -1 on error 457 458Writes the general purpose registers into the vcpu. 459 460See KVM_GET_REGS for the data structure. 461 462 4634.13 KVM_GET_SREGS 464------------------ 465 466:Capability: basic 467:Architectures: x86, ppc 468:Type: vcpu ioctl 469:Parameters: struct kvm_sregs (out) 470:Returns: 0 on success, -1 on error 471 472Reads special registers from the vcpu. 473 474:: 475 476 /* x86 */ 477 struct kvm_sregs { 478 struct kvm_segment cs, ds, es, fs, gs, ss; 479 struct kvm_segment tr, ldt; 480 struct kvm_dtable gdt, idt; 481 __u64 cr0, cr2, cr3, cr4, cr8; 482 __u64 efer; 483 __u64 apic_base; 484 __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64]; 485 }; 486 487 /* ppc -- see arch/powerpc/include/uapi/asm/kvm.h */ 488 489interrupt_bitmap is a bitmap of pending external interrupts. At most 490one bit may be set. This interrupt has been acknowledged by the APIC 491but not yet injected into the cpu core. 492 493 4944.14 KVM_SET_SREGS 495------------------ 496 497:Capability: basic 498:Architectures: x86, ppc 499:Type: vcpu ioctl 500:Parameters: struct kvm_sregs (in) 501:Returns: 0 on success, -1 on error 502 503Writes special registers into the vcpu. See KVM_GET_SREGS for the 504data structures. 505 506 5074.15 KVM_TRANSLATE 508------------------ 509 510:Capability: basic 511:Architectures: x86 512:Type: vcpu ioctl 513:Parameters: struct kvm_translation (in/out) 514:Returns: 0 on success, -1 on error 515 516Translates a virtual address according to the vcpu's current address 517translation mode. 518 519:: 520 521 struct kvm_translation { 522 /* in */ 523 __u64 linear_address; 524 525 /* out */ 526 __u64 physical_address; 527 __u8 valid; 528 __u8 writeable; 529 __u8 usermode; 530 __u8 pad[5]; 531 }; 532 533 5344.16 KVM_INTERRUPT 535------------------ 536 537:Capability: basic 538:Architectures: x86, ppc, mips, riscv 539:Type: vcpu ioctl 540:Parameters: struct kvm_interrupt (in) 541:Returns: 0 on success, negative on failure. 542 543Queues a hardware interrupt vector to be injected. 544 545:: 546 547 /* for KVM_INTERRUPT */ 548 struct kvm_interrupt { 549 /* in */ 550 __u32 irq; 551 }; 552 553X86: 554^^^^ 555 556:Returns: 557 558 ========= =================================== 559 0 on success, 560 -EEXIST if an interrupt is already enqueued 561 -EINVAL the irq number is invalid 562 -ENXIO if the PIC is in the kernel 563 -EFAULT if the pointer is invalid 564 ========= =================================== 565 566Note 'irq' is an interrupt vector, not an interrupt pin or line. This 567ioctl is useful if the in-kernel PIC is not used. 568 569PPC: 570^^^^ 571 572Queues an external interrupt to be injected. This ioctl is overleaded 573with 3 different irq values: 574 575a) KVM_INTERRUPT_SET 576 577 This injects an edge type external interrupt into the guest once it's ready 578 to receive interrupts. When injected, the interrupt is done. 579 580b) KVM_INTERRUPT_UNSET 581 582 This unsets any pending interrupt. 583 584 Only available with KVM_CAP_PPC_UNSET_IRQ. 585 586c) KVM_INTERRUPT_SET_LEVEL 587 588 This injects a level type external interrupt into the guest context. The 589 interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET 590 is triggered. 591 592 Only available with KVM_CAP_PPC_IRQ_LEVEL. 593 594Note that any value for 'irq' other than the ones stated above is invalid 595and incurs unexpected behavior. 596 597This is an asynchronous vcpu ioctl and can be invoked from any thread. 598 599MIPS: 600^^^^^ 601 602Queues an external interrupt to be injected into the virtual CPU. A negative 603interrupt number dequeues the interrupt. 604 605This is an asynchronous vcpu ioctl and can be invoked from any thread. 606 607RISC-V: 608^^^^^^^ 609 610Queues an external interrupt to be injected into the virutal CPU. This ioctl 611is overloaded with 2 different irq values: 612 613a) KVM_INTERRUPT_SET 614 615 This sets external interrupt for a virtual CPU and it will receive 616 once it is ready. 617 618b) KVM_INTERRUPT_UNSET 619 620 This clears pending external interrupt for a virtual CPU. 621 622This is an asynchronous vcpu ioctl and can be invoked from any thread. 623 624 6254.17 KVM_DEBUG_GUEST 626-------------------- 627 628:Capability: basic 629:Architectures: none 630:Type: vcpu ioctl 631:Parameters: none) 632:Returns: -1 on error 633 634Support for this has been removed. Use KVM_SET_GUEST_DEBUG instead. 635 636 6374.18 KVM_GET_MSRS 638----------------- 639 640:Capability: basic (vcpu), KVM_CAP_GET_MSR_FEATURES (system) 641:Architectures: x86 642:Type: system ioctl, vcpu ioctl 643:Parameters: struct kvm_msrs (in/out) 644:Returns: number of msrs successfully returned; 645 -1 on error 646 647When used as a system ioctl: 648Reads the values of MSR-based features that are available for the VM. This 649is similar to KVM_GET_SUPPORTED_CPUID, but it returns MSR indices and values. 650The list of msr-based features can be obtained using KVM_GET_MSR_FEATURE_INDEX_LIST 651in a system ioctl. 652 653When used as a vcpu ioctl: 654Reads model-specific registers from the vcpu. Supported msr indices can 655be obtained using KVM_GET_MSR_INDEX_LIST in a system ioctl. 656 657:: 658 659 struct kvm_msrs { 660 __u32 nmsrs; /* number of msrs in entries */ 661 __u32 pad; 662 663 struct kvm_msr_entry entries[0]; 664 }; 665 666 struct kvm_msr_entry { 667 __u32 index; 668 __u32 reserved; 669 __u64 data; 670 }; 671 672Application code should set the 'nmsrs' member (which indicates the 673size of the entries array) and the 'index' member of each array entry. 674kvm will fill in the 'data' member. 675 676 6774.19 KVM_SET_MSRS 678----------------- 679 680:Capability: basic 681:Architectures: x86 682:Type: vcpu ioctl 683:Parameters: struct kvm_msrs (in) 684:Returns: number of msrs successfully set (see below), -1 on error 685 686Writes model-specific registers to the vcpu. See KVM_GET_MSRS for the 687data structures. 688 689Application code should set the 'nmsrs' member (which indicates the 690size of the entries array), and the 'index' and 'data' members of each 691array entry. 692 693It tries to set the MSRs in array entries[] one by one. If setting an MSR 694fails, e.g., due to setting reserved bits, the MSR isn't supported/emulated 695by KVM, etc..., it stops processing the MSR list and returns the number of 696MSRs that have been set successfully. 697 698 6994.20 KVM_SET_CPUID 700------------------ 701 702:Capability: basic 703:Architectures: x86 704:Type: vcpu ioctl 705:Parameters: struct kvm_cpuid (in) 706:Returns: 0 on success, -1 on error 707 708Defines the vcpu responses to the cpuid instruction. Applications 709should use the KVM_SET_CPUID2 ioctl if available. 710 711Caveat emptor: 712 - If this IOCTL fails, KVM gives no guarantees that previous valid CPUID 713 configuration (if there is) is not corrupted. Userspace can get a copy 714 of the resulting CPUID configuration through KVM_GET_CPUID2 in case. 715 - Using KVM_SET_CPUID{,2} after KVM_RUN, i.e. changing the guest vCPU model 716 after running the guest, may cause guest instability. 717 - Using heterogeneous CPUID configurations, modulo APIC IDs, topology, etc... 718 may cause guest instability. 719 720:: 721 722 struct kvm_cpuid_entry { 723 __u32 function; 724 __u32 eax; 725 __u32 ebx; 726 __u32 ecx; 727 __u32 edx; 728 __u32 padding; 729 }; 730 731 /* for KVM_SET_CPUID */ 732 struct kvm_cpuid { 733 __u32 nent; 734 __u32 padding; 735 struct kvm_cpuid_entry entries[0]; 736 }; 737 738 7394.21 KVM_SET_SIGNAL_MASK 740------------------------ 741 742:Capability: basic 743:Architectures: all 744:Type: vcpu ioctl 745:Parameters: struct kvm_signal_mask (in) 746:Returns: 0 on success, -1 on error 747 748Defines which signals are blocked during execution of KVM_RUN. This 749signal mask temporarily overrides the threads signal mask. Any 750unblocked signal received (except SIGKILL and SIGSTOP, which retain 751their traditional behaviour) will cause KVM_RUN to return with -EINTR. 752 753Note the signal will only be delivered if not blocked by the original 754signal mask. 755 756:: 757 758 /* for KVM_SET_SIGNAL_MASK */ 759 struct kvm_signal_mask { 760 __u32 len; 761 __u8 sigset[0]; 762 }; 763 764 7654.22 KVM_GET_FPU 766---------------- 767 768:Capability: basic 769:Architectures: x86 770:Type: vcpu ioctl 771:Parameters: struct kvm_fpu (out) 772:Returns: 0 on success, -1 on error 773 774Reads the floating point state from 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 7944.23 KVM_SET_FPU 795---------------- 796 797:Capability: basic 798:Architectures: x86 799:Type: vcpu ioctl 800:Parameters: struct kvm_fpu (in) 801:Returns: 0 on success, -1 on error 802 803Writes the floating point state to the vcpu. 804 805:: 806 807 /* for KVM_GET_FPU and KVM_SET_FPU */ 808 struct kvm_fpu { 809 __u8 fpr[8][16]; 810 __u16 fcw; 811 __u16 fsw; 812 __u8 ftwx; /* in fxsave format */ 813 __u8 pad1; 814 __u16 last_opcode; 815 __u64 last_ip; 816 __u64 last_dp; 817 __u8 xmm[16][16]; 818 __u32 mxcsr; 819 __u32 pad2; 820 }; 821 822 8234.24 KVM_CREATE_IRQCHIP 824----------------------- 825 826:Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390) 827:Architectures: x86, arm64, s390 828:Type: vm ioctl 829:Parameters: none 830:Returns: 0 on success, -1 on error 831 832Creates an interrupt controller model in the kernel. 833On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up 834future vcpus to have a local APIC. IRQ routing for GSIs 0-15 is set to both 835PIC and IOAPIC; GSI 16-23 only go to the IOAPIC. 836On arm64, a GICv2 is created. Any other GIC versions require the usage of 837KVM_CREATE_DEVICE, which also supports creating a GICv2. Using 838KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2. 839On s390, a dummy irq routing table is created. 840 841Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled 842before KVM_CREATE_IRQCHIP can be used. 843 844 8454.25 KVM_IRQ_LINE 846----------------- 847 848:Capability: KVM_CAP_IRQCHIP 849:Architectures: x86, arm64 850:Type: vm ioctl 851:Parameters: struct kvm_irq_level 852:Returns: 0 on success, -1 on error 853 854Sets the level of a GSI input to the interrupt controller model in the kernel. 855On some architectures it is required that an interrupt controller model has 856been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered 857interrupts require the level to be set to 1 and then back to 0. 858 859On real hardware, interrupt pins can be active-low or active-high. This 860does not matter for the level field of struct kvm_irq_level: 1 always 861means active (asserted), 0 means inactive (deasserted). 862 863x86 allows the operating system to program the interrupt polarity 864(active-low/active-high) for level-triggered interrupts, and KVM used 865to consider the polarity. However, due to bitrot in the handling of 866active-low interrupts, the above convention is now valid on x86 too. 867This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace 868should not present interrupts to the guest as active-low unless this 869capability is present (or unless it is not using the in-kernel irqchip, 870of course). 871 872 873arm64 can signal an interrupt either at the CPU level, or at the 874in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to 875use PPIs designated for specific cpus. The irq field is interpreted 876like this:: 877 878 bits: | 31 ... 28 | 27 ... 24 | 23 ... 16 | 15 ... 0 | 879 field: | vcpu2_index | irq_type | vcpu_index | irq_id | 880 881The irq_type field has the following values: 882 883- irq_type[0]: 884 out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ 885- irq_type[1]: 886 in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.) 887 (the vcpu_index field is ignored) 888- irq_type[2]: 889 in-kernel GIC: PPI, irq_id between 16 and 31 (incl.) 890 891(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs) 892 893In both cases, level is used to assert/deassert the line. 894 895When KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 is supported, the target vcpu is 896identified as (256 * vcpu2_index + vcpu_index). Otherwise, vcpu2_index 897must be zero. 898 899Note that on arm64, the KVM_CAP_IRQCHIP capability only conditions 900injection of interrupts for the in-kernel irqchip. KVM_IRQ_LINE can always 901be used for a userspace interrupt controller. 902 903:: 904 905 struct kvm_irq_level { 906 union { 907 __u32 irq; /* GSI */ 908 __s32 status; /* not used for KVM_IRQ_LEVEL */ 909 }; 910 __u32 level; /* 0 or 1 */ 911 }; 912 913 9144.26 KVM_GET_IRQCHIP 915-------------------- 916 917:Capability: KVM_CAP_IRQCHIP 918:Architectures: x86 919:Type: vm ioctl 920:Parameters: struct kvm_irqchip (in/out) 921:Returns: 0 on success, -1 on error 922 923Reads the state of a kernel interrupt controller created with 924KVM_CREATE_IRQCHIP into a buffer provided by the caller. 925 926:: 927 928 struct kvm_irqchip { 929 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ 930 __u32 pad; 931 union { 932 char dummy[512]; /* reserving space */ 933 struct kvm_pic_state pic; 934 struct kvm_ioapic_state ioapic; 935 } chip; 936 }; 937 938 9394.27 KVM_SET_IRQCHIP 940-------------------- 941 942:Capability: KVM_CAP_IRQCHIP 943:Architectures: x86 944:Type: vm ioctl 945:Parameters: struct kvm_irqchip (in) 946:Returns: 0 on success, -1 on error 947 948Sets the state of a kernel interrupt controller created with 949KVM_CREATE_IRQCHIP from a buffer provided by the caller. 950 951:: 952 953 struct kvm_irqchip { 954 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ 955 __u32 pad; 956 union { 957 char dummy[512]; /* reserving space */ 958 struct kvm_pic_state pic; 959 struct kvm_ioapic_state ioapic; 960 } chip; 961 }; 962 963 9644.28 KVM_XEN_HVM_CONFIG 965----------------------- 966 967:Capability: KVM_CAP_XEN_HVM 968:Architectures: x86 969:Type: vm ioctl 970:Parameters: struct kvm_xen_hvm_config (in) 971:Returns: 0 on success, -1 on error 972 973Sets the MSR that the Xen HVM guest uses to initialize its hypercall 974page, and provides the starting address and size of the hypercall 975blobs in userspace. When the guest writes the MSR, kvm copies one 976page of a blob (32- or 64-bit, depending on the vcpu mode) to guest 977memory. 978 979:: 980 981 struct kvm_xen_hvm_config { 982 __u32 flags; 983 __u32 msr; 984 __u64 blob_addr_32; 985 __u64 blob_addr_64; 986 __u8 blob_size_32; 987 __u8 blob_size_64; 988 __u8 pad2[30]; 989 }; 990 991If the KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag is returned from the 992KVM_CAP_XEN_HVM check, it may be set in the flags field of this ioctl. 993This requests KVM to generate the contents of the hypercall page 994automatically; hypercalls will be intercepted and passed to userspace 995through KVM_EXIT_XEN. In this case, all of the blob size and address 996fields must be zero. 997 998No other flags are currently valid in the struct kvm_xen_hvm_config. 999 10004.29 KVM_GET_CLOCK 1001------------------ 1002 1003:Capability: KVM_CAP_ADJUST_CLOCK 1004:Architectures: x86 1005:Type: vm ioctl 1006:Parameters: struct kvm_clock_data (out) 1007:Returns: 0 on success, -1 on error 1008 1009Gets the current timestamp of kvmclock as seen by the current guest. In 1010conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios 1011such as migration. 1012 1013When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the 1014set of bits that KVM can return in struct kvm_clock_data's flag member. 1015 1016The following flags are defined: 1017 1018KVM_CLOCK_TSC_STABLE 1019 If set, the returned value is the exact kvmclock 1020 value seen by all VCPUs at the instant when KVM_GET_CLOCK was called. 1021 If clear, the returned value is simply CLOCK_MONOTONIC plus a constant 1022 offset; the offset can be modified with KVM_SET_CLOCK. KVM will try 1023 to make all VCPUs follow this clock, but the exact value read by each 1024 VCPU could differ, because the host TSC is not stable. 1025 1026KVM_CLOCK_REALTIME 1027 If set, the `realtime` field in the kvm_clock_data 1028 structure is populated with the value of the host's real time 1029 clocksource at the instant when KVM_GET_CLOCK was called. If clear, 1030 the `realtime` field does not contain a value. 1031 1032KVM_CLOCK_HOST_TSC 1033 If set, the `host_tsc` field in the kvm_clock_data 1034 structure is populated with the value of the host's timestamp counter (TSC) 1035 at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field 1036 does not contain a value. 1037 1038:: 1039 1040 struct kvm_clock_data { 1041 __u64 clock; /* kvmclock current value */ 1042 __u32 flags; 1043 __u32 pad0; 1044 __u64 realtime; 1045 __u64 host_tsc; 1046 __u32 pad[4]; 1047 }; 1048 1049 10504.30 KVM_SET_CLOCK 1051------------------ 1052 1053:Capability: KVM_CAP_ADJUST_CLOCK 1054:Architectures: x86 1055:Type: vm ioctl 1056:Parameters: struct kvm_clock_data (in) 1057:Returns: 0 on success, -1 on error 1058 1059Sets the current timestamp of kvmclock to the value specified in its parameter. 1060In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios 1061such as migration. 1062 1063The following flags can be passed: 1064 1065KVM_CLOCK_REALTIME 1066 If set, KVM will compare the value of the `realtime` field 1067 with the value of the host's real time clocksource at the instant when 1068 KVM_SET_CLOCK was called. The difference in elapsed time is added to the final 1069 kvmclock value that will be provided to guests. 1070 1071Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored. 1072 1073:: 1074 1075 struct kvm_clock_data { 1076 __u64 clock; /* kvmclock current value */ 1077 __u32 flags; 1078 __u32 pad0; 1079 __u64 realtime; 1080 __u64 host_tsc; 1081 __u32 pad[4]; 1082 }; 1083 1084 10854.31 KVM_GET_VCPU_EVENTS 1086------------------------ 1087 1088:Capability: KVM_CAP_VCPU_EVENTS 1089:Extended by: KVM_CAP_INTR_SHADOW 1090:Architectures: x86, arm64 1091:Type: vcpu ioctl 1092:Parameters: struct kvm_vcpu_event (out) 1093:Returns: 0 on success, -1 on error 1094 1095X86: 1096^^^^ 1097 1098Gets currently pending exceptions, interrupts, and NMIs as well as related 1099states of the vcpu. 1100 1101:: 1102 1103 struct kvm_vcpu_events { 1104 struct { 1105 __u8 injected; 1106 __u8 nr; 1107 __u8 has_error_code; 1108 __u8 pending; 1109 __u32 error_code; 1110 } exception; 1111 struct { 1112 __u8 injected; 1113 __u8 nr; 1114 __u8 soft; 1115 __u8 shadow; 1116 } interrupt; 1117 struct { 1118 __u8 injected; 1119 __u8 pending; 1120 __u8 masked; 1121 __u8 pad; 1122 } nmi; 1123 __u32 sipi_vector; 1124 __u32 flags; 1125 struct { 1126 __u8 smm; 1127 __u8 pending; 1128 __u8 smm_inside_nmi; 1129 __u8 latched_init; 1130 } smi; 1131 __u8 reserved[27]; 1132 __u8 exception_has_payload; 1133 __u64 exception_payload; 1134 }; 1135 1136The following bits are defined in the flags field: 1137 1138- KVM_VCPUEVENT_VALID_SHADOW may be set to signal that 1139 interrupt.shadow contains a valid state. 1140 1141- KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a 1142 valid state. 1143 1144- KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the 1145 exception_has_payload, exception_payload, and exception.pending 1146 fields contain a valid state. This bit will be set whenever 1147 KVM_CAP_EXCEPTION_PAYLOAD is enabled. 1148 1149ARM64: 1150^^^^^^ 1151 1152If the guest accesses a device that is being emulated by the host kernel in 1153such a way that a real device would generate a physical SError, KVM may make 1154a virtual SError pending for that VCPU. This system error interrupt remains 1155pending until the guest takes the exception by unmasking PSTATE.A. 1156 1157Running the VCPU may cause it to take a pending SError, or make an access that 1158causes an SError to become pending. The event's description is only valid while 1159the VPCU is not running. 1160 1161This API provides a way to read and write the pending 'event' state that is not 1162visible to the guest. To save, restore or migrate a VCPU the struct representing 1163the state can be read then written using this GET/SET API, along with the other 1164guest-visible registers. It is not possible to 'cancel' an SError that has been 1165made pending. 1166 1167A device being emulated in user-space may also wish to generate an SError. To do 1168this the events structure can be populated by user-space. The current state 1169should be read first, to ensure no existing SError is pending. If an existing 1170SError is pending, the architecture's 'Multiple SError interrupts' rules should 1171be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and 1172Serviceability (RAS) Specification"). 1173 1174SError exceptions always have an ESR value. Some CPUs have the ability to 1175specify what the virtual SError's ESR value should be. These systems will 1176advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will 1177always have a non-zero value when read, and the agent making an SError pending 1178should specify the ISS field in the lower 24 bits of exception.serror_esr. If 1179the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events 1180with exception.has_esr as zero, KVM will choose an ESR. 1181 1182Specifying exception.has_esr on a system that does not support it will return 1183-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr 1184will return -EINVAL. 1185 1186It is not possible to read back a pending external abort (injected via 1187KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered 1188directly to the virtual CPU). 1189 1190:: 1191 1192 struct kvm_vcpu_events { 1193 struct { 1194 __u8 serror_pending; 1195 __u8 serror_has_esr; 1196 __u8 ext_dabt_pending; 1197 /* Align it to 8 bytes */ 1198 __u8 pad[5]; 1199 __u64 serror_esr; 1200 } exception; 1201 __u32 reserved[12]; 1202 }; 1203 12044.32 KVM_SET_VCPU_EVENTS 1205------------------------ 1206 1207:Capability: KVM_CAP_VCPU_EVENTS 1208:Extended by: KVM_CAP_INTR_SHADOW 1209:Architectures: x86, arm64 1210:Type: vcpu ioctl 1211:Parameters: struct kvm_vcpu_event (in) 1212:Returns: 0 on success, -1 on error 1213 1214X86: 1215^^^^ 1216 1217Set pending exceptions, interrupts, and NMIs as well as related states of the 1218vcpu. 1219 1220See KVM_GET_VCPU_EVENTS for the data structure. 1221 1222Fields that may be modified asynchronously by running VCPUs can be excluded 1223from the update. These fields are nmi.pending, sipi_vector, smi.smm, 1224smi.pending. Keep the corresponding bits in the flags field cleared to 1225suppress overwriting the current in-kernel state. The bits are: 1226 1227=============================== ================================== 1228KVM_VCPUEVENT_VALID_NMI_PENDING transfer nmi.pending to the kernel 1229KVM_VCPUEVENT_VALID_SIPI_VECTOR transfer sipi_vector 1230KVM_VCPUEVENT_VALID_SMM transfer the smi sub-struct. 1231=============================== ================================== 1232 1233If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in 1234the flags field to signal that interrupt.shadow contains a valid state and 1235shall be written into the VCPU. 1236 1237KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. 1238 1239If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD 1240can be set in the flags field to signal that the 1241exception_has_payload, exception_payload, and exception.pending fields 1242contain a valid state and shall be written into the VCPU. 1243 1244ARM64: 1245^^^^^^ 1246 1247User space may need to inject several types of events to the guest. 1248 1249Set the pending SError exception state for this VCPU. It is not possible to 1250'cancel' an Serror that has been made pending. 1251 1252If the guest performed an access to I/O memory which could not be handled by 1253userspace, for example because of missing instruction syndrome decode 1254information or because there is no device mapped at the accessed IPA, then 1255userspace can ask the kernel to inject an external abort using the address 1256from the exiting fault on the VCPU. It is a programming error to set 1257ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or 1258KVM_EXIT_ARM_NISV. This feature is only available if the system supports 1259KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in 1260how userspace reports accesses for the above cases to guests, across different 1261userspace implementations. Nevertheless, userspace can still emulate all Arm 1262exceptions by manipulating individual registers using the KVM_SET_ONE_REG API. 1263 1264See KVM_GET_VCPU_EVENTS for the data structure. 1265 1266 12674.33 KVM_GET_DEBUGREGS 1268---------------------- 1269 1270:Capability: KVM_CAP_DEBUGREGS 1271:Architectures: x86 1272:Type: vm ioctl 1273:Parameters: struct kvm_debugregs (out) 1274:Returns: 0 on success, -1 on error 1275 1276Reads debug registers from the vcpu. 1277 1278:: 1279 1280 struct kvm_debugregs { 1281 __u64 db[4]; 1282 __u64 dr6; 1283 __u64 dr7; 1284 __u64 flags; 1285 __u64 reserved[9]; 1286 }; 1287 1288 12894.34 KVM_SET_DEBUGREGS 1290---------------------- 1291 1292:Capability: KVM_CAP_DEBUGREGS 1293:Architectures: x86 1294:Type: vm ioctl 1295:Parameters: struct kvm_debugregs (in) 1296:Returns: 0 on success, -1 on error 1297 1298Writes debug registers into the vcpu. 1299 1300See KVM_GET_DEBUGREGS for the data structure. The flags field is unused 1301yet and must be cleared on entry. 1302 1303 13044.35 KVM_SET_USER_MEMORY_REGION 1305------------------------------- 1306 1307:Capability: KVM_CAP_USER_MEMORY 1308:Architectures: all 1309:Type: vm ioctl 1310:Parameters: struct kvm_userspace_memory_region (in) 1311:Returns: 0 on success, -1 on error 1312 1313:: 1314 1315 struct kvm_userspace_memory_region { 1316 __u32 slot; 1317 __u32 flags; 1318 __u64 guest_phys_addr; 1319 __u64 memory_size; /* bytes */ 1320 __u64 userspace_addr; /* start of the userspace allocated memory */ 1321 }; 1322 1323 /* for kvm_memory_region::flags */ 1324 #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) 1325 #define KVM_MEM_READONLY (1UL << 1) 1326 1327This ioctl allows the user to create, modify or delete a guest physical 1328memory slot. Bits 0-15 of "slot" specify the slot id and this value 1329should be less than the maximum number of user memory slots supported per 1330VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS. 1331Slots may not overlap in guest physical address space. 1332 1333If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot" 1334specifies the address space which is being modified. They must be 1335less than the value that KVM_CHECK_EXTENSION returns for the 1336KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces 1337are unrelated; the restriction on overlapping slots only applies within 1338each address space. 1339 1340Deleting a slot is done by passing zero for memory_size. When changing 1341an existing slot, it may be moved in the guest physical memory space, 1342or its flags may be modified, but it may not be resized. 1343 1344Memory for the region is taken starting at the address denoted by the 1345field userspace_addr, which must point at user addressable memory for 1346the entire memory slot size. Any object may back this memory, including 1347anonymous memory, ordinary files, and hugetlbfs. 1348 1349On architectures that support a form of address tagging, userspace_addr must 1350be an untagged address. 1351 1352It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr 1353be identical. This allows large pages in the guest to be backed by large 1354pages in the host. 1355 1356The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and 1357KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of 1358writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to 1359use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it, 1360to make a new slot read-only. In this case, writes to this memory will be 1361posted to userspace as KVM_EXIT_MMIO exits. 1362 1363When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of 1364the memory region are automatically reflected into the guest. For example, an 1365mmap() that affects the region will be made visible immediately. Another 1366example is madvise(MADV_DROP). 1367 1368It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl. 1369The KVM_SET_MEMORY_REGION does not allow fine grained control over memory 1370allocation and is deprecated. 1371 1372 13734.36 KVM_SET_TSS_ADDR 1374--------------------- 1375 1376:Capability: KVM_CAP_SET_TSS_ADDR 1377:Architectures: x86 1378:Type: vm ioctl 1379:Parameters: unsigned long tss_address (in) 1380:Returns: 0 on success, -1 on error 1381 1382This ioctl defines the physical address of a three-page region in the guest 1383physical address space. The region must be within the first 4GB of the 1384guest physical address space and must not conflict with any memory slot 1385or any mmio address. The guest may malfunction if it accesses this memory 1386region. 1387 1388This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1389because of a quirk in the virtualization implementation (see the internals 1390documentation when it pops into existence). 1391 1392 13934.37 KVM_ENABLE_CAP 1394------------------- 1395 1396:Capability: KVM_CAP_ENABLE_CAP 1397:Architectures: mips, ppc, s390, x86 1398:Type: vcpu ioctl 1399:Parameters: struct kvm_enable_cap (in) 1400:Returns: 0 on success; -1 on error 1401 1402:Capability: KVM_CAP_ENABLE_CAP_VM 1403:Architectures: all 1404:Type: vm ioctl 1405:Parameters: struct kvm_enable_cap (in) 1406:Returns: 0 on success; -1 on error 1407 1408.. note:: 1409 1410 Not all extensions are enabled by default. Using this ioctl the application 1411 can enable an extension, making it available to the guest. 1412 1413On systems that do not support this ioctl, it always fails. On systems that 1414do support it, it only works for extensions that are supported for enablement. 1415 1416To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should 1417be used. 1418 1419:: 1420 1421 struct kvm_enable_cap { 1422 /* in */ 1423 __u32 cap; 1424 1425The capability that is supposed to get enabled. 1426 1427:: 1428 1429 __u32 flags; 1430 1431A bitfield indicating future enhancements. Has to be 0 for now. 1432 1433:: 1434 1435 __u64 args[4]; 1436 1437Arguments for enabling a feature. If a feature needs initial values to 1438function properly, this is the place to put them. 1439 1440:: 1441 1442 __u8 pad[64]; 1443 }; 1444 1445The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl 1446for vm-wide capabilities. 1447 14484.38 KVM_GET_MP_STATE 1449--------------------- 1450 1451:Capability: KVM_CAP_MP_STATE 1452:Architectures: x86, s390, arm64, riscv 1453:Type: vcpu ioctl 1454:Parameters: struct kvm_mp_state (out) 1455:Returns: 0 on success; -1 on error 1456 1457:: 1458 1459 struct kvm_mp_state { 1460 __u32 mp_state; 1461 }; 1462 1463Returns the vcpu's current "multiprocessing state" (though also valid on 1464uniprocessor guests). 1465 1466Possible values are: 1467 1468 ========================== =============================================== 1469 KVM_MP_STATE_RUNNABLE the vcpu is currently running 1470 [x86,arm64,riscv] 1471 KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP) 1472 which has not yet received an INIT signal [x86] 1473 KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is 1474 now ready for a SIPI [x86] 1475 KVM_MP_STATE_HALTED the vcpu has executed a HLT instruction and 1476 is waiting for an interrupt [x86] 1477 KVM_MP_STATE_SIPI_RECEIVED the vcpu has just received a SIPI (vector 1478 accessible via KVM_GET_VCPU_EVENTS) [x86] 1479 KVM_MP_STATE_STOPPED the vcpu is stopped [s390,arm64,riscv] 1480 KVM_MP_STATE_CHECK_STOP the vcpu is in a special error state [s390] 1481 KVM_MP_STATE_OPERATING the vcpu is operating (running or halted) 1482 [s390] 1483 KVM_MP_STATE_LOAD the vcpu is in a special load/startup state 1484 [s390] 1485 ========================== =============================================== 1486 1487On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1488in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1489these architectures. 1490 1491For arm64/riscv: 1492^^^^^^^^^^^^^^^^ 1493 1494The only states that are valid are KVM_MP_STATE_STOPPED and 1495KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not. 1496 14974.39 KVM_SET_MP_STATE 1498--------------------- 1499 1500:Capability: KVM_CAP_MP_STATE 1501:Architectures: x86, s390, arm64, riscv 1502:Type: vcpu ioctl 1503:Parameters: struct kvm_mp_state (in) 1504:Returns: 0 on success; -1 on error 1505 1506Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for 1507arguments. 1508 1509On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1510in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1511these architectures. 1512 1513For arm64/riscv: 1514^^^^^^^^^^^^^^^^ 1515 1516The only states that are valid are KVM_MP_STATE_STOPPED and 1517KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not. 1518 15194.40 KVM_SET_IDENTITY_MAP_ADDR 1520------------------------------ 1521 1522:Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR 1523:Architectures: x86 1524:Type: vm ioctl 1525:Parameters: unsigned long identity (in) 1526:Returns: 0 on success, -1 on error 1527 1528This ioctl defines the physical address of a one-page region in the guest 1529physical address space. The region must be within the first 4GB of the 1530guest physical address space and must not conflict with any memory slot 1531or any mmio address. The guest may malfunction if it accesses this memory 1532region. 1533 1534Setting the address to 0 will result in resetting the address to its default 1535(0xfffbc000). 1536 1537This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1538because of a quirk in the virtualization implementation (see the internals 1539documentation when it pops into existence). 1540 1541Fails if any VCPU has already been created. 1542 15434.41 KVM_SET_BOOT_CPU_ID 1544------------------------ 1545 1546:Capability: KVM_CAP_SET_BOOT_CPU_ID 1547:Architectures: x86 1548:Type: vm ioctl 1549:Parameters: unsigned long vcpu_id 1550:Returns: 0 on success, -1 on error 1551 1552Define which vcpu is the Bootstrap Processor (BSP). Values are the same 1553as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default 1554is vcpu 0. This ioctl has to be called before vcpu creation, 1555otherwise it will return EBUSY error. 1556 1557 15584.42 KVM_GET_XSAVE 1559------------------ 1560 1561:Capability: KVM_CAP_XSAVE 1562:Architectures: x86 1563:Type: vcpu ioctl 1564:Parameters: struct kvm_xsave (out) 1565:Returns: 0 on success, -1 on error 1566 1567 1568:: 1569 1570 struct kvm_xsave { 1571 __u32 region[1024]; 1572 __u32 extra[0]; 1573 }; 1574 1575This ioctl would copy current vcpu's xsave struct to the userspace. 1576 1577 15784.43 KVM_SET_XSAVE 1579------------------ 1580 1581:Capability: KVM_CAP_XSAVE and KVM_CAP_XSAVE2 1582:Architectures: x86 1583:Type: vcpu ioctl 1584:Parameters: struct kvm_xsave (in) 1585:Returns: 0 on success, -1 on error 1586 1587:: 1588 1589 1590 struct kvm_xsave { 1591 __u32 region[1024]; 1592 __u32 extra[0]; 1593 }; 1594 1595This ioctl would copy userspace's xsave struct to the kernel. It copies 1596as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2), 1597when invoked on the vm file descriptor. The size value returned by 1598KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 1599Currently, it is only greater than 4096 if a dynamic feature has been 1600enabled with ``arch_prctl()``, but this may change in the future. 1601 1602The offsets of the state save areas in struct kvm_xsave follow the 1603contents of CPUID leaf 0xD on the host. 1604 1605 16064.44 KVM_GET_XCRS 1607----------------- 1608 1609:Capability: KVM_CAP_XCRS 1610:Architectures: x86 1611:Type: vcpu ioctl 1612:Parameters: struct kvm_xcrs (out) 1613:Returns: 0 on success, -1 on error 1614 1615:: 1616 1617 struct kvm_xcr { 1618 __u32 xcr; 1619 __u32 reserved; 1620 __u64 value; 1621 }; 1622 1623 struct kvm_xcrs { 1624 __u32 nr_xcrs; 1625 __u32 flags; 1626 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1627 __u64 padding[16]; 1628 }; 1629 1630This ioctl would copy current vcpu's xcrs to the userspace. 1631 1632 16334.45 KVM_SET_XCRS 1634----------------- 1635 1636:Capability: KVM_CAP_XCRS 1637:Architectures: x86 1638:Type: vcpu ioctl 1639:Parameters: struct kvm_xcrs (in) 1640:Returns: 0 on success, -1 on error 1641 1642:: 1643 1644 struct kvm_xcr { 1645 __u32 xcr; 1646 __u32 reserved; 1647 __u64 value; 1648 }; 1649 1650 struct kvm_xcrs { 1651 __u32 nr_xcrs; 1652 __u32 flags; 1653 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1654 __u64 padding[16]; 1655 }; 1656 1657This ioctl would set vcpu's xcr to the value userspace specified. 1658 1659 16604.46 KVM_GET_SUPPORTED_CPUID 1661---------------------------- 1662 1663:Capability: KVM_CAP_EXT_CPUID 1664:Architectures: x86 1665:Type: system ioctl 1666:Parameters: struct kvm_cpuid2 (in/out) 1667:Returns: 0 on success, -1 on error 1668 1669:: 1670 1671 struct kvm_cpuid2 { 1672 __u32 nent; 1673 __u32 padding; 1674 struct kvm_cpuid_entry2 entries[0]; 1675 }; 1676 1677 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 1678 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 1679 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 1680 1681 struct kvm_cpuid_entry2 { 1682 __u32 function; 1683 __u32 index; 1684 __u32 flags; 1685 __u32 eax; 1686 __u32 ebx; 1687 __u32 ecx; 1688 __u32 edx; 1689 __u32 padding[3]; 1690 }; 1691 1692This ioctl returns x86 cpuid features which are supported by both the 1693hardware and kvm in its default configuration. Userspace can use the 1694information returned by this ioctl to construct cpuid information (for 1695KVM_SET_CPUID2) that is consistent with hardware, kernel, and 1696userspace capabilities, and with user requirements (for example, the 1697user may wish to constrain cpuid to emulate older hardware, or for 1698feature consistency across a cluster). 1699 1700Dynamically-enabled feature bits need to be requested with 1701``arch_prctl()`` before calling this ioctl. Feature bits that have not 1702been requested are excluded from the result. 1703 1704Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may 1705expose cpuid features (e.g. MONITOR) which are not supported by kvm in 1706its default configuration. If userspace enables such capabilities, it 1707is responsible for modifying the results of this ioctl appropriately. 1708 1709Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure 1710with the 'nent' field indicating the number of entries in the variable-size 1711array 'entries'. If the number of entries is too low to describe the cpu 1712capabilities, an error (E2BIG) is returned. If the number is too high, 1713the 'nent' field is adjusted and an error (ENOMEM) is returned. If the 1714number is just right, the 'nent' field is adjusted to the number of valid 1715entries in the 'entries' array, which is then filled. 1716 1717The entries returned are the host cpuid as returned by the cpuid instruction, 1718with unknown or unsupported features masked out. Some features (for example, 1719x2apic), may not be present in the host cpu, but are exposed by kvm if it can 1720emulate them efficiently. The fields in each entry are defined as follows: 1721 1722 function: 1723 the eax value used to obtain the entry 1724 1725 index: 1726 the ecx value used to obtain the entry (for entries that are 1727 affected by ecx) 1728 1729 flags: 1730 an OR of zero or more of the following: 1731 1732 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 1733 if the index field is valid 1734 1735 eax, ebx, ecx, edx: 1736 the values returned by the cpuid instruction for 1737 this function/index combination 1738 1739The TSC deadline timer feature (CPUID leaf 1, ecx[24]) is always returned 1740as false, since the feature depends on KVM_CREATE_IRQCHIP for local APIC 1741support. Instead it is reported via:: 1742 1743 ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER) 1744 1745if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the 1746feature in userspace, then you can enable the feature for KVM_SET_CPUID2. 1747 1748 17494.47 KVM_PPC_GET_PVINFO 1750----------------------- 1751 1752:Capability: KVM_CAP_PPC_GET_PVINFO 1753:Architectures: ppc 1754:Type: vm ioctl 1755:Parameters: struct kvm_ppc_pvinfo (out) 1756:Returns: 0 on success, !0 on error 1757 1758:: 1759 1760 struct kvm_ppc_pvinfo { 1761 __u32 flags; 1762 __u32 hcall[4]; 1763 __u8 pad[108]; 1764 }; 1765 1766This ioctl fetches PV specific information that need to be passed to the guest 1767using the device tree or other means from vm context. 1768 1769The hcall array defines 4 instructions that make up a hypercall. 1770 1771If any additional field gets added to this structure later on, a bit for that 1772additional piece of information will be set in the flags bitmap. 1773 1774The flags bitmap is defined as:: 1775 1776 /* the host supports the ePAPR idle hcall 1777 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0) 1778 17794.52 KVM_SET_GSI_ROUTING 1780------------------------ 1781 1782:Capability: KVM_CAP_IRQ_ROUTING 1783:Architectures: x86 s390 arm64 1784:Type: vm ioctl 1785:Parameters: struct kvm_irq_routing (in) 1786:Returns: 0 on success, -1 on error 1787 1788Sets the GSI routing table entries, overwriting any previously set entries. 1789 1790On arm64, GSI routing has the following limitation: 1791 1792- GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD. 1793 1794:: 1795 1796 struct kvm_irq_routing { 1797 __u32 nr; 1798 __u32 flags; 1799 struct kvm_irq_routing_entry entries[0]; 1800 }; 1801 1802No flags are specified so far, the corresponding field must be set to zero. 1803 1804:: 1805 1806 struct kvm_irq_routing_entry { 1807 __u32 gsi; 1808 __u32 type; 1809 __u32 flags; 1810 __u32 pad; 1811 union { 1812 struct kvm_irq_routing_irqchip irqchip; 1813 struct kvm_irq_routing_msi msi; 1814 struct kvm_irq_routing_s390_adapter adapter; 1815 struct kvm_irq_routing_hv_sint hv_sint; 1816 struct kvm_irq_routing_xen_evtchn xen_evtchn; 1817 __u32 pad[8]; 1818 } u; 1819 }; 1820 1821 /* gsi routing entry types */ 1822 #define KVM_IRQ_ROUTING_IRQCHIP 1 1823 #define KVM_IRQ_ROUTING_MSI 2 1824 #define KVM_IRQ_ROUTING_S390_ADAPTER 3 1825 #define KVM_IRQ_ROUTING_HV_SINT 4 1826 #define KVM_IRQ_ROUTING_XEN_EVTCHN 5 1827 1828flags: 1829 1830- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry 1831 type, specifies that the devid field contains a valid value. The per-VM 1832 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 1833 the device ID. If this capability is not available, userspace should 1834 never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 1835- zero otherwise 1836 1837:: 1838 1839 struct kvm_irq_routing_irqchip { 1840 __u32 irqchip; 1841 __u32 pin; 1842 }; 1843 1844 struct kvm_irq_routing_msi { 1845 __u32 address_lo; 1846 __u32 address_hi; 1847 __u32 data; 1848 union { 1849 __u32 pad; 1850 __u32 devid; 1851 }; 1852 }; 1853 1854If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 1855for the device that wrote the MSI message. For PCI, this is usually a 1856BFD identifier in the lower 16 bits. 1857 1858On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 1859feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 1860address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 1861address_hi must be zero. 1862 1863:: 1864 1865 struct kvm_irq_routing_s390_adapter { 1866 __u64 ind_addr; 1867 __u64 summary_addr; 1868 __u64 ind_offset; 1869 __u32 summary_offset; 1870 __u32 adapter_id; 1871 }; 1872 1873 struct kvm_irq_routing_hv_sint { 1874 __u32 vcpu; 1875 __u32 sint; 1876 }; 1877 1878 struct kvm_irq_routing_xen_evtchn { 1879 __u32 port; 1880 __u32 vcpu; 1881 __u32 priority; 1882 }; 1883 1884 1885When KVM_CAP_XEN_HVM includes the KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL bit 1886in its indication of supported features, routing to Xen event channels 1887is supported. Although the priority field is present, only the value 1888KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL is supported, which means delivery by 18892 level event channels. FIFO event channel support may be added in 1890the future. 1891 1892 18934.55 KVM_SET_TSC_KHZ 1894-------------------- 1895 1896:Capability: KVM_CAP_TSC_CONTROL 1897:Architectures: x86 1898:Type: vcpu ioctl 1899:Parameters: virtual tsc_khz 1900:Returns: 0 on success, -1 on error 1901 1902Specifies the tsc frequency for the virtual machine. The unit of the 1903frequency is KHz. 1904 1905 19064.56 KVM_GET_TSC_KHZ 1907-------------------- 1908 1909:Capability: KVM_CAP_GET_TSC_KHZ 1910:Architectures: x86 1911:Type: vcpu ioctl 1912:Parameters: none 1913:Returns: virtual tsc-khz on success, negative value on error 1914 1915Returns the tsc frequency of the guest. The unit of the return value is 1916KHz. If the host has unstable tsc this ioctl returns -EIO instead as an 1917error. 1918 1919 19204.57 KVM_GET_LAPIC 1921------------------ 1922 1923:Capability: KVM_CAP_IRQCHIP 1924:Architectures: x86 1925:Type: vcpu ioctl 1926:Parameters: struct kvm_lapic_state (out) 1927:Returns: 0 on success, -1 on error 1928 1929:: 1930 1931 #define KVM_APIC_REG_SIZE 0x400 1932 struct kvm_lapic_state { 1933 char regs[KVM_APIC_REG_SIZE]; 1934 }; 1935 1936Reads the Local APIC registers and copies them into the input argument. The 1937data format and layout are the same as documented in the architecture manual. 1938 1939If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is 1940enabled, then the format of APIC_ID register depends on the APIC mode 1941(reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in 1942the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID 1943which is stored in bits 31-24 of the APIC register, or equivalently in 1944byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then 1945be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR. 1946 1947If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state 1948always uses xAPIC format. 1949 1950 19514.58 KVM_SET_LAPIC 1952------------------ 1953 1954:Capability: KVM_CAP_IRQCHIP 1955:Architectures: x86 1956:Type: vcpu ioctl 1957:Parameters: struct kvm_lapic_state (in) 1958:Returns: 0 on success, -1 on error 1959 1960:: 1961 1962 #define KVM_APIC_REG_SIZE 0x400 1963 struct kvm_lapic_state { 1964 char regs[KVM_APIC_REG_SIZE]; 1965 }; 1966 1967Copies the input argument into the Local APIC registers. The data format 1968and layout are the same as documented in the architecture manual. 1969 1970The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's 1971regs field) depends on the state of the KVM_CAP_X2APIC_API capability. 1972See the note in KVM_GET_LAPIC. 1973 1974 19754.59 KVM_IOEVENTFD 1976------------------ 1977 1978:Capability: KVM_CAP_IOEVENTFD 1979:Architectures: all 1980:Type: vm ioctl 1981:Parameters: struct kvm_ioeventfd (in) 1982:Returns: 0 on success, !0 on error 1983 1984This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address 1985within the guest. A guest write in the registered address will signal the 1986provided event instead of triggering an exit. 1987 1988:: 1989 1990 struct kvm_ioeventfd { 1991 __u64 datamatch; 1992 __u64 addr; /* legal pio/mmio address */ 1993 __u32 len; /* 0, 1, 2, 4, or 8 bytes */ 1994 __s32 fd; 1995 __u32 flags; 1996 __u8 pad[36]; 1997 }; 1998 1999For the special case of virtio-ccw devices on s390, the ioevent is matched 2000to a subchannel/virtqueue tuple instead. 2001 2002The following flags are defined:: 2003 2004 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) 2005 #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) 2006 #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) 2007 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \ 2008 (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify) 2009 2010If datamatch flag is set, the event will be signaled only if the written value 2011to the registered address is equal to datamatch in struct kvm_ioeventfd. 2012 2013For virtio-ccw devices, addr contains the subchannel id and datamatch the 2014virtqueue index. 2015 2016With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and 2017the kernel will ignore the length of guest write and may get a faster vmexit. 2018The speedup may only apply to specific architectures, but the ioeventfd will 2019work anyway. 2020 20214.60 KVM_DIRTY_TLB 2022------------------ 2023 2024:Capability: KVM_CAP_SW_TLB 2025:Architectures: ppc 2026:Type: vcpu ioctl 2027:Parameters: struct kvm_dirty_tlb (in) 2028:Returns: 0 on success, -1 on error 2029 2030:: 2031 2032 struct kvm_dirty_tlb { 2033 __u64 bitmap; 2034 __u32 num_dirty; 2035 }; 2036 2037This must be called whenever userspace has changed an entry in the shared 2038TLB, prior to calling KVM_RUN on the associated vcpu. 2039 2040The "bitmap" field is the userspace address of an array. This array 2041consists of a number of bits, equal to the total number of TLB entries as 2042determined by the last successful call to KVM_CONFIG_TLB, rounded up to the 2043nearest multiple of 64. 2044 2045Each bit corresponds to one TLB entry, ordered the same as in the shared TLB 2046array. 2047 2048The array is little-endian: the bit 0 is the least significant bit of the 2049first byte, bit 8 is the least significant bit of the second byte, etc. 2050This avoids any complications with differing word sizes. 2051 2052The "num_dirty" field is a performance hint for KVM to determine whether it 2053should skip processing the bitmap and just invalidate everything. It must 2054be set to the number of set bits in the bitmap. 2055 2056 20574.62 KVM_CREATE_SPAPR_TCE 2058------------------------- 2059 2060:Capability: KVM_CAP_SPAPR_TCE 2061:Architectures: powerpc 2062:Type: vm ioctl 2063:Parameters: struct kvm_create_spapr_tce (in) 2064:Returns: file descriptor for manipulating the created TCE table 2065 2066This creates a virtual TCE (translation control entry) table, which 2067is an IOMMU for PAPR-style virtual I/O. It is used to translate 2068logical addresses used in virtual I/O into guest physical addresses, 2069and provides a scatter/gather capability for PAPR virtual I/O. 2070 2071:: 2072 2073 /* for KVM_CAP_SPAPR_TCE */ 2074 struct kvm_create_spapr_tce { 2075 __u64 liobn; 2076 __u32 window_size; 2077 }; 2078 2079The liobn field gives the logical IO bus number for which to create a 2080TCE table. The window_size field specifies the size of the DMA window 2081which this TCE table will translate - the table will contain one 64 2082bit TCE entry for every 4kiB of the DMA window. 2083 2084When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE 2085table has been created using this ioctl(), the kernel will handle it 2086in real mode, updating the TCE table. H_PUT_TCE calls for other 2087liobns will cause a vm exit and must be handled by userspace. 2088 2089The return value is a file descriptor which can be passed to mmap(2) 2090to map the created TCE table into userspace. This lets userspace read 2091the entries written by kernel-handled H_PUT_TCE calls, and also lets 2092userspace update the TCE table directly which is useful in some 2093circumstances. 2094 2095 20964.63 KVM_ALLOCATE_RMA 2097--------------------- 2098 2099:Capability: KVM_CAP_PPC_RMA 2100:Architectures: powerpc 2101:Type: vm ioctl 2102:Parameters: struct kvm_allocate_rma (out) 2103:Returns: file descriptor for mapping the allocated RMA 2104 2105This allocates a Real Mode Area (RMA) from the pool allocated at boot 2106time by the kernel. An RMA is a physically-contiguous, aligned region 2107of memory used on older POWER processors to provide the memory which 2108will be accessed by real-mode (MMU off) accesses in a KVM guest. 2109POWER processors support a set of sizes for the RMA that usually 2110includes 64MB, 128MB, 256MB and some larger powers of two. 2111 2112:: 2113 2114 /* for KVM_ALLOCATE_RMA */ 2115 struct kvm_allocate_rma { 2116 __u64 rma_size; 2117 }; 2118 2119The return value is a file descriptor which can be passed to mmap(2) 2120to map the allocated RMA into userspace. The mapped area can then be 2121passed to the KVM_SET_USER_MEMORY_REGION ioctl to establish it as the 2122RMA for a virtual machine. The size of the RMA in bytes (which is 2123fixed at host kernel boot time) is returned in the rma_size field of 2124the argument structure. 2125 2126The KVM_CAP_PPC_RMA capability is 1 or 2 if the KVM_ALLOCATE_RMA ioctl 2127is supported; 2 if the processor requires all virtual machines to have 2128an RMA, or 1 if the processor can use an RMA but doesn't require it, 2129because it supports the Virtual RMA (VRMA) facility. 2130 2131 21324.64 KVM_NMI 2133------------ 2134 2135:Capability: KVM_CAP_USER_NMI 2136:Architectures: x86 2137:Type: vcpu ioctl 2138:Parameters: none 2139:Returns: 0 on success, -1 on error 2140 2141Queues an NMI on the thread's vcpu. Note this is well defined only 2142when KVM_CREATE_IRQCHIP has not been called, since this is an interface 2143between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP 2144has been called, this interface is completely emulated within the kernel. 2145 2146To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the 2147following algorithm: 2148 2149 - pause the vcpu 2150 - read the local APIC's state (KVM_GET_LAPIC) 2151 - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1) 2152 - if so, issue KVM_NMI 2153 - resume the vcpu 2154 2155Some guests configure the LINT1 NMI input to cause a panic, aiding in 2156debugging. 2157 2158 21594.65 KVM_S390_UCAS_MAP 2160---------------------- 2161 2162:Capability: KVM_CAP_S390_UCONTROL 2163:Architectures: s390 2164:Type: vcpu ioctl 2165:Parameters: struct kvm_s390_ucas_mapping (in) 2166:Returns: 0 in case of success 2167 2168The parameter is defined like this:: 2169 2170 struct kvm_s390_ucas_mapping { 2171 __u64 user_addr; 2172 __u64 vcpu_addr; 2173 __u64 length; 2174 }; 2175 2176This ioctl maps the memory at "user_addr" with the length "length" to 2177the vcpu's address space starting at "vcpu_addr". All parameters need to 2178be aligned by 1 megabyte. 2179 2180 21814.66 KVM_S390_UCAS_UNMAP 2182------------------------ 2183 2184:Capability: KVM_CAP_S390_UCONTROL 2185:Architectures: s390 2186:Type: vcpu ioctl 2187:Parameters: struct kvm_s390_ucas_mapping (in) 2188:Returns: 0 in case of success 2189 2190The parameter is defined like this:: 2191 2192 struct kvm_s390_ucas_mapping { 2193 __u64 user_addr; 2194 __u64 vcpu_addr; 2195 __u64 length; 2196 }; 2197 2198This ioctl unmaps the memory in the vcpu's address space starting at 2199"vcpu_addr" with the length "length". The field "user_addr" is ignored. 2200All parameters need to be aligned by 1 megabyte. 2201 2202 22034.67 KVM_S390_VCPU_FAULT 2204------------------------ 2205 2206:Capability: KVM_CAP_S390_UCONTROL 2207:Architectures: s390 2208:Type: vcpu ioctl 2209:Parameters: vcpu absolute address (in) 2210:Returns: 0 in case of success 2211 2212This call creates a page table entry on the virtual cpu's address space 2213(for user controlled virtual machines) or the virtual machine's address 2214space (for regular virtual machines). This only works for minor faults, 2215thus it's recommended to access subject memory page via the user page 2216table upfront. This is useful to handle validity intercepts for user 2217controlled virtual machines to fault in the virtual cpu's lowcore pages 2218prior to calling the KVM_RUN ioctl. 2219 2220 22214.68 KVM_SET_ONE_REG 2222-------------------- 2223 2224:Capability: KVM_CAP_ONE_REG 2225:Architectures: all 2226:Type: vcpu ioctl 2227:Parameters: struct kvm_one_reg (in) 2228:Returns: 0 on success, negative value on failure 2229 2230Errors: 2231 2232 ====== ============================================================ 2233 ENOENT no such register 2234 EINVAL invalid register ID, or no such register or used with VMs in 2235 protected virtualization mode on s390 2236 EPERM (arm64) register access not allowed before vcpu finalization 2237 ====== ============================================================ 2238 2239(These error codes are indicative only: do not rely on a specific error 2240code being returned in a specific situation.) 2241 2242:: 2243 2244 struct kvm_one_reg { 2245 __u64 id; 2246 __u64 addr; 2247 }; 2248 2249Using this ioctl, a single vcpu register can be set to a specific value 2250defined by user space with the passed in struct kvm_one_reg, where id 2251refers to the register identifier as described below and addr is a pointer 2252to a variable with the respective size. There can be architecture agnostic 2253and architecture specific registers. Each have their own range of operation 2254and their own constants and width. To keep track of the implemented 2255registers, find a list below: 2256 2257 ======= =============================== ============ 2258 Arch Register Width (bits) 2259 ======= =============================== ============ 2260 PPC KVM_REG_PPC_HIOR 64 2261 PPC KVM_REG_PPC_IAC1 64 2262 PPC KVM_REG_PPC_IAC2 64 2263 PPC KVM_REG_PPC_IAC3 64 2264 PPC KVM_REG_PPC_IAC4 64 2265 PPC KVM_REG_PPC_DAC1 64 2266 PPC KVM_REG_PPC_DAC2 64 2267 PPC KVM_REG_PPC_DABR 64 2268 PPC KVM_REG_PPC_DSCR 64 2269 PPC KVM_REG_PPC_PURR 64 2270 PPC KVM_REG_PPC_SPURR 64 2271 PPC KVM_REG_PPC_DAR 64 2272 PPC KVM_REG_PPC_DSISR 32 2273 PPC KVM_REG_PPC_AMR 64 2274 PPC KVM_REG_PPC_UAMOR 64 2275 PPC KVM_REG_PPC_MMCR0 64 2276 PPC KVM_REG_PPC_MMCR1 64 2277 PPC KVM_REG_PPC_MMCRA 64 2278 PPC KVM_REG_PPC_MMCR2 64 2279 PPC KVM_REG_PPC_MMCRS 64 2280 PPC KVM_REG_PPC_MMCR3 64 2281 PPC KVM_REG_PPC_SIAR 64 2282 PPC KVM_REG_PPC_SDAR 64 2283 PPC KVM_REG_PPC_SIER 64 2284 PPC KVM_REG_PPC_SIER2 64 2285 PPC KVM_REG_PPC_SIER3 64 2286 PPC KVM_REG_PPC_PMC1 32 2287 PPC KVM_REG_PPC_PMC2 32 2288 PPC KVM_REG_PPC_PMC3 32 2289 PPC KVM_REG_PPC_PMC4 32 2290 PPC KVM_REG_PPC_PMC5 32 2291 PPC KVM_REG_PPC_PMC6 32 2292 PPC KVM_REG_PPC_PMC7 32 2293 PPC KVM_REG_PPC_PMC8 32 2294 PPC KVM_REG_PPC_FPR0 64 2295 ... 2296 PPC KVM_REG_PPC_FPR31 64 2297 PPC KVM_REG_PPC_VR0 128 2298 ... 2299 PPC KVM_REG_PPC_VR31 128 2300 PPC KVM_REG_PPC_VSR0 128 2301 ... 2302 PPC KVM_REG_PPC_VSR31 128 2303 PPC KVM_REG_PPC_FPSCR 64 2304 PPC KVM_REG_PPC_VSCR 32 2305 PPC KVM_REG_PPC_VPA_ADDR 64 2306 PPC KVM_REG_PPC_VPA_SLB 128 2307 PPC KVM_REG_PPC_VPA_DTL 128 2308 PPC KVM_REG_PPC_EPCR 32 2309 PPC KVM_REG_PPC_EPR 32 2310 PPC KVM_REG_PPC_TCR 32 2311 PPC KVM_REG_PPC_TSR 32 2312 PPC KVM_REG_PPC_OR_TSR 32 2313 PPC KVM_REG_PPC_CLEAR_TSR 32 2314 PPC KVM_REG_PPC_MAS0 32 2315 PPC KVM_REG_PPC_MAS1 32 2316 PPC KVM_REG_PPC_MAS2 64 2317 PPC KVM_REG_PPC_MAS7_3 64 2318 PPC KVM_REG_PPC_MAS4 32 2319 PPC KVM_REG_PPC_MAS6 32 2320 PPC KVM_REG_PPC_MMUCFG 32 2321 PPC KVM_REG_PPC_TLB0CFG 32 2322 PPC KVM_REG_PPC_TLB1CFG 32 2323 PPC KVM_REG_PPC_TLB2CFG 32 2324 PPC KVM_REG_PPC_TLB3CFG 32 2325 PPC KVM_REG_PPC_TLB0PS 32 2326 PPC KVM_REG_PPC_TLB1PS 32 2327 PPC KVM_REG_PPC_TLB2PS 32 2328 PPC KVM_REG_PPC_TLB3PS 32 2329 PPC KVM_REG_PPC_EPTCFG 32 2330 PPC KVM_REG_PPC_ICP_STATE 64 2331 PPC KVM_REG_PPC_VP_STATE 128 2332 PPC KVM_REG_PPC_TB_OFFSET 64 2333 PPC KVM_REG_PPC_SPMC1 32 2334 PPC KVM_REG_PPC_SPMC2 32 2335 PPC KVM_REG_PPC_IAMR 64 2336 PPC KVM_REG_PPC_TFHAR 64 2337 PPC KVM_REG_PPC_TFIAR 64 2338 PPC KVM_REG_PPC_TEXASR 64 2339 PPC KVM_REG_PPC_FSCR 64 2340 PPC KVM_REG_PPC_PSPB 32 2341 PPC KVM_REG_PPC_EBBHR 64 2342 PPC KVM_REG_PPC_EBBRR 64 2343 PPC KVM_REG_PPC_BESCR 64 2344 PPC KVM_REG_PPC_TAR 64 2345 PPC KVM_REG_PPC_DPDES 64 2346 PPC KVM_REG_PPC_DAWR 64 2347 PPC KVM_REG_PPC_DAWRX 64 2348 PPC KVM_REG_PPC_CIABR 64 2349 PPC KVM_REG_PPC_IC 64 2350 PPC KVM_REG_PPC_VTB 64 2351 PPC KVM_REG_PPC_CSIGR 64 2352 PPC KVM_REG_PPC_TACR 64 2353 PPC KVM_REG_PPC_TCSCR 64 2354 PPC KVM_REG_PPC_PID 64 2355 PPC KVM_REG_PPC_ACOP 64 2356 PPC KVM_REG_PPC_VRSAVE 32 2357 PPC KVM_REG_PPC_LPCR 32 2358 PPC KVM_REG_PPC_LPCR_64 64 2359 PPC KVM_REG_PPC_PPR 64 2360 PPC KVM_REG_PPC_ARCH_COMPAT 32 2361 PPC KVM_REG_PPC_DABRX 32 2362 PPC KVM_REG_PPC_WORT 64 2363 PPC KVM_REG_PPC_SPRG9 64 2364 PPC KVM_REG_PPC_DBSR 32 2365 PPC KVM_REG_PPC_TIDR 64 2366 PPC KVM_REG_PPC_PSSCR 64 2367 PPC KVM_REG_PPC_DEC_EXPIRY 64 2368 PPC KVM_REG_PPC_PTCR 64 2369 PPC KVM_REG_PPC_DAWR1 64 2370 PPC KVM_REG_PPC_DAWRX1 64 2371 PPC KVM_REG_PPC_TM_GPR0 64 2372 ... 2373 PPC KVM_REG_PPC_TM_GPR31 64 2374 PPC KVM_REG_PPC_TM_VSR0 128 2375 ... 2376 PPC KVM_REG_PPC_TM_VSR63 128 2377 PPC KVM_REG_PPC_TM_CR 64 2378 PPC KVM_REG_PPC_TM_LR 64 2379 PPC KVM_REG_PPC_TM_CTR 64 2380 PPC KVM_REG_PPC_TM_FPSCR 64 2381 PPC KVM_REG_PPC_TM_AMR 64 2382 PPC KVM_REG_PPC_TM_PPR 64 2383 PPC KVM_REG_PPC_TM_VRSAVE 64 2384 PPC KVM_REG_PPC_TM_VSCR 32 2385 PPC KVM_REG_PPC_TM_DSCR 64 2386 PPC KVM_REG_PPC_TM_TAR 64 2387 PPC KVM_REG_PPC_TM_XER 64 2388 2389 MIPS KVM_REG_MIPS_R0 64 2390 ... 2391 MIPS KVM_REG_MIPS_R31 64 2392 MIPS KVM_REG_MIPS_HI 64 2393 MIPS KVM_REG_MIPS_LO 64 2394 MIPS KVM_REG_MIPS_PC 64 2395 MIPS KVM_REG_MIPS_CP0_INDEX 32 2396 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64 2397 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64 2398 MIPS KVM_REG_MIPS_CP0_CONTEXT 64 2399 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32 2400 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64 2401 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64 2402 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32 2403 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32 2404 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64 2405 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64 2406 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64 2407 MIPS KVM_REG_MIPS_CP0_PWBASE 64 2408 MIPS KVM_REG_MIPS_CP0_PWFIELD 64 2409 MIPS KVM_REG_MIPS_CP0_PWSIZE 64 2410 MIPS KVM_REG_MIPS_CP0_WIRED 32 2411 MIPS KVM_REG_MIPS_CP0_PWCTL 32 2412 MIPS KVM_REG_MIPS_CP0_HWRENA 32 2413 MIPS KVM_REG_MIPS_CP0_BADVADDR 64 2414 MIPS KVM_REG_MIPS_CP0_BADINSTR 32 2415 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32 2416 MIPS KVM_REG_MIPS_CP0_COUNT 32 2417 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64 2418 MIPS KVM_REG_MIPS_CP0_COMPARE 32 2419 MIPS KVM_REG_MIPS_CP0_STATUS 32 2420 MIPS KVM_REG_MIPS_CP0_INTCTL 32 2421 MIPS KVM_REG_MIPS_CP0_CAUSE 32 2422 MIPS KVM_REG_MIPS_CP0_EPC 64 2423 MIPS KVM_REG_MIPS_CP0_PRID 32 2424 MIPS KVM_REG_MIPS_CP0_EBASE 64 2425 MIPS KVM_REG_MIPS_CP0_CONFIG 32 2426 MIPS KVM_REG_MIPS_CP0_CONFIG1 32 2427 MIPS KVM_REG_MIPS_CP0_CONFIG2 32 2428 MIPS KVM_REG_MIPS_CP0_CONFIG3 32 2429 MIPS KVM_REG_MIPS_CP0_CONFIG4 32 2430 MIPS KVM_REG_MIPS_CP0_CONFIG5 32 2431 MIPS KVM_REG_MIPS_CP0_CONFIG7 32 2432 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64 2433 MIPS KVM_REG_MIPS_CP0_ERROREPC 64 2434 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64 2435 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64 2436 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64 2437 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64 2438 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64 2439 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64 2440 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64 2441 MIPS KVM_REG_MIPS_COUNT_CTL 64 2442 MIPS KVM_REG_MIPS_COUNT_RESUME 64 2443 MIPS KVM_REG_MIPS_COUNT_HZ 64 2444 MIPS KVM_REG_MIPS_FPR_32(0..31) 32 2445 MIPS KVM_REG_MIPS_FPR_64(0..31) 64 2446 MIPS KVM_REG_MIPS_VEC_128(0..31) 128 2447 MIPS KVM_REG_MIPS_FCR_IR 32 2448 MIPS KVM_REG_MIPS_FCR_CSR 32 2449 MIPS KVM_REG_MIPS_MSA_IR 32 2450 MIPS KVM_REG_MIPS_MSA_CSR 32 2451 ======= =============================== ============ 2452 2453ARM registers are mapped using the lower 32 bits. The upper 16 of that 2454is the register group type, or coprocessor number: 2455 2456ARM core registers have the following id bit patterns:: 2457 2458 0x4020 0000 0010 <index into the kvm_regs struct:16> 2459 2460ARM 32-bit CP15 registers have the following id bit patterns:: 2461 2462 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3> 2463 2464ARM 64-bit CP15 registers have the following id bit patterns:: 2465 2466 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3> 2467 2468ARM CCSIDR registers are demultiplexed by CSSELR value:: 2469 2470 0x4020 0000 0011 00 <csselr:8> 2471 2472ARM 32-bit VFP control registers have the following id bit patterns:: 2473 2474 0x4020 0000 0012 1 <regno:12> 2475 2476ARM 64-bit FP registers have the following id bit patterns:: 2477 2478 0x4030 0000 0012 0 <regno:12> 2479 2480ARM firmware pseudo-registers have the following bit pattern:: 2481 2482 0x4030 0000 0014 <regno:16> 2483 2484 2485arm64 registers are mapped using the lower 32 bits. The upper 16 of 2486that is the register group type, or coprocessor number: 2487 2488arm64 core/FP-SIMD registers have the following id bit patterns. Note 2489that the size of the access is variable, as the kvm_regs structure 2490contains elements ranging from 32 to 128 bits. The index is a 32bit 2491value in the kvm_regs structure seen as a 32bit array:: 2492 2493 0x60x0 0000 0010 <index into the kvm_regs struct:16> 2494 2495Specifically: 2496 2497======================= ========= ===== ======================================= 2498 Encoding Register Bits kvm_regs member 2499======================= ========= ===== ======================================= 2500 0x6030 0000 0010 0000 X0 64 regs.regs[0] 2501 0x6030 0000 0010 0002 X1 64 regs.regs[1] 2502 ... 2503 0x6030 0000 0010 003c X30 64 regs.regs[30] 2504 0x6030 0000 0010 003e SP 64 regs.sp 2505 0x6030 0000 0010 0040 PC 64 regs.pc 2506 0x6030 0000 0010 0042 PSTATE 64 regs.pstate 2507 0x6030 0000 0010 0044 SP_EL1 64 sp_el1 2508 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1 2509 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC) 2510 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT] 2511 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND] 2512 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ] 2513 0x6060 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ] 2514 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_ 2515 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_ 2516 ... 2517 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_ 2518 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr 2519 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr 2520======================= ========= ===== ======================================= 2521 2522.. [1] These encodings are not accepted for SVE-enabled vcpus. See 2523 KVM_ARM_VCPU_INIT. 2524 2525 The equivalent register content can be accessed via bits [127:0] of 2526 the corresponding SVE Zn registers instead for vcpus that have SVE 2527 enabled (see below). 2528 2529arm64 CCSIDR registers are demultiplexed by CSSELR value:: 2530 2531 0x6020 0000 0011 00 <csselr:8> 2532 2533arm64 system registers have the following id bit patterns:: 2534 2535 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3> 2536 2537.. warning:: 2538 2539 Two system register IDs do not follow the specified pattern. These 2540 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to 2541 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These 2542 two had their values accidentally swapped, which means TIMER_CVAL is 2543 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is 2544 derived from the register encoding for CNTV_CVAL_EL0. As this is 2545 API, it must remain this way. 2546 2547arm64 firmware pseudo-registers have the following bit pattern:: 2548 2549 0x6030 0000 0014 <regno:16> 2550 2551arm64 SVE registers have the following bit patterns:: 2552 2553 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice] 2554 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice] 2555 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice] 2556 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register 2557 2558Access to register IDs where 2048 * slice >= 128 * max_vq will fail with 2559ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit 2560quadwords: see [2]_ below. 2561 2562These registers are only accessible on vcpus for which SVE is enabled. 2563See KVM_ARM_VCPU_INIT for details. 2564 2565In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not 2566accessible until the vcpu's SVE configuration has been finalized 2567using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT 2568and KVM_ARM_VCPU_FINALIZE for more information about this procedure. 2569 2570KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector 2571lengths supported by the vcpu to be discovered and configured by 2572userspace. When transferred to or from user memory via KVM_GET_ONE_REG 2573or KVM_SET_ONE_REG, the value of this register is of type 2574__u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as 2575follows:: 2576 2577 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS]; 2578 2579 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX && 2580 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >> 2581 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1)) 2582 /* Vector length vq * 16 bytes supported */ 2583 else 2584 /* Vector length vq * 16 bytes not supported */ 2585 2586.. [2] The maximum value vq for which the above condition is true is 2587 max_vq. This is the maximum vector length available to the guest on 2588 this vcpu, and determines which register slices are visible through 2589 this ioctl interface. 2590 2591(See Documentation/arm64/sve.rst for an explanation of the "vq" 2592nomenclature.) 2593 2594KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT. 2595KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that 2596the host supports. 2597 2598Userspace may subsequently modify it if desired until the vcpu's SVE 2599configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). 2600 2601Apart from simply removing all vector lengths from the host set that 2602exceed some value, support for arbitrarily chosen sets of vector lengths 2603is hardware-dependent and may not be available. Attempting to configure 2604an invalid set of vector lengths via KVM_SET_ONE_REG will fail with 2605EINVAL. 2606 2607After the vcpu's SVE configuration is finalized, further attempts to 2608write this register will fail with EPERM. 2609 2610 2611MIPS registers are mapped using the lower 32 bits. The upper 16 of that is 2612the register group type: 2613 2614MIPS core registers (see above) have the following id bit patterns:: 2615 2616 0x7030 0000 0000 <reg:16> 2617 2618MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit 2619patterns depending on whether they're 32-bit or 64-bit registers:: 2620 2621 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit) 2622 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2623 2624Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64 2625versions of the EntryLo registers regardless of the word size of the host 2626hardware, host kernel, guest, and whether XPA is present in the guest, i.e. 2627with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and 2628the PFNX field starting at bit 30. 2629 2630MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit 2631patterns:: 2632 2633 0x7030 0000 0001 01 <reg:8> 2634 2635MIPS KVM control registers (see above) have the following id bit patterns:: 2636 2637 0x7030 0000 0002 <reg:16> 2638 2639MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following 2640id bit patterns depending on the size of the register being accessed. They are 2641always accessed according to the current guest FPU mode (Status.FR and 2642Config5.FRE), i.e. as the guest would see them, and they become unpredictable 2643if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector 2644registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they 2645overlap the FPU registers:: 2646 2647 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers) 2648 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers) 2649 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers) 2650 2651MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the 2652following id bit patterns:: 2653 2654 0x7020 0000 0003 01 <0:3> <reg:5> 2655 2656MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the 2657following id bit patterns:: 2658 2659 0x7020 0000 0003 02 <0:3> <reg:5> 2660 2661RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of 2662that is the register group type. 2663 2664RISC-V config registers are meant for configuring a Guest VCPU and it has 2665the following id bit patterns:: 2666 2667 0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host) 2668 0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host) 2669 2670Following are the RISC-V config registers: 2671 2672======================= ========= ============================================= 2673 Encoding Register Description 2674======================= ========= ============================================= 2675 0x80x0 0000 0100 0000 isa ISA feature bitmap of Guest VCPU 2676======================= ========= ============================================= 2677 2678The isa config register can be read anytime but can only be written before 2679a Guest VCPU runs. It will have ISA feature bits matching underlying host 2680set by default. 2681 2682RISC-V core registers represent the general excution state of a Guest VCPU 2683and it has the following id bit patterns:: 2684 2685 0x8020 0000 02 <index into the kvm_riscv_core struct:24> (32bit Host) 2686 0x8030 0000 02 <index into the kvm_riscv_core struct:24> (64bit Host) 2687 2688Following are the RISC-V core registers: 2689 2690======================= ========= ============================================= 2691 Encoding Register Description 2692======================= ========= ============================================= 2693 0x80x0 0000 0200 0000 regs.pc Program counter 2694 0x80x0 0000 0200 0001 regs.ra Return address 2695 0x80x0 0000 0200 0002 regs.sp Stack pointer 2696 0x80x0 0000 0200 0003 regs.gp Global pointer 2697 0x80x0 0000 0200 0004 regs.tp Task pointer 2698 0x80x0 0000 0200 0005 regs.t0 Caller saved register 0 2699 0x80x0 0000 0200 0006 regs.t1 Caller saved register 1 2700 0x80x0 0000 0200 0007 regs.t2 Caller saved register 2 2701 0x80x0 0000 0200 0008 regs.s0 Callee saved register 0 2702 0x80x0 0000 0200 0009 regs.s1 Callee saved register 1 2703 0x80x0 0000 0200 000a regs.a0 Function argument (or return value) 0 2704 0x80x0 0000 0200 000b regs.a1 Function argument (or return value) 1 2705 0x80x0 0000 0200 000c regs.a2 Function argument 2 2706 0x80x0 0000 0200 000d regs.a3 Function argument 3 2707 0x80x0 0000 0200 000e regs.a4 Function argument 4 2708 0x80x0 0000 0200 000f regs.a5 Function argument 5 2709 0x80x0 0000 0200 0010 regs.a6 Function argument 6 2710 0x80x0 0000 0200 0011 regs.a7 Function argument 7 2711 0x80x0 0000 0200 0012 regs.s2 Callee saved register 2 2712 0x80x0 0000 0200 0013 regs.s3 Callee saved register 3 2713 0x80x0 0000 0200 0014 regs.s4 Callee saved register 4 2714 0x80x0 0000 0200 0015 regs.s5 Callee saved register 5 2715 0x80x0 0000 0200 0016 regs.s6 Callee saved register 6 2716 0x80x0 0000 0200 0017 regs.s7 Callee saved register 7 2717 0x80x0 0000 0200 0018 regs.s8 Callee saved register 8 2718 0x80x0 0000 0200 0019 regs.s9 Callee saved register 9 2719 0x80x0 0000 0200 001a regs.s10 Callee saved register 10 2720 0x80x0 0000 0200 001b regs.s11 Callee saved register 11 2721 0x80x0 0000 0200 001c regs.t3 Caller saved register 3 2722 0x80x0 0000 0200 001d regs.t4 Caller saved register 4 2723 0x80x0 0000 0200 001e regs.t5 Caller saved register 5 2724 0x80x0 0000 0200 001f regs.t6 Caller saved register 6 2725 0x80x0 0000 0200 0020 mode Privilege mode (1 = S-mode or 0 = U-mode) 2726======================= ========= ============================================= 2727 2728RISC-V csr registers represent the supervisor mode control/status registers 2729of a Guest VCPU and it has the following id bit patterns:: 2730 2731 0x8020 0000 03 <index into the kvm_riscv_csr struct:24> (32bit Host) 2732 0x8030 0000 03 <index into the kvm_riscv_csr struct:24> (64bit Host) 2733 2734Following are the RISC-V csr registers: 2735 2736======================= ========= ============================================= 2737 Encoding Register Description 2738======================= ========= ============================================= 2739 0x80x0 0000 0300 0000 sstatus Supervisor status 2740 0x80x0 0000 0300 0001 sie Supervisor interrupt enable 2741 0x80x0 0000 0300 0002 stvec Supervisor trap vector base 2742 0x80x0 0000 0300 0003 sscratch Supervisor scratch register 2743 0x80x0 0000 0300 0004 sepc Supervisor exception program counter 2744 0x80x0 0000 0300 0005 scause Supervisor trap cause 2745 0x80x0 0000 0300 0006 stval Supervisor bad address or instruction 2746 0x80x0 0000 0300 0007 sip Supervisor interrupt pending 2747 0x80x0 0000 0300 0008 satp Supervisor address translation and protection 2748======================= ========= ============================================= 2749 2750RISC-V timer registers represent the timer state of a Guest VCPU and it has 2751the following id bit patterns:: 2752 2753 0x8030 0000 04 <index into the kvm_riscv_timer struct:24> 2754 2755Following are the RISC-V timer registers: 2756 2757======================= ========= ============================================= 2758 Encoding Register Description 2759======================= ========= ============================================= 2760 0x8030 0000 0400 0000 frequency Time base frequency (read-only) 2761 0x8030 0000 0400 0001 time Time value visible to Guest 2762 0x8030 0000 0400 0002 compare Time compare programmed by Guest 2763 0x8030 0000 0400 0003 state Time compare state (1 = ON or 0 = OFF) 2764======================= ========= ============================================= 2765 2766RISC-V F-extension registers represent the single precision floating point 2767state of a Guest VCPU and it has the following id bit patterns:: 2768 2769 0x8020 0000 05 <index into the __riscv_f_ext_state struct:24> 2770 2771Following are the RISC-V F-extension registers: 2772 2773======================= ========= ============================================= 2774 Encoding Register Description 2775======================= ========= ============================================= 2776 0x8020 0000 0500 0000 f[0] Floating point register 0 2777 ... 2778 0x8020 0000 0500 001f f[31] Floating point register 31 2779 0x8020 0000 0500 0020 fcsr Floating point control and status register 2780======================= ========= ============================================= 2781 2782RISC-V D-extension registers represent the double precision floating point 2783state of a Guest VCPU and it has the following id bit patterns:: 2784 2785 0x8020 0000 06 <index into the __riscv_d_ext_state struct:24> (fcsr) 2786 0x8030 0000 06 <index into the __riscv_d_ext_state struct:24> (non-fcsr) 2787 2788Following are the RISC-V D-extension registers: 2789 2790======================= ========= ============================================= 2791 Encoding Register Description 2792======================= ========= ============================================= 2793 0x8030 0000 0600 0000 f[0] Floating point register 0 2794 ... 2795 0x8030 0000 0600 001f f[31] Floating point register 31 2796 0x8020 0000 0600 0020 fcsr Floating point control and status register 2797======================= ========= ============================================= 2798 2799 28004.69 KVM_GET_ONE_REG 2801-------------------- 2802 2803:Capability: KVM_CAP_ONE_REG 2804:Architectures: all 2805:Type: vcpu ioctl 2806:Parameters: struct kvm_one_reg (in and out) 2807:Returns: 0 on success, negative value on failure 2808 2809Errors include: 2810 2811 ======== ============================================================ 2812 ENOENT no such register 2813 EINVAL invalid register ID, or no such register or used with VMs in 2814 protected virtualization mode on s390 2815 EPERM (arm64) register access not allowed before vcpu finalization 2816 ======== ============================================================ 2817 2818(These error codes are indicative only: do not rely on a specific error 2819code being returned in a specific situation.) 2820 2821This ioctl allows to receive the value of a single register implemented 2822in a vcpu. The register to read is indicated by the "id" field of the 2823kvm_one_reg struct passed in. On success, the register value can be found 2824at the memory location pointed to by "addr". 2825 2826The list of registers accessible using this interface is identical to the 2827list in 4.68. 2828 2829 28304.70 KVM_KVMCLOCK_CTRL 2831---------------------- 2832 2833:Capability: KVM_CAP_KVMCLOCK_CTRL 2834:Architectures: Any that implement pvclocks (currently x86 only) 2835:Type: vcpu ioctl 2836:Parameters: None 2837:Returns: 0 on success, -1 on error 2838 2839This ioctl sets a flag accessible to the guest indicating that the specified 2840vCPU has been paused by the host userspace. 2841 2842The host will set a flag in the pvclock structure that is checked from the 2843soft lockup watchdog. The flag is part of the pvclock structure that is 2844shared between guest and host, specifically the second bit of the flags 2845field of the pvclock_vcpu_time_info structure. It will be set exclusively by 2846the host and read/cleared exclusively by the guest. The guest operation of 2847checking and clearing the flag must be an atomic operation so 2848load-link/store-conditional, or equivalent must be used. There are two cases 2849where the guest will clear the flag: when the soft lockup watchdog timer resets 2850itself or when a soft lockup is detected. This ioctl can be called any time 2851after pausing the vcpu, but before it is resumed. 2852 2853 28544.71 KVM_SIGNAL_MSI 2855------------------- 2856 2857:Capability: KVM_CAP_SIGNAL_MSI 2858:Architectures: x86 arm64 2859:Type: vm ioctl 2860:Parameters: struct kvm_msi (in) 2861:Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error 2862 2863Directly inject a MSI message. Only valid with in-kernel irqchip that handles 2864MSI messages. 2865 2866:: 2867 2868 struct kvm_msi { 2869 __u32 address_lo; 2870 __u32 address_hi; 2871 __u32 data; 2872 __u32 flags; 2873 __u32 devid; 2874 __u8 pad[12]; 2875 }; 2876 2877flags: 2878 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM 2879 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 2880 the device ID. If this capability is not available, userspace 2881 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 2882 2883If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 2884for the device that wrote the MSI message. For PCI, this is usually a 2885BFD identifier in the lower 16 bits. 2886 2887On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 2888feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 2889address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 2890address_hi must be zero. 2891 2892 28934.71 KVM_CREATE_PIT2 2894-------------------- 2895 2896:Capability: KVM_CAP_PIT2 2897:Architectures: x86 2898:Type: vm ioctl 2899:Parameters: struct kvm_pit_config (in) 2900:Returns: 0 on success, -1 on error 2901 2902Creates an in-kernel device model for the i8254 PIT. This call is only valid 2903after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following 2904parameters have to be passed:: 2905 2906 struct kvm_pit_config { 2907 __u32 flags; 2908 __u32 pad[15]; 2909 }; 2910 2911Valid flags are:: 2912 2913 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */ 2914 2915PIT timer interrupts may use a per-VM kernel thread for injection. If it 2916exists, this thread will have a name of the following pattern:: 2917 2918 kvm-pit/<owner-process-pid> 2919 2920When running a guest with elevated priorities, the scheduling parameters of 2921this thread may have to be adjusted accordingly. 2922 2923This IOCTL replaces the obsolete KVM_CREATE_PIT. 2924 2925 29264.72 KVM_GET_PIT2 2927----------------- 2928 2929:Capability: KVM_CAP_PIT_STATE2 2930:Architectures: x86 2931:Type: vm ioctl 2932:Parameters: struct kvm_pit_state2 (out) 2933:Returns: 0 on success, -1 on error 2934 2935Retrieves the state of the in-kernel PIT model. Only valid after 2936KVM_CREATE_PIT2. The state is returned in the following structure:: 2937 2938 struct kvm_pit_state2 { 2939 struct kvm_pit_channel_state channels[3]; 2940 __u32 flags; 2941 __u32 reserved[9]; 2942 }; 2943 2944Valid flags are:: 2945 2946 /* disable PIT in HPET legacy mode */ 2947 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 2948 2949This IOCTL replaces the obsolete KVM_GET_PIT. 2950 2951 29524.73 KVM_SET_PIT2 2953----------------- 2954 2955:Capability: KVM_CAP_PIT_STATE2 2956:Architectures: x86 2957:Type: vm ioctl 2958:Parameters: struct kvm_pit_state2 (in) 2959:Returns: 0 on success, -1 on error 2960 2961Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. 2962See KVM_GET_PIT2 for details on struct kvm_pit_state2. 2963 2964This IOCTL replaces the obsolete KVM_SET_PIT. 2965 2966 29674.74 KVM_PPC_GET_SMMU_INFO 2968-------------------------- 2969 2970:Capability: KVM_CAP_PPC_GET_SMMU_INFO 2971:Architectures: powerpc 2972:Type: vm ioctl 2973:Parameters: None 2974:Returns: 0 on success, -1 on error 2975 2976This populates and returns a structure describing the features of 2977the "Server" class MMU emulation supported by KVM. 2978This can in turn be used by userspace to generate the appropriate 2979device-tree properties for the guest operating system. 2980 2981The structure contains some global information, followed by an 2982array of supported segment page sizes:: 2983 2984 struct kvm_ppc_smmu_info { 2985 __u64 flags; 2986 __u32 slb_size; 2987 __u32 pad; 2988 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ]; 2989 }; 2990 2991The supported flags are: 2992 2993 - KVM_PPC_PAGE_SIZES_REAL: 2994 When that flag is set, guest page sizes must "fit" the backing 2995 store page sizes. When not set, any page size in the list can 2996 be used regardless of how they are backed by userspace. 2997 2998 - KVM_PPC_1T_SEGMENTS 2999 The emulated MMU supports 1T segments in addition to the 3000 standard 256M ones. 3001 3002 - KVM_PPC_NO_HASH 3003 This flag indicates that HPT guests are not supported by KVM, 3004 thus all guests must use radix MMU mode. 3005 3006The "slb_size" field indicates how many SLB entries are supported 3007 3008The "sps" array contains 8 entries indicating the supported base 3009page sizes for a segment in increasing order. Each entry is defined 3010as follow:: 3011 3012 struct kvm_ppc_one_seg_page_size { 3013 __u32 page_shift; /* Base page shift of segment (or 0) */ 3014 __u32 slb_enc; /* SLB encoding for BookS */ 3015 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3016 }; 3017 3018An entry with a "page_shift" of 0 is unused. Because the array is 3019organized in increasing order, a lookup can stop when encoutering 3020such an entry. 3021 3022The "slb_enc" field provides the encoding to use in the SLB for the 3023page size. The bits are in positions such as the value can directly 3024be OR'ed into the "vsid" argument of the slbmte instruction. 3025 3026The "enc" array is a list which for each of those segment base page 3027size provides the list of supported actual page sizes (which can be 3028only larger or equal to the base page size), along with the 3029corresponding encoding in the hash PTE. Similarly, the array is 30308 entries sorted by increasing sizes and an entry with a "0" shift 3031is an empty entry and a terminator:: 3032 3033 struct kvm_ppc_one_page_size { 3034 __u32 page_shift; /* Page shift (or 0) */ 3035 __u32 pte_enc; /* Encoding in the HPTE (>>12) */ 3036 }; 3037 3038The "pte_enc" field provides a value that can OR'ed into the hash 3039PTE's RPN field (ie, it needs to be shifted left by 12 to OR it 3040into the hash PTE second double word). 3041 30424.75 KVM_IRQFD 3043-------------- 3044 3045:Capability: KVM_CAP_IRQFD 3046:Architectures: x86 s390 arm64 3047:Type: vm ioctl 3048:Parameters: struct kvm_irqfd (in) 3049:Returns: 0 on success, -1 on error 3050 3051Allows setting an eventfd to directly trigger a guest interrupt. 3052kvm_irqfd.fd specifies the file descriptor to use as the eventfd and 3053kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When 3054an event is triggered on the eventfd, an interrupt is injected into 3055the guest using the specified gsi pin. The irqfd is removed using 3056the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd 3057and kvm_irqfd.gsi. 3058 3059With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify 3060mechanism allowing emulation of level-triggered, irqfd-based 3061interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an 3062additional eventfd in the kvm_irqfd.resamplefd field. When operating 3063in resample mode, posting of an interrupt through kvm_irq.fd asserts 3064the specified gsi in the irqchip. When the irqchip is resampled, such 3065as from an EOI, the gsi is de-asserted and the user is notified via 3066kvm_irqfd.resamplefd. It is the user's responsibility to re-queue 3067the interrupt if the device making use of it still requires service. 3068Note that closing the resamplefd is not sufficient to disable the 3069irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment 3070and need not be specified with KVM_IRQFD_FLAG_DEASSIGN. 3071 3072On arm64, gsi routing being supported, the following can happen: 3073 3074- in case no routing entry is associated to this gsi, injection fails 3075- in case the gsi is associated to an irqchip routing entry, 3076 irqchip.pin + 32 corresponds to the injected SPI ID. 3077- in case the gsi is associated to an MSI routing entry, the MSI 3078 message and device ID are translated into an LPI (support restricted 3079 to GICv3 ITS in-kernel emulation). 3080 30814.76 KVM_PPC_ALLOCATE_HTAB 3082-------------------------- 3083 3084:Capability: KVM_CAP_PPC_ALLOC_HTAB 3085:Architectures: powerpc 3086:Type: vm ioctl 3087:Parameters: Pointer to u32 containing hash table order (in/out) 3088:Returns: 0 on success, -1 on error 3089 3090This requests the host kernel to allocate an MMU hash table for a 3091guest using the PAPR paravirtualization interface. This only does 3092anything if the kernel is configured to use the Book 3S HV style of 3093virtualization. Otherwise the capability doesn't exist and the ioctl 3094returns an ENOTTY error. The rest of this description assumes Book 3S 3095HV. 3096 3097There must be no vcpus running when this ioctl is called; if there 3098are, it will do nothing and return an EBUSY error. 3099 3100The parameter is a pointer to a 32-bit unsigned integer variable 3101containing the order (log base 2) of the desired size of the hash 3102table, which must be between 18 and 46. On successful return from the 3103ioctl, the value will not be changed by the kernel. 3104 3105If no hash table has been allocated when any vcpu is asked to run 3106(with the KVM_RUN ioctl), the host kernel will allocate a 3107default-sized hash table (16 MB). 3108 3109If this ioctl is called when a hash table has already been allocated, 3110with a different order from the existing hash table, the existing hash 3111table will be freed and a new one allocated. If this is ioctl is 3112called when a hash table has already been allocated of the same order 3113as specified, the kernel will clear out the existing hash table (zero 3114all HPTEs). In either case, if the guest is using the virtualized 3115real-mode area (VRMA) facility, the kernel will re-create the VMRA 3116HPTEs on the next KVM_RUN of any vcpu. 3117 31184.77 KVM_S390_INTERRUPT 3119----------------------- 3120 3121:Capability: basic 3122:Architectures: s390 3123:Type: vm ioctl, vcpu ioctl 3124:Parameters: struct kvm_s390_interrupt (in) 3125:Returns: 0 on success, -1 on error 3126 3127Allows to inject an interrupt to the guest. Interrupts can be floating 3128(vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type. 3129 3130Interrupt parameters are passed via kvm_s390_interrupt:: 3131 3132 struct kvm_s390_interrupt { 3133 __u32 type; 3134 __u32 parm; 3135 __u64 parm64; 3136 }; 3137 3138type can be one of the following: 3139 3140KVM_S390_SIGP_STOP (vcpu) 3141 - sigp stop; optional flags in parm 3142KVM_S390_PROGRAM_INT (vcpu) 3143 - program check; code in parm 3144KVM_S390_SIGP_SET_PREFIX (vcpu) 3145 - sigp set prefix; prefix address in parm 3146KVM_S390_RESTART (vcpu) 3147 - restart 3148KVM_S390_INT_CLOCK_COMP (vcpu) 3149 - clock comparator interrupt 3150KVM_S390_INT_CPU_TIMER (vcpu) 3151 - CPU timer interrupt 3152KVM_S390_INT_VIRTIO (vm) 3153 - virtio external interrupt; external interrupt 3154 parameters in parm and parm64 3155KVM_S390_INT_SERVICE (vm) 3156 - sclp external interrupt; sclp parameter in parm 3157KVM_S390_INT_EMERGENCY (vcpu) 3158 - sigp emergency; source cpu in parm 3159KVM_S390_INT_EXTERNAL_CALL (vcpu) 3160 - sigp external call; source cpu in parm 3161KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) 3162 - compound value to indicate an 3163 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel); 3164 I/O interruption parameters in parm (subchannel) and parm64 (intparm, 3165 interruption subclass) 3166KVM_S390_MCHK (vm, vcpu) 3167 - machine check interrupt; cr 14 bits in parm, machine check interrupt 3168 code in parm64 (note that machine checks needing further payload are not 3169 supported by this ioctl) 3170 3171This is an asynchronous vcpu ioctl and can be invoked from any thread. 3172 31734.78 KVM_PPC_GET_HTAB_FD 3174------------------------ 3175 3176:Capability: KVM_CAP_PPC_HTAB_FD 3177:Architectures: powerpc 3178:Type: vm ioctl 3179:Parameters: Pointer to struct kvm_get_htab_fd (in) 3180:Returns: file descriptor number (>= 0) on success, -1 on error 3181 3182This returns a file descriptor that can be used either to read out the 3183entries in the guest's hashed page table (HPT), or to write entries to 3184initialize the HPT. The returned fd can only be written to if the 3185KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and 3186can only be read if that bit is clear. The argument struct looks like 3187this:: 3188 3189 /* For KVM_PPC_GET_HTAB_FD */ 3190 struct kvm_get_htab_fd { 3191 __u64 flags; 3192 __u64 start_index; 3193 __u64 reserved[2]; 3194 }; 3195 3196 /* Values for kvm_get_htab_fd.flags */ 3197 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1) 3198 #define KVM_GET_HTAB_WRITE ((__u64)0x2) 3199 3200The 'start_index' field gives the index in the HPT of the entry at 3201which to start reading. It is ignored when writing. 3202 3203Reads on the fd will initially supply information about all 3204"interesting" HPT entries. Interesting entries are those with the 3205bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise 3206all entries. When the end of the HPT is reached, the read() will 3207return. If read() is called again on the fd, it will start again from 3208the beginning of the HPT, but will only return HPT entries that have 3209changed since they were last read. 3210 3211Data read or written is structured as a header (8 bytes) followed by a 3212series of valid HPT entries (16 bytes) each. The header indicates how 3213many valid HPT entries there are and how many invalid entries follow 3214the valid entries. The invalid entries are not represented explicitly 3215in the stream. The header format is:: 3216 3217 struct kvm_get_htab_header { 3218 __u32 index; 3219 __u16 n_valid; 3220 __u16 n_invalid; 3221 }; 3222 3223Writes to the fd create HPT entries starting at the index given in the 3224header; first 'n_valid' valid entries with contents from the data 3225written, then 'n_invalid' invalid entries, invalidating any previously 3226valid entries found. 3227 32284.79 KVM_CREATE_DEVICE 3229---------------------- 3230 3231:Capability: KVM_CAP_DEVICE_CTRL 3232:Type: vm ioctl 3233:Parameters: struct kvm_create_device (in/out) 3234:Returns: 0 on success, -1 on error 3235 3236Errors: 3237 3238 ====== ======================================================= 3239 ENODEV The device type is unknown or unsupported 3240 EEXIST Device already created, and this type of device may not 3241 be instantiated multiple times 3242 ====== ======================================================= 3243 3244 Other error conditions may be defined by individual device types or 3245 have their standard meanings. 3246 3247Creates an emulated device in the kernel. The file descriptor returned 3248in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR. 3249 3250If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the 3251device type is supported (not necessarily whether it can be created 3252in the current vm). 3253 3254Individual devices should not define flags. Attributes should be used 3255for specifying any behavior that is not implied by the device type 3256number. 3257 3258:: 3259 3260 struct kvm_create_device { 3261 __u32 type; /* in: KVM_DEV_TYPE_xxx */ 3262 __u32 fd; /* out: device handle */ 3263 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ 3264 }; 3265 32664.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR 3267-------------------------------------------- 3268 3269:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3270 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3271 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device (no set) 3272:Type: device ioctl, vm ioctl, vcpu ioctl 3273:Parameters: struct kvm_device_attr 3274:Returns: 0 on success, -1 on error 3275 3276Errors: 3277 3278 ===== ============================================================= 3279 ENXIO The group or attribute is unknown/unsupported for this device 3280 or hardware support is missing. 3281 EPERM The attribute cannot (currently) be accessed this way 3282 (e.g. read-only attribute, or attribute that only makes 3283 sense when the device is in a different state) 3284 ===== ============================================================= 3285 3286 Other error conditions may be defined by individual device types. 3287 3288Gets/sets a specified piece of device configuration and/or state. The 3289semantics are device-specific. See individual device documentation in 3290the "devices" directory. As with ONE_REG, the size of the data 3291transferred is defined by the particular attribute. 3292 3293:: 3294 3295 struct kvm_device_attr { 3296 __u32 flags; /* no flags currently defined */ 3297 __u32 group; /* device-defined */ 3298 __u64 attr; /* group-defined */ 3299 __u64 addr; /* userspace address of attr data */ 3300 }; 3301 33024.81 KVM_HAS_DEVICE_ATTR 3303------------------------ 3304 3305:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3306 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3307 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device 3308:Type: device ioctl, vm ioctl, vcpu ioctl 3309:Parameters: struct kvm_device_attr 3310:Returns: 0 on success, -1 on error 3311 3312Errors: 3313 3314 ===== ============================================================= 3315 ENXIO The group or attribute is unknown/unsupported for this device 3316 or hardware support is missing. 3317 ===== ============================================================= 3318 3319Tests whether a device supports a particular attribute. A successful 3320return indicates the attribute is implemented. It does not necessarily 3321indicate that the attribute can be read or written in the device's 3322current state. "addr" is ignored. 3323 33244.82 KVM_ARM_VCPU_INIT 3325---------------------- 3326 3327:Capability: basic 3328:Architectures: arm64 3329:Type: vcpu ioctl 3330:Parameters: struct kvm_vcpu_init (in) 3331:Returns: 0 on success; -1 on error 3332 3333Errors: 3334 3335 ====== ================================================================= 3336 EINVAL the target is unknown, or the combination of features is invalid. 3337 ENOENT a features bit specified is unknown. 3338 ====== ================================================================= 3339 3340This tells KVM what type of CPU to present to the guest, and what 3341optional features it should have. This will cause a reset of the cpu 3342registers to their initial values. If this is not called, KVM_RUN will 3343return ENOEXEC for that vcpu. 3344 3345The initial values are defined as: 3346 - Processor state: 3347 * AArch64: EL1h, D, A, I and F bits set. All other bits 3348 are cleared. 3349 * AArch32: SVC, A, I and F bits set. All other bits are 3350 cleared. 3351 - General Purpose registers, including PC and SP: set to 0 3352 - FPSIMD/NEON registers: set to 0 3353 - SVE registers: set to 0 3354 - System registers: Reset to their architecturally defined 3355 values as for a warm reset to EL1 (resp. SVC) 3356 3357Note that because some registers reflect machine topology, all vcpus 3358should be created before this ioctl is invoked. 3359 3360Userspace can call this function multiple times for a given vcpu, including 3361after the vcpu has been run. This will reset the vcpu to its initial 3362state. All calls to this function after the initial call must use the same 3363target and same set of feature flags, otherwise EINVAL will be returned. 3364 3365Possible features: 3366 3367 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. 3368 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on 3369 and execute guest code when KVM_RUN is called. 3370 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. 3371 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). 3372 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision 3373 backward compatible with v0.2) for the CPU. 3374 Depends on KVM_CAP_ARM_PSCI_0_2. 3375 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. 3376 Depends on KVM_CAP_ARM_PMU_V3. 3377 3378 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication 3379 for arm64 only. 3380 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. 3381 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3382 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3383 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3384 requested. 3385 3386 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication 3387 for arm64 only. 3388 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. 3389 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3390 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3391 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3392 requested. 3393 3394 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). 3395 Depends on KVM_CAP_ARM_SVE. 3396 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3397 3398 * After KVM_ARM_VCPU_INIT: 3399 3400 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the 3401 initial value of this pseudo-register indicates the best set of 3402 vector lengths possible for a vcpu on this host. 3403 3404 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3405 3406 - KVM_RUN and KVM_GET_REG_LIST are not available; 3407 3408 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access 3409 the scalable archietctural SVE registers 3410 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or 3411 KVM_REG_ARM64_SVE_FFR; 3412 3413 - KVM_REG_ARM64_SVE_VLS may optionally be written using 3414 KVM_SET_ONE_REG, to modify the set of vector lengths available 3415 for the vcpu. 3416 3417 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3418 3419 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can 3420 no longer be written using KVM_SET_ONE_REG. 3421 34224.83 KVM_ARM_PREFERRED_TARGET 3423----------------------------- 3424 3425:Capability: basic 3426:Architectures: arm64 3427:Type: vm ioctl 3428:Parameters: struct kvm_vcpu_init (out) 3429:Returns: 0 on success; -1 on error 3430 3431Errors: 3432 3433 ====== ========================================== 3434 ENODEV no preferred target available for the host 3435 ====== ========================================== 3436 3437This queries KVM for preferred CPU target type which can be emulated 3438by KVM on underlying host. 3439 3440The ioctl returns struct kvm_vcpu_init instance containing information 3441about preferred CPU target type and recommended features for it. The 3442kvm_vcpu_init->features bitmap returned will have feature bits set if 3443the preferred target recommends setting these features, but this is 3444not mandatory. 3445 3446The information returned by this ioctl can be used to prepare an instance 3447of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in 3448VCPU matching underlying host. 3449 3450 34514.84 KVM_GET_REG_LIST 3452--------------------- 3453 3454:Capability: basic 3455:Architectures: arm64, mips 3456:Type: vcpu ioctl 3457:Parameters: struct kvm_reg_list (in/out) 3458:Returns: 0 on success; -1 on error 3459 3460Errors: 3461 3462 ===== ============================================================== 3463 E2BIG the reg index list is too big to fit in the array specified by 3464 the user (the number required will be written into n). 3465 ===== ============================================================== 3466 3467:: 3468 3469 struct kvm_reg_list { 3470 __u64 n; /* number of registers in reg[] */ 3471 __u64 reg[0]; 3472 }; 3473 3474This ioctl returns the guest registers that are supported for the 3475KVM_GET_ONE_REG/KVM_SET_ONE_REG calls. 3476 3477 34784.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) 3479----------------------------------------- 3480 3481:Capability: KVM_CAP_ARM_SET_DEVICE_ADDR 3482:Architectures: arm64 3483:Type: vm ioctl 3484:Parameters: struct kvm_arm_device_address (in) 3485:Returns: 0 on success, -1 on error 3486 3487Errors: 3488 3489 ====== ============================================ 3490 ENODEV The device id is unknown 3491 ENXIO Device not supported on current system 3492 EEXIST Address already set 3493 E2BIG Address outside guest physical address space 3494 EBUSY Address overlaps with other device range 3495 ====== ============================================ 3496 3497:: 3498 3499 struct kvm_arm_device_addr { 3500 __u64 id; 3501 __u64 addr; 3502 }; 3503 3504Specify a device address in the guest's physical address space where guests 3505can access emulated or directly exposed devices, which the host kernel needs 3506to know about. The id field is an architecture specific identifier for a 3507specific device. 3508 3509arm64 divides the id field into two parts, a device id and an 3510address type id specific to the individual device:: 3511 3512 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 | 3513 field: | 0x00000000 | device id | addr type id | 3514 3515arm64 currently only require this when using the in-kernel GIC 3516support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 3517as the device id. When setting the base address for the guest's 3518mapping of the VGIC virtual CPU and distributor interface, the ioctl 3519must be called after calling KVM_CREATE_IRQCHIP, but before calling 3520KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the 3521base addresses will return -EEXIST. 3522 3523Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API 3524should be used instead. 3525 3526 35274.86 KVM_PPC_RTAS_DEFINE_TOKEN 3528------------------------------ 3529 3530:Capability: KVM_CAP_PPC_RTAS 3531:Architectures: ppc 3532:Type: vm ioctl 3533:Parameters: struct kvm_rtas_token_args 3534:Returns: 0 on success, -1 on error 3535 3536Defines a token value for a RTAS (Run Time Abstraction Services) 3537service in order to allow it to be handled in the kernel. The 3538argument struct gives the name of the service, which must be the name 3539of a service that has a kernel-side implementation. If the token 3540value is non-zero, it will be associated with that service, and 3541subsequent RTAS calls by the guest specifying that token will be 3542handled by the kernel. If the token value is 0, then any token 3543associated with the service will be forgotten, and subsequent RTAS 3544calls by the guest for that service will be passed to userspace to be 3545handled. 3546 35474.87 KVM_SET_GUEST_DEBUG 3548------------------------ 3549 3550:Capability: KVM_CAP_SET_GUEST_DEBUG 3551:Architectures: x86, s390, ppc, arm64 3552:Type: vcpu ioctl 3553:Parameters: struct kvm_guest_debug (in) 3554:Returns: 0 on success; -1 on error 3555 3556:: 3557 3558 struct kvm_guest_debug { 3559 __u32 control; 3560 __u32 pad; 3561 struct kvm_guest_debug_arch arch; 3562 }; 3563 3564Set up the processor specific debug registers and configure vcpu for 3565handling guest debug events. There are two parts to the structure, the 3566first a control bitfield indicates the type of debug events to handle 3567when running. Common control bits are: 3568 3569 - KVM_GUESTDBG_ENABLE: guest debugging is enabled 3570 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step 3571 3572The top 16 bits of the control field are architecture specific control 3573flags which can include the following: 3574 3575 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] 3576 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] 3577 - KVM_GUESTDBG_USE_HW: using hardware debug events [arm64] 3578 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] 3579 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] 3580 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] 3581 - KVM_GUESTDBG_BLOCKIRQ: avoid injecting interrupts/NMI/SMI [x86] 3582 3583For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints 3584are enabled in memory so we need to ensure breakpoint exceptions are 3585correctly trapped and the KVM run loop exits at the breakpoint and not 3586running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP 3587we need to ensure the guest vCPUs architecture specific registers are 3588updated to the correct (supplied) values. 3589 3590The second part of the structure is architecture specific and 3591typically contains a set of debug registers. 3592 3593For arm64 the number of debug registers is implementation defined and 3594can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and 3595KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number 3596indicating the number of supported registers. 3597 3598For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether 3599the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported. 3600 3601Also when supported, KVM_CAP_SET_GUEST_DEBUG2 capability indicates the 3602supported KVM_GUESTDBG_* bits in the control field. 3603 3604When debug events exit the main run loop with the reason 3605KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run 3606structure containing architecture specific debug information. 3607 36084.88 KVM_GET_EMULATED_CPUID 3609--------------------------- 3610 3611:Capability: KVM_CAP_EXT_EMUL_CPUID 3612:Architectures: x86 3613:Type: system ioctl 3614:Parameters: struct kvm_cpuid2 (in/out) 3615:Returns: 0 on success, -1 on error 3616 3617:: 3618 3619 struct kvm_cpuid2 { 3620 __u32 nent; 3621 __u32 flags; 3622 struct kvm_cpuid_entry2 entries[0]; 3623 }; 3624 3625The member 'flags' is used for passing flags from userspace. 3626 3627:: 3628 3629 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 3630 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 3631 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 3632 3633 struct kvm_cpuid_entry2 { 3634 __u32 function; 3635 __u32 index; 3636 __u32 flags; 3637 __u32 eax; 3638 __u32 ebx; 3639 __u32 ecx; 3640 __u32 edx; 3641 __u32 padding[3]; 3642 }; 3643 3644This ioctl returns x86 cpuid features which are emulated by 3645kvm.Userspace can use the information returned by this ioctl to query 3646which features are emulated by kvm instead of being present natively. 3647 3648Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2 3649structure with the 'nent' field indicating the number of entries in 3650the variable-size array 'entries'. If the number of entries is too low 3651to describe the cpu capabilities, an error (E2BIG) is returned. If the 3652number is too high, the 'nent' field is adjusted and an error (ENOMEM) 3653is returned. If the number is just right, the 'nent' field is adjusted 3654to the number of valid entries in the 'entries' array, which is then 3655filled. 3656 3657The entries returned are the set CPUID bits of the respective features 3658which kvm emulates, as returned by the CPUID instruction, with unknown 3659or unsupported feature bits cleared. 3660 3661Features like x2apic, for example, may not be present in the host cpu 3662but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be 3663emulated efficiently and thus not included here. 3664 3665The fields in each entry are defined as follows: 3666 3667 function: 3668 the eax value used to obtain the entry 3669 index: 3670 the ecx value used to obtain the entry (for entries that are 3671 affected by ecx) 3672 flags: 3673 an OR of zero or more of the following: 3674 3675 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 3676 if the index field is valid 3677 3678 eax, ebx, ecx, edx: 3679 3680 the values returned by the cpuid instruction for 3681 this function/index combination 3682 36834.89 KVM_S390_MEM_OP 3684-------------------- 3685 3686:Capability: KVM_CAP_S390_MEM_OP, KVM_CAP_S390_PROTECTED, KVM_CAP_S390_MEM_OP_EXTENSION 3687:Architectures: s390 3688:Type: vm ioctl, vcpu ioctl 3689:Parameters: struct kvm_s390_mem_op (in) 3690:Returns: = 0 on success, 3691 < 0 on generic error (e.g. -EFAULT or -ENOMEM), 3692 > 0 if an exception occurred while walking the page tables 3693 3694Read or write data from/to the VM's memory. 3695The KVM_CAP_S390_MEM_OP_EXTENSION capability specifies what functionality is 3696supported. 3697 3698Parameters are specified via the following structure:: 3699 3700 struct kvm_s390_mem_op { 3701 __u64 gaddr; /* the guest address */ 3702 __u64 flags; /* flags */ 3703 __u32 size; /* amount of bytes */ 3704 __u32 op; /* type of operation */ 3705 __u64 buf; /* buffer in userspace */ 3706 union { 3707 struct { 3708 __u8 ar; /* the access register number */ 3709 __u8 key; /* access key, ignored if flag unset */ 3710 }; 3711 __u32 sida_offset; /* offset into the sida */ 3712 __u8 reserved[32]; /* ignored */ 3713 }; 3714 }; 3715 3716The start address of the memory region has to be specified in the "gaddr" 3717field, and the length of the region in the "size" field (which must not 3718be 0). The maximum value for "size" can be obtained by checking the 3719KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the 3720userspace application where the read data should be written to for 3721a read access, or where the data that should be written is stored for 3722a write access. The "reserved" field is meant for future extensions. 3723Reserved and unused values are ignored. Future extension that add members must 3724introduce new flags. 3725 3726The type of operation is specified in the "op" field. Flags modifying 3727their behavior can be set in the "flags" field. Undefined flag bits must 3728be set to 0. 3729 3730Possible operations are: 3731 * ``KVM_S390_MEMOP_LOGICAL_READ`` 3732 * ``KVM_S390_MEMOP_LOGICAL_WRITE`` 3733 * ``KVM_S390_MEMOP_ABSOLUTE_READ`` 3734 * ``KVM_S390_MEMOP_ABSOLUTE_WRITE`` 3735 * ``KVM_S390_MEMOP_SIDA_READ`` 3736 * ``KVM_S390_MEMOP_SIDA_WRITE`` 3737 3738Logical read/write: 3739^^^^^^^^^^^^^^^^^^^ 3740 3741Access logical memory, i.e. translate the given guest address to an absolute 3742address given the state of the VCPU and use the absolute address as target of 3743the access. "ar" designates the access register number to be used; the valid 3744range is 0..15. 3745Logical accesses are permitted for the VCPU ioctl only. 3746Logical accesses are permitted for non-protected guests only. 3747 3748Supported flags: 3749 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3750 * ``KVM_S390_MEMOP_F_INJECT_EXCEPTION`` 3751 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3752 3753The KVM_S390_MEMOP_F_CHECK_ONLY flag can be set to check whether the 3754corresponding memory access would cause an access exception; however, 3755no actual access to the data in memory at the destination is performed. 3756In this case, "buf" is unused and can be NULL. 3757 3758In case an access exception occurred during the access (or would occur 3759in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive 3760error number indicating the type of exception. This exception is also 3761raised directly at the corresponding VCPU if the flag 3762KVM_S390_MEMOP_F_INJECT_EXCEPTION is set. 3763 3764If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key 3765protection is also in effect and may cause exceptions if accesses are 3766prohibited given the access key designated by "key"; the valid range is 0..15. 3767KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION 3768is > 0. 3769 3770Absolute read/write: 3771^^^^^^^^^^^^^^^^^^^^ 3772 3773Access absolute memory. This operation is intended to be used with the 3774KVM_S390_MEMOP_F_SKEY_PROTECTION flag, to allow accessing memory and performing 3775the checks required for storage key protection as one operation (as opposed to 3776user space getting the storage keys, performing the checks, and accessing 3777memory thereafter, which could lead to a delay between check and access). 3778Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION 3779is > 0. 3780Currently absolute accesses are not permitted for VCPU ioctls. 3781Absolute accesses are permitted for non-protected guests only. 3782 3783Supported flags: 3784 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3785 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3786 3787The semantics of the flags are as for logical accesses. 3788 3789SIDA read/write: 3790^^^^^^^^^^^^^^^^ 3791 3792Access the secure instruction data area which contains memory operands necessary 3793for instruction emulation for protected guests. 3794SIDA accesses are available if the KVM_CAP_S390_PROTECTED capability is available. 3795SIDA accesses are permitted for the VCPU ioctl only. 3796SIDA accesses are permitted for protected guests only. 3797 3798No flags are supported. 3799 38004.90 KVM_S390_GET_SKEYS 3801----------------------- 3802 3803:Capability: KVM_CAP_S390_SKEYS 3804:Architectures: s390 3805:Type: vm ioctl 3806:Parameters: struct kvm_s390_skeys 3807:Returns: 0 on success, KVM_S390_GET_SKEYS_NONE if guest is not using storage 3808 keys, negative value on error 3809 3810This ioctl is used to get guest storage key values on the s390 3811architecture. The ioctl takes parameters via the kvm_s390_skeys struct:: 3812 3813 struct kvm_s390_skeys { 3814 __u64 start_gfn; 3815 __u64 count; 3816 __u64 skeydata_addr; 3817 __u32 flags; 3818 __u32 reserved[9]; 3819 }; 3820 3821The start_gfn field is the number of the first guest frame whose storage keys 3822you want to get. 3823 3824The count field is the number of consecutive frames (starting from start_gfn) 3825whose storage keys to get. The count field must be at least 1 and the maximum 3826allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3827will cause the ioctl to return -EINVAL. 3828 3829The skeydata_addr field is the address to a buffer large enough to hold count 3830bytes. This buffer will be filled with storage key data by the ioctl. 3831 38324.91 KVM_S390_SET_SKEYS 3833----------------------- 3834 3835:Capability: KVM_CAP_S390_SKEYS 3836:Architectures: s390 3837:Type: vm ioctl 3838:Parameters: struct kvm_s390_skeys 3839:Returns: 0 on success, negative value on error 3840 3841This ioctl is used to set guest storage key values on the s390 3842architecture. The ioctl takes parameters via the kvm_s390_skeys struct. 3843See section on KVM_S390_GET_SKEYS for struct definition. 3844 3845The start_gfn field is the number of the first guest frame whose storage keys 3846you want to set. 3847 3848The count field is the number of consecutive frames (starting from start_gfn) 3849whose storage keys to get. The count field must be at least 1 and the maximum 3850allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3851will cause the ioctl to return -EINVAL. 3852 3853The skeydata_addr field is the address to a buffer containing count bytes of 3854storage keys. Each byte in the buffer will be set as the storage key for a 3855single frame starting at start_gfn for count frames. 3856 3857Note: If any architecturally invalid key value is found in the given data then 3858the ioctl will return -EINVAL. 3859 38604.92 KVM_S390_IRQ 3861----------------- 3862 3863:Capability: KVM_CAP_S390_INJECT_IRQ 3864:Architectures: s390 3865:Type: vcpu ioctl 3866:Parameters: struct kvm_s390_irq (in) 3867:Returns: 0 on success, -1 on error 3868 3869Errors: 3870 3871 3872 ====== ================================================================= 3873 EINVAL interrupt type is invalid 3874 type is KVM_S390_SIGP_STOP and flag parameter is invalid value, 3875 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger 3876 than the maximum of VCPUs 3877 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped, 3878 type is KVM_S390_SIGP_STOP and a stop irq is already pending, 3879 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt 3880 is already pending 3881 ====== ================================================================= 3882 3883Allows to inject an interrupt to the guest. 3884 3885Using struct kvm_s390_irq as a parameter allows 3886to inject additional payload which is not 3887possible via KVM_S390_INTERRUPT. 3888 3889Interrupt parameters are passed via kvm_s390_irq:: 3890 3891 struct kvm_s390_irq { 3892 __u64 type; 3893 union { 3894 struct kvm_s390_io_info io; 3895 struct kvm_s390_ext_info ext; 3896 struct kvm_s390_pgm_info pgm; 3897 struct kvm_s390_emerg_info emerg; 3898 struct kvm_s390_extcall_info extcall; 3899 struct kvm_s390_prefix_info prefix; 3900 struct kvm_s390_stop_info stop; 3901 struct kvm_s390_mchk_info mchk; 3902 char reserved[64]; 3903 } u; 3904 }; 3905 3906type can be one of the following: 3907 3908- KVM_S390_SIGP_STOP - sigp stop; parameter in .stop 3909- KVM_S390_PROGRAM_INT - program check; parameters in .pgm 3910- KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix 3911- KVM_S390_RESTART - restart; no parameters 3912- KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters 3913- KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters 3914- KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg 3915- KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall 3916- KVM_S390_MCHK - machine check interrupt; parameters in .mchk 3917 3918This is an asynchronous vcpu ioctl and can be invoked from any thread. 3919 39204.94 KVM_S390_GET_IRQ_STATE 3921--------------------------- 3922 3923:Capability: KVM_CAP_S390_IRQ_STATE 3924:Architectures: s390 3925:Type: vcpu ioctl 3926:Parameters: struct kvm_s390_irq_state (out) 3927:Returns: >= number of bytes copied into buffer, 3928 -EINVAL if buffer size is 0, 3929 -ENOBUFS if buffer size is too small to fit all pending interrupts, 3930 -EFAULT if the buffer address was invalid 3931 3932This ioctl allows userspace to retrieve the complete state of all currently 3933pending interrupts in a single buffer. Use cases include migration 3934and introspection. The parameter structure contains the address of a 3935userspace buffer and its length:: 3936 3937 struct kvm_s390_irq_state { 3938 __u64 buf; 3939 __u32 flags; /* will stay unused for compatibility reasons */ 3940 __u32 len; 3941 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 3942 }; 3943 3944Userspace passes in the above struct and for each pending interrupt a 3945struct kvm_s390_irq is copied to the provided buffer. 3946 3947The structure contains a flags and a reserved field for future extensions. As 3948the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and 3949reserved, these fields can not be used in the future without breaking 3950compatibility. 3951 3952If -ENOBUFS is returned the buffer provided was too small and userspace 3953may retry with a bigger buffer. 3954 39554.95 KVM_S390_SET_IRQ_STATE 3956--------------------------- 3957 3958:Capability: KVM_CAP_S390_IRQ_STATE 3959:Architectures: s390 3960:Type: vcpu ioctl 3961:Parameters: struct kvm_s390_irq_state (in) 3962:Returns: 0 on success, 3963 -EFAULT if the buffer address was invalid, 3964 -EINVAL for an invalid buffer length (see below), 3965 -EBUSY if there were already interrupts pending, 3966 errors occurring when actually injecting the 3967 interrupt. See KVM_S390_IRQ. 3968 3969This ioctl allows userspace to set the complete state of all cpu-local 3970interrupts currently pending for the vcpu. It is intended for restoring 3971interrupt state after a migration. The input parameter is a userspace buffer 3972containing a struct kvm_s390_irq_state:: 3973 3974 struct kvm_s390_irq_state { 3975 __u64 buf; 3976 __u32 flags; /* will stay unused for compatibility reasons */ 3977 __u32 len; 3978 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 3979 }; 3980 3981The restrictions for flags and reserved apply as well. 3982(see KVM_S390_GET_IRQ_STATE) 3983 3984The userspace memory referenced by buf contains a struct kvm_s390_irq 3985for each interrupt to be injected into the guest. 3986If one of the interrupts could not be injected for some reason the 3987ioctl aborts. 3988 3989len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0 3990and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq), 3991which is the maximum number of possibly pending cpu-local interrupts. 3992 39934.96 KVM_SMI 3994------------ 3995 3996:Capability: KVM_CAP_X86_SMM 3997:Architectures: x86 3998:Type: vcpu ioctl 3999:Parameters: none 4000:Returns: 0 on success, -1 on error 4001 4002Queues an SMI on the thread's vcpu. 4003 40044.97 KVM_X86_SET_MSR_FILTER 4005---------------------------- 4006 4007:Capability: KVM_X86_SET_MSR_FILTER 4008:Architectures: x86 4009:Type: vm ioctl 4010:Parameters: struct kvm_msr_filter 4011:Returns: 0 on success, < 0 on error 4012 4013:: 4014 4015 struct kvm_msr_filter_range { 4016 #define KVM_MSR_FILTER_READ (1 << 0) 4017 #define KVM_MSR_FILTER_WRITE (1 << 1) 4018 __u32 flags; 4019 __u32 nmsrs; /* number of msrs in bitmap */ 4020 __u32 base; /* MSR index the bitmap starts at */ 4021 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ 4022 }; 4023 4024 #define KVM_MSR_FILTER_MAX_RANGES 16 4025 struct kvm_msr_filter { 4026 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) 4027 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) 4028 __u32 flags; 4029 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; 4030 }; 4031 4032flags values for ``struct kvm_msr_filter_range``: 4033 4034``KVM_MSR_FILTER_READ`` 4035 4036 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap 4037 indicates that a read should immediately fail, while a 1 indicates that 4038 a read for a particular MSR should be handled regardless of the default 4039 filter action. 4040 4041``KVM_MSR_FILTER_WRITE`` 4042 4043 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap 4044 indicates that a write should immediately fail, while a 1 indicates that 4045 a write for a particular MSR should be handled regardless of the default 4046 filter action. 4047 4048``KVM_MSR_FILTER_READ | KVM_MSR_FILTER_WRITE`` 4049 4050 Filter both read and write accesses to MSRs using the given bitmap. A 0 4051 in the bitmap indicates that both reads and writes should immediately fail, 4052 while a 1 indicates that reads and writes for a particular MSR are not 4053 filtered by this range. 4054 4055flags values for ``struct kvm_msr_filter``: 4056 4057``KVM_MSR_FILTER_DEFAULT_ALLOW`` 4058 4059 If no filter range matches an MSR index that is getting accessed, KVM will 4060 fall back to allowing access to the MSR. 4061 4062``KVM_MSR_FILTER_DEFAULT_DENY`` 4063 4064 If no filter range matches an MSR index that is getting accessed, KVM will 4065 fall back to rejecting access to the MSR. In this mode, all MSRs that should 4066 be processed by KVM need to explicitly be marked as allowed in the bitmaps. 4067 4068This ioctl allows user space to define up to 16 bitmaps of MSR ranges to 4069specify whether a certain MSR access should be explicitly filtered for or not. 4070 4071If this ioctl has never been invoked, MSR accesses are not guarded and the 4072default KVM in-kernel emulation behavior is fully preserved. 4073 4074Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR 4075filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes 4076an error. 4077 4078As soon as the filtering is in place, every MSR access is processed through 4079the filtering except for accesses to the x2APIC MSRs (from 0x800 to 0x8ff); 4080x2APIC MSRs are always allowed, independent of the ``default_allow`` setting, 4081and their behavior depends on the ``X2APIC_ENABLE`` bit of the APIC base 4082register. 4083 4084If a bit is within one of the defined ranges, read and write accesses are 4085guarded by the bitmap's value for the MSR index if the kind of access 4086is included in the ``struct kvm_msr_filter_range`` flags. If no range 4087cover this particular access, the behavior is determined by the flags 4088field in the kvm_msr_filter struct: ``KVM_MSR_FILTER_DEFAULT_ALLOW`` 4089and ``KVM_MSR_FILTER_DEFAULT_DENY``. 4090 4091Each bitmap range specifies a range of MSRs to potentially allow access on. 4092The range goes from MSR index [base .. base+nmsrs]. The flags field 4093indicates whether reads, writes or both reads and writes are filtered 4094by setting a 1 bit in the bitmap for the corresponding MSR index. 4095 4096If an MSR access is not permitted through the filtering, it generates a 4097#GP inside the guest. When combined with KVM_CAP_X86_USER_SPACE_MSR, that 4098allows user space to deflect and potentially handle various MSR accesses 4099into user space. 4100 4101If a vCPU is in running state while this ioctl is invoked, the vCPU may 4102experience inconsistent filtering behavior on MSR accesses. 4103 41044.98 KVM_CREATE_SPAPR_TCE_64 4105---------------------------- 4106 4107:Capability: KVM_CAP_SPAPR_TCE_64 4108:Architectures: powerpc 4109:Type: vm ioctl 4110:Parameters: struct kvm_create_spapr_tce_64 (in) 4111:Returns: file descriptor for manipulating the created TCE table 4112 4113This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit 4114windows, described in 4.62 KVM_CREATE_SPAPR_TCE 4115 4116This capability uses extended struct in ioctl interface:: 4117 4118 /* for KVM_CAP_SPAPR_TCE_64 */ 4119 struct kvm_create_spapr_tce_64 { 4120 __u64 liobn; 4121 __u32 page_shift; 4122 __u32 flags; 4123 __u64 offset; /* in pages */ 4124 __u64 size; /* in pages */ 4125 }; 4126 4127The aim of extension is to support an additional bigger DMA window with 4128a variable page size. 4129KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and 4130a bus offset of the corresponding DMA window, @size and @offset are numbers 4131of IOMMU pages. 4132 4133@flags are not used at the moment. 4134 4135The rest of functionality is identical to KVM_CREATE_SPAPR_TCE. 4136 41374.99 KVM_REINJECT_CONTROL 4138------------------------- 4139 4140:Capability: KVM_CAP_REINJECT_CONTROL 4141:Architectures: x86 4142:Type: vm ioctl 4143:Parameters: struct kvm_reinject_control (in) 4144:Returns: 0 on success, 4145 -EFAULT if struct kvm_reinject_control cannot be read, 4146 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier. 4147 4148i8254 (PIT) has two modes, reinject and !reinject. The default is reinject, 4149where KVM queues elapsed i8254 ticks and monitors completion of interrupt from 4150vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its 4151interrupt whenever there isn't a pending interrupt from i8254. 4152!reinject mode injects an interrupt as soon as a tick arrives. 4153 4154:: 4155 4156 struct kvm_reinject_control { 4157 __u8 pit_reinject; 4158 __u8 reserved[31]; 4159 }; 4160 4161pit_reinject = 0 (!reinject mode) is recommended, unless running an old 4162operating system that uses the PIT for timing (e.g. Linux 2.4.x). 4163 41644.100 KVM_PPC_CONFIGURE_V3_MMU 4165------------------------------ 4166 4167:Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3 4168:Architectures: ppc 4169:Type: vm ioctl 4170:Parameters: struct kvm_ppc_mmuv3_cfg (in) 4171:Returns: 0 on success, 4172 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read, 4173 -EINVAL if the configuration is invalid 4174 4175This ioctl controls whether the guest will use radix or HPT (hashed 4176page table) translation, and sets the pointer to the process table for 4177the guest. 4178 4179:: 4180 4181 struct kvm_ppc_mmuv3_cfg { 4182 __u64 flags; 4183 __u64 process_table; 4184 }; 4185 4186There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and 4187KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest 4188to use radix tree translation, and if clear, to use HPT translation. 4189KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest 4190to be able to use the global TLB and SLB invalidation instructions; 4191if clear, the guest may not use these instructions. 4192 4193The process_table field specifies the address and size of the guest 4194process table, which is in the guest's space. This field is formatted 4195as the second doubleword of the partition table entry, as defined in 4196the Power ISA V3.00, Book III section 5.7.6.1. 4197 41984.101 KVM_PPC_GET_RMMU_INFO 4199--------------------------- 4200 4201:Capability: KVM_CAP_PPC_RADIX_MMU 4202:Architectures: ppc 4203:Type: vm ioctl 4204:Parameters: struct kvm_ppc_rmmu_info (out) 4205:Returns: 0 on success, 4206 -EFAULT if struct kvm_ppc_rmmu_info cannot be written, 4207 -EINVAL if no useful information can be returned 4208 4209This ioctl returns a structure containing two things: (a) a list 4210containing supported radix tree geometries, and (b) a list that maps 4211page sizes to put in the "AP" (actual page size) field for the tlbie 4212(TLB invalidate entry) instruction. 4213 4214:: 4215 4216 struct kvm_ppc_rmmu_info { 4217 struct kvm_ppc_radix_geom { 4218 __u8 page_shift; 4219 __u8 level_bits[4]; 4220 __u8 pad[3]; 4221 } geometries[8]; 4222 __u32 ap_encodings[8]; 4223 }; 4224 4225The geometries[] field gives up to 8 supported geometries for the 4226radix page table, in terms of the log base 2 of the smallest page 4227size, and the number of bits indexed at each level of the tree, from 4228the PTE level up to the PGD level in that order. Any unused entries 4229will have 0 in the page_shift field. 4230 4231The ap_encodings gives the supported page sizes and their AP field 4232encodings, encoded with the AP value in the top 3 bits and the log 4233base 2 of the page size in the bottom 6 bits. 4234 42354.102 KVM_PPC_RESIZE_HPT_PREPARE 4236-------------------------------- 4237 4238:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4239:Architectures: powerpc 4240:Type: vm ioctl 4241:Parameters: struct kvm_ppc_resize_hpt (in) 4242:Returns: 0 on successful completion, 4243 >0 if a new HPT is being prepared, the value is an estimated 4244 number of milliseconds until preparation is complete, 4245 -EFAULT if struct kvm_reinject_control cannot be read, 4246 -EINVAL if the supplied shift or flags are invalid, 4247 -ENOMEM if unable to allocate the new HPT, 4248 4249Used to implement the PAPR extension for runtime resizing of a guest's 4250Hashed Page Table (HPT). Specifically this starts, stops or monitors 4251the preparation of a new potential HPT for the guest, essentially 4252implementing the H_RESIZE_HPT_PREPARE hypercall. 4253 4254:: 4255 4256 struct kvm_ppc_resize_hpt { 4257 __u64 flags; 4258 __u32 shift; 4259 __u32 pad; 4260 }; 4261 4262If called with shift > 0 when there is no pending HPT for the guest, 4263this begins preparation of a new pending HPT of size 2^(shift) bytes. 4264It then returns a positive integer with the estimated number of 4265milliseconds until preparation is complete. 4266 4267If called when there is a pending HPT whose size does not match that 4268requested in the parameters, discards the existing pending HPT and 4269creates a new one as above. 4270 4271If called when there is a pending HPT of the size requested, will: 4272 4273 * If preparation of the pending HPT is already complete, return 0 4274 * If preparation of the pending HPT has failed, return an error 4275 code, then discard the pending HPT. 4276 * If preparation of the pending HPT is still in progress, return an 4277 estimated number of milliseconds until preparation is complete. 4278 4279If called with shift == 0, discards any currently pending HPT and 4280returns 0 (i.e. cancels any in-progress preparation). 4281 4282flags is reserved for future expansion, currently setting any bits in 4283flags will result in an -EINVAL. 4284 4285Normally this will be called repeatedly with the same parameters until 4286it returns <= 0. The first call will initiate preparation, subsequent 4287ones will monitor preparation until it completes or fails. 4288 42894.103 KVM_PPC_RESIZE_HPT_COMMIT 4290------------------------------- 4291 4292:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4293:Architectures: powerpc 4294:Type: vm ioctl 4295:Parameters: struct kvm_ppc_resize_hpt (in) 4296:Returns: 0 on successful completion, 4297 -EFAULT if struct kvm_reinject_control cannot be read, 4298 -EINVAL if the supplied shift or flags are invalid, 4299 -ENXIO is there is no pending HPT, or the pending HPT doesn't 4300 have the requested size, 4301 -EBUSY if the pending HPT is not fully prepared, 4302 -ENOSPC if there was a hash collision when moving existing 4303 HPT entries to the new HPT, 4304 -EIO on other error conditions 4305 4306Used to implement the PAPR extension for runtime resizing of a guest's 4307Hashed Page Table (HPT). Specifically this requests that the guest be 4308transferred to working with the new HPT, essentially implementing the 4309H_RESIZE_HPT_COMMIT hypercall. 4310 4311:: 4312 4313 struct kvm_ppc_resize_hpt { 4314 __u64 flags; 4315 __u32 shift; 4316 __u32 pad; 4317 }; 4318 4319This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has 4320returned 0 with the same parameters. In other cases 4321KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or 4322-EBUSY, though others may be possible if the preparation was started, 4323but failed). 4324 4325This will have undefined effects on the guest if it has not already 4326placed itself in a quiescent state where no vcpu will make MMU enabled 4327memory accesses. 4328 4329On succsful completion, the pending HPT will become the guest's active 4330HPT and the previous HPT will be discarded. 4331 4332On failure, the guest will still be operating on its previous HPT. 4333 43344.104 KVM_X86_GET_MCE_CAP_SUPPORTED 4335----------------------------------- 4336 4337:Capability: KVM_CAP_MCE 4338:Architectures: x86 4339:Type: system ioctl 4340:Parameters: u64 mce_cap (out) 4341:Returns: 0 on success, -1 on error 4342 4343Returns supported MCE capabilities. The u64 mce_cap parameter 4344has the same format as the MSR_IA32_MCG_CAP register. Supported 4345capabilities will have the corresponding bits set. 4346 43474.105 KVM_X86_SETUP_MCE 4348----------------------- 4349 4350:Capability: KVM_CAP_MCE 4351:Architectures: x86 4352:Type: vcpu ioctl 4353:Parameters: u64 mcg_cap (in) 4354:Returns: 0 on success, 4355 -EFAULT if u64 mcg_cap cannot be read, 4356 -EINVAL if the requested number of banks is invalid, 4357 -EINVAL if requested MCE capability is not supported. 4358 4359Initializes MCE support for use. The u64 mcg_cap parameter 4360has the same format as the MSR_IA32_MCG_CAP register and 4361specifies which capabilities should be enabled. The maximum 4362supported number of error-reporting banks can be retrieved when 4363checking for KVM_CAP_MCE. The supported capabilities can be 4364retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED. 4365 43664.106 KVM_X86_SET_MCE 4367--------------------- 4368 4369:Capability: KVM_CAP_MCE 4370:Architectures: x86 4371:Type: vcpu ioctl 4372:Parameters: struct kvm_x86_mce (in) 4373:Returns: 0 on success, 4374 -EFAULT if struct kvm_x86_mce cannot be read, 4375 -EINVAL if the bank number is invalid, 4376 -EINVAL if VAL bit is not set in status field. 4377 4378Inject a machine check error (MCE) into the guest. The input 4379parameter is:: 4380 4381 struct kvm_x86_mce { 4382 __u64 status; 4383 __u64 addr; 4384 __u64 misc; 4385 __u64 mcg_status; 4386 __u8 bank; 4387 __u8 pad1[7]; 4388 __u64 pad2[3]; 4389 }; 4390 4391If the MCE being reported is an uncorrected error, KVM will 4392inject it as an MCE exception into the guest. If the guest 4393MCG_STATUS register reports that an MCE is in progress, KVM 4394causes an KVM_EXIT_SHUTDOWN vmexit. 4395 4396Otherwise, if the MCE is a corrected error, KVM will just 4397store it in the corresponding bank (provided this bank is 4398not holding a previously reported uncorrected error). 4399 44004.107 KVM_S390_GET_CMMA_BITS 4401---------------------------- 4402 4403:Capability: KVM_CAP_S390_CMMA_MIGRATION 4404:Architectures: s390 4405:Type: vm ioctl 4406:Parameters: struct kvm_s390_cmma_log (in, out) 4407:Returns: 0 on success, a negative value on error 4408 4409This ioctl is used to get the values of the CMMA bits on the s390 4410architecture. It is meant to be used in two scenarios: 4411 4412- During live migration to save the CMMA values. Live migration needs 4413 to be enabled via the KVM_REQ_START_MIGRATION VM property. 4414- To non-destructively peek at the CMMA values, with the flag 4415 KVM_S390_CMMA_PEEK set. 4416 4417The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired 4418values are written to a buffer whose location is indicated via the "values" 4419member in the kvm_s390_cmma_log struct. The values in the input struct are 4420also updated as needed. 4421 4422Each CMMA value takes up one byte. 4423 4424:: 4425 4426 struct kvm_s390_cmma_log { 4427 __u64 start_gfn; 4428 __u32 count; 4429 __u32 flags; 4430 union { 4431 __u64 remaining; 4432 __u64 mask; 4433 }; 4434 __u64 values; 4435 }; 4436 4437start_gfn is the number of the first guest frame whose CMMA values are 4438to be retrieved, 4439 4440count is the length of the buffer in bytes, 4441 4442values points to the buffer where the result will be written to. 4443 4444If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be 4445KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with 4446other ioctls. 4447 4448The result is written in the buffer pointed to by the field values, and 4449the values of the input parameter are updated as follows. 4450 4451Depending on the flags, different actions are performed. The only 4452supported flag so far is KVM_S390_CMMA_PEEK. 4453 4454The default behaviour if KVM_S390_CMMA_PEEK is not set is: 4455start_gfn will indicate the first page frame whose CMMA bits were dirty. 4456It is not necessarily the same as the one passed as input, as clean pages 4457are skipped. 4458 4459count will indicate the number of bytes actually written in the buffer. 4460It can (and very often will) be smaller than the input value, since the 4461buffer is only filled until 16 bytes of clean values are found (which 4462are then not copied in the buffer). Since a CMMA migration block needs 4463the base address and the length, for a total of 16 bytes, we will send 4464back some clean data if there is some dirty data afterwards, as long as 4465the size of the clean data does not exceed the size of the header. This 4466allows to minimize the amount of data to be saved or transferred over 4467the network at the expense of more roundtrips to userspace. The next 4468invocation of the ioctl will skip over all the clean values, saving 4469potentially more than just the 16 bytes we found. 4470 4471If KVM_S390_CMMA_PEEK is set: 4472the existing storage attributes are read even when not in migration 4473mode, and no other action is performed; 4474 4475the output start_gfn will be equal to the input start_gfn, 4476 4477the output count will be equal to the input count, except if the end of 4478memory has been reached. 4479 4480In both cases: 4481the field "remaining" will indicate the total number of dirty CMMA values 4482still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is 4483not enabled. 4484 4485mask is unused. 4486 4487values points to the userspace buffer where the result will be stored. 4488 4489This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4490complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4491KVM_S390_CMMA_PEEK is not set but migration mode was not enabled, with 4492-EFAULT if the userspace address is invalid or if no page table is 4493present for the addresses (e.g. when using hugepages). 4494 44954.108 KVM_S390_SET_CMMA_BITS 4496---------------------------- 4497 4498:Capability: KVM_CAP_S390_CMMA_MIGRATION 4499:Architectures: s390 4500:Type: vm ioctl 4501:Parameters: struct kvm_s390_cmma_log (in) 4502:Returns: 0 on success, a negative value on error 4503 4504This ioctl is used to set the values of the CMMA bits on the s390 4505architecture. It is meant to be used during live migration to restore 4506the CMMA values, but there are no restrictions on its use. 4507The ioctl takes parameters via the kvm_s390_cmma_values struct. 4508Each CMMA value takes up one byte. 4509 4510:: 4511 4512 struct kvm_s390_cmma_log { 4513 __u64 start_gfn; 4514 __u32 count; 4515 __u32 flags; 4516 union { 4517 __u64 remaining; 4518 __u64 mask; 4519 }; 4520 __u64 values; 4521 }; 4522 4523start_gfn indicates the starting guest frame number, 4524 4525count indicates how many values are to be considered in the buffer, 4526 4527flags is not used and must be 0. 4528 4529mask indicates which PGSTE bits are to be considered. 4530 4531remaining is not used. 4532 4533values points to the buffer in userspace where to store the values. 4534 4535This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4536complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4537the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or 4538if the flags field was not 0, with -EFAULT if the userspace address is 4539invalid, if invalid pages are written to (e.g. after the end of memory) 4540or if no page table is present for the addresses (e.g. when using 4541hugepages). 4542 45434.109 KVM_PPC_GET_CPU_CHAR 4544-------------------------- 4545 4546:Capability: KVM_CAP_PPC_GET_CPU_CHAR 4547:Architectures: powerpc 4548:Type: vm ioctl 4549:Parameters: struct kvm_ppc_cpu_char (out) 4550:Returns: 0 on successful completion, 4551 -EFAULT if struct kvm_ppc_cpu_char cannot be written 4552 4553This ioctl gives userspace information about certain characteristics 4554of the CPU relating to speculative execution of instructions and 4555possible information leakage resulting from speculative execution (see 4556CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is 4557returned in struct kvm_ppc_cpu_char, which looks like this:: 4558 4559 struct kvm_ppc_cpu_char { 4560 __u64 character; /* characteristics of the CPU */ 4561 __u64 behaviour; /* recommended software behaviour */ 4562 __u64 character_mask; /* valid bits in character */ 4563 __u64 behaviour_mask; /* valid bits in behaviour */ 4564 }; 4565 4566For extensibility, the character_mask and behaviour_mask fields 4567indicate which bits of character and behaviour have been filled in by 4568the kernel. If the set of defined bits is extended in future then 4569userspace will be able to tell whether it is running on a kernel that 4570knows about the new bits. 4571 4572The character field describes attributes of the CPU which can help 4573with preventing inadvertent information disclosure - specifically, 4574whether there is an instruction to flash-invalidate the L1 data cache 4575(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set 4576to a mode where entries can only be used by the thread that created 4577them, whether the bcctr[l] instruction prevents speculation, and 4578whether a speculation barrier instruction (ori 31,31,0) is provided. 4579 4580The behaviour field describes actions that software should take to 4581prevent inadvertent information disclosure, and thus describes which 4582vulnerabilities the hardware is subject to; specifically whether the 4583L1 data cache should be flushed when returning to user mode from the 4584kernel, and whether a speculation barrier should be placed between an 4585array bounds check and the array access. 4586 4587These fields use the same bit definitions as the new 4588H_GET_CPU_CHARACTERISTICS hypercall. 4589 45904.110 KVM_MEMORY_ENCRYPT_OP 4591--------------------------- 4592 4593:Capability: basic 4594:Architectures: x86 4595:Type: vm 4596:Parameters: an opaque platform specific structure (in/out) 4597:Returns: 0 on success; -1 on error 4598 4599If the platform supports creating encrypted VMs then this ioctl can be used 4600for issuing platform-specific memory encryption commands to manage those 4601encrypted VMs. 4602 4603Currently, this ioctl is used for issuing Secure Encrypted Virtualization 4604(SEV) commands on AMD Processors. The SEV commands are defined in 4605Documentation/virt/kvm/amd-memory-encryption.rst. 4606 46074.111 KVM_MEMORY_ENCRYPT_REG_REGION 4608----------------------------------- 4609 4610:Capability: basic 4611:Architectures: x86 4612:Type: system 4613:Parameters: struct kvm_enc_region (in) 4614:Returns: 0 on success; -1 on error 4615 4616This ioctl can be used to register a guest memory region which may 4617contain encrypted data (e.g. guest RAM, SMRAM etc). 4618 4619It is used in the SEV-enabled guest. When encryption is enabled, a guest 4620memory region may contain encrypted data. The SEV memory encryption 4621engine uses a tweak such that two identical plaintext pages, each at 4622different locations will have differing ciphertexts. So swapping or 4623moving ciphertext of those pages will not result in plaintext being 4624swapped. So relocating (or migrating) physical backing pages for the SEV 4625guest will require some additional steps. 4626 4627Note: The current SEV key management spec does not provide commands to 4628swap or migrate (move) ciphertext pages. Hence, for now we pin the guest 4629memory region registered with the ioctl. 4630 46314.112 KVM_MEMORY_ENCRYPT_UNREG_REGION 4632------------------------------------- 4633 4634:Capability: basic 4635:Architectures: x86 4636:Type: system 4637:Parameters: struct kvm_enc_region (in) 4638:Returns: 0 on success; -1 on error 4639 4640This ioctl can be used to unregister the guest memory region registered 4641with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above. 4642 46434.113 KVM_HYPERV_EVENTFD 4644------------------------ 4645 4646:Capability: KVM_CAP_HYPERV_EVENTFD 4647:Architectures: x86 4648:Type: vm ioctl 4649:Parameters: struct kvm_hyperv_eventfd (in) 4650 4651This ioctl (un)registers an eventfd to receive notifications from the guest on 4652the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without 4653causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number 4654(bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit. 4655 4656:: 4657 4658 struct kvm_hyperv_eventfd { 4659 __u32 conn_id; 4660 __s32 fd; 4661 __u32 flags; 4662 __u32 padding[3]; 4663 }; 4664 4665The conn_id field should fit within 24 bits:: 4666 4667 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff 4668 4669The acceptable values for the flags field are:: 4670 4671 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) 4672 4673:Returns: 0 on success, 4674 -EINVAL if conn_id or flags is outside the allowed range, 4675 -ENOENT on deassign if the conn_id isn't registered, 4676 -EEXIST on assign if the conn_id is already registered 4677 46784.114 KVM_GET_NESTED_STATE 4679-------------------------- 4680 4681:Capability: KVM_CAP_NESTED_STATE 4682:Architectures: x86 4683:Type: vcpu ioctl 4684:Parameters: struct kvm_nested_state (in/out) 4685:Returns: 0 on success, -1 on error 4686 4687Errors: 4688 4689 ===== ============================================================= 4690 E2BIG the total state size exceeds the value of 'size' specified by 4691 the user; the size required will be written into size. 4692 ===== ============================================================= 4693 4694:: 4695 4696 struct kvm_nested_state { 4697 __u16 flags; 4698 __u16 format; 4699 __u32 size; 4700 4701 union { 4702 struct kvm_vmx_nested_state_hdr vmx; 4703 struct kvm_svm_nested_state_hdr svm; 4704 4705 /* Pad the header to 128 bytes. */ 4706 __u8 pad[120]; 4707 } hdr; 4708 4709 union { 4710 struct kvm_vmx_nested_state_data vmx[0]; 4711 struct kvm_svm_nested_state_data svm[0]; 4712 } data; 4713 }; 4714 4715 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001 4716 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002 4717 #define KVM_STATE_NESTED_EVMCS 0x00000004 4718 4719 #define KVM_STATE_NESTED_FORMAT_VMX 0 4720 #define KVM_STATE_NESTED_FORMAT_SVM 1 4721 4722 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000 4723 4724 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001 4725 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002 4726 4727 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001 4728 4729 struct kvm_vmx_nested_state_hdr { 4730 __u64 vmxon_pa; 4731 __u64 vmcs12_pa; 4732 4733 struct { 4734 __u16 flags; 4735 } smm; 4736 4737 __u32 flags; 4738 __u64 preemption_timer_deadline; 4739 }; 4740 4741 struct kvm_vmx_nested_state_data { 4742 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4743 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4744 }; 4745 4746This ioctl copies the vcpu's nested virtualization state from the kernel to 4747userspace. 4748 4749The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE 4750to the KVM_CHECK_EXTENSION ioctl(). 4751 47524.115 KVM_SET_NESTED_STATE 4753-------------------------- 4754 4755:Capability: KVM_CAP_NESTED_STATE 4756:Architectures: x86 4757:Type: vcpu ioctl 4758:Parameters: struct kvm_nested_state (in) 4759:Returns: 0 on success, -1 on error 4760 4761This copies the vcpu's kvm_nested_state struct from userspace to the kernel. 4762For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE. 4763 47644.116 KVM_(UN)REGISTER_COALESCED_MMIO 4765------------------------------------- 4766 4767:Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio) 4768 KVM_CAP_COALESCED_PIO (for coalesced pio) 4769:Architectures: all 4770:Type: vm ioctl 4771:Parameters: struct kvm_coalesced_mmio_zone 4772:Returns: 0 on success, < 0 on error 4773 4774Coalesced I/O is a performance optimization that defers hardware 4775register write emulation so that userspace exits are avoided. It is 4776typically used to reduce the overhead of emulating frequently accessed 4777hardware registers. 4778 4779When a hardware register is configured for coalesced I/O, write accesses 4780do not exit to userspace and their value is recorded in a ring buffer 4781that is shared between kernel and userspace. 4782 4783Coalesced I/O is used if one or more write accesses to a hardware 4784register can be deferred until a read or a write to another hardware 4785register on the same device. This last access will cause a vmexit and 4786userspace will process accesses from the ring buffer before emulating 4787it. That will avoid exiting to userspace on repeated writes. 4788 4789Coalesced pio is based on coalesced mmio. There is little difference 4790between coalesced mmio and pio except that coalesced pio records accesses 4791to I/O ports. 4792 47934.117 KVM_CLEAR_DIRTY_LOG (vm ioctl) 4794------------------------------------ 4795 4796:Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4797:Architectures: x86, arm64, mips 4798:Type: vm ioctl 4799:Parameters: struct kvm_clear_dirty_log (in) 4800:Returns: 0 on success, -1 on error 4801 4802:: 4803 4804 /* for KVM_CLEAR_DIRTY_LOG */ 4805 struct kvm_clear_dirty_log { 4806 __u32 slot; 4807 __u32 num_pages; 4808 __u64 first_page; 4809 union { 4810 void __user *dirty_bitmap; /* one bit per page */ 4811 __u64 padding; 4812 }; 4813 }; 4814 4815The ioctl clears the dirty status of pages in a memory slot, according to 4816the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap 4817field. Bit 0 of the bitmap corresponds to page "first_page" in the 4818memory slot, and num_pages is the size in bits of the input bitmap. 4819first_page must be a multiple of 64; num_pages must also be a multiple of 482064 unless first_page + num_pages is the size of the memory slot. For each 4821bit that is set in the input bitmap, the corresponding page is marked "clean" 4822in KVM's dirty bitmap, and dirty tracking is re-enabled for that page 4823(for example via write-protection, or by clearing the dirty bit in 4824a page table entry). 4825 4826If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 4827the address space for which you want to clear the dirty status. See 4828KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 4829 4830This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4831is enabled; for more information, see the description of the capability. 4832However, it can always be used as long as KVM_CHECK_EXTENSION confirms 4833that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. 4834 48354.118 KVM_GET_SUPPORTED_HV_CPUID 4836-------------------------------- 4837 4838:Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system) 4839:Architectures: x86 4840:Type: system ioctl, vcpu ioctl 4841:Parameters: struct kvm_cpuid2 (in/out) 4842:Returns: 0 on success, -1 on error 4843 4844:: 4845 4846 struct kvm_cpuid2 { 4847 __u32 nent; 4848 __u32 padding; 4849 struct kvm_cpuid_entry2 entries[0]; 4850 }; 4851 4852 struct kvm_cpuid_entry2 { 4853 __u32 function; 4854 __u32 index; 4855 __u32 flags; 4856 __u32 eax; 4857 __u32 ebx; 4858 __u32 ecx; 4859 __u32 edx; 4860 __u32 padding[3]; 4861 }; 4862 4863This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in 4864KVM. Userspace can use the information returned by this ioctl to construct 4865cpuid information presented to guests consuming Hyper-V enlightenments (e.g. 4866Windows or Hyper-V guests). 4867 4868CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level 4869Functional Specification (TLFS). These leaves can't be obtained with 4870KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature 4871leaves (0x40000000, 0x40000001). 4872 4873Currently, the following list of CPUID leaves are returned: 4874 4875 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS 4876 - HYPERV_CPUID_INTERFACE 4877 - HYPERV_CPUID_VERSION 4878 - HYPERV_CPUID_FEATURES 4879 - HYPERV_CPUID_ENLIGHTMENT_INFO 4880 - HYPERV_CPUID_IMPLEMENT_LIMITS 4881 - HYPERV_CPUID_NESTED_FEATURES 4882 - HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS 4883 - HYPERV_CPUID_SYNDBG_INTERFACE 4884 - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES 4885 4886Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure 4887with the 'nent' field indicating the number of entries in the variable-size 4888array 'entries'. If the number of entries is too low to describe all Hyper-V 4889feature leaves, an error (E2BIG) is returned. If the number is more or equal 4890to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the 4891number of valid entries in the 'entries' array, which is then filled. 4892 4893'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, 4894userspace should not expect to get any particular value there. 4895 4896Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike 4897system ioctl which exposes all supported feature bits unconditionally, vcpu 4898version has the following quirks: 4899 4900- HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED 4901 feature bit are only exposed when Enlightened VMCS was previously enabled 4902 on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). 4903- HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC. 4904 (presumes KVM_CREATE_IRQCHIP has already been called). 4905 49064.119 KVM_ARM_VCPU_FINALIZE 4907--------------------------- 4908 4909:Architectures: arm64 4910:Type: vcpu ioctl 4911:Parameters: int feature (in) 4912:Returns: 0 on success, -1 on error 4913 4914Errors: 4915 4916 ====== ============================================================== 4917 EPERM feature not enabled, needs configuration, or already finalized 4918 EINVAL feature unknown or not present 4919 ====== ============================================================== 4920 4921Recognised values for feature: 4922 4923 ===== =========================================== 4924 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE) 4925 ===== =========================================== 4926 4927Finalizes the configuration of the specified vcpu feature. 4928 4929The vcpu must already have been initialised, enabling the affected feature, by 4930means of a successful KVM_ARM_VCPU_INIT call with the appropriate flag set in 4931features[]. 4932 4933For affected vcpu features, this is a mandatory step that must be performed 4934before the vcpu is fully usable. 4935 4936Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be 4937configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration 4938that should be performaned and how to do it are feature-dependent. 4939 4940Other calls that depend on a particular feature being finalized, such as 4941KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with 4942-EPERM unless the feature has already been finalized by means of a 4943KVM_ARM_VCPU_FINALIZE call. 4944 4945See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization 4946using this ioctl. 4947 49484.120 KVM_SET_PMU_EVENT_FILTER 4949------------------------------ 4950 4951:Capability: KVM_CAP_PMU_EVENT_FILTER 4952:Architectures: x86 4953:Type: vm ioctl 4954:Parameters: struct kvm_pmu_event_filter (in) 4955:Returns: 0 on success, -1 on error 4956 4957:: 4958 4959 struct kvm_pmu_event_filter { 4960 __u32 action; 4961 __u32 nevents; 4962 __u32 fixed_counter_bitmap; 4963 __u32 flags; 4964 __u32 pad[4]; 4965 __u64 events[0]; 4966 }; 4967 4968This ioctl restricts the set of PMU events that the guest can program. 4969The argument holds a list of events which will be allowed or denied. 4970The eventsel+umask of each event the guest attempts to program is compared 4971against the events field to determine whether the guest should have access. 4972The events field only controls general purpose counters; fixed purpose 4973counters are controlled by the fixed_counter_bitmap. 4974 4975No flags are defined yet, the field must be zero. 4976 4977Valid values for 'action':: 4978 4979 #define KVM_PMU_EVENT_ALLOW 0 4980 #define KVM_PMU_EVENT_DENY 1 4981 49824.121 KVM_PPC_SVM_OFF 4983--------------------- 4984 4985:Capability: basic 4986:Architectures: powerpc 4987:Type: vm ioctl 4988:Parameters: none 4989:Returns: 0 on successful completion, 4990 4991Errors: 4992 4993 ====== ================================================================ 4994 EINVAL if ultravisor failed to terminate the secure guest 4995 ENOMEM if hypervisor failed to allocate new radix page tables for guest 4996 ====== ================================================================ 4997 4998This ioctl is used to turn off the secure mode of the guest or transition 4999the guest from secure mode to normal mode. This is invoked when the guest 5000is reset. This has no effect if called for a normal guest. 5001 5002This ioctl issues an ultravisor call to terminate the secure guest, 5003unpins the VPA pages and releases all the device pages that are used to 5004track the secure pages by hypervisor. 5005 50064.122 KVM_S390_NORMAL_RESET 5007--------------------------- 5008 5009:Capability: KVM_CAP_S390_VCPU_RESETS 5010:Architectures: s390 5011:Type: vcpu ioctl 5012:Parameters: none 5013:Returns: 0 5014 5015This ioctl resets VCPU registers and control structures according to 5016the cpu reset definition in the POP (Principles Of Operation). 5017 50184.123 KVM_S390_INITIAL_RESET 5019---------------------------- 5020 5021:Capability: none 5022:Architectures: s390 5023:Type: vcpu ioctl 5024:Parameters: none 5025:Returns: 0 5026 5027This ioctl resets VCPU registers and control structures according to 5028the initial cpu reset definition in the POP. However, the cpu is not 5029put into ESA mode. This reset is a superset of the normal reset. 5030 50314.124 KVM_S390_CLEAR_RESET 5032-------------------------- 5033 5034:Capability: KVM_CAP_S390_VCPU_RESETS 5035:Architectures: s390 5036:Type: vcpu ioctl 5037:Parameters: none 5038:Returns: 0 5039 5040This ioctl resets VCPU registers and control structures according to 5041the clear cpu reset definition in the POP. However, the cpu is not put 5042into ESA mode. This reset is a superset of the initial reset. 5043 5044 50454.125 KVM_S390_PV_COMMAND 5046------------------------- 5047 5048:Capability: KVM_CAP_S390_PROTECTED 5049:Architectures: s390 5050:Type: vm ioctl 5051:Parameters: struct kvm_pv_cmd 5052:Returns: 0 on success, < 0 on error 5053 5054:: 5055 5056 struct kvm_pv_cmd { 5057 __u32 cmd; /* Command to be executed */ 5058 __u16 rc; /* Ultravisor return code */ 5059 __u16 rrc; /* Ultravisor return reason code */ 5060 __u64 data; /* Data or address */ 5061 __u32 flags; /* flags for future extensions. Must be 0 for now */ 5062 __u32 reserved[3]; 5063 }; 5064 5065cmd values: 5066 5067KVM_PV_ENABLE 5068 Allocate memory and register the VM with the Ultravisor, thereby 5069 donating memory to the Ultravisor that will become inaccessible to 5070 KVM. All existing CPUs are converted to protected ones. After this 5071 command has succeeded, any CPU added via hotplug will become 5072 protected during its creation as well. 5073 5074 Errors: 5075 5076 ===== ============================= 5077 EINTR an unmasked signal is pending 5078 ===== ============================= 5079 5080KVM_PV_DISABLE 5081 5082 Deregister the VM from the Ultravisor and reclaim the memory that 5083 had been donated to the Ultravisor, making it usable by the kernel 5084 again. All registered VCPUs are converted back to non-protected 5085 ones. 5086 5087KVM_PV_VM_SET_SEC_PARMS 5088 Pass the image header from VM memory to the Ultravisor in 5089 preparation of image unpacking and verification. 5090 5091KVM_PV_VM_UNPACK 5092 Unpack (protect and decrypt) a page of the encrypted boot image. 5093 5094KVM_PV_VM_VERIFY 5095 Verify the integrity of the unpacked image. Only if this succeeds, 5096 KVM is allowed to start protected VCPUs. 5097 50984.126 KVM_X86_SET_MSR_FILTER 5099---------------------------- 5100 5101:Capability: KVM_CAP_X86_MSR_FILTER 5102:Architectures: x86 5103:Type: vm ioctl 5104:Parameters: struct kvm_msr_filter 5105:Returns: 0 on success, < 0 on error 5106 5107:: 5108 5109 struct kvm_msr_filter_range { 5110 #define KVM_MSR_FILTER_READ (1 << 0) 5111 #define KVM_MSR_FILTER_WRITE (1 << 1) 5112 __u32 flags; 5113 __u32 nmsrs; /* number of msrs in bitmap */ 5114 __u32 base; /* MSR index the bitmap starts at */ 5115 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ 5116 }; 5117 5118 #define KVM_MSR_FILTER_MAX_RANGES 16 5119 struct kvm_msr_filter { 5120 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) 5121 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) 5122 __u32 flags; 5123 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; 5124 }; 5125 5126flags values for ``struct kvm_msr_filter_range``: 5127 5128``KVM_MSR_FILTER_READ`` 5129 5130 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap 5131 indicates that a read should immediately fail, while a 1 indicates that 5132 a read for a particular MSR should be handled regardless of the default 5133 filter action. 5134 5135``KVM_MSR_FILTER_WRITE`` 5136 5137 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap 5138 indicates that a write should immediately fail, while a 1 indicates that 5139 a write for a particular MSR should be handled regardless of the default 5140 filter action. 5141 5142``KVM_MSR_FILTER_READ | KVM_MSR_FILTER_WRITE`` 5143 5144 Filter both read and write accesses to MSRs using the given bitmap. A 0 5145 in the bitmap indicates that both reads and writes should immediately fail, 5146 while a 1 indicates that reads and writes for a particular MSR are not 5147 filtered by this range. 5148 5149flags values for ``struct kvm_msr_filter``: 5150 5151``KVM_MSR_FILTER_DEFAULT_ALLOW`` 5152 5153 If no filter range matches an MSR index that is getting accessed, KVM will 5154 fall back to allowing access to the MSR. 5155 5156``KVM_MSR_FILTER_DEFAULT_DENY`` 5157 5158 If no filter range matches an MSR index that is getting accessed, KVM will 5159 fall back to rejecting access to the MSR. In this mode, all MSRs that should 5160 be processed by KVM need to explicitly be marked as allowed in the bitmaps. 5161 5162This ioctl allows user space to define up to 16 bitmaps of MSR ranges to 5163specify whether a certain MSR access should be explicitly filtered for or not. 5164 5165If this ioctl has never been invoked, MSR accesses are not guarded and the 5166default KVM in-kernel emulation behavior is fully preserved. 5167 5168Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR 5169filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes 5170an error. 5171 5172As soon as the filtering is in place, every MSR access is processed through 5173the filtering except for accesses to the x2APIC MSRs (from 0x800 to 0x8ff); 5174x2APIC MSRs are always allowed, independent of the ``default_allow`` setting, 5175and their behavior depends on the ``X2APIC_ENABLE`` bit of the APIC base 5176register. 5177 5178If a bit is within one of the defined ranges, read and write accesses are 5179guarded by the bitmap's value for the MSR index if the kind of access 5180is included in the ``struct kvm_msr_filter_range`` flags. If no range 5181cover this particular access, the behavior is determined by the flags 5182field in the kvm_msr_filter struct: ``KVM_MSR_FILTER_DEFAULT_ALLOW`` 5183and ``KVM_MSR_FILTER_DEFAULT_DENY``. 5184 5185Each bitmap range specifies a range of MSRs to potentially allow access on. 5186The range goes from MSR index [base .. base+nmsrs]. The flags field 5187indicates whether reads, writes or both reads and writes are filtered 5188by setting a 1 bit in the bitmap for the corresponding MSR index. 5189 5190If an MSR access is not permitted through the filtering, it generates a 5191#GP inside the guest. When combined with KVM_CAP_X86_USER_SPACE_MSR, that 5192allows user space to deflect and potentially handle various MSR accesses 5193into user space. 5194 5195Note, invoking this ioctl with a vCPU is running is inherently racy. However, 5196KVM does guarantee that vCPUs will see either the previous filter or the new 5197filter, e.g. MSRs with identical settings in both the old and new filter will 5198have deterministic behavior. 5199 52004.127 KVM_XEN_HVM_SET_ATTR 5201-------------------------- 5202 5203:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5204:Architectures: x86 5205:Type: vm ioctl 5206:Parameters: struct kvm_xen_hvm_attr 5207:Returns: 0 on success, < 0 on error 5208 5209:: 5210 5211 struct kvm_xen_hvm_attr { 5212 __u16 type; 5213 __u16 pad[3]; 5214 union { 5215 __u8 long_mode; 5216 __u8 vector; 5217 struct { 5218 __u64 gfn; 5219 } shared_info; 5220 __u64 pad[4]; 5221 } u; 5222 }; 5223 5224type values: 5225 5226KVM_XEN_ATTR_TYPE_LONG_MODE 5227 Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This 5228 determines the layout of the shared info pages exposed to the VM. 5229 5230KVM_XEN_ATTR_TYPE_SHARED_INFO 5231 Sets the guest physical frame number at which the Xen "shared info" 5232 page resides. Note that although Xen places vcpu_info for the first 5233 32 vCPUs in the shared_info page, KVM does not automatically do so 5234 and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO be used 5235 explicitly even when the vcpu_info for a given vCPU resides at the 5236 "default" location in the shared_info page. This is because KVM is 5237 not aware of the Xen CPU id which is used as the index into the 5238 vcpu_info[] array, so cannot know the correct default location. 5239 5240 Note that the shared info page may be constantly written to by KVM; 5241 it contains the event channel bitmap used to deliver interrupts to 5242 a Xen guest, amongst other things. It is exempt from dirty tracking 5243 mechanisms — KVM will not explicitly mark the page as dirty each 5244 time an event channel interrupt is delivered to the guest! Thus, 5245 userspace should always assume that the designated GFN is dirty if 5246 any vCPU has been running or any event channel interrupts can be 5247 routed to the guest. 5248 5249KVM_XEN_ATTR_TYPE_UPCALL_VECTOR 5250 Sets the exception vector used to deliver Xen event channel upcalls. 5251 52524.127 KVM_XEN_HVM_GET_ATTR 5253-------------------------- 5254 5255:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5256:Architectures: x86 5257:Type: vm ioctl 5258:Parameters: struct kvm_xen_hvm_attr 5259:Returns: 0 on success, < 0 on error 5260 5261Allows Xen VM attributes to be read. For the structure and types, 5262see KVM_XEN_HVM_SET_ATTR above. 5263 52644.128 KVM_XEN_VCPU_SET_ATTR 5265--------------------------- 5266 5267:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5268:Architectures: x86 5269:Type: vcpu ioctl 5270:Parameters: struct kvm_xen_vcpu_attr 5271:Returns: 0 on success, < 0 on error 5272 5273:: 5274 5275 struct kvm_xen_vcpu_attr { 5276 __u16 type; 5277 __u16 pad[3]; 5278 union { 5279 __u64 gpa; 5280 __u64 pad[4]; 5281 struct { 5282 __u64 state; 5283 __u64 state_entry_time; 5284 __u64 time_running; 5285 __u64 time_runnable; 5286 __u64 time_blocked; 5287 __u64 time_offline; 5288 } runstate; 5289 } u; 5290 }; 5291 5292type values: 5293 5294KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO 5295 Sets the guest physical address of the vcpu_info for a given vCPU. 5296 5297KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO 5298 Sets the guest physical address of an additional pvclock structure 5299 for a given vCPU. This is typically used for guest vsyscall support. 5300 5301KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR 5302 Sets the guest physical address of the vcpu_runstate_info for a given 5303 vCPU. This is how a Xen guest tracks CPU state such as steal time. 5304 5305KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT 5306 Sets the runstate (RUNSTATE_running/_runnable/_blocked/_offline) of 5307 the given vCPU from the .u.runstate.state member of the structure. 5308 KVM automatically accounts running and runnable time but blocked 5309 and offline states are only entered explicitly. 5310 5311KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA 5312 Sets all fields of the vCPU runstate data from the .u.runstate member 5313 of the structure, including the current runstate. The state_entry_time 5314 must equal the sum of the other four times. 5315 5316KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST 5317 This *adds* the contents of the .u.runstate members of the structure 5318 to the corresponding members of the given vCPU's runstate data, thus 5319 permitting atomic adjustments to the runstate times. The adjustment 5320 to the state_entry_time must equal the sum of the adjustments to the 5321 other four times. The state field must be set to -1, or to a valid 5322 runstate value (RUNSTATE_running, RUNSTATE_runnable, RUNSTATE_blocked 5323 or RUNSTATE_offline) to set the current accounted state as of the 5324 adjusted state_entry_time. 5325 53264.129 KVM_XEN_VCPU_GET_ATTR 5327--------------------------- 5328 5329:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5330:Architectures: x86 5331:Type: vcpu ioctl 5332:Parameters: struct kvm_xen_vcpu_attr 5333:Returns: 0 on success, < 0 on error 5334 5335Allows Xen vCPU attributes to be read. For the structure and types, 5336see KVM_XEN_VCPU_SET_ATTR above. 5337 5338The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used 5339with the KVM_XEN_VCPU_GET_ATTR ioctl. 5340 53414.130 KVM_ARM_MTE_COPY_TAGS 5342--------------------------- 5343 5344:Capability: KVM_CAP_ARM_MTE 5345:Architectures: arm64 5346:Type: vm ioctl 5347:Parameters: struct kvm_arm_copy_mte_tags 5348:Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect 5349 arguments, -EFAULT if memory cannot be accessed). 5350 5351:: 5352 5353 struct kvm_arm_copy_mte_tags { 5354 __u64 guest_ipa; 5355 __u64 length; 5356 void __user *addr; 5357 __u64 flags; 5358 __u64 reserved[2]; 5359 }; 5360 5361Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The 5362``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. The ``addr`` 5363field must point to a buffer which the tags will be copied to or from. 5364 5365``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or 5366``KVM_ARM_TAGS_FROM_GUEST``. 5367 5368The size of the buffer to store the tags is ``(length / 16)`` bytes 5369(granules in MTE are 16 bytes long). Each byte contains a single tag 5370value. This matches the format of ``PTRACE_PEEKMTETAGS`` and 5371``PTRACE_POKEMTETAGS``. 5372 5373If an error occurs before any data is copied then a negative error code is 5374returned. If some tags have been copied before an error occurs then the number 5375of bytes successfully copied is returned. If the call completes successfully 5376then ``length`` is returned. 5377 53784.131 KVM_GET_SREGS2 5379-------------------- 5380 5381:Capability: KVM_CAP_SREGS2 5382:Architectures: x86 5383:Type: vcpu ioctl 5384:Parameters: struct kvm_sregs2 (out) 5385:Returns: 0 on success, -1 on error 5386 5387Reads special registers from the vcpu. 5388This ioctl (when supported) replaces the KVM_GET_SREGS. 5389 5390:: 5391 5392 struct kvm_sregs2 { 5393 /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ 5394 struct kvm_segment cs, ds, es, fs, gs, ss; 5395 struct kvm_segment tr, ldt; 5396 struct kvm_dtable gdt, idt; 5397 __u64 cr0, cr2, cr3, cr4, cr8; 5398 __u64 efer; 5399 __u64 apic_base; 5400 __u64 flags; 5401 __u64 pdptrs[4]; 5402 }; 5403 5404flags values for ``kvm_sregs2``: 5405 5406``KVM_SREGS2_FLAGS_PDPTRS_VALID`` 5407 5408 Indicates thats the struct contain valid PDPTR values. 5409 5410 54114.132 KVM_SET_SREGS2 5412-------------------- 5413 5414:Capability: KVM_CAP_SREGS2 5415:Architectures: x86 5416:Type: vcpu ioctl 5417:Parameters: struct kvm_sregs2 (in) 5418:Returns: 0 on success, -1 on error 5419 5420Writes special registers into the vcpu. 5421See KVM_GET_SREGS2 for the data structures. 5422This ioctl (when supported) replaces the KVM_SET_SREGS. 5423 54244.133 KVM_GET_STATS_FD 5425---------------------- 5426 5427:Capability: KVM_CAP_STATS_BINARY_FD 5428:Architectures: all 5429:Type: vm ioctl, vcpu ioctl 5430:Parameters: none 5431:Returns: statistics file descriptor on success, < 0 on error 5432 5433Errors: 5434 5435 ====== ====================================================== 5436 ENOMEM if the fd could not be created due to lack of memory 5437 EMFILE if the number of opened files exceeds the limit 5438 ====== ====================================================== 5439 5440The returned file descriptor can be used to read VM/vCPU statistics data in 5441binary format. The data in the file descriptor consists of four blocks 5442organized as follows: 5443 5444+-------------+ 5445| Header | 5446+-------------+ 5447| id string | 5448+-------------+ 5449| Descriptors | 5450+-------------+ 5451| Stats Data | 5452+-------------+ 5453 5454Apart from the header starting at offset 0, please be aware that it is 5455not guaranteed that the four blocks are adjacent or in the above order; 5456the offsets of the id, descriptors and data blocks are found in the 5457header. However, all four blocks are aligned to 64 bit offsets in the 5458file and they do not overlap. 5459 5460All blocks except the data block are immutable. Userspace can read them 5461only one time after retrieving the file descriptor, and then use ``pread`` or 5462``lseek`` to read the statistics repeatedly. 5463 5464All data is in system endianness. 5465 5466The format of the header is as follows:: 5467 5468 struct kvm_stats_header { 5469 __u32 flags; 5470 __u32 name_size; 5471 __u32 num_desc; 5472 __u32 id_offset; 5473 __u32 desc_offset; 5474 __u32 data_offset; 5475 }; 5476 5477The ``flags`` field is not used at the moment. It is always read as 0. 5478 5479The ``name_size`` field is the size (in byte) of the statistics name string 5480(including trailing '\0') which is contained in the "id string" block and 5481appended at the end of every descriptor. 5482 5483The ``num_desc`` field is the number of descriptors that are included in the 5484descriptor block. (The actual number of values in the data block may be 5485larger, since each descriptor may comprise more than one value). 5486 5487The ``id_offset`` field is the offset of the id string from the start of the 5488file indicated by the file descriptor. It is a multiple of 8. 5489 5490The ``desc_offset`` field is the offset of the Descriptors block from the start 5491of the file indicated by the file descriptor. It is a multiple of 8. 5492 5493The ``data_offset`` field is the offset of the Stats Data block from the start 5494of the file indicated by the file descriptor. It is a multiple of 8. 5495 5496The id string block contains a string which identifies the file descriptor on 5497which KVM_GET_STATS_FD was invoked. The size of the block, including the 5498trailing ``'\0'``, is indicated by the ``name_size`` field in the header. 5499 5500The descriptors block is only needed to be read once for the lifetime of the 5501file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed 5502by a string of size ``name_size``. 5503:: 5504 5505 #define KVM_STATS_TYPE_SHIFT 0 5506 #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT) 5507 #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT) 5508 #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT) 5509 #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT) 5510 #define KVM_STATS_TYPE_LINEAR_HIST (0x3 << KVM_STATS_TYPE_SHIFT) 5511 #define KVM_STATS_TYPE_LOG_HIST (0x4 << KVM_STATS_TYPE_SHIFT) 5512 #define KVM_STATS_TYPE_MAX KVM_STATS_TYPE_LOG_HIST 5513 5514 #define KVM_STATS_UNIT_SHIFT 4 5515 #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT) 5516 #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT) 5517 #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) 5518 #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) 5519 #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) 5520 #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_CYCLES 5521 5522 #define KVM_STATS_BASE_SHIFT 8 5523 #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT) 5524 #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT) 5525 #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT) 5526 #define KVM_STATS_BASE_MAX KVM_STATS_BASE_POW2 5527 5528 struct kvm_stats_desc { 5529 __u32 flags; 5530 __s16 exponent; 5531 __u16 size; 5532 __u32 offset; 5533 __u32 bucket_size; 5534 char name[]; 5535 }; 5536 5537The ``flags`` field contains the type and unit of the statistics data described 5538by this descriptor. Its endianness is CPU native. 5539The following flags are supported: 5540 5541Bits 0-3 of ``flags`` encode the type: 5542 5543 * ``KVM_STATS_TYPE_CUMULATIVE`` 5544 The statistics reports a cumulative count. The value of data can only be increased. 5545 Most of the counters used in KVM are of this type. 5546 The corresponding ``size`` field for this type is always 1. 5547 All cumulative statistics data are read/write. 5548 * ``KVM_STATS_TYPE_INSTANT`` 5549 The statistics reports an instantaneous value. Its value can be increased or 5550 decreased. This type is usually used as a measurement of some resources, 5551 like the number of dirty pages, the number of large pages, etc. 5552 All instant statistics are read only. 5553 The corresponding ``size`` field for this type is always 1. 5554 * ``KVM_STATS_TYPE_PEAK`` 5555 The statistics data reports a peak value, for example the maximum number 5556 of items in a hash table bucket, the longest time waited and so on. 5557 The value of data can only be increased. 5558 The corresponding ``size`` field for this type is always 1. 5559 * ``KVM_STATS_TYPE_LINEAR_HIST`` 5560 The statistic is reported as a linear histogram. The number of 5561 buckets is specified by the ``size`` field. The size of buckets is specified 5562 by the ``hist_param`` field. The range of the Nth bucket (1 <= N < ``size``) 5563 is [``hist_param``*(N-1), ``hist_param``*N), while the range of the last 5564 bucket is [``hist_param``*(``size``-1), +INF). (+INF means positive infinity 5565 value.) The bucket value indicates how many samples fell in the bucket's range. 5566 * ``KVM_STATS_TYPE_LOG_HIST`` 5567 The statistic is reported as a logarithmic histogram. The number of 5568 buckets is specified by the ``size`` field. The range of the first bucket is 5569 [0, 1), while the range of the last bucket is [pow(2, ``size``-2), +INF). 5570 Otherwise, The Nth bucket (1 < N < ``size``) covers 5571 [pow(2, N-2), pow(2, N-1)). The bucket value indicates how many samples fell 5572 in the bucket's range. 5573 5574Bits 4-7 of ``flags`` encode the unit: 5575 5576 * ``KVM_STATS_UNIT_NONE`` 5577 There is no unit for the value of statistics data. This usually means that 5578 the value is a simple counter of an event. 5579 * ``KVM_STATS_UNIT_BYTES`` 5580 It indicates that the statistics data is used to measure memory size, in the 5581 unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is 5582 determined by the ``exponent`` field in the descriptor. 5583 * ``KVM_STATS_UNIT_SECONDS`` 5584 It indicates that the statistics data is used to measure time or latency. 5585 * ``KVM_STATS_UNIT_CYCLES`` 5586 It indicates that the statistics data is used to measure CPU clock cycles. 5587 5588Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the 5589unit: 5590 5591 * ``KVM_STATS_BASE_POW10`` 5592 The scale is based on power of 10. It is used for measurement of time and 5593 CPU clock cycles. For example, an exponent of -9 can be used with 5594 ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds. 5595 * ``KVM_STATS_BASE_POW2`` 5596 The scale is based on power of 2. It is used for measurement of memory size. 5597 For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to 5598 express that the unit is MiB. 5599 5600The ``size`` field is the number of values of this statistics data. Its 5601value is usually 1 for most of simple statistics. 1 means it contains an 5602unsigned 64bit data. 5603 5604The ``offset`` field is the offset from the start of Data Block to the start of 5605the corresponding statistics data. 5606 5607The ``bucket_size`` field is used as a parameter for histogram statistics data. 5608It is only used by linear histogram statistics data, specifying the size of a 5609bucket. 5610 5611The ``name`` field is the name string of the statistics data. The name string 5612starts at the end of ``struct kvm_stats_desc``. The maximum length including 5613the trailing ``'\0'``, is indicated by ``name_size`` in the header. 5614 5615The Stats Data block contains an array of 64-bit values in the same order 5616as the descriptors in Descriptors block. 5617 56184.134 KVM_GET_XSAVE2 5619-------------------- 5620 5621:Capability: KVM_CAP_XSAVE2 5622:Architectures: x86 5623:Type: vcpu ioctl 5624:Parameters: struct kvm_xsave (out) 5625:Returns: 0 on success, -1 on error 5626 5627 5628:: 5629 5630 struct kvm_xsave { 5631 __u32 region[1024]; 5632 __u32 extra[0]; 5633 }; 5634 5635This ioctl would copy current vcpu's xsave struct to the userspace. It 5636copies as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) 5637when invoked on the vm file descriptor. The size value returned by 5638KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 5639Currently, it is only greater than 4096 if a dynamic feature has been 5640enabled with ``arch_prctl()``, but this may change in the future. 5641 5642The offsets of the state save areas in struct kvm_xsave follow the contents 5643of CPUID leaf 0xD on the host. 5644 5645 56465. The kvm_run structure 5647======================== 5648 5649Application code obtains a pointer to the kvm_run structure by 5650mmap()ing a vcpu fd. From that point, application code can control 5651execution by changing fields in kvm_run prior to calling the KVM_RUN 5652ioctl, and obtain information about the reason KVM_RUN returned by 5653looking up structure members. 5654 5655:: 5656 5657 struct kvm_run { 5658 /* in */ 5659 __u8 request_interrupt_window; 5660 5661Request that KVM_RUN return when it becomes possible to inject external 5662interrupts into the guest. Useful in conjunction with KVM_INTERRUPT. 5663 5664:: 5665 5666 __u8 immediate_exit; 5667 5668This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN 5669exits immediately, returning -EINTR. In the common scenario where a 5670signal is used to "kick" a VCPU out of KVM_RUN, this field can be used 5671to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability. 5672Rather than blocking the signal outside KVM_RUN, userspace can set up 5673a signal handler that sets run->immediate_exit to a non-zero value. 5674 5675This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available. 5676 5677:: 5678 5679 __u8 padding1[6]; 5680 5681 /* out */ 5682 __u32 exit_reason; 5683 5684When KVM_RUN has returned successfully (return value 0), this informs 5685application code why KVM_RUN has returned. Allowable values for this 5686field are detailed below. 5687 5688:: 5689 5690 __u8 ready_for_interrupt_injection; 5691 5692If request_interrupt_window has been specified, this field indicates 5693an interrupt can be injected now with KVM_INTERRUPT. 5694 5695:: 5696 5697 __u8 if_flag; 5698 5699The value of the current interrupt flag. Only valid if in-kernel 5700local APIC is not used. 5701 5702:: 5703 5704 __u16 flags; 5705 5706More architecture-specific flags detailing state of the VCPU that may 5707affect the device's behavior. Current defined flags:: 5708 5709 /* x86, set if the VCPU is in system management mode */ 5710 #define KVM_RUN_X86_SMM (1 << 0) 5711 /* x86, set if bus lock detected in VM */ 5712 #define KVM_RUN_BUS_LOCK (1 << 1) 5713 5714:: 5715 5716 /* in (pre_kvm_run), out (post_kvm_run) */ 5717 __u64 cr8; 5718 5719The value of the cr8 register. Only valid if in-kernel local APIC is 5720not used. Both input and output. 5721 5722:: 5723 5724 __u64 apic_base; 5725 5726The value of the APIC BASE msr. Only valid if in-kernel local 5727APIC is not used. Both input and output. 5728 5729:: 5730 5731 union { 5732 /* KVM_EXIT_UNKNOWN */ 5733 struct { 5734 __u64 hardware_exit_reason; 5735 } hw; 5736 5737If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown 5738reasons. Further architecture-specific information is available in 5739hardware_exit_reason. 5740 5741:: 5742 5743 /* KVM_EXIT_FAIL_ENTRY */ 5744 struct { 5745 __u64 hardware_entry_failure_reason; 5746 __u32 cpu; /* if KVM_LAST_CPU */ 5747 } fail_entry; 5748 5749If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due 5750to unknown reasons. Further architecture-specific information is 5751available in hardware_entry_failure_reason. 5752 5753:: 5754 5755 /* KVM_EXIT_EXCEPTION */ 5756 struct { 5757 __u32 exception; 5758 __u32 error_code; 5759 } ex; 5760 5761Unused. 5762 5763:: 5764 5765 /* KVM_EXIT_IO */ 5766 struct { 5767 #define KVM_EXIT_IO_IN 0 5768 #define KVM_EXIT_IO_OUT 1 5769 __u8 direction; 5770 __u8 size; /* bytes */ 5771 __u16 port; 5772 __u32 count; 5773 __u64 data_offset; /* relative to kvm_run start */ 5774 } io; 5775 5776If exit_reason is KVM_EXIT_IO, then the vcpu has 5777executed a port I/O instruction which could not be satisfied by kvm. 5778data_offset describes where the data is located (KVM_EXIT_IO_OUT) or 5779where kvm expects application code to place the data for the next 5780KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. 5781 5782:: 5783 5784 /* KVM_EXIT_DEBUG */ 5785 struct { 5786 struct kvm_debug_exit_arch arch; 5787 } debug; 5788 5789If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event 5790for which architecture specific information is returned. 5791 5792:: 5793 5794 /* KVM_EXIT_MMIO */ 5795 struct { 5796 __u64 phys_addr; 5797 __u8 data[8]; 5798 __u32 len; 5799 __u8 is_write; 5800 } mmio; 5801 5802If exit_reason is KVM_EXIT_MMIO, then the vcpu has 5803executed a memory-mapped I/O instruction which could not be satisfied 5804by kvm. The 'data' member contains the written data if 'is_write' is 5805true, and should be filled by application code otherwise. 5806 5807The 'data' member contains, in its first 'len' bytes, the value as it would 5808appear if the VCPU performed a load or store of the appropriate width directly 5809to the byte array. 5810 5811.. note:: 5812 5813 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN, 5814 KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding 5815 operations are complete (and guest state is consistent) only after userspace 5816 has re-entered the kernel with KVM_RUN. The kernel side will first finish 5817 incomplete operations and then check for pending signals. 5818 5819 The pending state of the operation is not preserved in state which is 5820 visible to userspace, thus userspace should ensure that the operation is 5821 completed before performing a live migration. Userspace can re-enter the 5822 guest with an unmasked signal pending or with the immediate_exit field set 5823 to complete pending operations without allowing any further instructions 5824 to be executed. 5825 5826:: 5827 5828 /* KVM_EXIT_HYPERCALL */ 5829 struct { 5830 __u64 nr; 5831 __u64 args[6]; 5832 __u64 ret; 5833 __u32 longmode; 5834 __u32 pad; 5835 } hypercall; 5836 5837Unused. This was once used for 'hypercall to userspace'. To implement 5838such functionality, use KVM_EXIT_IO (x86) or KVM_EXIT_MMIO (all except s390). 5839 5840.. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO. 5841 5842:: 5843 5844 /* KVM_EXIT_TPR_ACCESS */ 5845 struct { 5846 __u64 rip; 5847 __u32 is_write; 5848 __u32 pad; 5849 } tpr_access; 5850 5851To be documented (KVM_TPR_ACCESS_REPORTING). 5852 5853:: 5854 5855 /* KVM_EXIT_S390_SIEIC */ 5856 struct { 5857 __u8 icptcode; 5858 __u64 mask; /* psw upper half */ 5859 __u64 addr; /* psw lower half */ 5860 __u16 ipa; 5861 __u32 ipb; 5862 } s390_sieic; 5863 5864s390 specific. 5865 5866:: 5867 5868 /* KVM_EXIT_S390_RESET */ 5869 #define KVM_S390_RESET_POR 1 5870 #define KVM_S390_RESET_CLEAR 2 5871 #define KVM_S390_RESET_SUBSYSTEM 4 5872 #define KVM_S390_RESET_CPU_INIT 8 5873 #define KVM_S390_RESET_IPL 16 5874 __u64 s390_reset_flags; 5875 5876s390 specific. 5877 5878:: 5879 5880 /* KVM_EXIT_S390_UCONTROL */ 5881 struct { 5882 __u64 trans_exc_code; 5883 __u32 pgm_code; 5884 } s390_ucontrol; 5885 5886s390 specific. A page fault has occurred for a user controlled virtual 5887machine (KVM_VM_S390_UNCONTROL) on it's host page table that cannot be 5888resolved by the kernel. 5889The program code and the translation exception code that were placed 5890in the cpu's lowcore are presented here as defined by the z Architecture 5891Principles of Operation Book in the Chapter for Dynamic Address Translation 5892(DAT) 5893 5894:: 5895 5896 /* KVM_EXIT_DCR */ 5897 struct { 5898 __u32 dcrn; 5899 __u32 data; 5900 __u8 is_write; 5901 } dcr; 5902 5903Deprecated - was used for 440 KVM. 5904 5905:: 5906 5907 /* KVM_EXIT_OSI */ 5908 struct { 5909 __u64 gprs[32]; 5910 } osi; 5911 5912MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch 5913hypercalls and exit with this exit struct that contains all the guest gprs. 5914 5915If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall. 5916Userspace can now handle the hypercall and when it's done modify the gprs as 5917necessary. Upon guest entry all guest GPRs will then be replaced by the values 5918in this struct. 5919 5920:: 5921 5922 /* KVM_EXIT_PAPR_HCALL */ 5923 struct { 5924 __u64 nr; 5925 __u64 ret; 5926 __u64 args[9]; 5927 } papr_hcall; 5928 5929This is used on 64-bit PowerPC when emulating a pSeries partition, 5930e.g. with the 'pseries' machine type in qemu. It occurs when the 5931guest does a hypercall using the 'sc 1' instruction. The 'nr' field 5932contains the hypercall number (from the guest R3), and 'args' contains 5933the arguments (from the guest R4 - R12). Userspace should put the 5934return code in 'ret' and any extra returned values in args[]. 5935The possible hypercalls are defined in the Power Architecture Platform 5936Requirements (PAPR) document available from www.power.org (free 5937developer registration required to access it). 5938 5939:: 5940 5941 /* KVM_EXIT_S390_TSCH */ 5942 struct { 5943 __u16 subchannel_id; 5944 __u16 subchannel_nr; 5945 __u32 io_int_parm; 5946 __u32 io_int_word; 5947 __u32 ipb; 5948 __u8 dequeued; 5949 } s390_tsch; 5950 5951s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled 5952and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O 5953interrupt for the target subchannel has been dequeued and subchannel_id, 5954subchannel_nr, io_int_parm and io_int_word contain the parameters for that 5955interrupt. ipb is needed for instruction parameter decoding. 5956 5957:: 5958 5959 /* KVM_EXIT_EPR */ 5960 struct { 5961 __u32 epr; 5962 } epr; 5963 5964On FSL BookE PowerPC chips, the interrupt controller has a fast patch 5965interrupt acknowledge path to the core. When the core successfully 5966delivers an interrupt, it automatically populates the EPR register with 5967the interrupt vector number and acknowledges the interrupt inside 5968the interrupt controller. 5969 5970In case the interrupt controller lives in user space, we need to do 5971the interrupt acknowledge cycle through it to fetch the next to be 5972delivered interrupt vector using this exit. 5973 5974It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an 5975external interrupt has just been delivered into the guest. User space 5976should put the acknowledged interrupt vector into the 'epr' field. 5977 5978:: 5979 5980 /* KVM_EXIT_SYSTEM_EVENT */ 5981 struct { 5982 #define KVM_SYSTEM_EVENT_SHUTDOWN 1 5983 #define KVM_SYSTEM_EVENT_RESET 2 5984 #define KVM_SYSTEM_EVENT_CRASH 3 5985 __u32 type; 5986 __u64 flags; 5987 } system_event; 5988 5989If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered 5990a system-level event using some architecture specific mechanism (hypercall 5991or some special instruction). In case of ARM64, this is triggered using 5992HVC instruction based PSCI call from the vcpu. The 'type' field describes 5993the system-level event type. The 'flags' field describes architecture 5994specific flags for the system-level event. 5995 5996Valid values for 'type' are: 5997 5998 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the 5999 VM. Userspace is not obliged to honour this, and if it does honour 6000 this does not need to destroy the VM synchronously (ie it may call 6001 KVM_RUN again before shutdown finally occurs). 6002 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. 6003 As with SHUTDOWN, userspace can choose to ignore the request, or 6004 to schedule the reset to occur in the future and may call KVM_RUN again. 6005 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest 6006 has requested a crash condition maintenance. Userspace can choose 6007 to ignore the request, or to gather VM memory core dump and/or 6008 reset/shutdown of the VM. 6009 6010Valid flags are: 6011 6012 - KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 (arm64 only) -- the guest issued 6013 a SYSTEM_RESET2 call according to v1.1 of the PSCI specification. 6014 6015:: 6016 6017 /* KVM_EXIT_IOAPIC_EOI */ 6018 struct { 6019 __u8 vector; 6020 } eoi; 6021 6022Indicates that the VCPU's in-kernel local APIC received an EOI for a 6023level-triggered IOAPIC interrupt. This exit only triggers when the 6024IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled); 6025the userspace IOAPIC should process the EOI and retrigger the interrupt if 6026it is still asserted. Vector is the LAPIC interrupt vector for which the 6027EOI was received. 6028 6029:: 6030 6031 struct kvm_hyperv_exit { 6032 #define KVM_EXIT_HYPERV_SYNIC 1 6033 #define KVM_EXIT_HYPERV_HCALL 2 6034 #define KVM_EXIT_HYPERV_SYNDBG 3 6035 __u32 type; 6036 __u32 pad1; 6037 union { 6038 struct { 6039 __u32 msr; 6040 __u32 pad2; 6041 __u64 control; 6042 __u64 evt_page; 6043 __u64 msg_page; 6044 } synic; 6045 struct { 6046 __u64 input; 6047 __u64 result; 6048 __u64 params[2]; 6049 } hcall; 6050 struct { 6051 __u32 msr; 6052 __u32 pad2; 6053 __u64 control; 6054 __u64 status; 6055 __u64 send_page; 6056 __u64 recv_page; 6057 __u64 pending_page; 6058 } syndbg; 6059 } u; 6060 }; 6061 /* KVM_EXIT_HYPERV */ 6062 struct kvm_hyperv_exit hyperv; 6063 6064Indicates that the VCPU exits into userspace to process some tasks 6065related to Hyper-V emulation. 6066 6067Valid values for 'type' are: 6068 6069 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about 6070 6071Hyper-V SynIC state change. Notification is used to remap SynIC 6072event/message pages and to enable/disable SynIC messages/events processing 6073in userspace. 6074 6075 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about 6076 6077Hyper-V Synthetic debugger state change. Notification is used to either update 6078the pending_page location or to send a control command (send the buffer located 6079in send_page or recv a buffer to recv_page). 6080 6081:: 6082 6083 /* KVM_EXIT_ARM_NISV */ 6084 struct { 6085 __u64 esr_iss; 6086 __u64 fault_ipa; 6087 } arm_nisv; 6088 6089Used on arm64 systems. If a guest accesses memory not in a memslot, 6090KVM will typically return to userspace and ask it to do MMIO emulation on its 6091behalf. However, for certain classes of instructions, no instruction decode 6092(direction, length of memory access) is provided, and fetching and decoding 6093the instruction from the VM is overly complicated to live in the kernel. 6094 6095Historically, when this situation occurred, KVM would print a warning and kill 6096the VM. KVM assumed that if the guest accessed non-memslot memory, it was 6097trying to do I/O, which just couldn't be emulated, and the warning message was 6098phrased accordingly. However, what happened more often was that a guest bug 6099caused access outside the guest memory areas which should lead to a more 6100meaningful warning message and an external abort in the guest, if the access 6101did not fall within an I/O window. 6102 6103Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable 6104this capability at VM creation. Once this is done, these types of errors will 6105instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from 6106the ESR_EL2 in the esr_iss field, and the faulting IPA in the fault_ipa field. 6107Userspace can either fix up the access if it's actually an I/O access by 6108decoding the instruction from guest memory (if it's very brave) and continue 6109executing the guest, or it can decide to suspend, dump, or restart the guest. 6110 6111Note that KVM does not skip the faulting instruction as it does for 6112KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state 6113if it decides to decode and emulate the instruction. 6114 6115:: 6116 6117 /* KVM_EXIT_X86_RDMSR / KVM_EXIT_X86_WRMSR */ 6118 struct { 6119 __u8 error; /* user -> kernel */ 6120 __u8 pad[7]; 6121 __u32 reason; /* kernel -> user */ 6122 __u32 index; /* kernel -> user */ 6123 __u64 data; /* kernel <-> user */ 6124 } msr; 6125 6126Used on x86 systems. When the VM capability KVM_CAP_X86_USER_SPACE_MSR is 6127enabled, MSR accesses to registers that would invoke a #GP by KVM kernel code 6128will instead trigger a KVM_EXIT_X86_RDMSR exit for reads and KVM_EXIT_X86_WRMSR 6129exit for writes. 6130 6131The "reason" field specifies why the MSR trap occurred. User space will only 6132receive MSR exit traps when a particular reason was requested during through 6133ENABLE_CAP. Currently valid exit reasons are: 6134 6135 KVM_MSR_EXIT_REASON_UNKNOWN - access to MSR that is unknown to KVM 6136 KVM_MSR_EXIT_REASON_INVAL - access to invalid MSRs or reserved bits 6137 KVM_MSR_EXIT_REASON_FILTER - access blocked by KVM_X86_SET_MSR_FILTER 6138 6139For KVM_EXIT_X86_RDMSR, the "index" field tells user space which MSR the guest 6140wants to read. To respond to this request with a successful read, user space 6141writes the respective data into the "data" field and must continue guest 6142execution to ensure the read data is transferred into guest register state. 6143 6144If the RDMSR request was unsuccessful, user space indicates that with a "1" in 6145the "error" field. This will inject a #GP into the guest when the VCPU is 6146executed again. 6147 6148For KVM_EXIT_X86_WRMSR, the "index" field tells user space which MSR the guest 6149wants to write. Once finished processing the event, user space must continue 6150vCPU execution. If the MSR write was unsuccessful, user space also sets the 6151"error" field to "1". 6152 6153:: 6154 6155 6156 struct kvm_xen_exit { 6157 #define KVM_EXIT_XEN_HCALL 1 6158 __u32 type; 6159 union { 6160 struct { 6161 __u32 longmode; 6162 __u32 cpl; 6163 __u64 input; 6164 __u64 result; 6165 __u64 params[6]; 6166 } hcall; 6167 } u; 6168 }; 6169 /* KVM_EXIT_XEN */ 6170 struct kvm_hyperv_exit xen; 6171 6172Indicates that the VCPU exits into userspace to process some tasks 6173related to Xen emulation. 6174 6175Valid values for 'type' are: 6176 6177 - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall. 6178 Userspace is expected to place the hypercall result into the appropriate 6179 field before invoking KVM_RUN again. 6180 6181:: 6182 6183 /* KVM_EXIT_RISCV_SBI */ 6184 struct { 6185 unsigned long extension_id; 6186 unsigned long function_id; 6187 unsigned long args[6]; 6188 unsigned long ret[2]; 6189 } riscv_sbi; 6190If exit reason is KVM_EXIT_RISCV_SBI then it indicates that the VCPU has 6191done a SBI call which is not handled by KVM RISC-V kernel module. The details 6192of the SBI call are available in 'riscv_sbi' member of kvm_run structure. The 6193'extension_id' field of 'riscv_sbi' represents SBI extension ID whereas the 6194'function_id' field represents function ID of given SBI extension. The 'args' 6195array field of 'riscv_sbi' represents parameters for the SBI call and 'ret' 6196array field represents return values. The userspace should update the return 6197values of SBI call before resuming the VCPU. For more details on RISC-V SBI 6198spec refer, https://github.com/riscv/riscv-sbi-doc. 6199 6200:: 6201 6202 /* Fix the size of the union. */ 6203 char padding[256]; 6204 }; 6205 6206 /* 6207 * shared registers between kvm and userspace. 6208 * kvm_valid_regs specifies the register classes set by the host 6209 * kvm_dirty_regs specified the register classes dirtied by userspace 6210 * struct kvm_sync_regs is architecture specific, as well as the 6211 * bits for kvm_valid_regs and kvm_dirty_regs 6212 */ 6213 __u64 kvm_valid_regs; 6214 __u64 kvm_dirty_regs; 6215 union { 6216 struct kvm_sync_regs regs; 6217 char padding[SYNC_REGS_SIZE_BYTES]; 6218 } s; 6219 6220If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access 6221certain guest registers without having to call SET/GET_*REGS. Thus we can 6222avoid some system call overhead if userspace has to handle the exit. 6223Userspace can query the validity of the structure by checking 6224kvm_valid_regs for specific bits. These bits are architecture specific 6225and usually define the validity of a groups of registers. (e.g. one bit 6226for general purpose registers) 6227 6228Please note that the kernel is allowed to use the kvm_run structure as the 6229primary storage for certain register types. Therefore, the kernel may use the 6230values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set. 6231 6232:: 6233 6234 }; 6235 6236 6237 62386. Capabilities that can be enabled on vCPUs 6239============================================ 6240 6241There are certain capabilities that change the behavior of the virtual CPU or 6242the virtual machine when enabled. To enable them, please see section 4.37. 6243Below you can find a list of capabilities and what their effect on the vCPU or 6244the virtual machine is when enabling them. 6245 6246The following information is provided along with the description: 6247 6248 Architectures: 6249 which instruction set architectures provide this ioctl. 6250 x86 includes both i386 and x86_64. 6251 6252 Target: 6253 whether this is a per-vcpu or per-vm capability. 6254 6255 Parameters: 6256 what parameters are accepted by the capability. 6257 6258 Returns: 6259 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 6260 are not detailed, but errors with specific meanings are. 6261 6262 62636.1 KVM_CAP_PPC_OSI 6264------------------- 6265 6266:Architectures: ppc 6267:Target: vcpu 6268:Parameters: none 6269:Returns: 0 on success; -1 on error 6270 6271This capability enables interception of OSI hypercalls that otherwise would 6272be treated as normal system calls to be injected into the guest. OSI hypercalls 6273were invented by Mac-on-Linux to have a standardized communication mechanism 6274between the guest and the host. 6275 6276When this capability is enabled, KVM_EXIT_OSI can occur. 6277 6278 62796.2 KVM_CAP_PPC_PAPR 6280-------------------- 6281 6282:Architectures: ppc 6283:Target: vcpu 6284:Parameters: none 6285:Returns: 0 on success; -1 on error 6286 6287This capability enables interception of PAPR hypercalls. PAPR hypercalls are 6288done using the hypercall instruction "sc 1". 6289 6290It also sets the guest privilege level to "supervisor" mode. Usually the guest 6291runs in "hypervisor" privilege mode with a few missing features. 6292 6293In addition to the above, it changes the semantics of SDR1. In this mode, the 6294HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the 6295HTAB invisible to the guest. 6296 6297When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. 6298 6299 63006.3 KVM_CAP_SW_TLB 6301------------------ 6302 6303:Architectures: ppc 6304:Target: vcpu 6305:Parameters: args[0] is the address of a struct kvm_config_tlb 6306:Returns: 0 on success; -1 on error 6307 6308:: 6309 6310 struct kvm_config_tlb { 6311 __u64 params; 6312 __u64 array; 6313 __u32 mmu_type; 6314 __u32 array_len; 6315 }; 6316 6317Configures the virtual CPU's TLB array, establishing a shared memory area 6318between userspace and KVM. The "params" and "array" fields are userspace 6319addresses of mmu-type-specific data structures. The "array_len" field is an 6320safety mechanism, and should be set to the size in bytes of the memory that 6321userspace has reserved for the array. It must be at least the size dictated 6322by "mmu_type" and "params". 6323 6324While KVM_RUN is active, the shared region is under control of KVM. Its 6325contents are undefined, and any modification by userspace results in 6326boundedly undefined behavior. 6327 6328On return from KVM_RUN, the shared region will reflect the current state of 6329the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB 6330to tell KVM which entries have been changed, prior to calling KVM_RUN again 6331on this vcpu. 6332 6333For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV: 6334 6335 - The "params" field is of type "struct kvm_book3e_206_tlb_params". 6336 - The "array" field points to an array of type "struct 6337 kvm_book3e_206_tlb_entry". 6338 - The array consists of all entries in the first TLB, followed by all 6339 entries in the second TLB. 6340 - Within a TLB, entries are ordered first by increasing set number. Within a 6341 set, entries are ordered by way (increasing ESEL). 6342 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1) 6343 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value. 6344 - The tsize field of mas1 shall be set to 4K on TLB0, even though the 6345 hardware ignores this value for TLB0. 6346 63476.4 KVM_CAP_S390_CSS_SUPPORT 6348---------------------------- 6349 6350:Architectures: s390 6351:Target: vcpu 6352:Parameters: none 6353:Returns: 0 on success; -1 on error 6354 6355This capability enables support for handling of channel I/O instructions. 6356 6357TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are 6358handled in-kernel, while the other I/O instructions are passed to userspace. 6359 6360When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST 6361SUBCHANNEL intercepts. 6362 6363Note that even though this capability is enabled per-vcpu, the complete 6364virtual machine is affected. 6365 63666.5 KVM_CAP_PPC_EPR 6367------------------- 6368 6369:Architectures: ppc 6370:Target: vcpu 6371:Parameters: args[0] defines whether the proxy facility is active 6372:Returns: 0 on success; -1 on error 6373 6374This capability enables or disables the delivery of interrupts through the 6375external proxy facility. 6376 6377When enabled (args[0] != 0), every time the guest gets an external interrupt 6378delivered, it automatically exits into user space with a KVM_EXIT_EPR exit 6379to receive the topmost interrupt vector. 6380 6381When disabled (args[0] == 0), behavior is as if this facility is unsupported. 6382 6383When this capability is enabled, KVM_EXIT_EPR can occur. 6384 63856.6 KVM_CAP_IRQ_MPIC 6386-------------------- 6387 6388:Architectures: ppc 6389:Parameters: args[0] is the MPIC device fd; 6390 args[1] is the MPIC CPU number for this vcpu 6391 6392This capability connects the vcpu to an in-kernel MPIC device. 6393 63946.7 KVM_CAP_IRQ_XICS 6395-------------------- 6396 6397:Architectures: ppc 6398:Target: vcpu 6399:Parameters: args[0] is the XICS device fd; 6400 args[1] is the XICS CPU number (server ID) for this vcpu 6401 6402This capability connects the vcpu to an in-kernel XICS device. 6403 64046.8 KVM_CAP_S390_IRQCHIP 6405------------------------ 6406 6407:Architectures: s390 6408:Target: vm 6409:Parameters: none 6410 6411This capability enables the in-kernel irqchip for s390. Please refer to 6412"4.24 KVM_CREATE_IRQCHIP" for details. 6413 64146.9 KVM_CAP_MIPS_FPU 6415-------------------- 6416 6417:Architectures: mips 6418:Target: vcpu 6419:Parameters: args[0] is reserved for future use (should be 0). 6420 6421This capability allows the use of the host Floating Point Unit by the guest. It 6422allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is 6423done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be 6424accessed (depending on the current guest FPU register mode), and the Status.FR, 6425Config5.FRE bits are accessible via the KVM API and also from the guest, 6426depending on them being supported by the FPU. 6427 64286.10 KVM_CAP_MIPS_MSA 6429--------------------- 6430 6431:Architectures: mips 6432:Target: vcpu 6433:Parameters: args[0] is reserved for future use (should be 0). 6434 6435This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. 6436It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. 6437Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*`` 6438registers can be accessed, and the Config5.MSAEn bit is accessible via the 6439KVM API and also from the guest. 6440 64416.74 KVM_CAP_SYNC_REGS 6442---------------------- 6443 6444:Architectures: s390, x86 6445:Target: s390: always enabled, x86: vcpu 6446:Parameters: none 6447:Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register 6448 sets are supported 6449 (bitfields defined in arch/x86/include/uapi/asm/kvm.h). 6450 6451As described above in the kvm_sync_regs struct info in section 5 (kvm_run): 6452KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers 6453without having to call SET/GET_*REGS". This reduces overhead by eliminating 6454repeated ioctl calls for setting and/or getting register values. This is 6455particularly important when userspace is making synchronous guest state 6456modifications, e.g. when emulating and/or intercepting instructions in 6457userspace. 6458 6459For s390 specifics, please refer to the source code. 6460 6461For x86: 6462 6463- the register sets to be copied out to kvm_run are selectable 6464 by userspace (rather that all sets being copied out for every exit). 6465- vcpu_events are available in addition to regs and sregs. 6466 6467For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to 6468function as an input bit-array field set by userspace to indicate the 6469specific register sets to be copied out on the next exit. 6470 6471To indicate when userspace has modified values that should be copied into 6472the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set. 6473This is done using the same bitflags as for the 'kvm_valid_regs' field. 6474If the dirty bit is not set, then the register set values will not be copied 6475into the vCPU even if they've been modified. 6476 6477Unused bitfields in the bitarrays must be set to zero. 6478 6479:: 6480 6481 struct kvm_sync_regs { 6482 struct kvm_regs regs; 6483 struct kvm_sregs sregs; 6484 struct kvm_vcpu_events events; 6485 }; 6486 64876.75 KVM_CAP_PPC_IRQ_XIVE 6488------------------------- 6489 6490:Architectures: ppc 6491:Target: vcpu 6492:Parameters: args[0] is the XIVE device fd; 6493 args[1] is the XIVE CPU number (server ID) for this vcpu 6494 6495This capability connects the vcpu to an in-kernel XIVE device. 6496 64977. Capabilities that can be enabled on VMs 6498========================================== 6499 6500There are certain capabilities that change the behavior of the virtual 6501machine when enabled. To enable them, please see section 4.37. Below 6502you can find a list of capabilities and what their effect on the VM 6503is when enabling them. 6504 6505The following information is provided along with the description: 6506 6507 Architectures: 6508 which instruction set architectures provide this ioctl. 6509 x86 includes both i386 and x86_64. 6510 6511 Parameters: 6512 what parameters are accepted by the capability. 6513 6514 Returns: 6515 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 6516 are not detailed, but errors with specific meanings are. 6517 6518 65197.1 KVM_CAP_PPC_ENABLE_HCALL 6520---------------------------- 6521 6522:Architectures: ppc 6523:Parameters: args[0] is the sPAPR hcall number; 6524 args[1] is 0 to disable, 1 to enable in-kernel handling 6525 6526This capability controls whether individual sPAPR hypercalls (hcalls) 6527get handled by the kernel or not. Enabling or disabling in-kernel 6528handling of an hcall is effective across the VM. On creation, an 6529initial set of hcalls are enabled for in-kernel handling, which 6530consists of those hcalls for which in-kernel handlers were implemented 6531before this capability was implemented. If disabled, the kernel will 6532not to attempt to handle the hcall, but will always exit to userspace 6533to handle it. Note that it may not make sense to enable some and 6534disable others of a group of related hcalls, but KVM does not prevent 6535userspace from doing that. 6536 6537If the hcall number specified is not one that has an in-kernel 6538implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL 6539error. 6540 65417.2 KVM_CAP_S390_USER_SIGP 6542-------------------------- 6543 6544:Architectures: s390 6545:Parameters: none 6546 6547This capability controls which SIGP orders will be handled completely in user 6548space. With this capability enabled, all fast orders will be handled completely 6549in the kernel: 6550 6551- SENSE 6552- SENSE RUNNING 6553- EXTERNAL CALL 6554- EMERGENCY SIGNAL 6555- CONDITIONAL EMERGENCY SIGNAL 6556 6557All other orders will be handled completely in user space. 6558 6559Only privileged operation exceptions will be checked for in the kernel (or even 6560in the hardware prior to interception). If this capability is not enabled, the 6561old way of handling SIGP orders is used (partially in kernel and user space). 6562 65637.3 KVM_CAP_S390_VECTOR_REGISTERS 6564--------------------------------- 6565 6566:Architectures: s390 6567:Parameters: none 6568:Returns: 0 on success, negative value on error 6569 6570Allows use of the vector registers introduced with z13 processor, and 6571provides for the synchronization between host and user space. Will 6572return -EINVAL if the machine does not support vectors. 6573 65747.4 KVM_CAP_S390_USER_STSI 6575-------------------------- 6576 6577:Architectures: s390 6578:Parameters: none 6579 6580This capability allows post-handlers for the STSI instruction. After 6581initial handling in the kernel, KVM exits to user space with 6582KVM_EXIT_S390_STSI to allow user space to insert further data. 6583 6584Before exiting to userspace, kvm handlers should fill in s390_stsi field of 6585vcpu->run:: 6586 6587 struct { 6588 __u64 addr; 6589 __u8 ar; 6590 __u8 reserved; 6591 __u8 fc; 6592 __u8 sel1; 6593 __u16 sel2; 6594 } s390_stsi; 6595 6596 @addr - guest address of STSI SYSIB 6597 @fc - function code 6598 @sel1 - selector 1 6599 @sel2 - selector 2 6600 @ar - access register number 6601 6602KVM handlers should exit to userspace with rc = -EREMOTE. 6603 66047.5 KVM_CAP_SPLIT_IRQCHIP 6605------------------------- 6606 6607:Architectures: x86 6608:Parameters: args[0] - number of routes reserved for userspace IOAPICs 6609:Returns: 0 on success, -1 on error 6610 6611Create a local apic for each processor in the kernel. This can be used 6612instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the 6613IOAPIC and PIC (and also the PIT, even though this has to be enabled 6614separately). 6615 6616This capability also enables in kernel routing of interrupt requests; 6617when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are 6618used in the IRQ routing table. The first args[0] MSI routes are reserved 6619for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes, 6620a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace. 6621 6622Fails if VCPU has already been created, or if the irqchip is already in the 6623kernel (i.e. KVM_CREATE_IRQCHIP has already been called). 6624 66257.6 KVM_CAP_S390_RI 6626------------------- 6627 6628:Architectures: s390 6629:Parameters: none 6630 6631Allows use of runtime-instrumentation introduced with zEC12 processor. 6632Will return -EINVAL if the machine does not support runtime-instrumentation. 6633Will return -EBUSY if a VCPU has already been created. 6634 66357.7 KVM_CAP_X2APIC_API 6636---------------------- 6637 6638:Architectures: x86 6639:Parameters: args[0] - features that should be enabled 6640:Returns: 0 on success, -EINVAL when args[0] contains invalid features 6641 6642Valid feature flags in args[0] are:: 6643 6644 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) 6645 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) 6646 6647Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of 6648KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, 6649allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their 6650respective sections. 6651 6652KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work 6653in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff 6654as a broadcast even in x2APIC mode in order to support physical x2APIC 6655without interrupt remapping. This is undesirable in logical mode, 6656where 0xff represents CPUs 0-7 in cluster 0. 6657 66587.8 KVM_CAP_S390_USER_INSTR0 6659---------------------------- 6660 6661:Architectures: s390 6662:Parameters: none 6663 6664With this capability enabled, all illegal instructions 0x0000 (2 bytes) will 6665be intercepted and forwarded to user space. User space can use this 6666mechanism e.g. to realize 2-byte software breakpoints. The kernel will 6667not inject an operating exception for these instructions, user space has 6668to take care of that. 6669 6670This capability can be enabled dynamically even if VCPUs were already 6671created and are running. 6672 66737.9 KVM_CAP_S390_GS 6674------------------- 6675 6676:Architectures: s390 6677:Parameters: none 6678:Returns: 0 on success; -EINVAL if the machine does not support 6679 guarded storage; -EBUSY if a VCPU has already been created. 6680 6681Allows use of guarded storage for the KVM guest. 6682 66837.10 KVM_CAP_S390_AIS 6684--------------------- 6685 6686:Architectures: s390 6687:Parameters: none 6688 6689Allow use of adapter-interruption suppression. 6690:Returns: 0 on success; -EBUSY if a VCPU has already been created. 6691 66927.11 KVM_CAP_PPC_SMT 6693-------------------- 6694 6695:Architectures: ppc 6696:Parameters: vsmt_mode, flags 6697 6698Enabling this capability on a VM provides userspace with a way to set 6699the desired virtual SMT mode (i.e. the number of virtual CPUs per 6700virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2 6701between 1 and 8. On POWER8, vsmt_mode must also be no greater than 6702the number of threads per subcore for the host. Currently flags must 6703be 0. A successful call to enable this capability will result in 6704vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is 6705subsequently queried for the VM. This capability is only supported by 6706HV KVM, and can only be set before any VCPUs have been created. 6707The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT 6708modes are available. 6709 67107.12 KVM_CAP_PPC_FWNMI 6711---------------------- 6712 6713:Architectures: ppc 6714:Parameters: none 6715 6716With this capability a machine check exception in the guest address 6717space will cause KVM to exit the guest with NMI exit reason. This 6718enables QEMU to build error log and branch to guest kernel registered 6719machine check handling routine. Without this capability KVM will 6720branch to guests' 0x200 interrupt vector. 6721 67227.13 KVM_CAP_X86_DISABLE_EXITS 6723------------------------------ 6724 6725:Architectures: x86 6726:Parameters: args[0] defines which exits are disabled 6727:Returns: 0 on success, -EINVAL when args[0] contains invalid exits 6728 6729Valid bits in args[0] are:: 6730 6731 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) 6732 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1) 6733 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) 6734 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3) 6735 6736Enabling this capability on a VM provides userspace with a way to no 6737longer intercept some instructions for improved latency in some 6738workloads, and is suggested when vCPUs are associated to dedicated 6739physical CPUs. More bits can be added in the future; userspace can 6740just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable 6741all such vmexits. 6742 6743Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. 6744 67457.14 KVM_CAP_S390_HPAGE_1M 6746-------------------------- 6747 6748:Architectures: s390 6749:Parameters: none 6750:Returns: 0 on success, -EINVAL if hpage module parameter was not set 6751 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL 6752 flag set 6753 6754With this capability the KVM support for memory backing with 1m pages 6755through hugetlbfs can be enabled for a VM. After the capability is 6756enabled, cmma can't be enabled anymore and pfmfi and the storage key 6757interpretation are disabled. If cmma has already been enabled or the 6758hpage module parameter is not set to 1, -EINVAL is returned. 6759 6760While it is generally possible to create a huge page backed VM without 6761this capability, the VM will not be able to run. 6762 67637.15 KVM_CAP_MSR_PLATFORM_INFO 6764------------------------------ 6765 6766:Architectures: x86 6767:Parameters: args[0] whether feature should be enabled or not 6768 6769With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise, 6770a #GP would be raised when the guest tries to access. Currently, this 6771capability does not enable write permissions of this MSR for the guest. 6772 67737.16 KVM_CAP_PPC_NESTED_HV 6774-------------------------- 6775 6776:Architectures: ppc 6777:Parameters: none 6778:Returns: 0 on success, -EINVAL when the implementation doesn't support 6779 nested-HV virtualization. 6780 6781HV-KVM on POWER9 and later systems allows for "nested-HV" 6782virtualization, which provides a way for a guest VM to run guests that 6783can run using the CPU's supervisor mode (privileged non-hypervisor 6784state). Enabling this capability on a VM depends on the CPU having 6785the necessary functionality and on the facility being enabled with a 6786kvm-hv module parameter. 6787 67887.17 KVM_CAP_EXCEPTION_PAYLOAD 6789------------------------------ 6790 6791:Architectures: x86 6792:Parameters: args[0] whether feature should be enabled or not 6793 6794With this capability enabled, CR2 will not be modified prior to the 6795emulated VM-exit when L1 intercepts a #PF exception that occurs in 6796L2. Similarly, for kvm-intel only, DR6 will not be modified prior to 6797the emulated VM-exit when L1 intercepts a #DB exception that occurs in 6798L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or 6799#DB) exception for L2, exception.has_payload will be set and the 6800faulting address (or the new DR6 bits*) will be reported in the 6801exception_payload field. Similarly, when userspace injects a #PF (or 6802#DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set 6803exception.has_payload and to put the faulting address - or the new DR6 6804bits\ [#]_ - in the exception_payload field. 6805 6806This capability also enables exception.pending in struct 6807kvm_vcpu_events, which allows userspace to distinguish between pending 6808and injected exceptions. 6809 6810 6811.. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception 6812 will clear DR6.RTM. 6813 68147.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 6815 6816:Architectures: x86, arm64, mips 6817:Parameters: args[0] whether feature should be enabled or not 6818 6819Valid flags are:: 6820 6821 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0) 6822 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) 6823 6824With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not 6825automatically clear and write-protect all pages that are returned as dirty. 6826Rather, userspace will have to do this operation separately using 6827KVM_CLEAR_DIRTY_LOG. 6828 6829At the cost of a slightly more complicated operation, this provides better 6830scalability and responsiveness for two reasons. First, 6831KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather 6832than requiring to sync a full memslot; this ensures that KVM does not 6833take spinlocks for an extended period of time. Second, in some cases a 6834large amount of time can pass between a call to KVM_GET_DIRTY_LOG and 6835userspace actually using the data in the page. Pages can be modified 6836during this time, which is inefficient for both the guest and userspace: 6837the guest will incur a higher penalty due to write protection faults, 6838while userspace can see false reports of dirty pages. Manual reprotection 6839helps reducing this time, improving guest performance and reducing the 6840number of dirty log false positives. 6841 6842With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap 6843will be initialized to 1 when created. This also improves performance because 6844dirty logging can be enabled gradually in small chunks on the first call 6845to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on 6846KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on 6847x86 and arm64 for now). 6848 6849KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name 6850KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make 6851it hard or impossible to use it correctly. The availability of 6852KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed. 6853Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT. 6854 68557.19 KVM_CAP_PPC_SECURE_GUEST 6856------------------------------ 6857 6858:Architectures: ppc 6859 6860This capability indicates that KVM is running on a host that has 6861ultravisor firmware and thus can support a secure guest. On such a 6862system, a guest can ask the ultravisor to make it a secure guest, 6863one whose memory is inaccessible to the host except for pages which 6864are explicitly requested to be shared with the host. The ultravisor 6865notifies KVM when a guest requests to become a secure guest, and KVM 6866has the opportunity to veto the transition. 6867 6868If present, this capability can be enabled for a VM, meaning that KVM 6869will allow the transition to secure guest mode. Otherwise KVM will 6870veto the transition. 6871 68727.20 KVM_CAP_HALT_POLL 6873---------------------- 6874 6875:Architectures: all 6876:Target: VM 6877:Parameters: args[0] is the maximum poll time in nanoseconds 6878:Returns: 0 on success; -1 on error 6879 6880This capability overrides the kvm module parameter halt_poll_ns for the 6881target VM. 6882 6883VCPU polling allows a VCPU to poll for wakeup events instead of immediately 6884scheduling during guest halts. The maximum time a VCPU can spend polling is 6885controlled by the kvm module parameter halt_poll_ns. This capability allows 6886the maximum halt time to specified on a per-VM basis, effectively overriding 6887the module parameter for the target VM. 6888 68897.21 KVM_CAP_X86_USER_SPACE_MSR 6890------------------------------- 6891 6892:Architectures: x86 6893:Target: VM 6894:Parameters: args[0] contains the mask of KVM_MSR_EXIT_REASON_* events to report 6895:Returns: 0 on success; -1 on error 6896 6897This capability enables trapping of #GP invoking RDMSR and WRMSR instructions 6898into user space. 6899 6900When a guest requests to read or write an MSR, KVM may not implement all MSRs 6901that are relevant to a respective system. It also does not differentiate by 6902CPU type. 6903 6904To allow more fine grained control over MSR handling, user space may enable 6905this capability. With it enabled, MSR accesses that match the mask specified in 6906args[0] and trigger a #GP event inside the guest by KVM will instead trigger 6907KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications which user space 6908can then handle to implement model specific MSR handling and/or user notifications 6909to inform a user that an MSR was not handled. 6910 69117.22 KVM_CAP_X86_BUS_LOCK_EXIT 6912------------------------------- 6913 6914:Architectures: x86 6915:Target: VM 6916:Parameters: args[0] defines the policy used when bus locks detected in guest 6917:Returns: 0 on success, -EINVAL when args[0] contains invalid bits 6918 6919Valid bits in args[0] are:: 6920 6921 #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) 6922 #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) 6923 6924Enabling this capability on a VM provides userspace with a way to select 6925a policy to handle the bus locks detected in guest. Userspace can obtain 6926the supported modes from the result of KVM_CHECK_EXTENSION and define it 6927through the KVM_ENABLE_CAP. 6928 6929KVM_BUS_LOCK_DETECTION_OFF and KVM_BUS_LOCK_DETECTION_EXIT are supported 6930currently and mutually exclusive with each other. More bits can be added in 6931the future. 6932 6933With KVM_BUS_LOCK_DETECTION_OFF set, bus locks in guest will not cause vm exits 6934so that no additional actions are needed. This is the default mode. 6935 6936With KVM_BUS_LOCK_DETECTION_EXIT set, vm exits happen when bus lock detected 6937in VM. KVM just exits to userspace when handling them. Userspace can enforce 6938its own throttling or other policy based mitigations. 6939 6940This capability is aimed to address the thread that VM can exploit bus locks to 6941degree the performance of the whole system. Once the userspace enable this 6942capability and select the KVM_BUS_LOCK_DETECTION_EXIT mode, KVM will set the 6943KVM_RUN_BUS_LOCK flag in vcpu-run->flags field and exit to userspace. Concerning 6944the bus lock vm exit can be preempted by a higher priority VM exit, the exit 6945notifications to userspace can be KVM_EXIT_BUS_LOCK or other reasons. 6946KVM_RUN_BUS_LOCK flag is used to distinguish between them. 6947 69487.23 KVM_CAP_PPC_DAWR1 6949---------------------- 6950 6951:Architectures: ppc 6952:Parameters: none 6953:Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR 6954 6955This capability can be used to check / enable 2nd DAWR feature provided 6956by POWER10 processor. 6957 6958 69597.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 6960------------------------------------- 6961 6962Architectures: x86 SEV enabled 6963Type: vm 6964Parameters: args[0] is the fd of the source vm 6965Returns: 0 on success; ENOTTY on error 6966 6967This capability enables userspace to copy encryption context from the vm 6968indicated by the fd to the vm this is called on. 6969 6970This is intended to support in-guest workloads scheduled by the host. This 6971allows the in-guest workload to maintain its own NPTs and keeps the two vms 6972from accidentally clobbering each other with interrupts and the like (separate 6973APIC/MSRs/etc). 6974 69757.25 KVM_CAP_SGX_ATTRIBUTE 6976-------------------------- 6977 6978:Architectures: x86 6979:Target: VM 6980:Parameters: args[0] is a file handle of a SGX attribute file in securityfs 6981:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested 6982 attribute is not supported by KVM. 6983 6984KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or 6985more priveleged enclave attributes. args[0] must hold a file handle to a valid 6986SGX attribute file corresponding to an attribute that is supported/restricted 6987by KVM (currently only PROVISIONKEY). 6988 6989The SGX subsystem restricts access to a subset of enclave attributes to provide 6990additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY 6991is restricted to deter malware from using the PROVISIONKEY to obtain a stable 6992system fingerprint. To prevent userspace from circumventing such restrictions 6993by running an enclave in a VM, KVM prevents access to privileged attributes by 6994default. 6995 6996See Documentation/x86/sgx.rst for more details. 6997 69987.26 KVM_CAP_PPC_RPT_INVALIDATE 6999------------------------------- 7000 7001:Capability: KVM_CAP_PPC_RPT_INVALIDATE 7002:Architectures: ppc 7003:Type: vm 7004 7005This capability indicates that the kernel is capable of handling 7006H_RPT_INVALIDATE hcall. 7007 7008In order to enable the use of H_RPT_INVALIDATE in the guest, 7009user space might have to advertise it for the guest. For example, 7010IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is 7011present in the "ibm,hypertas-functions" device-tree property. 7012 7013This capability is enabled for hypervisors on platforms like POWER9 7014that support radix MMU. 7015 70167.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE 7017-------------------------------------- 7018 7019:Architectures: x86 7020:Parameters: args[0] whether the feature should be enabled or not 7021 7022When this capability is enabled, an emulation failure will result in an exit 7023to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked 7024to handle a VMware backdoor instruction). Furthermore, KVM will now provide up 7025to 15 instruction bytes for any exit to userspace resulting from an emulation 7026failure. When these exits to userspace occur use the emulation_failure struct 7027instead of the internal struct. They both have the same layout, but the 7028emulation_failure struct matches the content better. It also explicitly 7029defines the 'flags' field which is used to describe the fields in the struct 7030that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is 7031set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data 7032in them.) 7033 70347.28 KVM_CAP_ARM_MTE 7035-------------------- 7036 7037:Architectures: arm64 7038:Parameters: none 7039 7040This capability indicates that KVM (and the hardware) supports exposing the 7041Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the 7042VMM before creating any VCPUs to allow the guest access. Note that MTE is only 7043available to a guest running in AArch64 mode and enabling this capability will 7044cause attempts to create AArch32 VCPUs to fail. 7045 7046When enabled the guest is able to access tags associated with any memory given 7047to the guest. KVM will ensure that the tags are maintained during swap or 7048hibernation of the host; however the VMM needs to manually save/restore the 7049tags as appropriate if the VM is migrated. 7050 7051When this capability is enabled all memory in memslots must be mapped as 7052not-shareable (no MAP_SHARED), attempts to create a memslot with a 7053MAP_SHARED mmap will result in an -EINVAL return. 7054 7055When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to 7056perform a bulk copy of tags to/from the guest. 7057 70587.29 KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 7059------------------------------------- 7060 7061Architectures: x86 SEV enabled 7062Type: vm 7063Parameters: args[0] is the fd of the source vm 7064Returns: 0 on success 7065 7066This capability enables userspace to migrate the encryption context from the VM 7067indicated by the fd to the VM this is called on. 7068 7069This is intended to support intra-host migration of VMs between userspace VMMs, 7070upgrading the VMM process without interrupting the guest. 7071 70727.30 KVM_CAP_PPC_AIL_MODE_3 7073------------------------------- 7074 7075:Capability: KVM_CAP_PPC_AIL_MODE_3 7076:Architectures: ppc 7077:Type: vm 7078 7079This capability indicates that the kernel supports the mode 3 setting for the 7080"Address Translation Mode on Interrupt" aka "Alternate Interrupt Location" 7081resource that is controlled with the H_SET_MODE hypercall. 7082 7083This capability allows a guest kernel to use a better-performance mode for 7084handling interrupts and system calls. 7085 70867.31 KVM_CAP_DISABLE_QUIRKS2 7087---------------------------- 7088 7089:Capability: KVM_CAP_DISABLE_QUIRKS2 7090:Parameters: args[0] - set of KVM quirks to disable 7091:Architectures: x86 7092:Type: vm 7093 7094This capability, if enabled, will cause KVM to disable some behavior 7095quirks. 7096 7097Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 7098quirks that can be disabled in KVM. 7099 7100The argument to KVM_ENABLE_CAP for this capability is a bitmask of 7101quirks to disable, and must be a subset of the bitmask returned by 7102KVM_CHECK_EXTENSION. 7103 7104The valid bits in cap.args[0] are: 7105 7106=================================== ============================================ 7107 KVM_X86_QUIRK_LINT0_REENABLED By default, the reset value for the LVT 7108 LINT0 register is 0x700 (APIC_MODE_EXTINT). 7109 When this quirk is disabled, the reset value 7110 is 0x10000 (APIC_LVT_MASKED). 7111 7112 KVM_X86_QUIRK_CD_NW_CLEARED By default, KVM clears CR0.CD and CR0.NW. 7113 When this quirk is disabled, KVM does not 7114 change the value of CR0.CD and CR0.NW. 7115 7116 KVM_X86_QUIRK_LAPIC_MMIO_HOLE By default, the MMIO LAPIC interface is 7117 available even when configured for x2APIC 7118 mode. When this quirk is disabled, KVM 7119 disables the MMIO LAPIC interface if the 7120 LAPIC is in x2APIC mode. 7121 7122 KVM_X86_QUIRK_OUT_7E_INC_RIP By default, KVM pre-increments %rip before 7123 exiting to userspace for an OUT instruction 7124 to port 0x7e. When this quirk is disabled, 7125 KVM does not pre-increment %rip before 7126 exiting to userspace. 7127 7128 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT When this quirk is disabled, KVM sets 7129 CPUID.01H:ECX[bit 3] (MONITOR/MWAIT) if 7130 IA32_MISC_ENABLE[bit 18] (MWAIT) is set. 7131 Additionally, when this quirk is disabled, 7132 KVM clears CPUID.01H:ECX[bit 3] if 7133 IA32_MISC_ENABLE[bit 18] is cleared. 7134=================================== ============================================ 7135 71368. Other capabilities. 7137====================== 7138 7139This section lists capabilities that give information about other 7140features of the KVM implementation. 7141 71428.1 KVM_CAP_PPC_HWRNG 7143--------------------- 7144 7145:Architectures: ppc 7146 7147This capability, if KVM_CHECK_EXTENSION indicates that it is 7148available, means that the kernel has an implementation of the 7149H_RANDOM hypercall backed by a hardware random-number generator. 7150If present, the kernel H_RANDOM handler can be enabled for guest use 7151with the KVM_CAP_PPC_ENABLE_HCALL capability. 7152 71538.2 KVM_CAP_HYPERV_SYNIC 7154------------------------ 7155 7156:Architectures: x86 7157 7158This capability, if KVM_CHECK_EXTENSION indicates that it is 7159available, means that the kernel has an implementation of the 7160Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is 7161used to support Windows Hyper-V based guest paravirt drivers(VMBus). 7162 7163In order to use SynIC, it has to be activated by setting this 7164capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this 7165will disable the use of APIC hardware virtualization even if supported 7166by the CPU, as it's incompatible with SynIC auto-EOI behavior. 7167 71688.3 KVM_CAP_PPC_RADIX_MMU 7169------------------------- 7170 7171:Architectures: ppc 7172 7173This capability, if KVM_CHECK_EXTENSION indicates that it is 7174available, means that the kernel can support guests using the 7175radix MMU defined in Power ISA V3.00 (as implemented in the POWER9 7176processor). 7177 71788.4 KVM_CAP_PPC_HASH_MMU_V3 7179--------------------------- 7180 7181:Architectures: ppc 7182 7183This capability, if KVM_CHECK_EXTENSION indicates that it is 7184available, means that the kernel can support guests using the 7185hashed page table MMU defined in Power ISA V3.00 (as implemented in 7186the POWER9 processor), including in-memory segment tables. 7187 71888.5 KVM_CAP_MIPS_VZ 7189------------------- 7190 7191:Architectures: mips 7192 7193This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 7194it is available, means that full hardware assisted virtualization capabilities 7195of the hardware are available for use through KVM. An appropriate 7196KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which 7197utilises it. 7198 7199If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 7200available, it means that the VM is using full hardware assisted virtualization 7201capabilities of the hardware. This is useful to check after creating a VM with 7202KVM_VM_MIPS_DEFAULT. 7203 7204The value returned by KVM_CHECK_EXTENSION should be compared against known 7205values (see below). All other values are reserved. This is to allow for the 7206possibility of other hardware assisted virtualization implementations which 7207may be incompatible with the MIPS VZ ASE. 7208 7209== ========================================================================== 7210 0 The trap & emulate implementation is in use to run guest code in user 7211 mode. Guest virtual memory segments are rearranged to fit the guest in the 7212 user mode address space. 7213 7214 1 The MIPS VZ ASE is in use, providing full hardware assisted 7215 virtualization, including standard guest virtual memory segments. 7216== ========================================================================== 7217 72188.6 KVM_CAP_MIPS_TE 7219------------------- 7220 7221:Architectures: mips 7222 7223This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 7224it is available, means that the trap & emulate implementation is available to 7225run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware 7226assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed 7227to KVM_CREATE_VM to create a VM which utilises it. 7228 7229If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 7230available, it means that the VM is using trap & emulate. 7231 72328.7 KVM_CAP_MIPS_64BIT 7233---------------------- 7234 7235:Architectures: mips 7236 7237This capability indicates the supported architecture type of the guest, i.e. the 7238supported register and address width. 7239 7240The values returned when this capability is checked by KVM_CHECK_EXTENSION on a 7241kvm VM handle correspond roughly to the CP0_Config.AT register field, and should 7242be checked specifically against known values (see below). All other values are 7243reserved. 7244 7245== ======================================================================== 7246 0 MIPS32 or microMIPS32. 7247 Both registers and addresses are 32-bits wide. 7248 It will only be possible to run 32-bit guest code. 7249 7250 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments. 7251 Registers are 64-bits wide, but addresses are 32-bits wide. 7252 64-bit guest code may run but cannot access MIPS64 memory segments. 7253 It will also be possible to run 32-bit guest code. 7254 7255 2 MIPS64 or microMIPS64 with access to all address segments. 7256 Both registers and addresses are 64-bits wide. 7257 It will be possible to run 64-bit or 32-bit guest code. 7258== ======================================================================== 7259 72608.9 KVM_CAP_ARM_USER_IRQ 7261------------------------ 7262 7263:Architectures: arm64 7264 7265This capability, if KVM_CHECK_EXTENSION indicates that it is available, means 7266that if userspace creates a VM without an in-kernel interrupt controller, it 7267will be notified of changes to the output level of in-kernel emulated devices, 7268which can generate virtual interrupts, presented to the VM. 7269For such VMs, on every return to userspace, the kernel 7270updates the vcpu's run->s.regs.device_irq_level field to represent the actual 7271output level of the device. 7272 7273Whenever kvm detects a change in the device output level, kvm guarantees at 7274least one return to userspace before running the VM. This exit could either 7275be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way, 7276userspace can always sample the device output level and re-compute the state of 7277the userspace interrupt controller. Userspace should always check the state 7278of run->s.regs.device_irq_level on every kvm exit. 7279The value in run->s.regs.device_irq_level can represent both level and edge 7280triggered interrupt signals, depending on the device. Edge triggered interrupt 7281signals will exit to userspace with the bit in run->s.regs.device_irq_level 7282set exactly once per edge signal. 7283 7284The field run->s.regs.device_irq_level is available independent of 7285run->kvm_valid_regs or run->kvm_dirty_regs bits. 7286 7287If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a 7288number larger than 0 indicating the version of this capability is implemented 7289and thereby which bits in run->s.regs.device_irq_level can signal values. 7290 7291Currently the following bits are defined for the device_irq_level bitmap:: 7292 7293 KVM_CAP_ARM_USER_IRQ >= 1: 7294 7295 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer 7296 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer 7297 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal 7298 7299Future versions of kvm may implement additional events. These will get 7300indicated by returning a higher number from KVM_CHECK_EXTENSION and will be 7301listed above. 7302 73038.10 KVM_CAP_PPC_SMT_POSSIBLE 7304----------------------------- 7305 7306:Architectures: ppc 7307 7308Querying this capability returns a bitmap indicating the possible 7309virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N 7310(counting from the right) is set, then a virtual SMT mode of 2^N is 7311available. 7312 73138.11 KVM_CAP_HYPERV_SYNIC2 7314-------------------------- 7315 7316:Architectures: x86 7317 7318This capability enables a newer version of Hyper-V Synthetic interrupt 7319controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM 7320doesn't clear SynIC message and event flags pages when they are enabled by 7321writing to the respective MSRs. 7322 73238.12 KVM_CAP_HYPERV_VP_INDEX 7324---------------------------- 7325 7326:Architectures: x86 7327 7328This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its 7329value is used to denote the target vcpu for a SynIC interrupt. For 7330compatibilty, KVM initializes this msr to KVM's internal vcpu index. When this 7331capability is absent, userspace can still query this msr's value. 7332 73338.13 KVM_CAP_S390_AIS_MIGRATION 7334------------------------------- 7335 7336:Architectures: s390 7337:Parameters: none 7338 7339This capability indicates if the flic device will be able to get/set the 7340AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows 7341to discover this without having to create a flic device. 7342 73438.14 KVM_CAP_S390_PSW 7344--------------------- 7345 7346:Architectures: s390 7347 7348This capability indicates that the PSW is exposed via the kvm_run structure. 7349 73508.15 KVM_CAP_S390_GMAP 7351---------------------- 7352 7353:Architectures: s390 7354 7355This capability indicates that the user space memory used as guest mapping can 7356be anywhere in the user memory address space, as long as the memory slots are 7357aligned and sized to a segment (1MB) boundary. 7358 73598.16 KVM_CAP_S390_COW 7360--------------------- 7361 7362:Architectures: s390 7363 7364This capability indicates that the user space memory used as guest mapping can 7365use copy-on-write semantics as well as dirty pages tracking via read-only page 7366tables. 7367 73688.17 KVM_CAP_S390_BPB 7369--------------------- 7370 7371:Architectures: s390 7372 7373This capability indicates that kvm will implement the interfaces to handle 7374reset, migration and nested KVM for branch prediction blocking. The stfle 7375facility 82 should not be provided to the guest without this capability. 7376 73778.18 KVM_CAP_HYPERV_TLBFLUSH 7378---------------------------- 7379 7380:Architectures: x86 7381 7382This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush 7383hypercalls: 7384HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, 7385HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. 7386 73878.19 KVM_CAP_ARM_INJECT_SERROR_ESR 7388---------------------------------- 7389 7390:Architectures: arm64 7391 7392This capability indicates that userspace can specify (via the 7393KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it 7394takes a virtual SError interrupt exception. 7395If KVM advertises this capability, userspace can only specify the ISS field for 7396the ESR syndrome. Other parts of the ESR, such as the EC are generated by the 7397CPU when the exception is taken. If this virtual SError is taken to EL1 using 7398AArch64, this value will be reported in the ISS field of ESR_ELx. 7399 7400See KVM_CAP_VCPU_EVENTS for more details. 7401 74028.20 KVM_CAP_HYPERV_SEND_IPI 7403---------------------------- 7404 7405:Architectures: x86 7406 7407This capability indicates that KVM supports paravirtualized Hyper-V IPI send 7408hypercalls: 7409HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. 7410 74118.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH 7412----------------------------------- 7413 7414:Architectures: x86 7415 7416This capability indicates that KVM running on top of Hyper-V hypervisor 7417enables Direct TLB flush for its guests meaning that TLB flush 7418hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM. 7419Due to the different ABI for hypercall parameters between Hyper-V and 7420KVM, enabling this capability effectively disables all hypercall 7421handling by KVM (as some KVM hypercall may be mistakenly treated as TLB 7422flush hypercalls by Hyper-V) so userspace should disable KVM identification 7423in CPUID and only exposes Hyper-V identification. In this case, guest 7424thinks it's running on Hyper-V and only use Hyper-V hypercalls. 7425 74268.22 KVM_CAP_S390_VCPU_RESETS 7427----------------------------- 7428 7429:Architectures: s390 7430 7431This capability indicates that the KVM_S390_NORMAL_RESET and 7432KVM_S390_CLEAR_RESET ioctls are available. 7433 74348.23 KVM_CAP_S390_PROTECTED 7435--------------------------- 7436 7437:Architectures: s390 7438 7439This capability indicates that the Ultravisor has been initialized and 7440KVM can therefore start protected VMs. 7441This capability governs the KVM_S390_PV_COMMAND ioctl and the 7442KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected 7443guests when the state change is invalid. 7444 74458.24 KVM_CAP_STEAL_TIME 7446----------------------- 7447 7448:Architectures: arm64, x86 7449 7450This capability indicates that KVM supports steal time accounting. 7451When steal time accounting is supported it may be enabled with 7452architecture-specific interfaces. This capability and the architecture- 7453specific interfaces must be consistent, i.e. if one says the feature 7454is supported, than the other should as well and vice versa. For arm64 7455see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". 7456For x86 see Documentation/virt/kvm/msr.rst "MSR_KVM_STEAL_TIME". 7457 74588.25 KVM_CAP_S390_DIAG318 7459------------------------- 7460 7461:Architectures: s390 7462 7463This capability enables a guest to set information about its control program 7464(i.e. guest kernel type and version). The information is helpful during 7465system/firmware service events, providing additional data about the guest 7466environments running on the machine. 7467 7468The information is associated with the DIAGNOSE 0x318 instruction, which sets 7469an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and 7470a 7-byte Control Program Version Code (CPVC). The CPNC determines what 7471environment the control program is running in (e.g. Linux, z/VM...), and the 7472CPVC is used for information specific to OS (e.g. Linux version, Linux 7473distribution...) 7474 7475If this capability is available, then the CPNC and CPVC can be synchronized 7476between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318). 7477 74788.26 KVM_CAP_X86_USER_SPACE_MSR 7479------------------------------- 7480 7481:Architectures: x86 7482 7483This capability indicates that KVM supports deflection of MSR reads and 7484writes to user space. It can be enabled on a VM level. If enabled, MSR 7485accesses that would usually trigger a #GP by KVM into the guest will 7486instead get bounced to user space through the KVM_EXIT_X86_RDMSR and 7487KVM_EXIT_X86_WRMSR exit notifications. 7488 74898.27 KVM_CAP_X86_MSR_FILTER 7490--------------------------- 7491 7492:Architectures: x86 7493 7494This capability indicates that KVM supports that accesses to user defined MSRs 7495may be rejected. With this capability exposed, KVM exports new VM ioctl 7496KVM_X86_SET_MSR_FILTER which user space can call to specify bitmaps of MSR 7497ranges that KVM should reject access to. 7498 7499In combination with KVM_CAP_X86_USER_SPACE_MSR, this allows user space to 7500trap and emulate MSRs that are outside of the scope of KVM as well as 7501limit the attack surface on KVM's MSR emulation code. 7502 75038.28 KVM_CAP_ENFORCE_PV_FEATURE_CPUID 7504------------------------------------- 7505 7506Architectures: x86 7507 7508When enabled, KVM will disable paravirtual features provided to the 7509guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf 7510(0x40000001). Otherwise, a guest may use the paravirtual features 7511regardless of what has actually been exposed through the CPUID leaf. 7512 75138.29 KVM_CAP_DIRTY_LOG_RING 7514--------------------------- 7515 7516:Architectures: x86 7517:Parameters: args[0] - size of the dirty log ring 7518 7519KVM is capable of tracking dirty memory using ring buffers that are 7520mmaped into userspace; there is one dirty ring per vcpu. 7521 7522The dirty ring is available to userspace as an array of 7523``struct kvm_dirty_gfn``. Each dirty entry it's defined as:: 7524 7525 struct kvm_dirty_gfn { 7526 __u32 flags; 7527 __u32 slot; /* as_id | slot_id */ 7528 __u64 offset; 7529 }; 7530 7531The following values are defined for the flags field to define the 7532current state of the entry:: 7533 7534 #define KVM_DIRTY_GFN_F_DIRTY BIT(0) 7535 #define KVM_DIRTY_GFN_F_RESET BIT(1) 7536 #define KVM_DIRTY_GFN_F_MASK 0x3 7537 7538Userspace should call KVM_ENABLE_CAP ioctl right after KVM_CREATE_VM 7539ioctl to enable this capability for the new guest and set the size of 7540the rings. Enabling the capability is only allowed before creating any 7541vCPU, and the size of the ring must be a power of two. The larger the 7542ring buffer, the less likely the ring is full and the VM is forced to 7543exit to userspace. The optimal size depends on the workload, but it is 7544recommended that it be at least 64 KiB (4096 entries). 7545 7546Just like for dirty page bitmaps, the buffer tracks writes to 7547all user memory regions for which the KVM_MEM_LOG_DIRTY_PAGES flag was 7548set in KVM_SET_USER_MEMORY_REGION. Once a memory region is registered 7549with the flag set, userspace can start harvesting dirty pages from the 7550ring buffer. 7551 7552An entry in the ring buffer can be unused (flag bits ``00``), 7553dirty (flag bits ``01``) or harvested (flag bits ``1X``). The 7554state machine for the entry is as follows:: 7555 7556 dirtied harvested reset 7557 00 -----------> 01 -------------> 1X -------+ 7558 ^ | 7559 | | 7560 +------------------------------------------+ 7561 7562To harvest the dirty pages, userspace accesses the mmaped ring buffer 7563to read the dirty GFNs. If the flags has the DIRTY bit set (at this stage 7564the RESET bit must be cleared), then it means this GFN is a dirty GFN. 7565The userspace should harvest this GFN and mark the flags from state 7566``01b`` to ``1Xb`` (bit 0 will be ignored by KVM, but bit 1 must be set 7567to show that this GFN is harvested and waiting for a reset), and move 7568on to the next GFN. The userspace should continue to do this until the 7569flags of a GFN have the DIRTY bit cleared, meaning that it has harvested 7570all the dirty GFNs that were available. 7571 7572It's not necessary for userspace to harvest the all dirty GFNs at once. 7573However it must collect the dirty GFNs in sequence, i.e., the userspace 7574program cannot skip one dirty GFN to collect the one next to it. 7575 7576After processing one or more entries in the ring buffer, userspace 7577calls the VM ioctl KVM_RESET_DIRTY_RINGS to notify the kernel about 7578it, so that the kernel will reprotect those collected GFNs. 7579Therefore, the ioctl must be called *before* reading the content of 7580the dirty pages. 7581 7582The dirty ring can get full. When it happens, the KVM_RUN of the 7583vcpu will return with exit reason KVM_EXIT_DIRTY_LOG_FULL. 7584 7585The dirty ring interface has a major difference comparing to the 7586KVM_GET_DIRTY_LOG interface in that, when reading the dirty ring from 7587userspace, it's still possible that the kernel has not yet flushed the 7588processor's dirty page buffers into the kernel buffer (with dirty bitmaps, the 7589flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one 7590needs to kick the vcpu out of KVM_RUN using a signal. The resulting 7591vmexit ensures that all dirty GFNs are flushed to the dirty rings. 7592 7593NOTE: the capability KVM_CAP_DIRTY_LOG_RING and the corresponding 7594ioctl KVM_RESET_DIRTY_RINGS are mutual exclusive to the existing ioctls 7595KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG. After enabling 7596KVM_CAP_DIRTY_LOG_RING with an acceptable dirty ring size, the virtual 7597machine will switch to ring-buffer dirty page tracking and further 7598KVM_GET_DIRTY_LOG or KVM_CLEAR_DIRTY_LOG ioctls will fail. 7599 76008.30 KVM_CAP_XEN_HVM 7601-------------------- 7602 7603:Architectures: x86 7604 7605This capability indicates the features that Xen supports for hosting Xen 7606PVHVM guests. Valid flags are:: 7607 7608 #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0) 7609 #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1) 7610 #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2) 7611 #define KVM_XEN_HVM_CONFIG_RUNSTATE (1 << 2) 7612 #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 3) 7613 7614The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG 7615ioctl is available, for the guest to set its hypercall page. 7616 7617If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be 7618provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page 7619contents, to request that KVM generate hypercall page content automatically 7620and also enable interception of guest hypercalls with KVM_EXIT_XEN. 7621 7622The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the 7623KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and 7624KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors 7625for event channel upcalls when the evtchn_upcall_pending field of a vcpu's 7626vcpu_info is set. 7627 7628The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related 7629features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are 7630supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls. 7631 7632The KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL flag indicates that IRQ routing entries 7633of the type KVM_IRQ_ROUTING_XEN_EVTCHN are supported, with the priority 7634field set to indicate 2 level event channel delivery. 7635 76368.31 KVM_CAP_PPC_MULTITCE 7637------------------------- 7638 7639:Capability: KVM_CAP_PPC_MULTITCE 7640:Architectures: ppc 7641:Type: vm 7642 7643This capability means the kernel is capable of handling hypercalls 7644H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user 7645space. This significantly accelerates DMA operations for PPC KVM guests. 7646User space should expect that its handlers for these hypercalls 7647are not going to be called if user space previously registered LIOBN 7648in KVM (via KVM_CREATE_SPAPR_TCE or similar calls). 7649 7650In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest, 7651user space might have to advertise it for the guest. For example, 7652IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is 7653present in the "ibm,hypertas-functions" device-tree property. 7654 7655The hypercalls mentioned above may or may not be processed successfully 7656in the kernel based fast path. If they can not be handled by the kernel, 7657they will get passed on to user space. So user space still has to have 7658an implementation for these despite the in kernel acceleration. 7659 7660This capability is always enabled. 7661 76628.32 KVM_CAP_PTP_KVM 7663-------------------- 7664 7665:Architectures: arm64 7666 7667This capability indicates that the KVM virtual PTP service is 7668supported in the host. A VMM can check whether the service is 7669available to the guest on migration. 7670 76718.33 KVM_CAP_HYPERV_ENFORCE_CPUID 7672--------------------------------- 7673 7674Architectures: x86 7675 7676When enabled, KVM will disable emulated Hyper-V features provided to the 7677guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all 7678currently implmented Hyper-V features are provided unconditionally when 7679Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001) 7680leaf. 7681 76828.34 KVM_CAP_EXIT_HYPERCALL 7683--------------------------- 7684 7685:Capability: KVM_CAP_EXIT_HYPERCALL 7686:Architectures: x86 7687:Type: vm 7688 7689This capability, if enabled, will cause KVM to exit to userspace 7690with KVM_EXIT_HYPERCALL exit reason to process some hypercalls. 7691 7692Calling KVM_CHECK_EXTENSION for this capability will return a bitmask 7693of hypercalls that can be configured to exit to userspace. 7694Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE. 7695 7696The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset 7697of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace 7698the hypercalls whose corresponding bit is in the argument, and return 7699ENOSYS for the others. 7700 77018.35 KVM_CAP_PMU_CAPABILITY 7702--------------------------- 7703 7704:Capability KVM_CAP_PMU_CAPABILITY 7705:Architectures: x86 7706:Type: vm 7707:Parameters: arg[0] is bitmask of PMU virtualization capabilities. 7708:Returns 0 on success, -EINVAL when arg[0] contains invalid bits 7709 7710This capability alters PMU virtualization in KVM. 7711 7712Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 7713PMU virtualization capabilities that can be adjusted on a VM. 7714 7715The argument to KVM_ENABLE_CAP is also a bitmask and selects specific 7716PMU virtualization capabilities to be applied to the VM. This can 7717only be invoked on a VM prior to the creation of VCPUs. 7718 7719At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting 7720this capability will disable PMU virtualization for that VM. Usermode 7721should adjust CPUID leaf 0xA to reflect that the PMU is disabled. 7722