1 .. SPDX-License-Identifier: GPL-2.0
3 ===================================================================
4 The Definitive KVM (Kernel-based Virtual Machine) API Documentation
5 ===================================================================
10 The kvm API is a set of ioctls that are issued to control various aspects
11 of a virtual machine. The ioctls belong to the following classes:
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
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.
21 VM ioctls must be issued from the same process (address space) that was
22 used to create the VM.
24 - vcpu ioctls: These query and set attributes that control the operation
25 of a single virtual cpu.
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.
32 - device ioctls: These query and set attributes that control the operation
35 device ioctls must be issued from the same process (address space) that
36 was used to create the VM.
41 The kvm API is centered around file descriptors. An initial
42 open("/dev/kvm") obtains a handle to the kvm subsystem; this handle
43 can be used to issue system ioctls. A KVM_CREATE_VM ioctl on this
44 handle will create a VM file descriptor which can be used to issue VM
45 ioctls. A KVM_CREATE_VCPU or KVM_CREATE_DEVICE ioctl on a VM fd will
46 create a virtual cpu or device and return a file descriptor pointing to
47 the new resource. Finally, ioctls on a vcpu or device fd can be used
48 to control the vcpu or device. For vcpus, this includes the important
49 task of actually running guest code.
51 In general file descriptors can be migrated among processes by means
52 of fork() and the SCM_RIGHTS facility of unix domain socket. These
53 kinds of tricks are explicitly not supported by kvm. While they will
54 not cause harm to the host, their actual behavior is not guaranteed by
55 the API. See "General description" for details on the ioctl usage
56 model that is supported by KVM.
58 It is important to note that althought VM ioctls may only be issued from
59 the process that created the VM, a VM's lifecycle is associated with its
60 file descriptor, not its creator (process). In other words, the VM and
61 its resources, *including the associated address space*, are not freed
62 until the last reference to the VM's file descriptor has been released.
63 For example, if fork() is issued after ioctl(KVM_CREATE_VM), the VM will
64 not be freed until both the parent (original) process and its child have
65 put their references to the VM's file descriptor.
67 Because a VM's resources are not freed until the last reference to its
68 file descriptor is released, creating additional references to a VM
69 via fork(), dup(), etc... without careful consideration is strongly
70 discouraged and may have unwanted side effects, e.g. memory allocated
71 by and on behalf of the VM's process may not be freed/unaccounted when
78 As of Linux 2.6.22, the KVM ABI has been stabilized: no backward
79 incompatible change are allowed. However, there is an extension
80 facility that allows backward-compatible extensions to the API to be
83 The extension mechanism is not based on the Linux version number.
84 Instead, kvm defines extension identifiers and a facility to query
85 whether a particular extension identifier is available. If it is, a
86 set of ioctls is available for application use.
92 This section describes ioctls that can be used to control kvm guests.
93 For each ioctl, the following information is provided along with a
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.
107 which instruction set architectures provide this ioctl.
108 x86 includes both i386 and x86_64.
114 what parameters are accepted by the ioctl.
117 the return value. General error numbers (EBADF, ENOMEM, EINVAL)
118 are not detailed, but errors with specific meanings are.
121 4.1 KVM_GET_API_VERSION
122 -----------------------
128 :Returns: the constant KVM_API_VERSION (=12)
130 This identifies the API version as the stable kvm API. It is not
131 expected that this number will change. However, Linux 2.6.20 and
132 2.6.21 report earlier versions; these are not documented and not
133 supported. Applications should refuse to run if KVM_GET_API_VERSION
134 returns a value other than 12. If this check passes, all ioctls
135 described as 'basic' will be available.
144 :Parameters: machine type identifier (KVM_VM_*)
145 :Returns: a VM fd that can be used to control the new virtual machine.
147 The new VM has no virtual cpus and no memory.
148 You probably want to use 0 as machine type.
150 In order to create user controlled virtual machines on S390, check
151 KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as
152 privileged user (CAP_SYS_ADMIN).
154 To use hardware assisted virtualization on MIPS (VZ ASE) rather than
155 the default trap & emulate implementation (which changes the virtual
156 memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the
160 On arm64, the physical address size for a VM (IPA Size limit) is limited
161 to 40bits by default. The limit can be configured if the host supports the
162 extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use
163 KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type
164 identifier, where IPA_Bits is the maximum width of any physical
165 address used by the VM. The IPA_Bits is encoded in bits[7-0] of the
166 machine type identifier.
168 e.g, to configure a guest to use 48bit physical address size::
170 vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48));
172 The requested size (IPA_Bits) must be:
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 == =========================================================
180 Host_IPA_Limit is the maximum possible value for IPA_Bits on the host and
181 is dependent on the CPU capability and the kernel configuration. The limit can
182 be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the KVM_CHECK_EXTENSION
185 Please note that configuring the IPA size does not affect the capability
186 exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects
187 size of the address translated by the stage2 level (guest physical to
188 host physical address translations).
191 4.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST
192 ----------------------------------------------------------
194 :Capability: basic, KVM_CAP_GET_MSR_FEATURES for KVM_GET_MSR_FEATURE_INDEX_LIST
197 :Parameters: struct kvm_msr_list (in/out)
198 :Returns: 0 on success; -1 on error
202 ====== ============================================================
203 EFAULT the msr index list cannot be read from or written to
204 E2BIG the msr index list is to be to fit in the array specified by
206 ====== ============================================================
210 struct kvm_msr_list {
211 __u32 nmsrs; /* number of msrs in entries */
215 The user fills in the size of the indices array in nmsrs, and in return
216 kvm adjusts nmsrs to reflect the actual number of msrs and fills in the
217 indices array with their numbers.
219 KVM_GET_MSR_INDEX_LIST returns the guest msrs that are supported. The list
220 varies by kvm version and host processor, but does not change otherwise.
222 Note: if kvm indicates supports MCE (KVM_CAP_MCE), then the MCE bank MSRs are
223 not returned in the MSR list, as different vcpus can have a different number
224 of banks, as set via the KVM_X86_SETUP_MCE ioctl.
226 KVM_GET_MSR_FEATURE_INDEX_LIST returns the list of MSRs that can be passed
227 to the KVM_GET_MSRS system ioctl. This lets userspace probe host capabilities
228 and processor features that are exposed via MSRs (e.g., VMX capabilities).
229 This list also varies by kvm version and host processor, but does not change
233 4.4 KVM_CHECK_EXTENSION
234 -----------------------
236 :Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl
238 :Type: system ioctl, vm ioctl
239 :Parameters: extension identifier (KVM_CAP_*)
240 :Returns: 0 if unsupported; 1 (or some other positive integer) if supported
242 The API allows the application to query about extensions to the core
243 kvm API. Userspace passes an extension identifier (an integer) and
244 receives an integer that describes the extension availability.
245 Generally 0 means no and 1 means yes, but some extensions may report
246 additional information in the integer return value.
248 Based on their initialization different VMs may have different capabilities.
249 It is thus encouraged to use the vm ioctl to query for capabilities (available
250 with KVM_CAP_CHECK_EXTENSION_VM on the vm fd)
252 4.5 KVM_GET_VCPU_MMAP_SIZE
253 --------------------------
259 :Returns: size of vcpu mmap area, in bytes
261 The KVM_RUN ioctl (cf.) communicates with userspace via a shared
262 memory region. This ioctl returns the size of that region. See the
263 KVM_RUN documentation for details.
266 4.6 KVM_SET_MEMORY_REGION
267 -------------------------
272 :Parameters: struct kvm_memory_region (in)
273 :Returns: 0 on success, -1 on error
275 This ioctl is obsolete and has been removed.
284 :Parameters: vcpu id (apic id on x86)
285 :Returns: vcpu fd on success, -1 on error
287 This API adds a vcpu to a virtual machine. No more than max_vcpus may be added.
288 The vcpu id is an integer in the range [0, max_vcpu_id).
290 The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of
291 the KVM_CHECK_EXTENSION ioctl() at run-time.
292 The maximum possible value for max_vcpus can be retrieved using the
293 KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time.
295 If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4
297 If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is
298 same as the value returned from KVM_CAP_NR_VCPUS.
300 The maximum possible value for max_vcpu_id can be retrieved using the
301 KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time.
303 If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that max_vcpu_id
304 is the same as the value returned from KVM_CAP_MAX_VCPUS.
306 On powerpc using book3s_hv mode, the vcpus are mapped onto virtual
307 threads in one or more virtual CPU cores. (This is because the
308 hardware requires all the hardware threads in a CPU core to be in the
309 same partition.) The KVM_CAP_PPC_SMT capability indicates the number
310 of vcpus per virtual core (vcore). The vcore id is obtained by
311 dividing the vcpu id by the number of vcpus per vcore. The vcpus in a
312 given vcore will always be in the same physical core as each other
313 (though that might be a different physical core from time to time).
314 Userspace can control the threading (SMT) mode of the guest by its
315 allocation of vcpu ids. For example, if userspace wants
316 single-threaded guest vcpus, it should make all vcpu ids be a multiple
317 of the number of vcpus per vcore.
319 For virtual cpus that have been created with S390 user controlled virtual
320 machines, the resulting vcpu fd can be memory mapped at page offset
321 KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of the virtual
322 cpu's hardware control block.
325 4.8 KVM_GET_DIRTY_LOG (vm ioctl)
326 --------------------------------
331 :Parameters: struct kvm_dirty_log (in/out)
332 :Returns: 0 on success, -1 on error
336 /* for KVM_GET_DIRTY_LOG */
337 struct kvm_dirty_log {
341 void __user *dirty_bitmap; /* one bit per page */
346 Given a memory slot, return a bitmap containing any pages dirtied
347 since the last call to this ioctl. Bit 0 is the first page in the
348 memory slot. Ensure the entire structure is cleared to avoid padding
351 If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 specifies
352 the address space for which you want to return the dirty bitmap.
353 They must be less than the value that KVM_CHECK_EXTENSION returns for
354 the KVM_CAP_MULTI_ADDRESS_SPACE capability.
356 The bits in the dirty bitmap are cleared before the ioctl returns, unless
357 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information,
358 see the description of the capability.
360 4.9 KVM_SET_MEMORY_ALIAS
361 ------------------------
366 :Parameters: struct kvm_memory_alias (in)
367 :Returns: 0 (success), -1 (error)
369 This ioctl is obsolete and has been removed.
379 :Returns: 0 on success, -1 on error
383 ===== =============================
384 EINTR an unmasked signal is pending
385 ===== =============================
387 This ioctl is used to run a guest virtual cpu. While there are no
388 explicit parameters, there is an implicit parameter block that can be
389 obtained by mmap()ing the vcpu fd at offset 0, with the size given by
390 KVM_GET_VCPU_MMAP_SIZE. The parameter block is formatted as a 'struct
391 kvm_run' (see below).
398 :Architectures: all except ARM, arm64
400 :Parameters: struct kvm_regs (out)
401 :Returns: 0 on success, -1 on error
403 Reads the general purpose registers from the vcpu.
409 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
410 __u64 rax, rbx, rcx, rdx;
411 __u64 rsi, rdi, rsp, rbp;
412 __u64 r8, r9, r10, r11;
413 __u64 r12, r13, r14, r15;
419 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
431 :Architectures: all except ARM, arm64
433 :Parameters: struct kvm_regs (in)
434 :Returns: 0 on success, -1 on error
436 Writes the general purpose registers into the vcpu.
438 See KVM_GET_REGS for the data structure.
445 :Architectures: x86, ppc
447 :Parameters: struct kvm_sregs (out)
448 :Returns: 0 on success, -1 on error
450 Reads special registers from the vcpu.
456 struct kvm_segment cs, ds, es, fs, gs, ss;
457 struct kvm_segment tr, ldt;
458 struct kvm_dtable gdt, idt;
459 __u64 cr0, cr2, cr3, cr4, cr8;
462 __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64];
465 /* ppc -- see arch/powerpc/include/uapi/asm/kvm.h */
467 interrupt_bitmap is a bitmap of pending external interrupts. At most
468 one bit may be set. This interrupt has been acknowledged by the APIC
469 but not yet injected into the cpu core.
476 :Architectures: x86, ppc
478 :Parameters: struct kvm_sregs (in)
479 :Returns: 0 on success, -1 on error
481 Writes special registers into the vcpu. See KVM_GET_SREGS for the
491 :Parameters: struct kvm_translation (in/out)
492 :Returns: 0 on success, -1 on error
494 Translates a virtual address according to the vcpu's current address
499 struct kvm_translation {
501 __u64 linear_address;
504 __u64 physical_address;
516 :Architectures: x86, ppc, mips
518 :Parameters: struct kvm_interrupt (in)
519 :Returns: 0 on success, negative on failure.
521 Queues a hardware interrupt vector to be injected.
525 /* for KVM_INTERRUPT */
526 struct kvm_interrupt {
536 ========= ===================================
538 -EEXIST if an interrupt is already enqueued
539 -EINVAL the irq number is invalid
540 -ENXIO if the PIC is in the kernel
541 -EFAULT if the pointer is invalid
542 ========= ===================================
544 Note 'irq' is an interrupt vector, not an interrupt pin or line. This
545 ioctl is useful if the in-kernel PIC is not used.
550 Queues an external interrupt to be injected. This ioctl is overleaded
551 with 3 different irq values:
555 This injects an edge type external interrupt into the guest once it's ready
556 to receive interrupts. When injected, the interrupt is done.
558 b) KVM_INTERRUPT_UNSET
560 This unsets any pending interrupt.
562 Only available with KVM_CAP_PPC_UNSET_IRQ.
564 c) KVM_INTERRUPT_SET_LEVEL
566 This injects a level type external interrupt into the guest context. The
567 interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET
570 Only available with KVM_CAP_PPC_IRQ_LEVEL.
572 Note that any value for 'irq' other than the ones stated above is invalid
573 and incurs unexpected behavior.
575 This is an asynchronous vcpu ioctl and can be invoked from any thread.
580 Queues an external interrupt to be injected into the virtual CPU. A negative
581 interrupt number dequeues the interrupt.
583 This is an asynchronous vcpu ioctl and can be invoked from any thread.
593 :Returns: -1 on error
595 Support for this has been removed. Use KVM_SET_GUEST_DEBUG instead.
601 :Capability: basic (vcpu), KVM_CAP_GET_MSR_FEATURES (system)
603 :Type: system ioctl, vcpu ioctl
604 :Parameters: struct kvm_msrs (in/out)
605 :Returns: number of msrs successfully returned;
608 When used as a system ioctl:
609 Reads the values of MSR-based features that are available for the VM. This
610 is similar to KVM_GET_SUPPORTED_CPUID, but it returns MSR indices and values.
611 The list of msr-based features can be obtained using KVM_GET_MSR_FEATURE_INDEX_LIST
614 When used as a vcpu ioctl:
615 Reads model-specific registers from the vcpu. Supported msr indices can
616 be obtained using KVM_GET_MSR_INDEX_LIST in a system ioctl.
621 __u32 nmsrs; /* number of msrs in entries */
624 struct kvm_msr_entry entries[0];
627 struct kvm_msr_entry {
633 Application code should set the 'nmsrs' member (which indicates the
634 size of the entries array) and the 'index' member of each array entry.
635 kvm will fill in the 'data' member.
644 :Parameters: struct kvm_msrs (in)
645 :Returns: number of msrs successfully set (see below), -1 on error
647 Writes model-specific registers to the vcpu. See KVM_GET_MSRS for the
650 Application code should set the 'nmsrs' member (which indicates the
651 size of the entries array), and the 'index' and 'data' members of each
654 It tries to set the MSRs in array entries[] one by one. If setting an MSR
655 fails, e.g., due to setting reserved bits, the MSR isn't supported/emulated
656 by KVM, etc..., it stops processing the MSR list and returns the number of
657 MSRs that have been set successfully.
666 :Parameters: struct kvm_cpuid (in)
667 :Returns: 0 on success, -1 on error
669 Defines the vcpu responses to the cpuid instruction. Applications
670 should use the KVM_SET_CPUID2 ioctl if available.
672 Note, when this IOCTL fails, KVM gives no guarantees that previous valid CPUID
673 configuration (if there is) is not corrupted. Userspace can get a copy of the
674 resulting CPUID configuration through KVM_GET_CPUID2 in case.
678 struct kvm_cpuid_entry {
687 /* for KVM_SET_CPUID */
691 struct kvm_cpuid_entry entries[0];
695 4.21 KVM_SET_SIGNAL_MASK
696 ------------------------
701 :Parameters: struct kvm_signal_mask (in)
702 :Returns: 0 on success, -1 on error
704 Defines which signals are blocked during execution of KVM_RUN. This
705 signal mask temporarily overrides the threads signal mask. Any
706 unblocked signal received (except SIGKILL and SIGSTOP, which retain
707 their traditional behaviour) will cause KVM_RUN to return with -EINTR.
709 Note the signal will only be delivered if not blocked by the original
714 /* for KVM_SET_SIGNAL_MASK */
715 struct kvm_signal_mask {
727 :Parameters: struct kvm_fpu (out)
728 :Returns: 0 on success, -1 on error
730 Reads the floating point state from the vcpu.
734 /* for KVM_GET_FPU and KVM_SET_FPU */
739 __u8 ftwx; /* in fxsave format */
756 :Parameters: struct kvm_fpu (in)
757 :Returns: 0 on success, -1 on error
759 Writes the floating point state to the vcpu.
763 /* for KVM_GET_FPU and KVM_SET_FPU */
768 __u8 ftwx; /* in fxsave format */
779 4.24 KVM_CREATE_IRQCHIP
780 -----------------------
782 :Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390)
783 :Architectures: x86, ARM, arm64, s390
786 :Returns: 0 on success, -1 on error
788 Creates an interrupt controller model in the kernel.
789 On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up
790 future vcpus to have a local APIC. IRQ routing for GSIs 0-15 is set to both
791 PIC and IOAPIC; GSI 16-23 only go to the IOAPIC.
792 On ARM/arm64, a GICv2 is created. Any other GIC versions require the usage of
793 KVM_CREATE_DEVICE, which also supports creating a GICv2. Using
794 KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2.
795 On s390, a dummy irq routing table is created.
797 Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled
798 before KVM_CREATE_IRQCHIP can be used.
804 :Capability: KVM_CAP_IRQCHIP
805 :Architectures: x86, arm, arm64
807 :Parameters: struct kvm_irq_level
808 :Returns: 0 on success, -1 on error
810 Sets the level of a GSI input to the interrupt controller model in the kernel.
811 On some architectures it is required that an interrupt controller model has
812 been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered
813 interrupts require the level to be set to 1 and then back to 0.
815 On real hardware, interrupt pins can be active-low or active-high. This
816 does not matter for the level field of struct kvm_irq_level: 1 always
817 means active (asserted), 0 means inactive (deasserted).
819 x86 allows the operating system to program the interrupt polarity
820 (active-low/active-high) for level-triggered interrupts, and KVM used
821 to consider the polarity. However, due to bitrot in the handling of
822 active-low interrupts, the above convention is now valid on x86 too.
823 This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace
824 should not present interrupts to the guest as active-low unless this
825 capability is present (or unless it is not using the in-kernel irqchip,
829 ARM/arm64 can signal an interrupt either at the CPU level, or at the
830 in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to
831 use PPIs designated for specific cpus. The irq field is interpreted
834 Â bits: | 31 ... 28 | 27 ... 24 | 23 ... 16 | 15 ... 0 |
835 field: | vcpu2_index | irq_type | vcpu_index | irq_id |
837 The irq_type field has the following values:
840 out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ
842 in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.)
843 (the vcpu_index field is ignored)
845 in-kernel GIC: PPI, irq_id between 16 and 31 (incl.)
847 (The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs)
849 In both cases, level is used to assert/deassert the line.
851 When KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 is supported, the target vcpu is
852 identified as (256 * vcpu2_index + vcpu_index). Otherwise, vcpu2_index
855 Note that on arm/arm64, the KVM_CAP_IRQCHIP capability only conditions
856 injection of interrupts for the in-kernel irqchip. KVM_IRQ_LINE can always
857 be used for a userspace interrupt controller.
861 struct kvm_irq_level {
864 __s32 status; /* not used for KVM_IRQ_LEVEL */
866 __u32 level; /* 0 or 1 */
873 :Capability: KVM_CAP_IRQCHIP
876 :Parameters: struct kvm_irqchip (in/out)
877 :Returns: 0 on success, -1 on error
879 Reads the state of a kernel interrupt controller created with
880 KVM_CREATE_IRQCHIP into a buffer provided by the caller.
885 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */
888 char dummy[512]; /* reserving space */
889 struct kvm_pic_state pic;
890 struct kvm_ioapic_state ioapic;
898 :Capability: KVM_CAP_IRQCHIP
901 :Parameters: struct kvm_irqchip (in)
902 :Returns: 0 on success, -1 on error
904 Sets the state of a kernel interrupt controller created with
905 KVM_CREATE_IRQCHIP from a buffer provided by the caller.
910 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */
913 char dummy[512]; /* reserving space */
914 struct kvm_pic_state pic;
915 struct kvm_ioapic_state ioapic;
920 4.28 KVM_XEN_HVM_CONFIG
921 -----------------------
923 :Capability: KVM_CAP_XEN_HVM
926 :Parameters: struct kvm_xen_hvm_config (in)
927 :Returns: 0 on success, -1 on error
929 Sets the MSR that the Xen HVM guest uses to initialize its hypercall
930 page, and provides the starting address and size of the hypercall
931 blobs in userspace. When the guest writes the MSR, kvm copies one
932 page of a blob (32- or 64-bit, depending on the vcpu mode) to guest
937 struct kvm_xen_hvm_config {
951 :Capability: KVM_CAP_ADJUST_CLOCK
954 :Parameters: struct kvm_clock_data (out)
955 :Returns: 0 on success, -1 on error
957 Gets the current timestamp of kvmclock as seen by the current guest. In
958 conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios
961 When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the
962 set of bits that KVM can return in struct kvm_clock_data's flag member.
964 The only flag defined now is KVM_CLOCK_TSC_STABLE. If set, the returned
965 value is the exact kvmclock value seen by all VCPUs at the instant
966 when KVM_GET_CLOCK was called. If clear, the returned value is simply
967 CLOCK_MONOTONIC plus a constant offset; the offset can be modified
968 with KVM_SET_CLOCK. KVM will try to make all VCPUs follow this clock,
969 but the exact value read by each VCPU could differ, because the host
974 struct kvm_clock_data {
975 __u64 clock; /* kvmclock current value */
984 :Capability: KVM_CAP_ADJUST_CLOCK
987 :Parameters: struct kvm_clock_data (in)
988 :Returns: 0 on success, -1 on error
990 Sets the current timestamp of kvmclock to the value specified in its parameter.
991 In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios
996 struct kvm_clock_data {
997 __u64 clock; /* kvmclock current value */
1003 4.31 KVM_GET_VCPU_EVENTS
1004 ------------------------
1006 :Capability: KVM_CAP_VCPU_EVENTS
1007 :Extended by: KVM_CAP_INTR_SHADOW
1008 :Architectures: x86, arm, arm64
1010 :Parameters: struct kvm_vcpu_event (out)
1011 :Returns: 0 on success, -1 on error
1016 Gets currently pending exceptions, interrupts, and NMIs as well as related
1021 struct kvm_vcpu_events {
1025 __u8 has_error_code;
1046 __u8 smm_inside_nmi;
1050 __u8 exception_has_payload;
1051 __u64 exception_payload;
1054 The following bits are defined in the flags field:
1056 - KVM_VCPUEVENT_VALID_SHADOW may be set to signal that
1057 interrupt.shadow contains a valid state.
1059 - KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a
1062 - KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the
1063 exception_has_payload, exception_payload, and exception.pending
1064 fields contain a valid state. This bit will be set whenever
1065 KVM_CAP_EXCEPTION_PAYLOAD is enabled.
1070 If the guest accesses a device that is being emulated by the host kernel in
1071 such a way that a real device would generate a physical SError, KVM may make
1072 a virtual SError pending for that VCPU. This system error interrupt remains
1073 pending until the guest takes the exception by unmasking PSTATE.A.
1075 Running the VCPU may cause it to take a pending SError, or make an access that
1076 causes an SError to become pending. The event's description is only valid while
1077 the VPCU is not running.
1079 This API provides a way to read and write the pending 'event' state that is not
1080 visible to the guest. To save, restore or migrate a VCPU the struct representing
1081 the state can be read then written using this GET/SET API, along with the other
1082 guest-visible registers. It is not possible to 'cancel' an SError that has been
1085 A device being emulated in user-space may also wish to generate an SError. To do
1086 this the events structure can be populated by user-space. The current state
1087 should be read first, to ensure no existing SError is pending. If an existing
1088 SError is pending, the architecture's 'Multiple SError interrupts' rules should
1089 be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and
1090 Serviceability (RAS) Specification").
1092 SError exceptions always have an ESR value. Some CPUs have the ability to
1093 specify what the virtual SError's ESR value should be. These systems will
1094 advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will
1095 always have a non-zero value when read, and the agent making an SError pending
1096 should specify the ISS field in the lower 24 bits of exception.serror_esr. If
1097 the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events
1098 with exception.has_esr as zero, KVM will choose an ESR.
1100 Specifying exception.has_esr on a system that does not support it will return
1101 -EINVAL. Setting anything other than the lower 24bits of exception.serror_esr
1102 will return -EINVAL.
1104 It is not possible to read back a pending external abort (injected via
1105 KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered
1106 directly to the virtual CPU).
1110 struct kvm_vcpu_events {
1112 __u8 serror_pending;
1113 __u8 serror_has_esr;
1114 __u8 ext_dabt_pending;
1115 /* Align it to 8 bytes */
1122 4.32 KVM_SET_VCPU_EVENTS
1123 ------------------------
1125 :Capability: KVM_CAP_VCPU_EVENTS
1126 :Extended by: KVM_CAP_INTR_SHADOW
1127 :Architectures: x86, arm, arm64
1129 :Parameters: struct kvm_vcpu_event (in)
1130 :Returns: 0 on success, -1 on error
1135 Set pending exceptions, interrupts, and NMIs as well as related states of the
1138 See KVM_GET_VCPU_EVENTS for the data structure.
1140 Fields that may be modified asynchronously by running VCPUs can be excluded
1141 from the update. These fields are nmi.pending, sipi_vector, smi.smm,
1142 smi.pending. Keep the corresponding bits in the flags field cleared to
1143 suppress overwriting the current in-kernel state. The bits are:
1145 =============================== ==================================
1146 KVM_VCPUEVENT_VALID_NMI_PENDING transfer nmi.pending to the kernel
1147 KVM_VCPUEVENT_VALID_SIPI_VECTOR transfer sipi_vector
1148 KVM_VCPUEVENT_VALID_SMM transfer the smi sub-struct.
1149 =============================== ==================================
1151 If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in
1152 the flags field to signal that interrupt.shadow contains a valid state and
1153 shall be written into the VCPU.
1155 KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available.
1157 If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD
1158 can be set in the flags field to signal that the
1159 exception_has_payload, exception_payload, and exception.pending fields
1160 contain a valid state and shall be written into the VCPU.
1165 User space may need to inject several types of events to the guest.
1167 Set the pending SError exception state for this VCPU. It is not possible to
1168 'cancel' an Serror that has been made pending.
1170 If the guest performed an access to I/O memory which could not be handled by
1171 userspace, for example because of missing instruction syndrome decode
1172 information or because there is no device mapped at the accessed IPA, then
1173 userspace can ask the kernel to inject an external abort using the address
1174 from the exiting fault on the VCPU. It is a programming error to set
1175 ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or
1176 KVM_EXIT_ARM_NISV. This feature is only available if the system supports
1177 KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in
1178 how userspace reports accesses for the above cases to guests, across different
1179 userspace implementations. Nevertheless, userspace can still emulate all Arm
1180 exceptions by manipulating individual registers using the KVM_SET_ONE_REG API.
1182 See KVM_GET_VCPU_EVENTS for the data structure.
1185 4.33 KVM_GET_DEBUGREGS
1186 ----------------------
1188 :Capability: KVM_CAP_DEBUGREGS
1191 :Parameters: struct kvm_debugregs (out)
1192 :Returns: 0 on success, -1 on error
1194 Reads debug registers from the vcpu.
1198 struct kvm_debugregs {
1207 4.34 KVM_SET_DEBUGREGS
1208 ----------------------
1210 :Capability: KVM_CAP_DEBUGREGS
1213 :Parameters: struct kvm_debugregs (in)
1214 :Returns: 0 on success, -1 on error
1216 Writes debug registers into the vcpu.
1218 See KVM_GET_DEBUGREGS for the data structure. The flags field is unused
1219 yet and must be cleared on entry.
1222 4.35 KVM_SET_USER_MEMORY_REGION
1223 -------------------------------
1225 :Capability: KVM_CAP_USER_MEMORY
1228 :Parameters: struct kvm_userspace_memory_region (in)
1229 :Returns: 0 on success, -1 on error
1233 struct kvm_userspace_memory_region {
1236 __u64 guest_phys_addr;
1237 __u64 memory_size; /* bytes */
1238 __u64 userspace_addr; /* start of the userspace allocated memory */
1241 /* for kvm_memory_region::flags */
1242 #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0)
1243 #define KVM_MEM_READONLY (1UL << 1)
1245 This ioctl allows the user to create, modify or delete a guest physical
1246 memory slot. Bits 0-15 of "slot" specify the slot id and this value
1247 should be less than the maximum number of user memory slots supported per
1248 VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS.
1249 Slots may not overlap in guest physical address space.
1251 If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot"
1252 specifies the address space which is being modified. They must be
1253 less than the value that KVM_CHECK_EXTENSION returns for the
1254 KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces
1255 are unrelated; the restriction on overlapping slots only applies within
1258 Deleting a slot is done by passing zero for memory_size. When changing
1259 an existing slot, it may be moved in the guest physical memory space,
1260 or its flags may be modified, but it may not be resized.
1262 Memory for the region is taken starting at the address denoted by the
1263 field userspace_addr, which must point at user addressable memory for
1264 the entire memory slot size. Any object may back this memory, including
1265 anonymous memory, ordinary files, and hugetlbfs.
1267 It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
1268 be identical. This allows large pages in the guest to be backed by large
1271 The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and
1272 KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of
1273 writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to
1274 use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it,
1275 to make a new slot read-only. In this case, writes to this memory will be
1276 posted to userspace as KVM_EXIT_MMIO exits.
1278 When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of
1279 the memory region are automatically reflected into the guest. For example, an
1280 mmap() that affects the region will be made visible immediately. Another
1281 example is madvise(MADV_DROP).
1283 It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl.
1284 The KVM_SET_MEMORY_REGION does not allow fine grained control over memory
1285 allocation and is deprecated.
1288 4.36 KVM_SET_TSS_ADDR
1289 ---------------------
1291 :Capability: KVM_CAP_SET_TSS_ADDR
1294 :Parameters: unsigned long tss_address (in)
1295 :Returns: 0 on success, -1 on error
1297 This ioctl defines the physical address of a three-page region in the guest
1298 physical address space. The region must be within the first 4GB of the
1299 guest physical address space and must not conflict with any memory slot
1300 or any mmio address. The guest may malfunction if it accesses this memory
1303 This ioctl is required on Intel-based hosts. This is needed on Intel hardware
1304 because of a quirk in the virtualization implementation (see the internals
1305 documentation when it pops into existence).
1311 :Capability: KVM_CAP_ENABLE_CAP
1312 :Architectures: mips, ppc, s390
1314 :Parameters: struct kvm_enable_cap (in)
1315 :Returns: 0 on success; -1 on error
1317 :Capability: KVM_CAP_ENABLE_CAP_VM
1320 :Parameters: struct kvm_enable_cap (in)
1321 :Returns: 0 on success; -1 on error
1325 Not all extensions are enabled by default. Using this ioctl the application
1326 can enable an extension, making it available to the guest.
1328 On systems that do not support this ioctl, it always fails. On systems that
1329 do support it, it only works for extensions that are supported for enablement.
1331 To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should
1336 struct kvm_enable_cap {
1340 The capability that is supposed to get enabled.
1346 A bitfield indicating future enhancements. Has to be 0 for now.
1352 Arguments for enabling a feature. If a feature needs initial values to
1353 function properly, this is the place to put them.
1360 The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl
1361 for vm-wide capabilities.
1363 4.38 KVM_GET_MP_STATE
1364 ---------------------
1366 :Capability: KVM_CAP_MP_STATE
1367 :Architectures: x86, s390, arm, arm64
1369 :Parameters: struct kvm_mp_state (out)
1370 :Returns: 0 on success; -1 on error
1374 struct kvm_mp_state {
1378 Returns the vcpu's current "multiprocessing state" (though also valid on
1379 uniprocessor guests).
1381 Possible values are:
1383 ========================== ===============================================
1384 KVM_MP_STATE_RUNNABLE the vcpu is currently running [x86,arm/arm64]
1385 KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP)
1386 which has not yet received an INIT signal [x86]
1387 KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is
1388 now ready for a SIPI [x86]
1389 KVM_MP_STATE_HALTED the vcpu has executed a HLT instruction and
1390 is waiting for an interrupt [x86]
1391 KVM_MP_STATE_SIPI_RECEIVED the vcpu has just received a SIPI (vector
1392 accessible via KVM_GET_VCPU_EVENTS) [x86]
1393 KVM_MP_STATE_STOPPED the vcpu is stopped [s390,arm/arm64]
1394 KVM_MP_STATE_CHECK_STOP the vcpu is in a special error state [s390]
1395 KVM_MP_STATE_OPERATING the vcpu is operating (running or halted)
1397 KVM_MP_STATE_LOAD the vcpu is in a special load/startup state
1399 ========================== ===============================================
1401 On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an
1402 in-kernel irqchip, the multiprocessing state must be maintained by userspace on
1403 these architectures.
1408 The only states that are valid are KVM_MP_STATE_STOPPED and
1409 KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not.
1411 4.39 KVM_SET_MP_STATE
1412 ---------------------
1414 :Capability: KVM_CAP_MP_STATE
1415 :Architectures: x86, s390, arm, arm64
1417 :Parameters: struct kvm_mp_state (in)
1418 :Returns: 0 on success; -1 on error
1420 Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for
1423 On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an
1424 in-kernel irqchip, the multiprocessing state must be maintained by userspace on
1425 these architectures.
1430 The only states that are valid are KVM_MP_STATE_STOPPED and
1431 KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not.
1433 4.40 KVM_SET_IDENTITY_MAP_ADDR
1434 ------------------------------
1436 :Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR
1439 :Parameters: unsigned long identity (in)
1440 :Returns: 0 on success, -1 on error
1442 This ioctl defines the physical address of a one-page region in the guest
1443 physical address space. The region must be within the first 4GB of the
1444 guest physical address space and must not conflict with any memory slot
1445 or any mmio address. The guest may malfunction if it accesses this memory
1448 Setting the address to 0 will result in resetting the address to its default
1451 This ioctl is required on Intel-based hosts. This is needed on Intel hardware
1452 because of a quirk in the virtualization implementation (see the internals
1453 documentation when it pops into existence).
1455 Fails if any VCPU has already been created.
1457 4.41 KVM_SET_BOOT_CPU_ID
1458 ------------------------
1460 :Capability: KVM_CAP_SET_BOOT_CPU_ID
1463 :Parameters: unsigned long vcpu_id
1464 :Returns: 0 on success, -1 on error
1466 Define which vcpu is the Bootstrap Processor (BSP). Values are the same
1467 as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default
1474 :Capability: KVM_CAP_XSAVE
1477 :Parameters: struct kvm_xsave (out)
1478 :Returns: 0 on success, -1 on error
1487 This ioctl would copy current vcpu's xsave struct to the userspace.
1493 :Capability: KVM_CAP_XSAVE
1496 :Parameters: struct kvm_xsave (in)
1497 :Returns: 0 on success, -1 on error
1506 This ioctl would copy userspace's xsave struct to the kernel.
1512 :Capability: KVM_CAP_XCRS
1515 :Parameters: struct kvm_xcrs (out)
1516 :Returns: 0 on success, -1 on error
1529 struct kvm_xcr xcrs[KVM_MAX_XCRS];
1533 This ioctl would copy current vcpu's xcrs to the userspace.
1539 :Capability: KVM_CAP_XCRS
1542 :Parameters: struct kvm_xcrs (in)
1543 :Returns: 0 on success, -1 on error
1556 struct kvm_xcr xcrs[KVM_MAX_XCRS];
1560 This ioctl would set vcpu's xcr to the value userspace specified.
1563 4.46 KVM_GET_SUPPORTED_CPUID
1564 ----------------------------
1566 :Capability: KVM_CAP_EXT_CPUID
1569 :Parameters: struct kvm_cpuid2 (in/out)
1570 :Returns: 0 on success, -1 on error
1577 struct kvm_cpuid_entry2 entries[0];
1580 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0)
1581 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */
1582 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */
1584 struct kvm_cpuid_entry2 {
1595 This ioctl returns x86 cpuid features which are supported by both the
1596 hardware and kvm in its default configuration. Userspace can use the
1597 information returned by this ioctl to construct cpuid information (for
1598 KVM_SET_CPUID2) that is consistent with hardware, kernel, and
1599 userspace capabilities, and with user requirements (for example, the
1600 user may wish to constrain cpuid to emulate older hardware, or for
1601 feature consistency across a cluster).
1603 Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may
1604 expose cpuid features (e.g. MONITOR) which are not supported by kvm in
1605 its default configuration. If userspace enables such capabilities, it
1606 is responsible for modifying the results of this ioctl appropriately.
1608 Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure
1609 with the 'nent' field indicating the number of entries in the variable-size
1610 array 'entries'. If the number of entries is too low to describe the cpu
1611 capabilities, an error (E2BIG) is returned. If the number is too high,
1612 the 'nent' field is adjusted and an error (ENOMEM) is returned. If the
1613 number is just right, the 'nent' field is adjusted to the number of valid
1614 entries in the 'entries' array, which is then filled.
1616 The entries returned are the host cpuid as returned by the cpuid instruction,
1617 with unknown or unsupported features masked out. Some features (for example,
1618 x2apic), may not be present in the host cpu, but are exposed by kvm if it can
1619 emulate them efficiently. The fields in each entry are defined as follows:
1622 the eax value used to obtain the entry
1625 the ecx value used to obtain the entry (for entries that are
1629 an OR of zero or more of the following:
1631 KVM_CPUID_FLAG_SIGNIFCANT_INDEX:
1632 if the index field is valid
1635 the values returned by the cpuid instruction for
1636 this function/index combination
1638 The TSC deadline timer feature (CPUID leaf 1, ecx[24]) is always returned
1639 as false, since the feature depends on KVM_CREATE_IRQCHIP for local APIC
1640 support. Instead it is reported via::
1642 ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER)
1644 if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the
1645 feature in userspace, then you can enable the feature for KVM_SET_CPUID2.
1648 4.47 KVM_PPC_GET_PVINFO
1649 -----------------------
1651 :Capability: KVM_CAP_PPC_GET_PVINFO
1654 :Parameters: struct kvm_ppc_pvinfo (out)
1655 :Returns: 0 on success, !0 on error
1659 struct kvm_ppc_pvinfo {
1665 This ioctl fetches PV specific information that need to be passed to the guest
1666 using the device tree or other means from vm context.
1668 The hcall array defines 4 instructions that make up a hypercall.
1670 If any additional field gets added to this structure later on, a bit for that
1671 additional piece of information will be set in the flags bitmap.
1673 The flags bitmap is defined as::
1675 /* the host supports the ePAPR idle hcall
1676 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0)
1678 4.52 KVM_SET_GSI_ROUTING
1679 ------------------------
1681 :Capability: KVM_CAP_IRQ_ROUTING
1682 :Architectures: x86 s390 arm arm64
1684 :Parameters: struct kvm_irq_routing (in)
1685 :Returns: 0 on success, -1 on error
1687 Sets the GSI routing table entries, overwriting any previously set entries.
1689 On arm/arm64, GSI routing has the following limitation:
1691 - GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD.
1695 struct kvm_irq_routing {
1698 struct kvm_irq_routing_entry entries[0];
1701 No flags are specified so far, the corresponding field must be set to zero.
1705 struct kvm_irq_routing_entry {
1711 struct kvm_irq_routing_irqchip irqchip;
1712 struct kvm_irq_routing_msi msi;
1713 struct kvm_irq_routing_s390_adapter adapter;
1714 struct kvm_irq_routing_hv_sint hv_sint;
1719 /* gsi routing entry types */
1720 #define KVM_IRQ_ROUTING_IRQCHIP 1
1721 #define KVM_IRQ_ROUTING_MSI 2
1722 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
1723 #define KVM_IRQ_ROUTING_HV_SINT 4
1727 - KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry
1728 type, specifies that the devid field contains a valid value. The per-VM
1729 KVM_CAP_MSI_DEVID capability advertises the requirement to provide
1730 the device ID. If this capability is not available, userspace should
1731 never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail.
1736 struct kvm_irq_routing_irqchip {
1741 struct kvm_irq_routing_msi {
1751 If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier
1752 for the device that wrote the MSI message. For PCI, this is usually a
1753 BFD identifier in the lower 16 bits.
1755 On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS
1756 feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled,
1757 address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of
1758 address_hi must be zero.
1762 struct kvm_irq_routing_s390_adapter {
1766 __u32 summary_offset;
1770 struct kvm_irq_routing_hv_sint {
1776 4.55 KVM_SET_TSC_KHZ
1777 --------------------
1779 :Capability: KVM_CAP_TSC_CONTROL
1782 :Parameters: virtual tsc_khz
1783 :Returns: 0 on success, -1 on error
1785 Specifies the tsc frequency for the virtual machine. The unit of the
1789 4.56 KVM_GET_TSC_KHZ
1790 --------------------
1792 :Capability: KVM_CAP_GET_TSC_KHZ
1796 :Returns: virtual tsc-khz on success, negative value on error
1798 Returns the tsc frequency of the guest. The unit of the return value is
1799 KHz. If the host has unstable tsc this ioctl returns -EIO instead as an
1806 :Capability: KVM_CAP_IRQCHIP
1809 :Parameters: struct kvm_lapic_state (out)
1810 :Returns: 0 on success, -1 on error
1814 #define KVM_APIC_REG_SIZE 0x400
1815 struct kvm_lapic_state {
1816 char regs[KVM_APIC_REG_SIZE];
1819 Reads the Local APIC registers and copies them into the input argument. The
1820 data format and layout are the same as documented in the architecture manual.
1822 If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is
1823 enabled, then the format of APIC_ID register depends on the APIC mode
1824 (reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in
1825 the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID
1826 which is stored in bits 31-24 of the APIC register, or equivalently in
1827 byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then
1828 be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR.
1830 If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state
1831 always uses xAPIC format.
1837 :Capability: KVM_CAP_IRQCHIP
1840 :Parameters: struct kvm_lapic_state (in)
1841 :Returns: 0 on success, -1 on error
1845 #define KVM_APIC_REG_SIZE 0x400
1846 struct kvm_lapic_state {
1847 char regs[KVM_APIC_REG_SIZE];
1850 Copies the input argument into the Local APIC registers. The data format
1851 and layout are the same as documented in the architecture manual.
1853 The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's
1854 regs field) depends on the state of the KVM_CAP_X2APIC_API capability.
1855 See the note in KVM_GET_LAPIC.
1861 :Capability: KVM_CAP_IOEVENTFD
1864 :Parameters: struct kvm_ioeventfd (in)
1865 :Returns: 0 on success, !0 on error
1867 This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address
1868 within the guest. A guest write in the registered address will signal the
1869 provided event instead of triggering an exit.
1873 struct kvm_ioeventfd {
1875 __u64 addr; /* legal pio/mmio address */
1876 __u32 len; /* 0, 1, 2, 4, or 8 bytes */
1882 For the special case of virtio-ccw devices on s390, the ioevent is matched
1883 to a subchannel/virtqueue tuple instead.
1885 The following flags are defined::
1887 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
1888 #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
1889 #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
1890 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \
1891 (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify)
1893 If datamatch flag is set, the event will be signaled only if the written value
1894 to the registered address is equal to datamatch in struct kvm_ioeventfd.
1896 For virtio-ccw devices, addr contains the subchannel id and datamatch the
1899 With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and
1900 the kernel will ignore the length of guest write and may get a faster vmexit.
1901 The speedup may only apply to specific architectures, but the ioeventfd will
1907 :Capability: KVM_CAP_SW_TLB
1910 :Parameters: struct kvm_dirty_tlb (in)
1911 :Returns: 0 on success, -1 on error
1915 struct kvm_dirty_tlb {
1920 This must be called whenever userspace has changed an entry in the shared
1921 TLB, prior to calling KVM_RUN on the associated vcpu.
1923 The "bitmap" field is the userspace address of an array. This array
1924 consists of a number of bits, equal to the total number of TLB entries as
1925 determined by the last successful call to KVM_CONFIG_TLB, rounded up to the
1926 nearest multiple of 64.
1928 Each bit corresponds to one TLB entry, ordered the same as in the shared TLB
1931 The array is little-endian: the bit 0 is the least significant bit of the
1932 first byte, bit 8 is the least significant bit of the second byte, etc.
1933 This avoids any complications with differing word sizes.
1935 The "num_dirty" field is a performance hint for KVM to determine whether it
1936 should skip processing the bitmap and just invalidate everything. It must
1937 be set to the number of set bits in the bitmap.
1940 4.62 KVM_CREATE_SPAPR_TCE
1941 -------------------------
1943 :Capability: KVM_CAP_SPAPR_TCE
1944 :Architectures: powerpc
1946 :Parameters: struct kvm_create_spapr_tce (in)
1947 :Returns: file descriptor for manipulating the created TCE table
1949 This creates a virtual TCE (translation control entry) table, which
1950 is an IOMMU for PAPR-style virtual I/O. It is used to translate
1951 logical addresses used in virtual I/O into guest physical addresses,
1952 and provides a scatter/gather capability for PAPR virtual I/O.
1956 /* for KVM_CAP_SPAPR_TCE */
1957 struct kvm_create_spapr_tce {
1962 The liobn field gives the logical IO bus number for which to create a
1963 TCE table. The window_size field specifies the size of the DMA window
1964 which this TCE table will translate - the table will contain one 64
1965 bit TCE entry for every 4kiB of the DMA window.
1967 When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE
1968 table has been created using this ioctl(), the kernel will handle it
1969 in real mode, updating the TCE table. H_PUT_TCE calls for other
1970 liobns will cause a vm exit and must be handled by userspace.
1972 The return value is a file descriptor which can be passed to mmap(2)
1973 to map the created TCE table into userspace. This lets userspace read
1974 the entries written by kernel-handled H_PUT_TCE calls, and also lets
1975 userspace update the TCE table directly which is useful in some
1979 4.63 KVM_ALLOCATE_RMA
1980 ---------------------
1982 :Capability: KVM_CAP_PPC_RMA
1983 :Architectures: powerpc
1985 :Parameters: struct kvm_allocate_rma (out)
1986 :Returns: file descriptor for mapping the allocated RMA
1988 This allocates a Real Mode Area (RMA) from the pool allocated at boot
1989 time by the kernel. An RMA is a physically-contiguous, aligned region
1990 of memory used on older POWER processors to provide the memory which
1991 will be accessed by real-mode (MMU off) accesses in a KVM guest.
1992 POWER processors support a set of sizes for the RMA that usually
1993 includes 64MB, 128MB, 256MB and some larger powers of two.
1997 /* for KVM_ALLOCATE_RMA */
1998 struct kvm_allocate_rma {
2002 The return value is a file descriptor which can be passed to mmap(2)
2003 to map the allocated RMA into userspace. The mapped area can then be
2004 passed to the KVM_SET_USER_MEMORY_REGION ioctl to establish it as the
2005 RMA for a virtual machine. The size of the RMA in bytes (which is
2006 fixed at host kernel boot time) is returned in the rma_size field of
2007 the argument structure.
2009 The KVM_CAP_PPC_RMA capability is 1 or 2 if the KVM_ALLOCATE_RMA ioctl
2010 is supported; 2 if the processor requires all virtual machines to have
2011 an RMA, or 1 if the processor can use an RMA but doesn't require it,
2012 because it supports the Virtual RMA (VRMA) facility.
2018 :Capability: KVM_CAP_USER_NMI
2022 :Returns: 0 on success, -1 on error
2024 Queues an NMI on the thread's vcpu. Note this is well defined only
2025 when KVM_CREATE_IRQCHIP has not been called, since this is an interface
2026 between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP
2027 has been called, this interface is completely emulated within the kernel.
2029 To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the
2030 following algorithm:
2033 - read the local APIC's state (KVM_GET_LAPIC)
2034 - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1)
2035 - if so, issue KVM_NMI
2038 Some guests configure the LINT1 NMI input to cause a panic, aiding in
2042 4.65 KVM_S390_UCAS_MAP
2043 ----------------------
2045 :Capability: KVM_CAP_S390_UCONTROL
2046 :Architectures: s390
2048 :Parameters: struct kvm_s390_ucas_mapping (in)
2049 :Returns: 0 in case of success
2051 The parameter is defined like this::
2053 struct kvm_s390_ucas_mapping {
2059 This ioctl maps the memory at "user_addr" with the length "length" to
2060 the vcpu's address space starting at "vcpu_addr". All parameters need to
2061 be aligned by 1 megabyte.
2064 4.66 KVM_S390_UCAS_UNMAP
2065 ------------------------
2067 :Capability: KVM_CAP_S390_UCONTROL
2068 :Architectures: s390
2070 :Parameters: struct kvm_s390_ucas_mapping (in)
2071 :Returns: 0 in case of success
2073 The parameter is defined like this::
2075 struct kvm_s390_ucas_mapping {
2081 This ioctl unmaps the memory in the vcpu's address space starting at
2082 "vcpu_addr" with the length "length". The field "user_addr" is ignored.
2083 All parameters need to be aligned by 1 megabyte.
2086 4.67 KVM_S390_VCPU_FAULT
2087 ------------------------
2089 :Capability: KVM_CAP_S390_UCONTROL
2090 :Architectures: s390
2092 :Parameters: vcpu absolute address (in)
2093 :Returns: 0 in case of success
2095 This call creates a page table entry on the virtual cpu's address space
2096 (for user controlled virtual machines) or the virtual machine's address
2097 space (for regular virtual machines). This only works for minor faults,
2098 thus it's recommended to access subject memory page via the user page
2099 table upfront. This is useful to handle validity intercepts for user
2100 controlled virtual machines to fault in the virtual cpu's lowcore pages
2101 prior to calling the KVM_RUN ioctl.
2104 4.68 KVM_SET_ONE_REG
2105 --------------------
2107 :Capability: KVM_CAP_ONE_REG
2110 :Parameters: struct kvm_one_reg (in)
2111 :Returns: 0 on success, negative value on failure
2115 ====== ============================================================
2116 Â ENOENT Â Â no such register
2117 Â EINVAL Â Â invalid register ID, or no such register or used with VMs in
2118 protected virtualization mode on s390
2119 Â EPERM Â Â Â (arm64) register access not allowed before vcpu finalization
2120 ====== ============================================================
2122 (These error codes are indicative only: do not rely on a specific error
2123 code being returned in a specific situation.)
2127 struct kvm_one_reg {
2132 Using this ioctl, a single vcpu register can be set to a specific value
2133 defined by user space with the passed in struct kvm_one_reg, where id
2134 refers to the register identifier as described below and addr is a pointer
2135 to a variable with the respective size. There can be architecture agnostic
2136 and architecture specific registers. Each have their own range of operation
2137 and their own constants and width. To keep track of the implemented
2138 registers, find a list below:
2140 ======= =============================== ============
2141 Arch Register Width (bits)
2142 ======= =============================== ============
2143 PPC KVM_REG_PPC_HIOR 64
2144 PPC KVM_REG_PPC_IAC1 64
2145 PPC KVM_REG_PPC_IAC2 64
2146 PPC KVM_REG_PPC_IAC3 64
2147 PPC KVM_REG_PPC_IAC4 64
2148 PPC KVM_REG_PPC_DAC1 64
2149 PPC KVM_REG_PPC_DAC2 64
2150 PPC KVM_REG_PPC_DABR 64
2151 PPC KVM_REG_PPC_DSCR 64
2152 PPC KVM_REG_PPC_PURR 64
2153 PPC KVM_REG_PPC_SPURR 64
2154 PPC KVM_REG_PPC_DAR 64
2155 PPC KVM_REG_PPC_DSISR 32
2156 PPC KVM_REG_PPC_AMR 64
2157 PPC KVM_REG_PPC_UAMOR 64
2158 PPC KVM_REG_PPC_MMCR0 64
2159 PPC KVM_REG_PPC_MMCR1 64
2160 PPC KVM_REG_PPC_MMCRA 64
2161 PPC KVM_REG_PPC_MMCR2 64
2162 PPC KVM_REG_PPC_MMCRS 64
2163 PPC KVM_REG_PPC_SIAR 64
2164 PPC KVM_REG_PPC_SDAR 64
2165 PPC KVM_REG_PPC_SIER 64
2166 PPC KVM_REG_PPC_PMC1 32
2167 PPC KVM_REG_PPC_PMC2 32
2168 PPC KVM_REG_PPC_PMC3 32
2169 PPC KVM_REG_PPC_PMC4 32
2170 PPC KVM_REG_PPC_PMC5 32
2171 PPC KVM_REG_PPC_PMC6 32
2172 PPC KVM_REG_PPC_PMC7 32
2173 PPC KVM_REG_PPC_PMC8 32
2174 PPC KVM_REG_PPC_FPR0 64
2176 PPC KVM_REG_PPC_FPR31 64
2177 PPC KVM_REG_PPC_VR0 128
2179 PPC KVM_REG_PPC_VR31 128
2180 PPC KVM_REG_PPC_VSR0 128
2182 PPC KVM_REG_PPC_VSR31 128
2183 PPC KVM_REG_PPC_FPSCR 64
2184 PPC KVM_REG_PPC_VSCR 32
2185 PPC KVM_REG_PPC_VPA_ADDR 64
2186 PPC KVM_REG_PPC_VPA_SLB 128
2187 PPC KVM_REG_PPC_VPA_DTL 128
2188 PPC KVM_REG_PPC_EPCR 32
2189 PPC KVM_REG_PPC_EPR 32
2190 PPC KVM_REG_PPC_TCR 32
2191 PPC KVM_REG_PPC_TSR 32
2192 PPC KVM_REG_PPC_OR_TSR 32
2193 PPC KVM_REG_PPC_CLEAR_TSR 32
2194 PPC KVM_REG_PPC_MAS0 32
2195 PPC KVM_REG_PPC_MAS1 32
2196 PPC KVM_REG_PPC_MAS2 64
2197 PPC KVM_REG_PPC_MAS7_3 64
2198 PPC KVM_REG_PPC_MAS4 32
2199 PPC KVM_REG_PPC_MAS6 32
2200 PPC KVM_REG_PPC_MMUCFG 32
2201 PPC KVM_REG_PPC_TLB0CFG 32
2202 PPC KVM_REG_PPC_TLB1CFG 32
2203 PPC KVM_REG_PPC_TLB2CFG 32
2204 PPC KVM_REG_PPC_TLB3CFG 32
2205 PPC KVM_REG_PPC_TLB0PS 32
2206 PPC KVM_REG_PPC_TLB1PS 32
2207 PPC KVM_REG_PPC_TLB2PS 32
2208 PPC KVM_REG_PPC_TLB3PS 32
2209 PPC KVM_REG_PPC_EPTCFG 32
2210 PPC KVM_REG_PPC_ICP_STATE 64
2211 PPC KVM_REG_PPC_VP_STATE 128
2212 PPC KVM_REG_PPC_TB_OFFSET 64
2213 PPC KVM_REG_PPC_SPMC1 32
2214 PPC KVM_REG_PPC_SPMC2 32
2215 PPC KVM_REG_PPC_IAMR 64
2216 PPC KVM_REG_PPC_TFHAR 64
2217 PPC KVM_REG_PPC_TFIAR 64
2218 PPC KVM_REG_PPC_TEXASR 64
2219 PPC KVM_REG_PPC_FSCR 64
2220 PPC KVM_REG_PPC_PSPB 32
2221 PPC KVM_REG_PPC_EBBHR 64
2222 PPC KVM_REG_PPC_EBBRR 64
2223 PPC KVM_REG_PPC_BESCR 64
2224 PPC KVM_REG_PPC_TAR 64
2225 PPC KVM_REG_PPC_DPDES 64
2226 PPC KVM_REG_PPC_DAWR 64
2227 PPC KVM_REG_PPC_DAWRX 64
2228 PPC KVM_REG_PPC_CIABR 64
2229 PPC KVM_REG_PPC_IC 64
2230 PPC KVM_REG_PPC_VTB 64
2231 PPC KVM_REG_PPC_CSIGR 64
2232 PPC KVM_REG_PPC_TACR 64
2233 PPC KVM_REG_PPC_TCSCR 64
2234 PPC KVM_REG_PPC_PID 64
2235 PPC KVM_REG_PPC_ACOP 64
2236 PPC KVM_REG_PPC_VRSAVE 32
2237 PPC KVM_REG_PPC_LPCR 32
2238 PPC KVM_REG_PPC_LPCR_64 64
2239 PPC KVM_REG_PPC_PPR 64
2240 PPC KVM_REG_PPC_ARCH_COMPAT 32
2241 PPC KVM_REG_PPC_DABRX 32
2242 PPC KVM_REG_PPC_WORT 64
2243 PPC KVM_REG_PPC_SPRG9 64
2244 PPC KVM_REG_PPC_DBSR 32
2245 PPC KVM_REG_PPC_TIDR 64
2246 PPC KVM_REG_PPC_PSSCR 64
2247 PPC KVM_REG_PPC_DEC_EXPIRY 64
2248 PPC KVM_REG_PPC_PTCR 64
2249 PPC KVM_REG_PPC_TM_GPR0 64
2251 PPC KVM_REG_PPC_TM_GPR31 64
2252 PPC KVM_REG_PPC_TM_VSR0 128
2254 PPC KVM_REG_PPC_TM_VSR63 128
2255 PPC KVM_REG_PPC_TM_CR 64
2256 PPC KVM_REG_PPC_TM_LR 64
2257 PPC KVM_REG_PPC_TM_CTR 64
2258 PPC KVM_REG_PPC_TM_FPSCR 64
2259 PPC KVM_REG_PPC_TM_AMR 64
2260 PPC KVM_REG_PPC_TM_PPR 64
2261 PPC KVM_REG_PPC_TM_VRSAVE 64
2262 PPC KVM_REG_PPC_TM_VSCR 32
2263 PPC KVM_REG_PPC_TM_DSCR 64
2264 PPC KVM_REG_PPC_TM_TAR 64
2265 PPC KVM_REG_PPC_TM_XER 64
2267 MIPS KVM_REG_MIPS_R0 64
2269 MIPS KVM_REG_MIPS_R31 64
2270 MIPS KVM_REG_MIPS_HI 64
2271 MIPS KVM_REG_MIPS_LO 64
2272 MIPS KVM_REG_MIPS_PC 64
2273 MIPS KVM_REG_MIPS_CP0_INDEX 32
2274 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64
2275 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64
2276 MIPS KVM_REG_MIPS_CP0_CONTEXT 64
2277 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32
2278 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64
2279 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64
2280 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32
2281 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32
2282 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64
2283 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64
2284 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64
2285 MIPS KVM_REG_MIPS_CP0_PWBASE 64
2286 MIPS KVM_REG_MIPS_CP0_PWFIELD 64
2287 MIPS KVM_REG_MIPS_CP0_PWSIZE 64
2288 MIPS KVM_REG_MIPS_CP0_WIRED 32
2289 MIPS KVM_REG_MIPS_CP0_PWCTL 32
2290 MIPS KVM_REG_MIPS_CP0_HWRENA 32
2291 MIPS KVM_REG_MIPS_CP0_BADVADDR 64
2292 MIPS KVM_REG_MIPS_CP0_BADINSTR 32
2293 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32
2294 MIPS KVM_REG_MIPS_CP0_COUNT 32
2295 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64
2296 MIPS KVM_REG_MIPS_CP0_COMPARE 32
2297 MIPS KVM_REG_MIPS_CP0_STATUS 32
2298 MIPS KVM_REG_MIPS_CP0_INTCTL 32
2299 MIPS KVM_REG_MIPS_CP0_CAUSE 32
2300 MIPS KVM_REG_MIPS_CP0_EPC 64
2301 MIPS KVM_REG_MIPS_CP0_PRID 32
2302 MIPS KVM_REG_MIPS_CP0_EBASE 64
2303 MIPS KVM_REG_MIPS_CP0_CONFIG 32
2304 MIPS KVM_REG_MIPS_CP0_CONFIG1 32
2305 MIPS KVM_REG_MIPS_CP0_CONFIG2 32
2306 MIPS KVM_REG_MIPS_CP0_CONFIG3 32
2307 MIPS KVM_REG_MIPS_CP0_CONFIG4 32
2308 MIPS KVM_REG_MIPS_CP0_CONFIG5 32
2309 MIPS KVM_REG_MIPS_CP0_CONFIG7 32
2310 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64
2311 MIPS KVM_REG_MIPS_CP0_ERROREPC 64
2312 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64
2313 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64
2314 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64
2315 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64
2316 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64
2317 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64
2318 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64
2319 MIPS KVM_REG_MIPS_COUNT_CTL 64
2320 MIPS KVM_REG_MIPS_COUNT_RESUME 64
2321 MIPS KVM_REG_MIPS_COUNT_HZ 64
2322 MIPS KVM_REG_MIPS_FPR_32(0..31) 32
2323 MIPS KVM_REG_MIPS_FPR_64(0..31) 64
2324 MIPS KVM_REG_MIPS_VEC_128(0..31) 128
2325 MIPS KVM_REG_MIPS_FCR_IR 32
2326 MIPS KVM_REG_MIPS_FCR_CSR 32
2327 MIPS KVM_REG_MIPS_MSA_IR 32
2328 MIPS KVM_REG_MIPS_MSA_CSR 32
2329 ======= =============================== ============
2331 ARM registers are mapped using the lower 32 bits. The upper 16 of that
2332 is the register group type, or coprocessor number:
2334 ARM core registers have the following id bit patterns::
2336 0x4020 0000 0010 <index into the kvm_regs struct:16>
2338 ARM 32-bit CP15 registers have the following id bit patterns::
2340 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3>
2342 ARM 64-bit CP15 registers have the following id bit patterns::
2344 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3>
2346 ARM CCSIDR registers are demultiplexed by CSSELR value::
2348 0x4020 0000 0011 00 <csselr:8>
2350 ARM 32-bit VFP control registers have the following id bit patterns::
2352 0x4020 0000 0012 1 <regno:12>
2354 ARM 64-bit FP registers have the following id bit patterns::
2356 0x4030 0000 0012 0 <regno:12>
2358 ARM firmware pseudo-registers have the following bit pattern::
2360 0x4030 0000 0014 <regno:16>
2363 arm64 registers are mapped using the lower 32 bits. The upper 16 of
2364 that is the register group type, or coprocessor number:
2366 arm64 core/FP-SIMD registers have the following id bit patterns. Note
2367 that the size of the access is variable, as the kvm_regs structure
2368 contains elements ranging from 32 to 128 bits. The index is a 32bit
2369 value in the kvm_regs structure seen as a 32bit array::
2371 0x60x0 0000 0010 <index into the kvm_regs struct:16>
2375 ======================= ========= ===== =======================================
2376 Encoding Register Bits kvm_regs member
2377 ======================= ========= ===== =======================================
2378 0x6030 0000 0010 0000 X0 64 regs.regs[0]
2379 0x6030 0000 0010 0002 X1 64 regs.regs[1]
2381 0x6030 0000 0010 003c X30 64 regs.regs[30]
2382 0x6030 0000 0010 003e SP 64 regs.sp
2383 0x6030 0000 0010 0040 PC 64 regs.pc
2384 0x6030 0000 0010 0042 PSTATE 64 regs.pstate
2385 0x6030 0000 0010 0044 SP_EL1 64 sp_el1
2386 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1
2387 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC)
2388 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT]
2389 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND]
2390 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ]
2391 0x6060 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ]
2392 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_
2393 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_
2395 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_
2396 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr
2397 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr
2398 ======================= ========= ===== =======================================
2400 .. [1] These encodings are not accepted for SVE-enabled vcpus. See
2403 The equivalent register content can be accessed via bits [127:0] of
2404 the corresponding SVE Zn registers instead for vcpus that have SVE
2405 enabled (see below).
2407 arm64 CCSIDR registers are demultiplexed by CSSELR value::
2409 0x6020 0000 0011 00 <csselr:8>
2411 arm64 system registers have the following id bit patterns::
2413 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3>
2417 Two system register IDs do not follow the specified pattern. These
2418 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to
2419 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These
2420 two had their values accidentally swapped, which means TIMER_CVAL is
2421 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is
2422 derived from the register encoding for CNTV_CVAL_EL0. As this is
2423 API, it must remain this way.
2425 arm64 firmware pseudo-registers have the following bit pattern::
2427 0x6030 0000 0014 <regno:16>
2429 arm64 SVE registers have the following bit patterns::
2431 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice]
2432 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice]
2433 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice]
2434 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register
2436 Access to register IDs where 2048 * slice >= 128 * max_vq will fail with
2437 ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit
2438 quadwords: see [2]_ below.
2440 These registers are only accessible on vcpus for which SVE is enabled.
2441 See KVM_ARM_VCPU_INIT for details.
2443 In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not
2444 accessible until the vcpu's SVE configuration has been finalized
2445 using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT
2446 and KVM_ARM_VCPU_FINALIZE for more information about this procedure.
2448 KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector
2449 lengths supported by the vcpu to be discovered and configured by
2450 userspace. When transferred to or from user memory via KVM_GET_ONE_REG
2451 or KVM_SET_ONE_REG, the value of this register is of type
2452 __u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as
2455 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS];
2457 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX &&
2458 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >>
2459 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1))
2460 /* Vector length vq * 16 bytes supported */
2462 /* Vector length vq * 16 bytes not supported */
2464 .. [2] The maximum value vq for which the above condition is true is
2465 max_vq. This is the maximum vector length available to the guest on
2466 this vcpu, and determines which register slices are visible through
2467 this ioctl interface.
2469 (See Documentation/arm64/sve.rst for an explanation of the "vq"
2472 KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT.
2473 KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that
2476 Userspace may subsequently modify it if desired until the vcpu's SVE
2477 configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE).
2479 Apart from simply removing all vector lengths from the host set that
2480 exceed some value, support for arbitrarily chosen sets of vector lengths
2481 is hardware-dependent and may not be available. Attempting to configure
2482 an invalid set of vector lengths via KVM_SET_ONE_REG will fail with
2485 After the vcpu's SVE configuration is finalized, further attempts to
2486 write this register will fail with EPERM.
2489 MIPS registers are mapped using the lower 32 bits. The upper 16 of that is
2490 the register group type:
2492 MIPS core registers (see above) have the following id bit patterns::
2494 0x7030 0000 0000 <reg:16>
2496 MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit
2497 patterns depending on whether they're 32-bit or 64-bit registers::
2499 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit)
2500 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit)
2502 Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64
2503 versions of the EntryLo registers regardless of the word size of the host
2504 hardware, host kernel, guest, and whether XPA is present in the guest, i.e.
2505 with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and
2506 the PFNX field starting at bit 30.
2508 MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit
2511 0x7030 0000 0001 01 <reg:8>
2513 MIPS KVM control registers (see above) have the following id bit patterns::
2515 0x7030 0000 0002 <reg:16>
2517 MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following
2518 id bit patterns depending on the size of the register being accessed. They are
2519 always accessed according to the current guest FPU mode (Status.FR and
2520 Config5.FRE), i.e. as the guest would see them, and they become unpredictable
2521 if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector
2522 registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they
2523 overlap the FPU registers::
2525 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers)
2526 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers)
2527 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers)
2529 MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the
2530 following id bit patterns::
2532 0x7020 0000 0003 01 <0:3> <reg:5>
2534 MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the
2535 following id bit patterns::
2537 0x7020 0000 0003 02 <0:3> <reg:5>
2540 4.69 KVM_GET_ONE_REG
2541 --------------------
2543 :Capability: KVM_CAP_ONE_REG
2546 :Parameters: struct kvm_one_reg (in and out)
2547 :Returns: 0 on success, negative value on failure
2551 ======== ============================================================
2552 Â ENOENT Â Â no such register
2553 Â EINVAL Â Â invalid register ID, or no such register or used with VMs in
2554 protected virtualization mode on s390
2555 Â EPERM Â Â Â (arm64) register access not allowed before vcpu finalization
2556 ======== ============================================================
2558 (These error codes are indicative only: do not rely on a specific error
2559 code being returned in a specific situation.)
2561 This ioctl allows to receive the value of a single register implemented
2562 in a vcpu. The register to read is indicated by the "id" field of the
2563 kvm_one_reg struct passed in. On success, the register value can be found
2564 at the memory location pointed to by "addr".
2566 The list of registers accessible using this interface is identical to the
2570 4.70 KVM_KVMCLOCK_CTRL
2571 ----------------------
2573 :Capability: KVM_CAP_KVMCLOCK_CTRL
2574 :Architectures: Any that implement pvclocks (currently x86 only)
2577 :Returns: 0 on success, -1 on error
2579 This ioctl sets a flag accessible to the guest indicating that the specified
2580 vCPU has been paused by the host userspace.
2582 The host will set a flag in the pvclock structure that is checked from the
2583 soft lockup watchdog. The flag is part of the pvclock structure that is
2584 shared between guest and host, specifically the second bit of the flags
2585 field of the pvclock_vcpu_time_info structure. It will be set exclusively by
2586 the host and read/cleared exclusively by the guest. The guest operation of
2587 checking and clearing the flag must be an atomic operation so
2588 load-link/store-conditional, or equivalent must be used. There are two cases
2589 where the guest will clear the flag: when the soft lockup watchdog timer resets
2590 itself or when a soft lockup is detected. This ioctl can be called any time
2591 after pausing the vcpu, but before it is resumed.
2597 :Capability: KVM_CAP_SIGNAL_MSI
2598 :Architectures: x86 arm arm64
2600 :Parameters: struct kvm_msi (in)
2601 :Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error
2603 Directly inject a MSI message. Only valid with in-kernel irqchip that handles
2618 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM
2619 KVM_CAP_MSI_DEVID capability advertises the requirement to provide
2620 the device ID. If this capability is not available, userspace
2621 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail.
2623 If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier
2624 for the device that wrote the MSI message. For PCI, this is usually a
2625 BFD identifier in the lower 16 bits.
2627 On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS
2628 feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled,
2629 address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of
2630 address_hi must be zero.
2633 4.71 KVM_CREATE_PIT2
2634 --------------------
2636 :Capability: KVM_CAP_PIT2
2639 :Parameters: struct kvm_pit_config (in)
2640 :Returns: 0 on success, -1 on error
2642 Creates an in-kernel device model for the i8254 PIT. This call is only valid
2643 after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following
2644 parameters have to be passed::
2646 struct kvm_pit_config {
2653 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */
2655 PIT timer interrupts may use a per-VM kernel thread for injection. If it
2656 exists, this thread will have a name of the following pattern::
2658 kvm-pit/<owner-process-pid>
2660 When running a guest with elevated priorities, the scheduling parameters of
2661 this thread may have to be adjusted accordingly.
2663 This IOCTL replaces the obsolete KVM_CREATE_PIT.
2669 :Capability: KVM_CAP_PIT_STATE2
2672 :Parameters: struct kvm_pit_state2 (out)
2673 :Returns: 0 on success, -1 on error
2675 Retrieves the state of the in-kernel PIT model. Only valid after
2676 KVM_CREATE_PIT2. The state is returned in the following structure::
2678 struct kvm_pit_state2 {
2679 struct kvm_pit_channel_state channels[3];
2686 /* disable PIT in HPET legacy mode */
2687 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001
2689 This IOCTL replaces the obsolete KVM_GET_PIT.
2695 :Capability: KVM_CAP_PIT_STATE2
2698 :Parameters: struct kvm_pit_state2 (in)
2699 :Returns: 0 on success, -1 on error
2701 Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2.
2702 See KVM_GET_PIT2 for details on struct kvm_pit_state2.
2704 This IOCTL replaces the obsolete KVM_SET_PIT.
2707 4.74 KVM_PPC_GET_SMMU_INFO
2708 --------------------------
2710 :Capability: KVM_CAP_PPC_GET_SMMU_INFO
2711 :Architectures: powerpc
2714 :Returns: 0 on success, -1 on error
2716 This populates and returns a structure describing the features of
2717 the "Server" class MMU emulation supported by KVM.
2718 This can in turn be used by userspace to generate the appropriate
2719 device-tree properties for the guest operating system.
2721 The structure contains some global information, followed by an
2722 array of supported segment page sizes::
2724 struct kvm_ppc_smmu_info {
2728 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ];
2731 The supported flags are:
2733 - KVM_PPC_PAGE_SIZES_REAL:
2734 When that flag is set, guest page sizes must "fit" the backing
2735 store page sizes. When not set, any page size in the list can
2736 be used regardless of how they are backed by userspace.
2738 - KVM_PPC_1T_SEGMENTS
2739 The emulated MMU supports 1T segments in addition to the
2743 This flag indicates that HPT guests are not supported by KVM,
2744 thus all guests must use radix MMU mode.
2746 The "slb_size" field indicates how many SLB entries are supported
2748 The "sps" array contains 8 entries indicating the supported base
2749 page sizes for a segment in increasing order. Each entry is defined
2752 struct kvm_ppc_one_seg_page_size {
2753 __u32 page_shift; /* Base page shift of segment (or 0) */
2754 __u32 slb_enc; /* SLB encoding for BookS */
2755 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ];
2758 An entry with a "page_shift" of 0 is unused. Because the array is
2759 organized in increasing order, a lookup can stop when encoutering
2762 The "slb_enc" field provides the encoding to use in the SLB for the
2763 page size. The bits are in positions such as the value can directly
2764 be OR'ed into the "vsid" argument of the slbmte instruction.
2766 The "enc" array is a list which for each of those segment base page
2767 size provides the list of supported actual page sizes (which can be
2768 only larger or equal to the base page size), along with the
2769 corresponding encoding in the hash PTE. Similarly, the array is
2770 8 entries sorted by increasing sizes and an entry with a "0" shift
2771 is an empty entry and a terminator::
2773 struct kvm_ppc_one_page_size {
2774 __u32 page_shift; /* Page shift (or 0) */
2775 __u32 pte_enc; /* Encoding in the HPTE (>>12) */
2778 The "pte_enc" field provides a value that can OR'ed into the hash
2779 PTE's RPN field (ie, it needs to be shifted left by 12 to OR it
2780 into the hash PTE second double word).
2785 :Capability: KVM_CAP_IRQFD
2786 :Architectures: x86 s390 arm arm64
2788 :Parameters: struct kvm_irqfd (in)
2789 :Returns: 0 on success, -1 on error
2791 Allows setting an eventfd to directly trigger a guest interrupt.
2792 kvm_irqfd.fd specifies the file descriptor to use as the eventfd and
2793 kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When
2794 an event is triggered on the eventfd, an interrupt is injected into
2795 the guest using the specified gsi pin. The irqfd is removed using
2796 the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd
2799 With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify
2800 mechanism allowing emulation of level-triggered, irqfd-based
2801 interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an
2802 additional eventfd in the kvm_irqfd.resamplefd field. When operating
2803 in resample mode, posting of an interrupt through kvm_irq.fd asserts
2804 the specified gsi in the irqchip. When the irqchip is resampled, such
2805 as from an EOI, the gsi is de-asserted and the user is notified via
2806 kvm_irqfd.resamplefd. It is the user's responsibility to re-queue
2807 the interrupt if the device making use of it still requires service.
2808 Note that closing the resamplefd is not sufficient to disable the
2809 irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
2810 and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
2812 On arm/arm64, gsi routing being supported, the following can happen:
2814 - in case no routing entry is associated to this gsi, injection fails
2815 - in case the gsi is associated to an irqchip routing entry,
2816 irqchip.pin + 32 corresponds to the injected SPI ID.
2817 - in case the gsi is associated to an MSI routing entry, the MSI
2818 message and device ID are translated into an LPI (support restricted
2819 to GICv3 ITS in-kernel emulation).
2821 4.76 KVM_PPC_ALLOCATE_HTAB
2822 --------------------------
2824 :Capability: KVM_CAP_PPC_ALLOC_HTAB
2825 :Architectures: powerpc
2827 :Parameters: Pointer to u32 containing hash table order (in/out)
2828 :Returns: 0 on success, -1 on error
2830 This requests the host kernel to allocate an MMU hash table for a
2831 guest using the PAPR paravirtualization interface. This only does
2832 anything if the kernel is configured to use the Book 3S HV style of
2833 virtualization. Otherwise the capability doesn't exist and the ioctl
2834 returns an ENOTTY error. The rest of this description assumes Book 3S
2837 There must be no vcpus running when this ioctl is called; if there
2838 are, it will do nothing and return an EBUSY error.
2840 The parameter is a pointer to a 32-bit unsigned integer variable
2841 containing the order (log base 2) of the desired size of the hash
2842 table, which must be between 18 and 46. On successful return from the
2843 ioctl, the value will not be changed by the kernel.
2845 If no hash table has been allocated when any vcpu is asked to run
2846 (with the KVM_RUN ioctl), the host kernel will allocate a
2847 default-sized hash table (16 MB).
2849 If this ioctl is called when a hash table has already been allocated,
2850 with a different order from the existing hash table, the existing hash
2851 table will be freed and a new one allocated. If this is ioctl is
2852 called when a hash table has already been allocated of the same order
2853 as specified, the kernel will clear out the existing hash table (zero
2854 all HPTEs). In either case, if the guest is using the virtualized
2855 real-mode area (VRMA) facility, the kernel will re-create the VMRA
2856 HPTEs on the next KVM_RUN of any vcpu.
2858 4.77 KVM_S390_INTERRUPT
2859 -----------------------
2862 :Architectures: s390
2863 :Type: vm ioctl, vcpu ioctl
2864 :Parameters: struct kvm_s390_interrupt (in)
2865 :Returns: 0 on success, -1 on error
2867 Allows to inject an interrupt to the guest. Interrupts can be floating
2868 (vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type.
2870 Interrupt parameters are passed via kvm_s390_interrupt::
2872 struct kvm_s390_interrupt {
2878 type can be one of the following:
2880 KVM_S390_SIGP_STOP (vcpu)
2881 - sigp stop; optional flags in parm
2882 KVM_S390_PROGRAM_INT (vcpu)
2883 - program check; code in parm
2884 KVM_S390_SIGP_SET_PREFIX (vcpu)
2885 - sigp set prefix; prefix address in parm
2886 KVM_S390_RESTART (vcpu)
2888 KVM_S390_INT_CLOCK_COMP (vcpu)
2889 - clock comparator interrupt
2890 KVM_S390_INT_CPU_TIMER (vcpu)
2891 - CPU timer interrupt
2892 KVM_S390_INT_VIRTIO (vm)
2893 - virtio external interrupt; external interrupt
2894 parameters in parm and parm64
2895 KVM_S390_INT_SERVICE (vm)
2896 - sclp external interrupt; sclp parameter in parm
2897 KVM_S390_INT_EMERGENCY (vcpu)
2898 - sigp emergency; source cpu in parm
2899 KVM_S390_INT_EXTERNAL_CALL (vcpu)
2900 - sigp external call; source cpu in parm
2901 KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm)
2902 - compound value to indicate an
2903 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel);
2904 I/O interruption parameters in parm (subchannel) and parm64 (intparm,
2905 interruption subclass)
2906 KVM_S390_MCHK (vm, vcpu)
2907 - machine check interrupt; cr 14 bits in parm, machine check interrupt
2908 code in parm64 (note that machine checks needing further payload are not
2909 supported by this ioctl)
2911 This is an asynchronous vcpu ioctl and can be invoked from any thread.
2913 4.78 KVM_PPC_GET_HTAB_FD
2914 ------------------------
2916 :Capability: KVM_CAP_PPC_HTAB_FD
2917 :Architectures: powerpc
2919 :Parameters: Pointer to struct kvm_get_htab_fd (in)
2920 :Returns: file descriptor number (>= 0) on success, -1 on error
2922 This returns a file descriptor that can be used either to read out the
2923 entries in the guest's hashed page table (HPT), or to write entries to
2924 initialize the HPT. The returned fd can only be written to if the
2925 KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and
2926 can only be read if that bit is clear. The argument struct looks like
2929 /* For KVM_PPC_GET_HTAB_FD */
2930 struct kvm_get_htab_fd {
2936 /* Values for kvm_get_htab_fd.flags */
2937 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1)
2938 #define KVM_GET_HTAB_WRITE ((__u64)0x2)
2940 The 'start_index' field gives the index in the HPT of the entry at
2941 which to start reading. It is ignored when writing.
2943 Reads on the fd will initially supply information about all
2944 "interesting" HPT entries. Interesting entries are those with the
2945 bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise
2946 all entries. When the end of the HPT is reached, the read() will
2947 return. If read() is called again on the fd, it will start again from
2948 the beginning of the HPT, but will only return HPT entries that have
2949 changed since they were last read.
2951 Data read or written is structured as a header (8 bytes) followed by a
2952 series of valid HPT entries (16 bytes) each. The header indicates how
2953 many valid HPT entries there are and how many invalid entries follow
2954 the valid entries. The invalid entries are not represented explicitly
2955 in the stream. The header format is::
2957 struct kvm_get_htab_header {
2963 Writes to the fd create HPT entries starting at the index given in the
2964 header; first 'n_valid' valid entries with contents from the data
2965 written, then 'n_invalid' invalid entries, invalidating any previously
2966 valid entries found.
2968 4.79 KVM_CREATE_DEVICE
2969 ----------------------
2971 :Capability: KVM_CAP_DEVICE_CTRL
2973 :Parameters: struct kvm_create_device (in/out)
2974 :Returns: 0 on success, -1 on error
2978 ====== =======================================================
2979 ENODEV The device type is unknown or unsupported
2980 EEXIST Device already created, and this type of device may not
2981 be instantiated multiple times
2982 ====== =======================================================
2984 Other error conditions may be defined by individual device types or
2985 have their standard meanings.
2987 Creates an emulated device in the kernel. The file descriptor returned
2988 in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR.
2990 If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the
2991 device type is supported (not necessarily whether it can be created
2994 Individual devices should not define flags. Attributes should be used
2995 for specifying any behavior that is not implied by the device type
3000 struct kvm_create_device {
3001 __u32 type; /* in: KVM_DEV_TYPE_xxx */
3002 __u32 fd; /* out: device handle */
3003 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */
3006 4.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR
3007 --------------------------------------------
3009 :Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
3010 KVM_CAP_VCPU_ATTRIBUTES for vcpu device
3011 :Type: device ioctl, vm ioctl, vcpu ioctl
3012 :Parameters: struct kvm_device_attr
3013 :Returns: 0 on success, -1 on error
3017 ===== =============================================================
3018 ENXIO The group or attribute is unknown/unsupported for this device
3019 or hardware support is missing.
3020 EPERM The attribute cannot (currently) be accessed this way
3021 (e.g. read-only attribute, or attribute that only makes
3022 sense when the device is in a different state)
3023 ===== =============================================================
3025 Other error conditions may be defined by individual device types.
3027 Gets/sets a specified piece of device configuration and/or state. The
3028 semantics are device-specific. See individual device documentation in
3029 the "devices" directory. As with ONE_REG, the size of the data
3030 transferred is defined by the particular attribute.
3034 struct kvm_device_attr {
3035 __u32 flags; /* no flags currently defined */
3036 __u32 group; /* device-defined */
3037 __u64 attr; /* group-defined */
3038 __u64 addr; /* userspace address of attr data */
3041 4.81 KVM_HAS_DEVICE_ATTR
3042 ------------------------
3044 :Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
3045 KVM_CAP_VCPU_ATTRIBUTES for vcpu device
3046 :Type: device ioctl, vm ioctl, vcpu ioctl
3047 :Parameters: struct kvm_device_attr
3048 :Returns: 0 on success, -1 on error
3052 ===== =============================================================
3053 ENXIO The group or attribute is unknown/unsupported for this device
3054 or hardware support is missing.
3055 ===== =============================================================
3057 Tests whether a device supports a particular attribute. A successful
3058 return indicates the attribute is implemented. It does not necessarily
3059 indicate that the attribute can be read or written in the device's
3060 current state. "addr" is ignored.
3062 4.82 KVM_ARM_VCPU_INIT
3063 ----------------------
3066 :Architectures: arm, arm64
3068 :Parameters: struct kvm_vcpu_init (in)
3069 :Returns: 0 on success; -1 on error
3073 ====== =================================================================
3074 Â EINVAL Â Â Â the target is unknown, or the combination of features is invalid.
3075 Â ENOENT Â Â Â a features bit specified is unknown.
3076 ====== =================================================================
3078 This tells KVM what type of CPU to present to the guest, and what
3079 optional features it should have. Â This will cause a reset of the cpu
3080 registers to their initial values. Â If this is not called, KVM_RUN will
3081 return ENOEXEC for that vcpu.
3083 Note that because some registers reflect machine topology, all vcpus
3084 should be created before this ioctl is invoked.
3086 Userspace can call this function multiple times for a given vcpu, including
3087 after the vcpu has been run. This will reset the vcpu to its initial
3088 state. All calls to this function after the initial call must use the same
3089 target and same set of feature flags, otherwise EINVAL will be returned.
3093 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
3094 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on
3095 and execute guest code when KVM_RUN is called.
3096 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode.
3097 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only).
3098 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision
3099 backward compatible with v0.2) for the CPU.
3100 Depends on KVM_CAP_ARM_PSCI_0_2.
3101 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU.
3102 Depends on KVM_CAP_ARM_PMU_V3.
3104 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication
3106 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS.
3107 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are
3108 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and
3109 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be
3112 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication
3114 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC.
3115 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are
3116 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and
3117 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be
3120 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only).
3121 Depends on KVM_CAP_ARM_SVE.
3122 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):
3124 * After KVM_ARM_VCPU_INIT:
3126 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the
3127 initial value of this pseudo-register indicates the best set of
3128 vector lengths possible for a vcpu on this host.
3130 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):
3132 - KVM_RUN and KVM_GET_REG_LIST are not available;
3134 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access
3135 the scalable archietctural SVE registers
3136 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or
3137 KVM_REG_ARM64_SVE_FFR;
3139 - KVM_REG_ARM64_SVE_VLS may optionally be written using
3140 KVM_SET_ONE_REG, to modify the set of vector lengths available
3143 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):
3145 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can
3146 no longer be written using KVM_SET_ONE_REG.
3148 4.83 KVM_ARM_PREFERRED_TARGET
3149 -----------------------------
3152 :Architectures: arm, arm64
3154 :Parameters: struct kvm_vcpu_init (out)
3155 :Returns: 0 on success; -1 on error
3159 ====== ==========================================
3160 ENODEV no preferred target available for the host
3161 ====== ==========================================
3163 This queries KVM for preferred CPU target type which can be emulated
3164 by KVM on underlying host.
3166 The ioctl returns struct kvm_vcpu_init instance containing information
3167 about preferred CPU target type and recommended features for it. The
3168 kvm_vcpu_init->features bitmap returned will have feature bits set if
3169 the preferred target recommends setting these features, but this is
3172 The information returned by this ioctl can be used to prepare an instance
3173 of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in
3174 VCPU matching underlying host.
3177 4.84 KVM_GET_REG_LIST
3178 ---------------------
3181 :Architectures: arm, arm64, mips
3183 :Parameters: struct kvm_reg_list (in/out)
3184 :Returns: 0 on success; -1 on error
3188 ===== ==============================================================
3189 Â E2BIG Â Â Â Â the reg index list is too big to fit in the array specified by
3190 Â Â Â Â Â Â Â Â Â Â Â Â the user (the number required will be written into n).
3191 ===== ==============================================================
3195 struct kvm_reg_list {
3196 __u64 n; /* number of registers in reg[] */
3200 This ioctl returns the guest registers that are supported for the
3201 KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
3204 4.85 KVM_ARM_SET_DEVICE_ADDR (deprecated)
3205 -----------------------------------------
3207 :Capability: KVM_CAP_ARM_SET_DEVICE_ADDR
3208 :Architectures: arm, arm64
3210 :Parameters: struct kvm_arm_device_address (in)
3211 :Returns: 0 on success, -1 on error
3215 ====== ============================================
3216 ENODEV The device id is unknown
3217 ENXIO Device not supported on current system
3218 EEXIST Address already set
3219 E2BIG Address outside guest physical address space
3220 EBUSY Address overlaps with other device range
3221 ====== ============================================
3225 struct kvm_arm_device_addr {
3230 Specify a device address in the guest's physical address space where guests
3231 can access emulated or directly exposed devices, which the host kernel needs
3232 to know about. The id field is an architecture specific identifier for a
3235 ARM/arm64 divides the id field into two parts, a device id and an
3236 address type id specific to the individual device::
3238 Â bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 |
3239 field: | 0x00000000 | device id | addr type id |
3241 ARM/arm64 currently only require this when using the in-kernel GIC
3242 support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2
3243 as the device id. When setting the base address for the guest's
3244 mapping of the VGIC virtual CPU and distributor interface, the ioctl
3245 must be called after calling KVM_CREATE_IRQCHIP, but before calling
3246 KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the
3247 base addresses will return -EEXIST.
3249 Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API
3250 should be used instead.
3253 4.86 KVM_PPC_RTAS_DEFINE_TOKEN
3254 ------------------------------
3256 :Capability: KVM_CAP_PPC_RTAS
3259 :Parameters: struct kvm_rtas_token_args
3260 :Returns: 0 on success, -1 on error
3262 Defines a token value for a RTAS (Run Time Abstraction Services)
3263 service in order to allow it to be handled in the kernel. The
3264 argument struct gives the name of the service, which must be the name
3265 of a service that has a kernel-side implementation. If the token
3266 value is non-zero, it will be associated with that service, and
3267 subsequent RTAS calls by the guest specifying that token will be
3268 handled by the kernel. If the token value is 0, then any token
3269 associated with the service will be forgotten, and subsequent RTAS
3270 calls by the guest for that service will be passed to userspace to be
3273 4.87 KVM_SET_GUEST_DEBUG
3274 ------------------------
3276 :Capability: KVM_CAP_SET_GUEST_DEBUG
3277 :Architectures: x86, s390, ppc, arm64
3279 :Parameters: struct kvm_guest_debug (in)
3280 :Returns: 0 on success; -1 on error
3284 struct kvm_guest_debug {
3287 struct kvm_guest_debug_arch arch;
3290 Set up the processor specific debug registers and configure vcpu for
3291 handling guest debug events. There are two parts to the structure, the
3292 first a control bitfield indicates the type of debug events to handle
3293 when running. Common control bits are:
3295 - KVM_GUESTDBG_ENABLE: guest debugging is enabled
3296 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step
3298 The top 16 bits of the control field are architecture specific control
3299 flags which can include the following:
3301 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64]
3302 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390, arm64]
3303 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86]
3304 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86]
3305 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390]
3307 For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints
3308 are enabled in memory so we need to ensure breakpoint exceptions are
3309 correctly trapped and the KVM run loop exits at the breakpoint and not
3310 running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP
3311 we need to ensure the guest vCPUs architecture specific registers are
3312 updated to the correct (supplied) values.
3314 The second part of the structure is architecture specific and
3315 typically contains a set of debug registers.
3317 For arm64 the number of debug registers is implementation defined and
3318 can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and
3319 KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number
3320 indicating the number of supported registers.
3322 For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether
3323 the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported.
3325 When debug events exit the main run loop with the reason
3326 KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run
3327 structure containing architecture specific debug information.
3329 4.88 KVM_GET_EMULATED_CPUID
3330 ---------------------------
3332 :Capability: KVM_CAP_EXT_EMUL_CPUID
3335 :Parameters: struct kvm_cpuid2 (in/out)
3336 :Returns: 0 on success, -1 on error
3343 struct kvm_cpuid_entry2 entries[0];
3346 The member 'flags' is used for passing flags from userspace.
3350 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0)
3351 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */
3352 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */
3354 struct kvm_cpuid_entry2 {
3365 This ioctl returns x86 cpuid features which are emulated by
3366 kvm.Userspace can use the information returned by this ioctl to query
3367 which features are emulated by kvm instead of being present natively.
3369 Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2
3370 structure with the 'nent' field indicating the number of entries in
3371 the variable-size array 'entries'. If the number of entries is too low
3372 to describe the cpu capabilities, an error (E2BIG) is returned. If the
3373 number is too high, the 'nent' field is adjusted and an error (ENOMEM)
3374 is returned. If the number is just right, the 'nent' field is adjusted
3375 to the number of valid entries in the 'entries' array, which is then
3378 The entries returned are the set CPUID bits of the respective features
3379 which kvm emulates, as returned by the CPUID instruction, with unknown
3380 or unsupported feature bits cleared.
3382 Features like x2apic, for example, may not be present in the host cpu
3383 but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be
3384 emulated efficiently and thus not included here.
3386 The fields in each entry are defined as follows:
3389 the eax value used to obtain the entry
3391 the ecx value used to obtain the entry (for entries that are
3394 an OR of zero or more of the following:
3396 KVM_CPUID_FLAG_SIGNIFCANT_INDEX:
3397 if the index field is valid
3401 the values returned by the cpuid instruction for
3402 this function/index combination
3404 4.89 KVM_S390_MEM_OP
3405 --------------------
3407 :Capability: KVM_CAP_S390_MEM_OP
3408 :Architectures: s390
3410 :Parameters: struct kvm_s390_mem_op (in)
3411 :Returns: = 0 on success,
3412 < 0 on generic error (e.g. -EFAULT or -ENOMEM),
3413 > 0 if an exception occurred while walking the page tables
3415 Read or write data from/to the logical (virtual) memory of a VCPU.
3417 Parameters are specified via the following structure::
3419 struct kvm_s390_mem_op {
3420 __u64 gaddr; /* the guest address */
3421 __u64 flags; /* flags */
3422 __u32 size; /* amount of bytes */
3423 __u32 op; /* type of operation */
3424 __u64 buf; /* buffer in userspace */
3425 __u8 ar; /* the access register number */
3426 __u8 reserved[31]; /* should be set to 0 */
3429 The type of operation is specified in the "op" field. It is either
3430 KVM_S390_MEMOP_LOGICAL_READ for reading from logical memory space or
3431 KVM_S390_MEMOP_LOGICAL_WRITE for writing to logical memory space. The
3432 KVM_S390_MEMOP_F_CHECK_ONLY flag can be set in the "flags" field to check
3433 whether the corresponding memory access would create an access exception
3434 (without touching the data in the memory at the destination). In case an
3435 access exception occurred while walking the MMU tables of the guest, the
3436 ioctl returns a positive error number to indicate the type of exception.
3437 This exception is also raised directly at the corresponding VCPU if the
3438 flag KVM_S390_MEMOP_F_INJECT_EXCEPTION is set in the "flags" field.
3440 The start address of the memory region has to be specified in the "gaddr"
3441 field, and the length of the region in the "size" field (which must not
3442 be 0). The maximum value for "size" can be obtained by checking the
3443 KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the
3444 userspace application where the read data should be written to for
3445 KVM_S390_MEMOP_LOGICAL_READ, or where the data that should be written is
3446 stored for a KVM_S390_MEMOP_LOGICAL_WRITE. When KVM_S390_MEMOP_F_CHECK_ONLY
3447 is specified, "buf" is unused and can be NULL. "ar" designates the access
3448 register number to be used; the valid range is 0..15.
3450 The "reserved" field is meant for future extensions. It is not used by
3451 KVM with the currently defined set of flags.
3453 4.90 KVM_S390_GET_SKEYS
3454 -----------------------
3456 :Capability: KVM_CAP_S390_SKEYS
3457 :Architectures: s390
3459 :Parameters: struct kvm_s390_skeys
3460 :Returns: 0 on success, KVM_S390_GET_KEYS_NONE if guest is not using storage
3461 keys, negative value on error
3463 This ioctl is used to get guest storage key values on the s390
3464 architecture. The ioctl takes parameters via the kvm_s390_skeys struct::
3466 struct kvm_s390_skeys {
3469 __u64 skeydata_addr;
3474 The start_gfn field is the number of the first guest frame whose storage keys
3477 The count field is the number of consecutive frames (starting from start_gfn)
3478 whose storage keys to get. The count field must be at least 1 and the maximum
3479 allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
3480 will cause the ioctl to return -EINVAL.
3482 The skeydata_addr field is the address to a buffer large enough to hold count
3483 bytes. This buffer will be filled with storage key data by the ioctl.
3485 4.91 KVM_S390_SET_SKEYS
3486 -----------------------
3488 :Capability: KVM_CAP_S390_SKEYS
3489 :Architectures: s390
3491 :Parameters: struct kvm_s390_skeys
3492 :Returns: 0 on success, negative value on error
3494 This ioctl is used to set guest storage key values on the s390
3495 architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
3496 See section on KVM_S390_GET_SKEYS for struct definition.
3498 The start_gfn field is the number of the first guest frame whose storage keys
3501 The count field is the number of consecutive frames (starting from start_gfn)
3502 whose storage keys to get. The count field must be at least 1 and the maximum
3503 allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
3504 will cause the ioctl to return -EINVAL.
3506 The skeydata_addr field is the address to a buffer containing count bytes of
3507 storage keys. Each byte in the buffer will be set as the storage key for a
3508 single frame starting at start_gfn for count frames.
3510 Note: If any architecturally invalid key value is found in the given data then
3511 the ioctl will return -EINVAL.
3516 :Capability: KVM_CAP_S390_INJECT_IRQ
3517 :Architectures: s390
3519 :Parameters: struct kvm_s390_irq (in)
3520 :Returns: 0 on success, -1 on error
3525 ====== =================================================================
3526 EINVAL interrupt type is invalid
3527 type is KVM_S390_SIGP_STOP and flag parameter is invalid value,
3528 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger
3529 than the maximum of VCPUs
3530 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped,
3531 type is KVM_S390_SIGP_STOP and a stop irq is already pending,
3532 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt
3534 ====== =================================================================
3536 Allows to inject an interrupt to the guest.
3538 Using struct kvm_s390_irq as a parameter allows
3539 to inject additional payload which is not
3540 possible via KVM_S390_INTERRUPT.
3542 Interrupt parameters are passed via kvm_s390_irq::
3544 struct kvm_s390_irq {
3547 struct kvm_s390_io_info io;
3548 struct kvm_s390_ext_info ext;
3549 struct kvm_s390_pgm_info pgm;
3550 struct kvm_s390_emerg_info emerg;
3551 struct kvm_s390_extcall_info extcall;
3552 struct kvm_s390_prefix_info prefix;
3553 struct kvm_s390_stop_info stop;
3554 struct kvm_s390_mchk_info mchk;
3559 type can be one of the following:
3561 - KVM_S390_SIGP_STOP - sigp stop; parameter in .stop
3562 - KVM_S390_PROGRAM_INT - program check; parameters in .pgm
3563 - KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix
3564 - KVM_S390_RESTART - restart; no parameters
3565 - KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters
3566 - KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters
3567 - KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg
3568 - KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall
3569 - KVM_S390_MCHK - machine check interrupt; parameters in .mchk
3571 This is an asynchronous vcpu ioctl and can be invoked from any thread.
3573 4.94 KVM_S390_GET_IRQ_STATE
3574 ---------------------------
3576 :Capability: KVM_CAP_S390_IRQ_STATE
3577 :Architectures: s390
3579 :Parameters: struct kvm_s390_irq_state (out)
3580 :Returns: >= number of bytes copied into buffer,
3581 -EINVAL if buffer size is 0,
3582 -ENOBUFS if buffer size is too small to fit all pending interrupts,
3583 -EFAULT if the buffer address was invalid
3585 This ioctl allows userspace to retrieve the complete state of all currently
3586 pending interrupts in a single buffer. Use cases include migration
3587 and introspection. The parameter structure contains the address of a
3588 userspace buffer and its length::
3590 struct kvm_s390_irq_state {
3592 __u32 flags; /* will stay unused for compatibility reasons */
3594 __u32 reserved[4]; /* will stay unused for compatibility reasons */
3597 Userspace passes in the above struct and for each pending interrupt a
3598 struct kvm_s390_irq is copied to the provided buffer.
3600 The structure contains a flags and a reserved field for future extensions. As
3601 the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and
3602 reserved, these fields can not be used in the future without breaking
3605 If -ENOBUFS is returned the buffer provided was too small and userspace
3606 may retry with a bigger buffer.
3608 4.95 KVM_S390_SET_IRQ_STATE
3609 ---------------------------
3611 :Capability: KVM_CAP_S390_IRQ_STATE
3612 :Architectures: s390
3614 :Parameters: struct kvm_s390_irq_state (in)
3615 :Returns: 0 on success,
3616 -EFAULT if the buffer address was invalid,
3617 -EINVAL for an invalid buffer length (see below),
3618 -EBUSY if there were already interrupts pending,
3619 errors occurring when actually injecting the
3620 interrupt. See KVM_S390_IRQ.
3622 This ioctl allows userspace to set the complete state of all cpu-local
3623 interrupts currently pending for the vcpu. It is intended for restoring
3624 interrupt state after a migration. The input parameter is a userspace buffer
3625 containing a struct kvm_s390_irq_state::
3627 struct kvm_s390_irq_state {
3629 __u32 flags; /* will stay unused for compatibility reasons */
3631 __u32 reserved[4]; /* will stay unused for compatibility reasons */
3634 The restrictions for flags and reserved apply as well.
3635 (see KVM_S390_GET_IRQ_STATE)
3637 The userspace memory referenced by buf contains a struct kvm_s390_irq
3638 for each interrupt to be injected into the guest.
3639 If one of the interrupts could not be injected for some reason the
3642 len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0
3643 and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq),
3644 which is the maximum number of possibly pending cpu-local interrupts.
3649 :Capability: KVM_CAP_X86_SMM
3653 :Returns: 0 on success, -1 on error
3655 Queues an SMI on the thread's vcpu.
3657 4.97 KVM_CAP_PPC_MULTITCE
3658 -------------------------
3660 :Capability: KVM_CAP_PPC_MULTITCE
3664 This capability means the kernel is capable of handling hypercalls
3665 H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user
3666 space. This significantly accelerates DMA operations for PPC KVM guests.
3667 User space should expect that its handlers for these hypercalls
3668 are not going to be called if user space previously registered LIOBN
3669 in KVM (via KVM_CREATE_SPAPR_TCE or similar calls).
3671 In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest,
3672 user space might have to advertise it for the guest. For example,
3673 IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is
3674 present in the "ibm,hypertas-functions" device-tree property.
3676 The hypercalls mentioned above may or may not be processed successfully
3677 in the kernel based fast path. If they can not be handled by the kernel,
3678 they will get passed on to user space. So user space still has to have
3679 an implementation for these despite the in kernel acceleration.
3681 This capability is always enabled.
3683 4.98 KVM_CREATE_SPAPR_TCE_64
3684 ----------------------------
3686 :Capability: KVM_CAP_SPAPR_TCE_64
3687 :Architectures: powerpc
3689 :Parameters: struct kvm_create_spapr_tce_64 (in)
3690 :Returns: file descriptor for manipulating the created TCE table
3692 This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit
3693 windows, described in 4.62 KVM_CREATE_SPAPR_TCE
3695 This capability uses extended struct in ioctl interface::
3697 /* for KVM_CAP_SPAPR_TCE_64 */
3698 struct kvm_create_spapr_tce_64 {
3702 __u64 offset; /* in pages */
3703 __u64 size; /* in pages */
3706 The aim of extension is to support an additional bigger DMA window with
3707 a variable page size.
3708 KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and
3709 a bus offset of the corresponding DMA window, @size and @offset are numbers
3712 @flags are not used at the moment.
3714 The rest of functionality is identical to KVM_CREATE_SPAPR_TCE.
3716 4.99 KVM_REINJECT_CONTROL
3717 -------------------------
3719 :Capability: KVM_CAP_REINJECT_CONTROL
3722 :Parameters: struct kvm_reinject_control (in)
3723 :Returns: 0 on success,
3724 -EFAULT if struct kvm_reinject_control cannot be read,
3725 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier.
3727 i8254 (PIT) has two modes, reinject and !reinject. The default is reinject,
3728 where KVM queues elapsed i8254 ticks and monitors completion of interrupt from
3729 vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its
3730 interrupt whenever there isn't a pending interrupt from i8254.
3731 !reinject mode injects an interrupt as soon as a tick arrives.
3735 struct kvm_reinject_control {
3740 pit_reinject = 0 (!reinject mode) is recommended, unless running an old
3741 operating system that uses the PIT for timing (e.g. Linux 2.4.x).
3743 4.100 KVM_PPC_CONFIGURE_V3_MMU
3744 ------------------------------
3746 :Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3
3749 :Parameters: struct kvm_ppc_mmuv3_cfg (in)
3750 :Returns: 0 on success,
3751 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read,
3752 -EINVAL if the configuration is invalid
3754 This ioctl controls whether the guest will use radix or HPT (hashed
3755 page table) translation, and sets the pointer to the process table for
3760 struct kvm_ppc_mmuv3_cfg {
3762 __u64 process_table;
3765 There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and
3766 KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest
3767 to use radix tree translation, and if clear, to use HPT translation.
3768 KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest
3769 to be able to use the global TLB and SLB invalidation instructions;
3770 if clear, the guest may not use these instructions.
3772 The process_table field specifies the address and size of the guest
3773 process table, which is in the guest's space. This field is formatted
3774 as the second doubleword of the partition table entry, as defined in
3775 the Power ISA V3.00, Book III section 5.7.6.1.
3777 4.101 KVM_PPC_GET_RMMU_INFO
3778 ---------------------------
3780 :Capability: KVM_CAP_PPC_RADIX_MMU
3783 :Parameters: struct kvm_ppc_rmmu_info (out)
3784 :Returns: 0 on success,
3785 -EFAULT if struct kvm_ppc_rmmu_info cannot be written,
3786 -EINVAL if no useful information can be returned
3788 This ioctl returns a structure containing two things: (a) a list
3789 containing supported radix tree geometries, and (b) a list that maps
3790 page sizes to put in the "AP" (actual page size) field for the tlbie
3791 (TLB invalidate entry) instruction.
3795 struct kvm_ppc_rmmu_info {
3796 struct kvm_ppc_radix_geom {
3801 __u32 ap_encodings[8];
3804 The geometries[] field gives up to 8 supported geometries for the
3805 radix page table, in terms of the log base 2 of the smallest page
3806 size, and the number of bits indexed at each level of the tree, from
3807 the PTE level up to the PGD level in that order. Any unused entries
3808 will have 0 in the page_shift field.
3810 The ap_encodings gives the supported page sizes and their AP field
3811 encodings, encoded with the AP value in the top 3 bits and the log
3812 base 2 of the page size in the bottom 6 bits.
3814 4.102 KVM_PPC_RESIZE_HPT_PREPARE
3815 --------------------------------
3817 :Capability: KVM_CAP_SPAPR_RESIZE_HPT
3818 :Architectures: powerpc
3820 :Parameters: struct kvm_ppc_resize_hpt (in)
3821 :Returns: 0 on successful completion,
3822 >0 if a new HPT is being prepared, the value is an estimated
3823 number of milliseconds until preparation is complete,
3824 -EFAULT if struct kvm_reinject_control cannot be read,
3825 -EINVAL if the supplied shift or flags are invalid,
3826 -ENOMEM if unable to allocate the new HPT,
3827 -ENOSPC if there was a hash collision
3831 struct kvm_ppc_rmmu_info {
3832 struct kvm_ppc_radix_geom {
3837 __u32 ap_encodings[8];
3840 The geometries[] field gives up to 8 supported geometries for the
3841 radix page table, in terms of the log base 2 of the smallest page
3842 size, and the number of bits indexed at each level of the tree, from
3843 the PTE level up to the PGD level in that order. Any unused entries
3844 will have 0 in the page_shift field.
3846 The ap_encodings gives the supported page sizes and their AP field
3847 encodings, encoded with the AP value in the top 3 bits and the log
3848 base 2 of the page size in the bottom 6 bits.
3850 4.102 KVM_PPC_RESIZE_HPT_PREPARE
3851 --------------------------------
3853 :Capability: KVM_CAP_SPAPR_RESIZE_HPT
3854 :Architectures: powerpc
3856 :Parameters: struct kvm_ppc_resize_hpt (in)
3857 :Returns: 0 on successful completion,
3858 >0 if a new HPT is being prepared, the value is an estimated
3859 number of milliseconds until preparation is complete,
3860 -EFAULT if struct kvm_reinject_control cannot be read,
3861 -EINVAL if the supplied shift or flags are invalid,when moving existing
3862 HPT entries to the new HPT,
3863 -EIO on other error conditions
3865 Used to implement the PAPR extension for runtime resizing of a guest's
3866 Hashed Page Table (HPT). Specifically this starts, stops or monitors
3867 the preparation of a new potential HPT for the guest, essentially
3868 implementing the H_RESIZE_HPT_PREPARE hypercall.
3870 If called with shift > 0 when there is no pending HPT for the guest,
3871 this begins preparation of a new pending HPT of size 2^(shift) bytes.
3872 It then returns a positive integer with the estimated number of
3873 milliseconds until preparation is complete.
3875 If called when there is a pending HPT whose size does not match that
3876 requested in the parameters, discards the existing pending HPT and
3877 creates a new one as above.
3879 If called when there is a pending HPT of the size requested, will:
3881 * If preparation of the pending HPT is already complete, return 0
3882 * If preparation of the pending HPT has failed, return an error
3883 code, then discard the pending HPT.
3884 * If preparation of the pending HPT is still in progress, return an
3885 estimated number of milliseconds until preparation is complete.
3887 If called with shift == 0, discards any currently pending HPT and
3888 returns 0 (i.e. cancels any in-progress preparation).
3890 flags is reserved for future expansion, currently setting any bits in
3891 flags will result in an -EINVAL.
3893 Normally this will be called repeatedly with the same parameters until
3894 it returns <= 0. The first call will initiate preparation, subsequent
3895 ones will monitor preparation until it completes or fails.
3899 struct kvm_ppc_resize_hpt {
3905 4.103 KVM_PPC_RESIZE_HPT_COMMIT
3906 -------------------------------
3908 :Capability: KVM_CAP_SPAPR_RESIZE_HPT
3909 :Architectures: powerpc
3911 :Parameters: struct kvm_ppc_resize_hpt (in)
3912 :Returns: 0 on successful completion,
3913 -EFAULT if struct kvm_reinject_control cannot be read,
3914 -EINVAL if the supplied shift or flags are invalid,
3915 -ENXIO is there is no pending HPT, or the pending HPT doesn't
3916 have the requested size,
3917 -EBUSY if the pending HPT is not fully prepared,
3918 -ENOSPC if there was a hash collision when moving existing
3919 HPT entries to the new HPT,
3920 -EIO on other error conditions
3922 Used to implement the PAPR extension for runtime resizing of a guest's
3923 Hashed Page Table (HPT). Specifically this requests that the guest be
3924 transferred to working with the new HPT, essentially implementing the
3925 H_RESIZE_HPT_COMMIT hypercall.
3927 This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has
3928 returned 0 with the same parameters. In other cases
3929 KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or
3930 -EBUSY, though others may be possible if the preparation was started,
3933 This will have undefined effects on the guest if it has not already
3934 placed itself in a quiescent state where no vcpu will make MMU enabled
3937 On succsful completion, the pending HPT will become the guest's active
3938 HPT and the previous HPT will be discarded.
3940 On failure, the guest will still be operating on its previous HPT.
3944 struct kvm_ppc_resize_hpt {
3950 4.104 KVM_X86_GET_MCE_CAP_SUPPORTED
3951 -----------------------------------
3953 :Capability: KVM_CAP_MCE
3956 :Parameters: u64 mce_cap (out)
3957 :Returns: 0 on success, -1 on error
3959 Returns supported MCE capabilities. The u64 mce_cap parameter
3960 has the same format as the MSR_IA32_MCG_CAP register. Supported
3961 capabilities will have the corresponding bits set.
3963 4.105 KVM_X86_SETUP_MCE
3964 -----------------------
3966 :Capability: KVM_CAP_MCE
3969 :Parameters: u64 mcg_cap (in)
3970 :Returns: 0 on success,
3971 -EFAULT if u64 mcg_cap cannot be read,
3972 -EINVAL if the requested number of banks is invalid,
3973 -EINVAL if requested MCE capability is not supported.
3975 Initializes MCE support for use. The u64 mcg_cap parameter
3976 has the same format as the MSR_IA32_MCG_CAP register and
3977 specifies which capabilities should be enabled. The maximum
3978 supported number of error-reporting banks can be retrieved when
3979 checking for KVM_CAP_MCE. The supported capabilities can be
3980 retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED.
3982 4.106 KVM_X86_SET_MCE
3983 ---------------------
3985 :Capability: KVM_CAP_MCE
3988 :Parameters: struct kvm_x86_mce (in)
3989 :Returns: 0 on success,
3990 -EFAULT if struct kvm_x86_mce cannot be read,
3991 -EINVAL if the bank number is invalid,
3992 -EINVAL if VAL bit is not set in status field.
3994 Inject a machine check error (MCE) into the guest. The input
3997 struct kvm_x86_mce {
4007 If the MCE being reported is an uncorrected error, KVM will
4008 inject it as an MCE exception into the guest. If the guest
4009 MCG_STATUS register reports that an MCE is in progress, KVM
4010 causes an KVM_EXIT_SHUTDOWN vmexit.
4012 Otherwise, if the MCE is a corrected error, KVM will just
4013 store it in the corresponding bank (provided this bank is
4014 not holding a previously reported uncorrected error).
4016 4.107 KVM_S390_GET_CMMA_BITS
4017 ----------------------------
4019 :Capability: KVM_CAP_S390_CMMA_MIGRATION
4020 :Architectures: s390
4022 :Parameters: struct kvm_s390_cmma_log (in, out)
4023 :Returns: 0 on success, a negative value on error
4025 This ioctl is used to get the values of the CMMA bits on the s390
4026 architecture. It is meant to be used in two scenarios:
4028 - During live migration to save the CMMA values. Live migration needs
4029 to be enabled via the KVM_REQ_START_MIGRATION VM property.
4030 - To non-destructively peek at the CMMA values, with the flag
4031 KVM_S390_CMMA_PEEK set.
4033 The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired
4034 values are written to a buffer whose location is indicated via the "values"
4035 member in the kvm_s390_cmma_log struct. The values in the input struct are
4036 also updated as needed.
4038 Each CMMA value takes up one byte.
4042 struct kvm_s390_cmma_log {
4053 start_gfn is the number of the first guest frame whose CMMA values are
4056 count is the length of the buffer in bytes,
4058 values points to the buffer where the result will be written to.
4060 If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be
4061 KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with
4064 The result is written in the buffer pointed to by the field values, and
4065 the values of the input parameter are updated as follows.
4067 Depending on the flags, different actions are performed. The only
4068 supported flag so far is KVM_S390_CMMA_PEEK.
4070 The default behaviour if KVM_S390_CMMA_PEEK is not set is:
4071 start_gfn will indicate the first page frame whose CMMA bits were dirty.
4072 It is not necessarily the same as the one passed as input, as clean pages
4075 count will indicate the number of bytes actually written in the buffer.
4076 It can (and very often will) be smaller than the input value, since the
4077 buffer is only filled until 16 bytes of clean values are found (which
4078 are then not copied in the buffer). Since a CMMA migration block needs
4079 the base address and the length, for a total of 16 bytes, we will send
4080 back some clean data if there is some dirty data afterwards, as long as
4081 the size of the clean data does not exceed the size of the header. This
4082 allows to minimize the amount of data to be saved or transferred over
4083 the network at the expense of more roundtrips to userspace. The next
4084 invocation of the ioctl will skip over all the clean values, saving
4085 potentially more than just the 16 bytes we found.
4087 If KVM_S390_CMMA_PEEK is set:
4088 the existing storage attributes are read even when not in migration
4089 mode, and no other action is performed;
4091 the output start_gfn will be equal to the input start_gfn,
4093 the output count will be equal to the input count, except if the end of
4094 memory has been reached.
4097 the field "remaining" will indicate the total number of dirty CMMA values
4098 still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is
4103 values points to the userspace buffer where the result will be stored.
4105 This ioctl can fail with -ENOMEM if not enough memory can be allocated to
4106 complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if
4107 KVM_S390_CMMA_PEEK is not set but migration mode was not enabled, with
4108 -EFAULT if the userspace address is invalid or if no page table is
4109 present for the addresses (e.g. when using hugepages).
4111 4.108 KVM_S390_SET_CMMA_BITS
4112 ----------------------------
4114 :Capability: KVM_CAP_S390_CMMA_MIGRATION
4115 :Architectures: s390
4117 :Parameters: struct kvm_s390_cmma_log (in)
4118 :Returns: 0 on success, a negative value on error
4120 This ioctl is used to set the values of the CMMA bits on the s390
4121 architecture. It is meant to be used during live migration to restore
4122 the CMMA values, but there are no restrictions on its use.
4123 The ioctl takes parameters via the kvm_s390_cmma_values struct.
4124 Each CMMA value takes up one byte.
4128 struct kvm_s390_cmma_log {
4139 start_gfn indicates the starting guest frame number,
4141 count indicates how many values are to be considered in the buffer,
4143 flags is not used and must be 0.
4145 mask indicates which PGSTE bits are to be considered.
4147 remaining is not used.
4149 values points to the buffer in userspace where to store the values.
4151 This ioctl can fail with -ENOMEM if not enough memory can be allocated to
4152 complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if
4153 the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or
4154 if the flags field was not 0, with -EFAULT if the userspace address is
4155 invalid, if invalid pages are written to (e.g. after the end of memory)
4156 or if no page table is present for the addresses (e.g. when using
4159 4.109 KVM_PPC_GET_CPU_CHAR
4160 --------------------------
4162 :Capability: KVM_CAP_PPC_GET_CPU_CHAR
4163 :Architectures: powerpc
4165 :Parameters: struct kvm_ppc_cpu_char (out)
4166 :Returns: 0 on successful completion,
4167 -EFAULT if struct kvm_ppc_cpu_char cannot be written
4169 This ioctl gives userspace information about certain characteristics
4170 of the CPU relating to speculative execution of instructions and
4171 possible information leakage resulting from speculative execution (see
4172 CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is
4173 returned in struct kvm_ppc_cpu_char, which looks like this::
4175 struct kvm_ppc_cpu_char {
4176 __u64 character; /* characteristics of the CPU */
4177 __u64 behaviour; /* recommended software behaviour */
4178 __u64 character_mask; /* valid bits in character */
4179 __u64 behaviour_mask; /* valid bits in behaviour */
4182 For extensibility, the character_mask and behaviour_mask fields
4183 indicate which bits of character and behaviour have been filled in by
4184 the kernel. If the set of defined bits is extended in future then
4185 userspace will be able to tell whether it is running on a kernel that
4186 knows about the new bits.
4188 The character field describes attributes of the CPU which can help
4189 with preventing inadvertent information disclosure - specifically,
4190 whether there is an instruction to flash-invalidate the L1 data cache
4191 (ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set
4192 to a mode where entries can only be used by the thread that created
4193 them, whether the bcctr[l] instruction prevents speculation, and
4194 whether a speculation barrier instruction (ori 31,31,0) is provided.
4196 The behaviour field describes actions that software should take to
4197 prevent inadvertent information disclosure, and thus describes which
4198 vulnerabilities the hardware is subject to; specifically whether the
4199 L1 data cache should be flushed when returning to user mode from the
4200 kernel, and whether a speculation barrier should be placed between an
4201 array bounds check and the array access.
4203 These fields use the same bit definitions as the new
4204 H_GET_CPU_CHARACTERISTICS hypercall.
4206 4.110 KVM_MEMORY_ENCRYPT_OP
4207 ---------------------------
4212 :Parameters: an opaque platform specific structure (in/out)
4213 :Returns: 0 on success; -1 on error
4215 If the platform supports creating encrypted VMs then this ioctl can be used
4216 for issuing platform-specific memory encryption commands to manage those
4219 Currently, this ioctl is used for issuing Secure Encrypted Virtualization
4220 (SEV) commands on AMD Processors. The SEV commands are defined in
4221 Documentation/virt/kvm/amd-memory-encryption.rst.
4223 4.111 KVM_MEMORY_ENCRYPT_REG_REGION
4224 -----------------------------------
4229 :Parameters: struct kvm_enc_region (in)
4230 :Returns: 0 on success; -1 on error
4232 This ioctl can be used to register a guest memory region which may
4233 contain encrypted data (e.g. guest RAM, SMRAM etc).
4235 It is used in the SEV-enabled guest. When encryption is enabled, a guest
4236 memory region may contain encrypted data. The SEV memory encryption
4237 engine uses a tweak such that two identical plaintext pages, each at
4238 different locations will have differing ciphertexts. So swapping or
4239 moving ciphertext of those pages will not result in plaintext being
4240 swapped. So relocating (or migrating) physical backing pages for the SEV
4241 guest will require some additional steps.
4243 Note: The current SEV key management spec does not provide commands to
4244 swap or migrate (move) ciphertext pages. Hence, for now we pin the guest
4245 memory region registered with the ioctl.
4247 4.112 KVM_MEMORY_ENCRYPT_UNREG_REGION
4248 -------------------------------------
4253 :Parameters: struct kvm_enc_region (in)
4254 :Returns: 0 on success; -1 on error
4256 This ioctl can be used to unregister the guest memory region registered
4257 with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above.
4259 4.113 KVM_HYPERV_EVENTFD
4260 ------------------------
4262 :Capability: KVM_CAP_HYPERV_EVENTFD
4265 :Parameters: struct kvm_hyperv_eventfd (in)
4267 This ioctl (un)registers an eventfd to receive notifications from the guest on
4268 the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without
4269 causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number
4270 (bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit.
4274 struct kvm_hyperv_eventfd {
4281 The conn_id field should fit within 24 bits::
4283 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff
4285 The acceptable values for the flags field are::
4287 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0)
4289 :Returns: 0 on success,
4290 -EINVAL if conn_id or flags is outside the allowed range,
4291 -ENOENT on deassign if the conn_id isn't registered,
4292 -EEXIST on assign if the conn_id is already registered
4294 4.114 KVM_GET_NESTED_STATE
4295 --------------------------
4297 :Capability: KVM_CAP_NESTED_STATE
4300 :Parameters: struct kvm_nested_state (in/out)
4301 :Returns: 0 on success, -1 on error
4305 ===== =============================================================
4306 E2BIG the total state size exceeds the value of 'size' specified by
4307 the user; the size required will be written into size.
4308 ===== =============================================================
4312 struct kvm_nested_state {
4318 struct kvm_vmx_nested_state_hdr vmx;
4319 struct kvm_svm_nested_state_hdr svm;
4321 /* Pad the header to 128 bytes. */
4326 struct kvm_vmx_nested_state_data vmx[0];
4327 struct kvm_svm_nested_state_data svm[0];
4331 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001
4332 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002
4333 #define KVM_STATE_NESTED_EVMCS 0x00000004
4335 #define KVM_STATE_NESTED_FORMAT_VMX 0
4336 #define KVM_STATE_NESTED_FORMAT_SVM 1
4338 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000
4340 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001
4341 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002
4343 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001
4345 struct kvm_vmx_nested_state_hdr {
4354 __u64 preemption_timer_deadline;
4357 struct kvm_vmx_nested_state_data {
4358 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
4359 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
4362 This ioctl copies the vcpu's nested virtualization state from the kernel to
4365 The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE
4366 to the KVM_CHECK_EXTENSION ioctl().
4368 4.115 KVM_SET_NESTED_STATE
4369 --------------------------
4371 :Capability: KVM_CAP_NESTED_STATE
4374 :Parameters: struct kvm_nested_state (in)
4375 :Returns: 0 on success, -1 on error
4377 This copies the vcpu's kvm_nested_state struct from userspace to the kernel.
4378 For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE.
4380 4.116 KVM_(UN)REGISTER_COALESCED_MMIO
4381 -------------------------------------
4383 :Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio)
4384 KVM_CAP_COALESCED_PIO (for coalesced pio)
4387 :Parameters: struct kvm_coalesced_mmio_zone
4388 :Returns: 0 on success, < 0 on error
4390 Coalesced I/O is a performance optimization that defers hardware
4391 register write emulation so that userspace exits are avoided. It is
4392 typically used to reduce the overhead of emulating frequently accessed
4395 When a hardware register is configured for coalesced I/O, write accesses
4396 do not exit to userspace and their value is recorded in a ring buffer
4397 that is shared between kernel and userspace.
4399 Coalesced I/O is used if one or more write accesses to a hardware
4400 register can be deferred until a read or a write to another hardware
4401 register on the same device. This last access will cause a vmexit and
4402 userspace will process accesses from the ring buffer before emulating
4403 it. That will avoid exiting to userspace on repeated writes.
4405 Coalesced pio is based on coalesced mmio. There is little difference
4406 between coalesced mmio and pio except that coalesced pio records accesses
4409 4.117 KVM_CLEAR_DIRTY_LOG (vm ioctl)
4410 ------------------------------------
4412 :Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
4413 :Architectures: x86, arm, arm64, mips
4415 :Parameters: struct kvm_dirty_log (in)
4416 :Returns: 0 on success, -1 on error
4420 /* for KVM_CLEAR_DIRTY_LOG */
4421 struct kvm_clear_dirty_log {
4426 void __user *dirty_bitmap; /* one bit per page */
4431 The ioctl clears the dirty status of pages in a memory slot, according to
4432 the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap
4433 field. Bit 0 of the bitmap corresponds to page "first_page" in the
4434 memory slot, and num_pages is the size in bits of the input bitmap.
4435 first_page must be a multiple of 64; num_pages must also be a multiple of
4436 64 unless first_page + num_pages is the size of the memory slot. For each
4437 bit that is set in the input bitmap, the corresponding page is marked "clean"
4438 in KVM's dirty bitmap, and dirty tracking is re-enabled for that page
4439 (for example via write-protection, or by clearing the dirty bit in
4440 a page table entry).
4442 If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 specifies
4443 the address space for which you want to return the dirty bitmap.
4444 They must be less than the value that KVM_CHECK_EXTENSION returns for
4445 the KVM_CAP_MULTI_ADDRESS_SPACE capability.
4447 This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
4448 is enabled; for more information, see the description of the capability.
4449 However, it can always be used as long as KVM_CHECK_EXTENSION confirms
4450 that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present.
4452 4.118 KVM_GET_SUPPORTED_HV_CPUID
4453 --------------------------------
4455 :Capability: KVM_CAP_HYPERV_CPUID
4458 :Parameters: struct kvm_cpuid2 (in/out)
4459 :Returns: 0 on success, -1 on error
4466 struct kvm_cpuid_entry2 entries[0];
4469 struct kvm_cpuid_entry2 {
4480 This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in
4481 KVM. Userspace can use the information returned by this ioctl to construct
4482 cpuid information presented to guests consuming Hyper-V enlightenments (e.g.
4483 Windows or Hyper-V guests).
4485 CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level
4486 Functional Specification (TLFS). These leaves can't be obtained with
4487 KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature
4488 leaves (0x40000000, 0x40000001).
4490 Currently, the following list of CPUID leaves are returned:
4491 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS
4492 - HYPERV_CPUID_INTERFACE
4493 - HYPERV_CPUID_VERSION
4494 - HYPERV_CPUID_FEATURES
4495 - HYPERV_CPUID_ENLIGHTMENT_INFO
4496 - HYPERV_CPUID_IMPLEMENT_LIMITS
4497 - HYPERV_CPUID_NESTED_FEATURES
4499 HYPERV_CPUID_NESTED_FEATURES leaf is only exposed when Enlightened VMCS was
4500 enabled on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS).
4502 Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure
4503 with the 'nent' field indicating the number of entries in the variable-size
4504 array 'entries'. If the number of entries is too low to describe all Hyper-V
4505 feature leaves, an error (E2BIG) is returned. If the number is more or equal
4506 to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the
4507 number of valid entries in the 'entries' array, which is then filled.
4509 'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved,
4510 userspace should not expect to get any particular value there.
4512 4.119 KVM_ARM_VCPU_FINALIZE
4513 ---------------------------
4515 :Architectures: arm, arm64
4517 :Parameters: int feature (in)
4518 :Returns: 0 on success, -1 on error
4522 ====== ==============================================================
4523 EPERM feature not enabled, needs configuration, or already finalized
4524 EINVAL feature unknown or not present
4525 ====== ==============================================================
4527 Recognised values for feature:
4529 ===== ===========================================
4530 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE)
4531 ===== ===========================================
4533 Finalizes the configuration of the specified vcpu feature.
4535 The vcpu must already have been initialised, enabling the affected feature, by
4536 means of a successful KVM_ARM_VCPU_INIT call with the appropriate flag set in
4539 For affected vcpu features, this is a mandatory step that must be performed
4540 before the vcpu is fully usable.
4542 Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be
4543 configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration
4544 that should be performaned and how to do it are feature-dependent.
4546 Other calls that depend on a particular feature being finalized, such as
4547 KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with
4548 -EPERM unless the feature has already been finalized by means of a
4549 KVM_ARM_VCPU_FINALIZE call.
4551 See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization
4554 4.120 KVM_SET_PMU_EVENT_FILTER
4555 ------------------------------
4557 :Capability: KVM_CAP_PMU_EVENT_FILTER
4560 :Parameters: struct kvm_pmu_event_filter (in)
4561 :Returns: 0 on success, -1 on error
4565 struct kvm_pmu_event_filter {
4568 __u32 fixed_counter_bitmap;
4574 This ioctl restricts the set of PMU events that the guest can program.
4575 The argument holds a list of events which will be allowed or denied.
4576 The eventsel+umask of each event the guest attempts to program is compared
4577 against the events field to determine whether the guest should have access.
4578 The events field only controls general purpose counters; fixed purpose
4579 counters are controlled by the fixed_counter_bitmap.
4581 No flags are defined yet, the field must be zero.
4583 Valid values for 'action'::
4585 #define KVM_PMU_EVENT_ALLOW 0
4586 #define KVM_PMU_EVENT_DENY 1
4588 4.121 KVM_PPC_SVM_OFF
4589 ---------------------
4592 :Architectures: powerpc
4595 :Returns: 0 on successful completion,
4599 ====== ================================================================
4600 EINVAL if ultravisor failed to terminate the secure guest
4601 ENOMEM if hypervisor failed to allocate new radix page tables for guest
4602 ====== ================================================================
4604 This ioctl is used to turn off the secure mode of the guest or transition
4605 the guest from secure mode to normal mode. This is invoked when the guest
4606 is reset. This has no effect if called for a normal guest.
4608 This ioctl issues an ultravisor call to terminate the secure guest,
4609 unpins the VPA pages and releases all the device pages that are used to
4610 track the secure pages by hypervisor.
4612 4.122 KVM_S390_NORMAL_RESET
4613 ---------------------------
4615 :Capability: KVM_CAP_S390_VCPU_RESETS
4616 :Architectures: s390
4621 This ioctl resets VCPU registers and control structures according to
4622 the cpu reset definition in the POP (Principles Of Operation).
4624 4.123 KVM_S390_INITIAL_RESET
4625 ----------------------------
4628 :Architectures: s390
4633 This ioctl resets VCPU registers and control structures according to
4634 the initial cpu reset definition in the POP. However, the cpu is not
4635 put into ESA mode. This reset is a superset of the normal reset.
4637 4.124 KVM_S390_CLEAR_RESET
4638 --------------------------
4640 :Capability: KVM_CAP_S390_VCPU_RESETS
4641 :Architectures: s390
4646 This ioctl resets VCPU registers and control structures according to
4647 the clear cpu reset definition in the POP. However, the cpu is not put
4648 into ESA mode. This reset is a superset of the initial reset.
4651 4.125 KVM_S390_PV_COMMAND
4652 -------------------------
4654 :Capability: KVM_CAP_S390_PROTECTED
4655 :Architectures: s390
4657 :Parameters: struct kvm_pv_cmd
4658 :Returns: 0 on success, < 0 on error
4663 __u32 cmd; /* Command to be executed */
4664 __u16 rc; /* Ultravisor return code */
4665 __u16 rrc; /* Ultravisor return reason code */
4666 __u64 data; /* Data or address */
4667 __u32 flags; /* flags for future extensions. Must be 0 for now */
4674 Allocate memory and register the VM with the Ultravisor, thereby
4675 donating memory to the Ultravisor that will become inaccessible to
4676 KVM. All existing CPUs are converted to protected ones. After this
4677 command has succeeded, any CPU added via hotplug will become
4678 protected during its creation as well.
4682 ===== =============================
4683 EINTR an unmasked signal is pending
4684 ===== =============================
4688 Deregister the VM from the Ultravisor and reclaim the memory that
4689 had been donated to the Ultravisor, making it usable by the kernel
4690 again. All registered VCPUs are converted back to non-protected
4693 KVM_PV_VM_SET_SEC_PARMS
4694 Pass the image header from VM memory to the Ultravisor in
4695 preparation of image unpacking and verification.
4698 Unpack (protect and decrypt) a page of the encrypted boot image.
4701 Verify the integrity of the unpacked image. Only if this succeeds,
4702 KVM is allowed to start protected VCPUs.
4705 5. The kvm_run structure
4706 ========================
4708 Application code obtains a pointer to the kvm_run structure by
4709 mmap()ing a vcpu fd. From that point, application code can control
4710 execution by changing fields in kvm_run prior to calling the KVM_RUN
4711 ioctl, and obtain information about the reason KVM_RUN returned by
4712 looking up structure members.
4718 __u8 request_interrupt_window;
4720 Request that KVM_RUN return when it becomes possible to inject external
4721 interrupts into the guest. Useful in conjunction with KVM_INTERRUPT.
4725 __u8 immediate_exit;
4727 This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN
4728 exits immediately, returning -EINTR. In the common scenario where a
4729 signal is used to "kick" a VCPU out of KVM_RUN, this field can be used
4730 to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability.
4731 Rather than blocking the signal outside KVM_RUN, userspace can set up
4732 a signal handler that sets run->immediate_exit to a non-zero value.
4734 This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available.
4743 When KVM_RUN has returned successfully (return value 0), this informs
4744 application code why KVM_RUN has returned. Allowable values for this
4745 field are detailed below.
4749 __u8 ready_for_interrupt_injection;
4751 If request_interrupt_window has been specified, this field indicates
4752 an interrupt can be injected now with KVM_INTERRUPT.
4758 The value of the current interrupt flag. Only valid if in-kernel
4759 local APIC is not used.
4765 More architecture-specific flags detailing state of the VCPU that may
4766 affect the device's behavior. The only currently defined flag is
4767 KVM_RUN_X86_SMM, which is valid on x86 machines and is set if the
4768 VCPU is in system management mode.
4772 /* in (pre_kvm_run), out (post_kvm_run) */
4775 The value of the cr8 register. Only valid if in-kernel local APIC is
4776 not used. Both input and output.
4782 The value of the APIC BASE msr. Only valid if in-kernel local
4783 APIC is not used. Both input and output.
4788 /* KVM_EXIT_UNKNOWN */
4790 __u64 hardware_exit_reason;
4793 If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown
4794 reasons. Further architecture-specific information is available in
4795 hardware_exit_reason.
4799 /* KVM_EXIT_FAIL_ENTRY */
4801 __u64 hardware_entry_failure_reason;
4802 __u32 cpu; /* if KVM_LAST_CPU */
4805 If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due
4806 to unknown reasons. Further architecture-specific information is
4807 available in hardware_entry_failure_reason.
4811 /* KVM_EXIT_EXCEPTION */
4823 #define KVM_EXIT_IO_IN 0
4824 #define KVM_EXIT_IO_OUT 1
4826 __u8 size; /* bytes */
4829 __u64 data_offset; /* relative to kvm_run start */
4832 If exit_reason is KVM_EXIT_IO, then the vcpu has
4833 executed a port I/O instruction which could not be satisfied by kvm.
4834 data_offset describes where the data is located (KVM_EXIT_IO_OUT) or
4835 where kvm expects application code to place the data for the next
4836 KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array.
4840 /* KVM_EXIT_DEBUG */
4842 struct kvm_debug_exit_arch arch;
4845 If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event
4846 for which architecture specific information is returned.
4858 If exit_reason is KVM_EXIT_MMIO, then the vcpu has
4859 executed a memory-mapped I/O instruction which could not be satisfied
4860 by kvm. The 'data' member contains the written data if 'is_write' is
4861 true, and should be filled by application code otherwise.
4863 The 'data' member contains, in its first 'len' bytes, the value as it would
4864 appear if the VCPU performed a load or store of the appropriate width directly
4869 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR and
4870 KVM_EXIT_EPR the corresponding
4872 operations are complete (and guest state is consistent) only after userspace
4873 has re-entered the kernel with KVM_RUN. The kernel side will first finish
4874 incomplete operations and then check for pending signals. Userspace
4875 can re-enter the guest with an unmasked signal pending to complete
4880 /* KVM_EXIT_HYPERCALL */
4889 Unused. This was once used for 'hypercall to userspace'. To implement
4890 such functionality, use KVM_EXIT_IO (x86) or KVM_EXIT_MMIO (all except s390).
4892 .. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO.
4896 /* KVM_EXIT_TPR_ACCESS */
4903 To be documented (KVM_TPR_ACCESS_REPORTING).
4907 /* KVM_EXIT_S390_SIEIC */
4910 __u64 mask; /* psw upper half */
4911 __u64 addr; /* psw lower half */
4920 /* KVM_EXIT_S390_RESET */
4921 #define KVM_S390_RESET_POR 1
4922 #define KVM_S390_RESET_CLEAR 2
4923 #define KVM_S390_RESET_SUBSYSTEM 4
4924 #define KVM_S390_RESET_CPU_INIT 8
4925 #define KVM_S390_RESET_IPL 16
4926 __u64 s390_reset_flags;
4932 /* KVM_EXIT_S390_UCONTROL */
4934 __u64 trans_exc_code;
4938 s390 specific. A page fault has occurred for a user controlled virtual
4939 machine (KVM_VM_S390_UNCONTROL) on it's host page table that cannot be
4940 resolved by the kernel.
4941 The program code and the translation exception code that were placed
4942 in the cpu's lowcore are presented here as defined by the z Architecture
4943 Principles of Operation Book in the Chapter for Dynamic Address Translation
4955 Deprecated - was used for 440 KVM.
4964 MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch
4965 hypercalls and exit with this exit struct that contains all the guest gprs.
4967 If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall.
4968 Userspace can now handle the hypercall and when it's done modify the gprs as
4969 necessary. Upon guest entry all guest GPRs will then be replaced by the values
4974 /* KVM_EXIT_PAPR_HCALL */
4981 This is used on 64-bit PowerPC when emulating a pSeries partition,
4982 e.g. with the 'pseries' machine type in qemu. It occurs when the
4983 guest does a hypercall using the 'sc 1' instruction. The 'nr' field
4984 contains the hypercall number (from the guest R3), and 'args' contains
4985 the arguments (from the guest R4 - R12). Userspace should put the
4986 return code in 'ret' and any extra returned values in args[].
4987 The possible hypercalls are defined in the Power Architecture Platform
4988 Requirements (PAPR) document available from www.power.org (free
4989 developer registration required to access it).
4993 /* KVM_EXIT_S390_TSCH */
4995 __u16 subchannel_id;
4996 __u16 subchannel_nr;
5003 s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled
5004 and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O
5005 interrupt for the target subchannel has been dequeued and subchannel_id,
5006 subchannel_nr, io_int_parm and io_int_word contain the parameters for that
5007 interrupt. ipb is needed for instruction parameter decoding.
5016 On FSL BookE PowerPC chips, the interrupt controller has a fast patch
5017 interrupt acknowledge path to the core. When the core successfully
5018 delivers an interrupt, it automatically populates the EPR register with
5019 the interrupt vector number and acknowledges the interrupt inside
5020 the interrupt controller.
5022 In case the interrupt controller lives in user space, we need to do
5023 the interrupt acknowledge cycle through it to fetch the next to be
5024 delivered interrupt vector using this exit.
5026 It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an
5027 external interrupt has just been delivered into the guest. User space
5028 should put the acknowledged interrupt vector into the 'epr' field.
5032 /* KVM_EXIT_SYSTEM_EVENT */
5034 #define KVM_SYSTEM_EVENT_SHUTDOWN 1
5035 #define KVM_SYSTEM_EVENT_RESET 2
5036 #define KVM_SYSTEM_EVENT_CRASH 3
5041 If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered
5042 a system-level event using some architecture specific mechanism (hypercall
5043 or some special instruction). In case of ARM/ARM64, this is triggered using
5044 HVC instruction based PSCI call from the vcpu. The 'type' field describes
5045 the system-level event type. The 'flags' field describes architecture
5046 specific flags for the system-level event.
5048 Valid values for 'type' are:
5050 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the
5051 VM. Userspace is not obliged to honour this, and if it does honour
5052 this does not need to destroy the VM synchronously (ie it may call
5053 KVM_RUN again before shutdown finally occurs).
5054 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM.
5055 As with SHUTDOWN, userspace can choose to ignore the request, or
5056 to schedule the reset to occur in the future and may call KVM_RUN again.
5057 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest
5058 has requested a crash condition maintenance. Userspace can choose
5059 to ignore the request, or to gather VM memory core dump and/or
5060 reset/shutdown of the VM.
5064 /* KVM_EXIT_IOAPIC_EOI */
5069 Indicates that the VCPU's in-kernel local APIC received an EOI for a
5070 level-triggered IOAPIC interrupt. This exit only triggers when the
5071 IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled);
5072 the userspace IOAPIC should process the EOI and retrigger the interrupt if
5073 it is still asserted. Vector is the LAPIC interrupt vector for which the
5078 struct kvm_hyperv_exit {
5079 #define KVM_EXIT_HYPERV_SYNIC 1
5080 #define KVM_EXIT_HYPERV_HCALL 2
5081 #define KVM_EXIT_HYPERV_SYNDBG 3
5108 /* KVM_EXIT_HYPERV */
5109 struct kvm_hyperv_exit hyperv;
5111 Indicates that the VCPU exits into userspace to process some tasks
5112 related to Hyper-V emulation.
5114 Valid values for 'type' are:
5116 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about
5118 Hyper-V SynIC state change. Notification is used to remap SynIC
5119 event/message pages and to enable/disable SynIC messages/events processing
5122 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about
5124 Hyper-V Synthetic debugger state change. Notification is used to either update
5125 the pending_page location or to send a control command (send the buffer located
5126 in send_page or recv a buffer to recv_page).
5130 /* KVM_EXIT_ARM_NISV */
5136 Used on arm and arm64 systems. If a guest accesses memory not in a memslot,
5137 KVM will typically return to userspace and ask it to do MMIO emulation on its
5138 behalf. However, for certain classes of instructions, no instruction decode
5139 (direction, length of memory access) is provided, and fetching and decoding
5140 the instruction from the VM is overly complicated to live in the kernel.
5142 Historically, when this situation occurred, KVM would print a warning and kill
5143 the VM. KVM assumed that if the guest accessed non-memslot memory, it was
5144 trying to do I/O, which just couldn't be emulated, and the warning message was
5145 phrased accordingly. However, what happened more often was that a guest bug
5146 caused access outside the guest memory areas which should lead to a more
5147 meaningful warning message and an external abort in the guest, if the access
5148 did not fall within an I/O window.
5150 Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable
5151 this capability at VM creation. Once this is done, these types of errors will
5152 instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from
5153 the HSR (arm) and ESR_EL2 (arm64) in the esr_iss field, and the faulting IPA
5154 in the fault_ipa field. Userspace can either fix up the access if it's
5155 actually an I/O access by decoding the instruction from guest memory (if it's
5156 very brave) and continue executing the guest, or it can decide to suspend,
5157 dump, or restart the guest.
5159 Note that KVM does not skip the faulting instruction as it does for
5160 KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state
5161 if it decides to decode and emulate the instruction.
5165 /* Fix the size of the union. */
5170 * shared registers between kvm and userspace.
5171 * kvm_valid_regs specifies the register classes set by the host
5172 * kvm_dirty_regs specified the register classes dirtied by userspace
5173 * struct kvm_sync_regs is architecture specific, as well as the
5174 * bits for kvm_valid_regs and kvm_dirty_regs
5176 __u64 kvm_valid_regs;
5177 __u64 kvm_dirty_regs;
5179 struct kvm_sync_regs regs;
5180 char padding[SYNC_REGS_SIZE_BYTES];
5183 If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access
5184 certain guest registers without having to call SET/GET_*REGS. Thus we can
5185 avoid some system call overhead if userspace has to handle the exit.
5186 Userspace can query the validity of the structure by checking
5187 kvm_valid_regs for specific bits. These bits are architecture specific
5188 and usually define the validity of a groups of registers. (e.g. one bit
5189 for general purpose registers)
5191 Please note that the kernel is allowed to use the kvm_run structure as the
5192 primary storage for certain register types. Therefore, the kernel may use the
5193 values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set.
5201 6. Capabilities that can be enabled on vCPUs
5202 ============================================
5204 There are certain capabilities that change the behavior of the virtual CPU or
5205 the virtual machine when enabled. To enable them, please see section 4.37.
5206 Below you can find a list of capabilities and what their effect on the vCPU or
5207 the virtual machine is when enabling them.
5209 The following information is provided along with the description:
5212 which instruction set architectures provide this ioctl.
5213 x86 includes both i386 and x86_64.
5216 whether this is a per-vcpu or per-vm capability.
5219 what parameters are accepted by the capability.
5222 the return value. General error numbers (EBADF, ENOMEM, EINVAL)
5223 are not detailed, but errors with specific meanings are.
5232 :Returns: 0 on success; -1 on error
5234 This capability enables interception of OSI hypercalls that otherwise would
5235 be treated as normal system calls to be injected into the guest. OSI hypercalls
5236 were invented by Mac-on-Linux to have a standardized communication mechanism
5237 between the guest and the host.
5239 When this capability is enabled, KVM_EXIT_OSI can occur.
5242 6.2 KVM_CAP_PPC_PAPR
5243 --------------------
5248 :Returns: 0 on success; -1 on error
5250 This capability enables interception of PAPR hypercalls. PAPR hypercalls are
5251 done using the hypercall instruction "sc 1".
5253 It also sets the guest privilege level to "supervisor" mode. Usually the guest
5254 runs in "hypervisor" privilege mode with a few missing features.
5256 In addition to the above, it changes the semantics of SDR1. In this mode, the
5257 HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the
5258 HTAB invisible to the guest.
5260 When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur.
5268 :Parameters: args[0] is the address of a struct kvm_config_tlb
5269 :Returns: 0 on success; -1 on error
5273 struct kvm_config_tlb {
5280 Configures the virtual CPU's TLB array, establishing a shared memory area
5281 between userspace and KVM. The "params" and "array" fields are userspace
5282 addresses of mmu-type-specific data structures. The "array_len" field is an
5283 safety mechanism, and should be set to the size in bytes of the memory that
5284 userspace has reserved for the array. It must be at least the size dictated
5285 by "mmu_type" and "params".
5287 While KVM_RUN is active, the shared region is under control of KVM. Its
5288 contents are undefined, and any modification by userspace results in
5289 boundedly undefined behavior.
5291 On return from KVM_RUN, the shared region will reflect the current state of
5292 the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB
5293 to tell KVM which entries have been changed, prior to calling KVM_RUN again
5296 For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV:
5298 - The "params" field is of type "struct kvm_book3e_206_tlb_params".
5299 - The "array" field points to an array of type "struct
5300 kvm_book3e_206_tlb_entry".
5301 - The array consists of all entries in the first TLB, followed by all
5302 entries in the second TLB.
5303 - Within a TLB, entries are ordered first by increasing set number. Within a
5304 set, entries are ordered by way (increasing ESEL).
5305 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1)
5306 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value.
5307 - The tsize field of mas1 shall be set to 4K on TLB0, even though the
5308 hardware ignores this value for TLB0.
5310 6.4 KVM_CAP_S390_CSS_SUPPORT
5311 ----------------------------
5313 :Architectures: s390
5316 :Returns: 0 on success; -1 on error
5318 This capability enables support for handling of channel I/O instructions.
5320 TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are
5321 handled in-kernel, while the other I/O instructions are passed to userspace.
5323 When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST
5324 SUBCHANNEL intercepts.
5326 Note that even though this capability is enabled per-vcpu, the complete
5327 virtual machine is affected.
5334 :Parameters: args[0] defines whether the proxy facility is active
5335 :Returns: 0 on success; -1 on error
5337 This capability enables or disables the delivery of interrupts through the
5338 external proxy facility.
5340 When enabled (args[0] != 0), every time the guest gets an external interrupt
5341 delivered, it automatically exits into user space with a KVM_EXIT_EPR exit
5342 to receive the topmost interrupt vector.
5344 When disabled (args[0] == 0), behavior is as if this facility is unsupported.
5346 When this capability is enabled, KVM_EXIT_EPR can occur.
5348 6.6 KVM_CAP_IRQ_MPIC
5349 --------------------
5352 :Parameters: args[0] is the MPIC device fd;
5353 args[1] is the MPIC CPU number for this vcpu
5355 This capability connects the vcpu to an in-kernel MPIC device.
5357 6.7 KVM_CAP_IRQ_XICS
5358 --------------------
5362 :Parameters: args[0] is the XICS device fd;
5363 args[1] is the XICS CPU number (server ID) for this vcpu
5365 This capability connects the vcpu to an in-kernel XICS device.
5367 6.8 KVM_CAP_S390_IRQCHIP
5368 ------------------------
5370 :Architectures: s390
5374 This capability enables the in-kernel irqchip for s390. Please refer to
5375 "4.24 KVM_CREATE_IRQCHIP" for details.
5377 6.9 KVM_CAP_MIPS_FPU
5378 --------------------
5380 :Architectures: mips
5382 :Parameters: args[0] is reserved for future use (should be 0).
5384 This capability allows the use of the host Floating Point Unit by the guest. It
5385 allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is
5386 done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be
5387 accessed (depending on the current guest FPU register mode), and the Status.FR,
5388 Config5.FRE bits are accessible via the KVM API and also from the guest,
5389 depending on them being supported by the FPU.
5391 6.10 KVM_CAP_MIPS_MSA
5392 ---------------------
5394 :Architectures: mips
5396 :Parameters: args[0] is reserved for future use (should be 0).
5398 This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest.
5399 It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest.
5400 Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*``
5401 registers can be accessed, and the Config5.MSAEn bit is accessible via the
5402 KVM API and also from the guest.
5404 6.74 KVM_CAP_SYNC_REGS
5405 ----------------------
5407 :Architectures: s390, x86
5408 :Target: s390: always enabled, x86: vcpu
5410 :Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register
5412 (bitfields defined in arch/x86/include/uapi/asm/kvm.h).
5414 As described above in the kvm_sync_regs struct info in section 5 (kvm_run):
5415 KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers
5416 without having to call SET/GET_*REGS". This reduces overhead by eliminating
5417 repeated ioctl calls for setting and/or getting register values. This is
5418 particularly important when userspace is making synchronous guest state
5419 modifications, e.g. when emulating and/or intercepting instructions in
5422 For s390 specifics, please refer to the source code.
5426 - the register sets to be copied out to kvm_run are selectable
5427 by userspace (rather that all sets being copied out for every exit).
5428 - vcpu_events are available in addition to regs and sregs.
5430 For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to
5431 function as an input bit-array field set by userspace to indicate the
5432 specific register sets to be copied out on the next exit.
5434 To indicate when userspace has modified values that should be copied into
5435 the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set.
5436 This is done using the same bitflags as for the 'kvm_valid_regs' field.
5437 If the dirty bit is not set, then the register set values will not be copied
5438 into the vCPU even if they've been modified.
5440 Unused bitfields in the bitarrays must be set to zero.
5444 struct kvm_sync_regs {
5445 struct kvm_regs regs;
5446 struct kvm_sregs sregs;
5447 struct kvm_vcpu_events events;
5450 6.75 KVM_CAP_PPC_IRQ_XIVE
5451 -------------------------
5455 :Parameters: args[0] is the XIVE device fd;
5456 args[1] is the XIVE CPU number (server ID) for this vcpu
5458 This capability connects the vcpu to an in-kernel XIVE device.
5460 7. Capabilities that can be enabled on VMs
5461 ==========================================
5463 There are certain capabilities that change the behavior of the virtual
5464 machine when enabled. To enable them, please see section 4.37. Below
5465 you can find a list of capabilities and what their effect on the VM
5466 is when enabling them.
5468 The following information is provided along with the description:
5471 which instruction set architectures provide this ioctl.
5472 x86 includes both i386 and x86_64.
5475 what parameters are accepted by the capability.
5478 the return value. General error numbers (EBADF, ENOMEM, EINVAL)
5479 are not detailed, but errors with specific meanings are.
5482 7.1 KVM_CAP_PPC_ENABLE_HCALL
5483 ----------------------------
5486 :Parameters: args[0] is the sPAPR hcall number;
5487 args[1] is 0 to disable, 1 to enable in-kernel handling
5489 This capability controls whether individual sPAPR hypercalls (hcalls)
5490 get handled by the kernel or not. Enabling or disabling in-kernel
5491 handling of an hcall is effective across the VM. On creation, an
5492 initial set of hcalls are enabled for in-kernel handling, which
5493 consists of those hcalls for which in-kernel handlers were implemented
5494 before this capability was implemented. If disabled, the kernel will
5495 not to attempt to handle the hcall, but will always exit to userspace
5496 to handle it. Note that it may not make sense to enable some and
5497 disable others of a group of related hcalls, but KVM does not prevent
5498 userspace from doing that.
5500 If the hcall number specified is not one that has an in-kernel
5501 implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL
5504 7.2 KVM_CAP_S390_USER_SIGP
5505 --------------------------
5507 :Architectures: s390
5510 This capability controls which SIGP orders will be handled completely in user
5511 space. With this capability enabled, all fast orders will be handled completely
5518 - CONDITIONAL EMERGENCY SIGNAL
5520 All other orders will be handled completely in user space.
5522 Only privileged operation exceptions will be checked for in the kernel (or even
5523 in the hardware prior to interception). If this capability is not enabled, the
5524 old way of handling SIGP orders is used (partially in kernel and user space).
5526 7.3 KVM_CAP_S390_VECTOR_REGISTERS
5527 ---------------------------------
5529 :Architectures: s390
5531 :Returns: 0 on success, negative value on error
5533 Allows use of the vector registers introduced with z13 processor, and
5534 provides for the synchronization between host and user space. Will
5535 return -EINVAL if the machine does not support vectors.
5537 7.4 KVM_CAP_S390_USER_STSI
5538 --------------------------
5540 :Architectures: s390
5543 This capability allows post-handlers for the STSI instruction. After
5544 initial handling in the kernel, KVM exits to user space with
5545 KVM_EXIT_S390_STSI to allow user space to insert further data.
5547 Before exiting to userspace, kvm handlers should fill in s390_stsi field of
5559 @addr - guest address of STSI SYSIB
5563 @ar - access register number
5565 KVM handlers should exit to userspace with rc = -EREMOTE.
5567 7.5 KVM_CAP_SPLIT_IRQCHIP
5568 -------------------------
5571 :Parameters: args[0] - number of routes reserved for userspace IOAPICs
5572 :Returns: 0 on success, -1 on error
5574 Create a local apic for each processor in the kernel. This can be used
5575 instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the
5576 IOAPIC and PIC (and also the PIT, even though this has to be enabled
5579 This capability also enables in kernel routing of interrupt requests;
5580 when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are
5581 used in the IRQ routing table. The first args[0] MSI routes are reserved
5582 for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes,
5583 a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace.
5585 Fails if VCPU has already been created, or if the irqchip is already in the
5586 kernel (i.e. KVM_CREATE_IRQCHIP has already been called).
5591 :Architectures: s390
5594 Allows use of runtime-instrumentation introduced with zEC12 processor.
5595 Will return -EINVAL if the machine does not support runtime-instrumentation.
5596 Will return -EBUSY if a VCPU has already been created.
5598 7.7 KVM_CAP_X2APIC_API
5599 ----------------------
5602 :Parameters: args[0] - features that should be enabled
5603 :Returns: 0 on success, -EINVAL when args[0] contains invalid features
5605 Valid feature flags in args[0] are::
5607 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0)
5608 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1)
5610 Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of
5611 KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC,
5612 allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their
5613 respective sections.
5615 KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work
5616 in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff
5617 as a broadcast even in x2APIC mode in order to support physical x2APIC
5618 without interrupt remapping. This is undesirable in logical mode,
5619 where 0xff represents CPUs 0-7 in cluster 0.
5621 7.8 KVM_CAP_S390_USER_INSTR0
5622 ----------------------------
5624 :Architectures: s390
5627 With this capability enabled, all illegal instructions 0x0000 (2 bytes) will
5628 be intercepted and forwarded to user space. User space can use this
5629 mechanism e.g. to realize 2-byte software breakpoints. The kernel will
5630 not inject an operating exception for these instructions, user space has
5631 to take care of that.
5633 This capability can be enabled dynamically even if VCPUs were already
5634 created and are running.
5639 :Architectures: s390
5641 :Returns: 0 on success; -EINVAL if the machine does not support
5642 guarded storage; -EBUSY if a VCPU has already been created.
5644 Allows use of guarded storage for the KVM guest.
5646 7.10 KVM_CAP_S390_AIS
5647 ---------------------
5649 :Architectures: s390
5652 Allow use of adapter-interruption suppression.
5653 :Returns: 0 on success; -EBUSY if a VCPU has already been created.
5655 7.11 KVM_CAP_PPC_SMT
5656 --------------------
5659 :Parameters: vsmt_mode, flags
5661 Enabling this capability on a VM provides userspace with a way to set
5662 the desired virtual SMT mode (i.e. the number of virtual CPUs per
5663 virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2
5664 between 1 and 8. On POWER8, vsmt_mode must also be no greater than
5665 the number of threads per subcore for the host. Currently flags must
5666 be 0. A successful call to enable this capability will result in
5667 vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is
5668 subsequently queried for the VM. This capability is only supported by
5669 HV KVM, and can only be set before any VCPUs have been created.
5670 The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT
5671 modes are available.
5673 7.12 KVM_CAP_PPC_FWNMI
5674 ----------------------
5679 With this capability a machine check exception in the guest address
5680 space will cause KVM to exit the guest with NMI exit reason. This
5681 enables QEMU to build error log and branch to guest kernel registered
5682 machine check handling routine. Without this capability KVM will
5683 branch to guests' 0x200 interrupt vector.
5685 7.13 KVM_CAP_X86_DISABLE_EXITS
5686 ------------------------------
5689 :Parameters: args[0] defines which exits are disabled
5690 :Returns: 0 on success, -EINVAL when args[0] contains invalid exits
5692 Valid bits in args[0] are::
5694 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
5695 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
5696 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2)
5697 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3)
5699 Enabling this capability on a VM provides userspace with a way to no
5700 longer intercept some instructions for improved latency in some
5701 workloads, and is suggested when vCPUs are associated to dedicated
5702 physical CPUs. More bits can be added in the future; userspace can
5703 just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable
5706 Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits.
5708 7.14 KVM_CAP_S390_HPAGE_1M
5709 --------------------------
5711 :Architectures: s390
5713 :Returns: 0 on success, -EINVAL if hpage module parameter was not set
5714 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL
5717 With this capability the KVM support for memory backing with 1m pages
5718 through hugetlbfs can be enabled for a VM. After the capability is
5719 enabled, cmma can't be enabled anymore and pfmfi and the storage key
5720 interpretation are disabled. If cmma has already been enabled or the
5721 hpage module parameter is not set to 1, -EINVAL is returned.
5723 While it is generally possible to create a huge page backed VM without
5724 this capability, the VM will not be able to run.
5726 7.15 KVM_CAP_MSR_PLATFORM_INFO
5727 ------------------------------
5730 :Parameters: args[0] whether feature should be enabled or not
5732 With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise,
5733 a #GP would be raised when the guest tries to access. Currently, this
5734 capability does not enable write permissions of this MSR for the guest.
5736 7.16 KVM_CAP_PPC_NESTED_HV
5737 --------------------------
5741 :Returns: 0 on success, -EINVAL when the implementation doesn't support
5742 nested-HV virtualization.
5744 HV-KVM on POWER9 and later systems allows for "nested-HV"
5745 virtualization, which provides a way for a guest VM to run guests that
5746 can run using the CPU's supervisor mode (privileged non-hypervisor
5747 state). Enabling this capability on a VM depends on the CPU having
5748 the necessary functionality and on the facility being enabled with a
5749 kvm-hv module parameter.
5751 7.17 KVM_CAP_EXCEPTION_PAYLOAD
5752 ------------------------------
5755 :Parameters: args[0] whether feature should be enabled or not
5757 With this capability enabled, CR2 will not be modified prior to the
5758 emulated VM-exit when L1 intercepts a #PF exception that occurs in
5759 L2. Similarly, for kvm-intel only, DR6 will not be modified prior to
5760 the emulated VM-exit when L1 intercepts a #DB exception that occurs in
5761 L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or
5762 #DB) exception for L2, exception.has_payload will be set and the
5763 faulting address (or the new DR6 bits*) will be reported in the
5764 exception_payload field. Similarly, when userspace injects a #PF (or
5765 #DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set
5766 exception.has_payload and to put the faulting address - or the new DR6
5767 bits\ [#]_ - in the exception_payload field.
5769 This capability also enables exception.pending in struct
5770 kvm_vcpu_events, which allows userspace to distinguish between pending
5771 and injected exceptions.
5774 .. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception
5777 7.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
5779 :Architectures: x86, arm, arm64, mips
5780 :Parameters: args[0] whether feature should be enabled or not
5784 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0)
5785 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1)
5787 With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not
5788 automatically clear and write-protect all pages that are returned as dirty.
5789 Rather, userspace will have to do this operation separately using
5790 KVM_CLEAR_DIRTY_LOG.
5792 At the cost of a slightly more complicated operation, this provides better
5793 scalability and responsiveness for two reasons. First,
5794 KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather
5795 than requiring to sync a full memslot; this ensures that KVM does not
5796 take spinlocks for an extended period of time. Second, in some cases a
5797 large amount of time can pass between a call to KVM_GET_DIRTY_LOG and
5798 userspace actually using the data in the page. Pages can be modified
5799 during this time, which is inefficient for both the guest and userspace:
5800 the guest will incur a higher penalty due to write protection faults,
5801 while userspace can see false reports of dirty pages. Manual reprotection
5802 helps reducing this time, improving guest performance and reducing the
5803 number of dirty log false positives.
5805 With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap
5806 will be initialized to 1 when created. This also improves performance because
5807 dirty logging can be enabled gradually in small chunks on the first call
5808 to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on
5809 KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on
5810 x86 and arm64 for now).
5812 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name
5813 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make
5814 it hard or impossible to use it correctly. The availability of
5815 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed.
5816 Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT.
5818 7.19 KVM_CAP_PPC_SECURE_GUEST
5819 ------------------------------
5823 This capability indicates that KVM is running on a host that has
5824 ultravisor firmware and thus can support a secure guest. On such a
5825 system, a guest can ask the ultravisor to make it a secure guest,
5826 one whose memory is inaccessible to the host except for pages which
5827 are explicitly requested to be shared with the host. The ultravisor
5828 notifies KVM when a guest requests to become a secure guest, and KVM
5829 has the opportunity to veto the transition.
5831 If present, this capability can be enabled for a VM, meaning that KVM
5832 will allow the transition to secure guest mode. Otherwise KVM will
5833 veto the transition.
5835 7.20 KVM_CAP_HALT_POLL
5836 ----------------------
5840 :Parameters: args[0] is the maximum poll time in nanoseconds
5841 :Returns: 0 on success; -1 on error
5843 This capability overrides the kvm module parameter halt_poll_ns for the
5846 VCPU polling allows a VCPU to poll for wakeup events instead of immediately
5847 scheduling during guest halts. The maximum time a VCPU can spend polling is
5848 controlled by the kvm module parameter halt_poll_ns. This capability allows
5849 the maximum halt time to specified on a per-VM basis, effectively overriding
5850 the module parameter for the target VM.
5852 8. Other capabilities.
5853 ======================
5855 This section lists capabilities that give information about other
5856 features of the KVM implementation.
5858 8.1 KVM_CAP_PPC_HWRNG
5859 ---------------------
5863 This capability, if KVM_CHECK_EXTENSION indicates that it is
5864 available, means that the kernel has an implementation of the
5865 H_RANDOM hypercall backed by a hardware random-number generator.
5866 If present, the kernel H_RANDOM handler can be enabled for guest use
5867 with the KVM_CAP_PPC_ENABLE_HCALL capability.
5869 8.2 KVM_CAP_HYPERV_SYNIC
5870 ------------------------
5874 This capability, if KVM_CHECK_EXTENSION indicates that it is
5875 available, means that the kernel has an implementation of the
5876 Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is
5877 used to support Windows Hyper-V based guest paravirt drivers(VMBus).
5879 In order to use SynIC, it has to be activated by setting this
5880 capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this
5881 will disable the use of APIC hardware virtualization even if supported
5882 by the CPU, as it's incompatible with SynIC auto-EOI behavior.
5884 8.3 KVM_CAP_PPC_RADIX_MMU
5885 -------------------------
5889 This capability, if KVM_CHECK_EXTENSION indicates that it is
5890 available, means that the kernel can support guests using the
5891 radix MMU defined in Power ISA V3.00 (as implemented in the POWER9
5894 8.4 KVM_CAP_PPC_HASH_MMU_V3
5895 ---------------------------
5899 This capability, if KVM_CHECK_EXTENSION indicates that it is
5900 available, means that the kernel can support guests using the
5901 hashed page table MMU defined in Power ISA V3.00 (as implemented in
5902 the POWER9 processor), including in-memory segment tables.
5907 :Architectures: mips
5909 This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that
5910 it is available, means that full hardware assisted virtualization capabilities
5911 of the hardware are available for use through KVM. An appropriate
5912 KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which
5915 If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is
5916 available, it means that the VM is using full hardware assisted virtualization
5917 capabilities of the hardware. This is useful to check after creating a VM with
5918 KVM_VM_MIPS_DEFAULT.
5920 The value returned by KVM_CHECK_EXTENSION should be compared against known
5921 values (see below). All other values are reserved. This is to allow for the
5922 possibility of other hardware assisted virtualization implementations which
5923 may be incompatible with the MIPS VZ ASE.
5925 == ==========================================================================
5926 0 The trap & emulate implementation is in use to run guest code in user
5927 mode. Guest virtual memory segments are rearranged to fit the guest in the
5928 user mode address space.
5930 1 The MIPS VZ ASE is in use, providing full hardware assisted
5931 virtualization, including standard guest virtual memory segments.
5932 == ==========================================================================
5937 :Architectures: mips
5939 This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that
5940 it is available, means that the trap & emulate implementation is available to
5941 run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware
5942 assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed
5943 to KVM_CREATE_VM to create a VM which utilises it.
5945 If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is
5946 available, it means that the VM is using trap & emulate.
5948 8.7 KVM_CAP_MIPS_64BIT
5949 ----------------------
5951 :Architectures: mips
5953 This capability indicates the supported architecture type of the guest, i.e. the
5954 supported register and address width.
5956 The values returned when this capability is checked by KVM_CHECK_EXTENSION on a
5957 kvm VM handle correspond roughly to the CP0_Config.AT register field, and should
5958 be checked specifically against known values (see below). All other values are
5961 == ========================================================================
5962 0 MIPS32 or microMIPS32.
5963 Both registers and addresses are 32-bits wide.
5964 It will only be possible to run 32-bit guest code.
5966 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments.
5967 Registers are 64-bits wide, but addresses are 32-bits wide.
5968 64-bit guest code may run but cannot access MIPS64 memory segments.
5969 It will also be possible to run 32-bit guest code.
5971 2 MIPS64 or microMIPS64 with access to all address segments.
5972 Both registers and addresses are 64-bits wide.
5973 It will be possible to run 64-bit or 32-bit guest code.
5974 == ========================================================================
5976 8.9 KVM_CAP_ARM_USER_IRQ
5977 ------------------------
5979 :Architectures: arm, arm64
5981 This capability, if KVM_CHECK_EXTENSION indicates that it is available, means
5982 that if userspace creates a VM without an in-kernel interrupt controller, it
5983 will be notified of changes to the output level of in-kernel emulated devices,
5984 which can generate virtual interrupts, presented to the VM.
5985 For such VMs, on every return to userspace, the kernel
5986 updates the vcpu's run->s.regs.device_irq_level field to represent the actual
5987 output level of the device.
5989 Whenever kvm detects a change in the device output level, kvm guarantees at
5990 least one return to userspace before running the VM. This exit could either
5991 be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way,
5992 userspace can always sample the device output level and re-compute the state of
5993 the userspace interrupt controller. Userspace should always check the state
5994 of run->s.regs.device_irq_level on every kvm exit.
5995 The value in run->s.regs.device_irq_level can represent both level and edge
5996 triggered interrupt signals, depending on the device. Edge triggered interrupt
5997 signals will exit to userspace with the bit in run->s.regs.device_irq_level
5998 set exactly once per edge signal.
6000 The field run->s.regs.device_irq_level is available independent of
6001 run->kvm_valid_regs or run->kvm_dirty_regs bits.
6003 If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a
6004 number larger than 0 indicating the version of this capability is implemented
6005 and thereby which bits in run->s.regs.device_irq_level can signal values.
6007 Currently the following bits are defined for the device_irq_level bitmap::
6009 KVM_CAP_ARM_USER_IRQ >= 1:
6011 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer
6012 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer
6013 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal
6015 Future versions of kvm may implement additional events. These will get
6016 indicated by returning a higher number from KVM_CHECK_EXTENSION and will be
6019 8.10 KVM_CAP_PPC_SMT_POSSIBLE
6020 -----------------------------
6024 Querying this capability returns a bitmap indicating the possible
6025 virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N
6026 (counting from the right) is set, then a virtual SMT mode of 2^N is
6029 8.11 KVM_CAP_HYPERV_SYNIC2
6030 --------------------------
6034 This capability enables a newer version of Hyper-V Synthetic interrupt
6035 controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM
6036 doesn't clear SynIC message and event flags pages when they are enabled by
6037 writing to the respective MSRs.
6039 8.12 KVM_CAP_HYPERV_VP_INDEX
6040 ----------------------------
6044 This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its
6045 value is used to denote the target vcpu for a SynIC interrupt. For
6046 compatibilty, KVM initializes this msr to KVM's internal vcpu index. When this
6047 capability is absent, userspace can still query this msr's value.
6049 8.13 KVM_CAP_S390_AIS_MIGRATION
6050 -------------------------------
6052 :Architectures: s390
6055 This capability indicates if the flic device will be able to get/set the
6056 AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows
6057 to discover this without having to create a flic device.
6059 8.14 KVM_CAP_S390_PSW
6060 ---------------------
6062 :Architectures: s390
6064 This capability indicates that the PSW is exposed via the kvm_run structure.
6066 8.15 KVM_CAP_S390_GMAP
6067 ----------------------
6069 :Architectures: s390
6071 This capability indicates that the user space memory used as guest mapping can
6072 be anywhere in the user memory address space, as long as the memory slots are
6073 aligned and sized to a segment (1MB) boundary.
6075 8.16 KVM_CAP_S390_COW
6076 ---------------------
6078 :Architectures: s390
6080 This capability indicates that the user space memory used as guest mapping can
6081 use copy-on-write semantics as well as dirty pages tracking via read-only page
6084 8.17 KVM_CAP_S390_BPB
6085 ---------------------
6087 :Architectures: s390
6089 This capability indicates that kvm will implement the interfaces to handle
6090 reset, migration and nested KVM for branch prediction blocking. The stfle
6091 facility 82 should not be provided to the guest without this capability.
6093 8.18 KVM_CAP_HYPERV_TLBFLUSH
6094 ----------------------------
6098 This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush
6100 HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx,
6101 HvFlushVirtualAddressList, HvFlushVirtualAddressListEx.
6103 8.19 KVM_CAP_ARM_INJECT_SERROR_ESR
6104 ----------------------------------
6106 :Architectures: arm, arm64
6108 This capability indicates that userspace can specify (via the
6109 KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it
6110 takes a virtual SError interrupt exception.
6111 If KVM advertises this capability, userspace can only specify the ISS field for
6112 the ESR syndrome. Other parts of the ESR, such as the EC are generated by the
6113 CPU when the exception is taken. If this virtual SError is taken to EL1 using
6114 AArch64, this value will be reported in the ISS field of ESR_ELx.
6116 See KVM_CAP_VCPU_EVENTS for more details.
6118 8.20 KVM_CAP_HYPERV_SEND_IPI
6119 ----------------------------
6123 This capability indicates that KVM supports paravirtualized Hyper-V IPI send
6125 HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx.
6127 8.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH
6128 -----------------------------------
6132 This capability indicates that KVM running on top of Hyper-V hypervisor
6133 enables Direct TLB flush for its guests meaning that TLB flush
6134 hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM.
6135 Due to the different ABI for hypercall parameters between Hyper-V and
6136 KVM, enabling this capability effectively disables all hypercall
6137 handling by KVM (as some KVM hypercall may be mistakenly treated as TLB
6138 flush hypercalls by Hyper-V) so userspace should disable KVM identification
6139 in CPUID and only exposes Hyper-V identification. In this case, guest
6140 thinks it's running on Hyper-V and only use Hyper-V hypercalls.
6142 8.22 KVM_CAP_S390_VCPU_RESETS
6146 This capability indicates that the KVM_S390_NORMAL_RESET and
6147 KVM_S390_CLEAR_RESET ioctls are available.
6149 8.23 KVM_CAP_S390_PROTECTED
6154 This capability indicates that the Ultravisor has been initialized and
6155 KVM can therefore start protected VMs.
6156 This capability governs the KVM_S390_PV_COMMAND ioctl and the
6157 KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected
6158 guests when the state change is invalid.