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| author | Christoph Hellwig <hch@lst.de> | 2019-07-24 10:24:49 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-24 11:52:11 +0300 |
| commit | 2f5947dfcaecb99f2dd559156eecbeb7b95e4c02 (patch) | |
| tree | a16db9103d69f0d5fae6de67987a1f1476f4598b /Documentation/virtual/kvm/api.txt | |
| parent | c6bf2ae931adbd3e10967e12142856439a211813 (diff) | |
| download | linux-2f5947dfcaecb99f2dd559156eecbeb7b95e4c02.tar.xz | |
Documentation: move Documentation/virtual to Documentation/virt
Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories. We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory. Fix up the documentation
to match that.
Fixes: ed16648eb5b8 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virtual/kvm/api.txt')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 5296 |
1 files changed, 0 insertions, 5296 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt deleted file mode 100644 index e54a3f51ddc5..000000000000 --- a/Documentation/virtual/kvm/api.txt +++ /dev/null @@ -1,5296 +0,0 @@ -The Definitive KVM (Kernel-based Virtual Machine) API Documentation -=================================================================== - -1. General description ----------------------- - -The kvm API is a set of ioctls that are issued to control various aspects -of a virtual machine. The ioctls belong to three classes: - - - System ioctls: These query and set global attributes which affect the - whole kvm subsystem. In addition a system ioctl is used to create - virtual machines. - - - VM ioctls: These query and set attributes that affect an entire virtual - machine, for example memory layout. In addition a VM ioctl is used to - create virtual cpus (vcpus) and devices. - - VM ioctls must be issued from the same process (address space) that was - used to create the VM. - - - vcpu ioctls: These query and set attributes that control the operation - of a single virtual cpu. - - vcpu ioctls should be issued from the same thread that was used to create - the vcpu, except for asynchronous vcpu ioctl that are marked as such in - the documentation. Otherwise, the first ioctl after switching threads - could see a performance impact. - - - device ioctls: These query and set attributes that control the operation - of a single device. - - device ioctls must be issued from the same process (address space) that - was used to create the VM. - -2. File descriptors -------------------- - -The kvm API is centered around file descriptors. An initial -open("/dev/kvm") obtains a handle to the kvm subsystem; this handle -can be used to issue system ioctls. A KVM_CREATE_VM ioctl on this -handle will create a VM file descriptor which can be used to issue VM -ioctls. A KVM_CREATE_VCPU or KVM_CREATE_DEVICE ioctl on a VM fd will -create a virtual cpu or device and return a file descriptor pointing to -the new resource. Finally, ioctls on a vcpu or device fd can be used -to control the vcpu or device. For vcpus, this includes the important -task of actually running guest code. - -In general file descriptors can be migrated among processes by means -of fork() and the SCM_RIGHTS facility of unix domain socket. These -kinds of tricks are explicitly not supported by kvm. While they will -not cause harm to the host, their actual behavior is not guaranteed by -the API. See "General description" for details on the ioctl usage -model that is supported by KVM. - -It is important to note that althought VM ioctls may only be issued from -the process that created the VM, a VM's lifecycle is associated with its -file descriptor, not its creator (process). In other words, the VM and -its resources, *including the associated address space*, are not freed -until the last reference to the VM's file descriptor has been released. -For example, if fork() is issued after ioctl(KVM_CREATE_VM), the VM will -not be freed until both the parent (original) process and its child have -put their references to the VM's file descriptor. - -Because a VM's resources are not freed until the last reference to its -file descriptor is released, creating additional references to a VM via -via fork(), dup(), etc... without careful consideration is strongly -discouraged and may have unwanted side effects, e.g. memory allocated -by and on behalf of the VM's process may not be freed/unaccounted when -the VM is shut down. - - -3. Extensions -------------- - -As of Linux 2.6.22, the KVM ABI has been stabilized: no backward -incompatible change are allowed. However, there is an extension -facility that allows backward-compatible extensions to the API to be -queried and used. - -The extension mechanism is not based on the Linux version number. -Instead, kvm defines extension identifiers and a facility to query -whether a particular extension identifier is available. If it is, a -set of ioctls is available for application use. - - -4. API description ------------------- - -This section describes ioctls that can be used to control kvm guests. -For each ioctl, the following information is provided along with a -description: - - Capability: which KVM extension provides this ioctl. Can be 'basic', - which means that is will be provided by any kernel that supports - API version 12 (see section 4.1), a KVM_CAP_xyz constant, which - means availability needs to be checked with KVM_CHECK_EXTENSION - (see section 4.4), or 'none' which means that while not all kernels - support this ioctl, there's no capability bit to check its - availability: for kernels that don't support the ioctl, - the ioctl returns -ENOTTY. - - Architectures: which instruction set architectures provide this ioctl. - x86 includes both i386 and x86_64. - - Type: system, vm, or vcpu. - - Parameters: what parameters are accepted by the ioctl. - - Returns: the return value. General error numbers (EBADF, ENOMEM, EINVAL) - are not detailed, but errors with specific meanings are. - - -4.1 KVM_GET_API_VERSION - -Capability: basic -Architectures: all -Type: system ioctl -Parameters: none -Returns: the constant KVM_API_VERSION (=12) - -This identifies the API version as the stable kvm API. It is not -expected that this number will change. However, Linux 2.6.20 and -2.6.21 report earlier versions; these are not documented and not -supported. Applications should refuse to run if KVM_GET_API_VERSION -returns a value other than 12. If this check passes, all ioctls -described as 'basic' will be available. - - -4.2 KVM_CREATE_VM - -Capability: basic -Architectures: all -Type: system ioctl -Parameters: machine type identifier (KVM_VM_*) -Returns: a VM fd that can be used to control the new virtual machine. - -The new VM has no virtual cpus and no memory. -You probably want to use 0 as machine type. - -In order to create user controlled virtual machines on S390, check -KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as -privileged user (CAP_SYS_ADMIN). - -To use hardware assisted virtualization on MIPS (VZ ASE) rather than -the default trap & emulate implementation (which changes the virtual -memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the -flag KVM_VM_MIPS_VZ. - - -On arm64, the physical address size for a VM (IPA Size limit) is limited -to 40bits by default. The limit can be configured if the host supports the -extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use -KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type -identifier, where IPA_Bits is the maximum width of any physical -address used by the VM. The IPA_Bits is encoded in bits[7-0] of the -machine type identifier. - -e.g, to configure a guest to use 48bit physical address size : - - vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48)); - -The requested size (IPA_Bits) must be : - 0 - Implies default size, 40bits (for backward compatibility) - - or - - N - Implies N bits, where N is a positive integer such that, - 32 <= N <= Host_IPA_Limit - -Host_IPA_Limit is the maximum possible value for IPA_Bits on the host and -is dependent on the CPU capability and the kernel configuration. The limit can -be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the KVM_CHECK_EXTENSION -ioctl() at run-time. - -Please note that configuring the IPA size does not affect the capability -exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects -size of the address translated by the stage2 level (guest physical to -host physical address translations). - - -4.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST - -Capability: basic, KVM_CAP_GET_MSR_FEATURES for KVM_GET_MSR_FEATURE_INDEX_LIST -Architectures: x86 -Type: system ioctl -Parameters: struct kvm_msr_list (in/out) -Returns: 0 on success; -1 on error -Errors: - EFAULT: the msr index list cannot be read from or written to - E2BIG: the msr index list is to be to fit in the array specified by - the user. - -struct kvm_msr_list { - __u32 nmsrs; /* number of msrs in entries */ - __u32 indices[0]; -}; - -The user fills in the size of the indices array in nmsrs, and in return -kvm adjusts nmsrs to reflect the actual number of msrs and fills in the -indices array with their numbers. - -KVM_GET_MSR_INDEX_LIST returns the guest msrs that are supported. The list -varies by kvm version and host processor, but does not change otherwise. - -Note: if kvm indicates supports MCE (KVM_CAP_MCE), then the MCE bank MSRs are -not returned in the MSR list, as different vcpus can have a different number -of banks, as set via the KVM_X86_SETUP_MCE ioctl. - -KVM_GET_MSR_FEATURE_INDEX_LIST returns the list of MSRs that can be passed -to the KVM_GET_MSRS system ioctl. This lets userspace probe host capabilities -and processor features that are exposed via MSRs (e.g., VMX capabilities). -This list also varies by kvm version and host processor, but does not change -otherwise. - - -4.4 KVM_CHECK_EXTENSION - -Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl -Architectures: all -Type: system ioctl, vm ioctl -Parameters: extension identifier (KVM_CAP_*) -Returns: 0 if unsupported; 1 (or some other positive integer) if supported - -The API allows the application to query about extensions to the core -kvm API. Userspace passes an extension identifier (an integer) and -receives an integer that describes the extension availability. -Generally 0 means no and 1 means yes, but some extensions may report -additional information in the integer return value. - -Based on their initialization different VMs may have different capabilities. -It is thus encouraged to use the vm ioctl to query for capabilities (available -with KVM_CAP_CHECK_EXTENSION_VM on the vm fd) - -4.5 KVM_GET_VCPU_MMAP_SIZE - -Capability: basic -Architectures: all -Type: system ioctl -Parameters: none -Returns: size of vcpu mmap area, in bytes - -The KVM_RUN ioctl (cf.) communicates with userspace via a shared -memory region. This ioctl returns the size of that region. See the -KVM_RUN documentation for details. - - -4.6 KVM_SET_MEMORY_REGION - -Capability: basic -Architectures: all -Type: vm ioctl -Parameters: struct kvm_memory_region (in) -Returns: 0 on success, -1 on error - -This ioctl is obsolete and has been removed. - - -4.7 KVM_CREATE_VCPU - -Capability: basic -Architectures: all -Type: vm ioctl -Parameters: vcpu id (apic id on x86) -Returns: vcpu fd on success, -1 on error - -This API adds a vcpu to a virtual machine. No more than max_vcpus may be added. -The vcpu id is an integer in the range [0, max_vcpu_id). - -The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of -the KVM_CHECK_EXTENSION ioctl() at run-time. -The maximum possible value for max_vcpus can be retrieved using the -KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. - -If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 -cpus max. -If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is -same as the value returned from KVM_CAP_NR_VCPUS. - -The maximum possible value for max_vcpu_id can be retrieved using the -KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time. - -If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that max_vcpu_id -is the same as the value returned from KVM_CAP_MAX_VCPUS. - -On powerpc using book3s_hv mode, the vcpus are mapped onto virtual -threads in one or more virtual CPU cores. (This is because the -hardware requires all the hardware threads in a CPU core to be in the -same partition.) The KVM_CAP_PPC_SMT capability indicates the number -of vcpus per virtual core (vcore). The vcore id is obtained by -dividing the vcpu id by the number of vcpus per vcore. The vcpus in a -given vcore will always be in the same physical core as each other -(though that might be a different physical core from time to time). -Userspace can control the threading (SMT) mode of the guest by its -allocation of vcpu ids. For example, if userspace wants -single-threaded guest vcpus, it should make all vcpu ids be a multiple -of the number of vcpus per vcore. - -For virtual cpus that have been created with S390 user controlled virtual -machines, the resulting vcpu fd can be memory mapped at page offset -KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of the virtual -cpu's hardware control block. - - -4.8 KVM_GET_DIRTY_LOG (vm ioctl) - -Capability: basic -Architectures: all -Type: vm ioctl -Parameters: struct kvm_dirty_log (in/out) -Returns: 0 on success, -1 on error - -/* for KVM_GET_DIRTY_LOG */ -struct kvm_dirty_log { - __u32 slot; - __u32 padding; - union { - void __user *dirty_bitmap; /* one bit per page */ - __u64 padding; - }; -}; - -Given a memory slot, return a bitmap containing any pages dirtied -since the last call to this ioctl. Bit 0 is the first page in the -memory slot. Ensure the entire structure is cleared to avoid padding -issues. - -If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 specifies -the address space for which you want to return the dirty bitmap. -They must be less than the value that KVM_CHECK_EXTENSION returns for -the KVM_CAP_MULTI_ADDRESS_SPACE capability. - -The bits in the dirty bitmap are cleared before the ioctl returns, unless -KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information, -see the description of the capability. - -4.9 KVM_SET_MEMORY_ALIAS - -Capability: basic -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_memory_alias (in) -Returns: 0 (success), -1 (error) - -This ioctl is obsolete and has been removed. - - -4.10 KVM_RUN - -Capability: basic -Architectures: all -Type: vcpu ioctl -Parameters: none -Returns: 0 on success, -1 on error -Errors: - EINTR: an unmasked signal is pending - -This ioctl is used to run a guest virtual cpu. While there are no -explicit parameters, there is an implicit parameter block that can be -obtained by mmap()ing the vcpu fd at offset 0, with the size given by -KVM_GET_VCPU_MMAP_SIZE. The parameter block is formatted as a 'struct -kvm_run' (see below). - - -4.11 KVM_GET_REGS - -Capability: basic -Architectures: all except ARM, arm64 -Type: vcpu ioctl -Parameters: struct kvm_regs (out) -Returns: 0 on success, -1 on error - -Reads the general purpose registers from the vcpu. - -/* x86 */ -struct kvm_regs { - /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ - __u64 rax, rbx, rcx, rdx; - __u64 rsi, rdi, rsp, rbp; - __u64 r8, r9, r10, r11; - __u64 r12, r13, r14, r15; - __u64 rip, rflags; -}; - -/* mips */ -struct kvm_regs { - /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ - __u64 gpr[32]; - __u64 hi; - __u64 lo; - __u64 pc; -}; - - -4.12 KVM_SET_REGS - -Capability: basic -Architectures: all except ARM, arm64 -Type: vcpu ioctl -Parameters: struct kvm_regs (in) -Returns: 0 on success, -1 on error - -Writes the general purpose registers into the vcpu. - -See KVM_GET_REGS for the data structure. - - -4.13 KVM_GET_SREGS - -Capability: basic -Architectures: x86, ppc -Type: vcpu ioctl -Parameters: struct kvm_sregs (out) -Returns: 0 on success, -1 on error - -Reads special registers from the vcpu. - -/* x86 */ -struct kvm_sregs { - struct kvm_segment cs, ds, es, fs, gs, ss; - struct kvm_segment tr, ldt; - struct kvm_dtable gdt, idt; - __u64 cr0, cr2, cr3, cr4, cr8; - __u64 efer; - __u64 apic_base; - __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64]; -}; - -/* ppc -- see arch/powerpc/include/uapi/asm/kvm.h */ - -interrupt_bitmap is a bitmap of pending external interrupts. At most -one bit may be set. This interrupt has been acknowledged by the APIC -but not yet injected into the cpu core. - - -4.14 KVM_SET_SREGS - -Capability: basic -Architectures: x86, ppc -Type: vcpu ioctl -Parameters: struct kvm_sregs (in) -Returns: 0 on success, -1 on error - -Writes special registers into the vcpu. See KVM_GET_SREGS for the -data structures. - - -4.15 KVM_TRANSLATE - -Capability: basic -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_translation (in/out) -Returns: 0 on success, -1 on error - -Translates a virtual address according to the vcpu's current address -translation mode. - -struct kvm_translation { - /* in */ - __u64 linear_address; - - /* out */ - __u64 physical_address; - __u8 valid; - __u8 writeable; - __u8 usermode; - __u8 pad[5]; -}; - - -4.16 KVM_INTERRUPT - -Capability: basic -Architectures: x86, ppc, mips -Type: vcpu ioctl -Parameters: struct kvm_interrupt (in) -Returns: 0 on success, negative on failure. - -Queues a hardware interrupt vector to be injected. - -/* for KVM_INTERRUPT */ -struct kvm_interrupt { - /* in */ - __u32 irq; -}; - -X86: - -Returns: 0 on success, - -EEXIST if an interrupt is already enqueued - -EINVAL the the irq number is invalid - -ENXIO if the PIC is in the kernel - -EFAULT if the pointer is invalid - -Note 'irq' is an interrupt vector, not an interrupt pin or line. This -ioctl is useful if the in-kernel PIC is not used. - -PPC: - -Queues an external interrupt to be injected. This ioctl is overleaded -with 3 different irq values: - -a) KVM_INTERRUPT_SET - - This injects an edge type external interrupt into the guest once it's ready - to receive interrupts. When injected, the interrupt is done. - -b) KVM_INTERRUPT_UNSET - - This unsets any pending interrupt. - - Only available with KVM_CAP_PPC_UNSET_IRQ. - -c) KVM_INTERRUPT_SET_LEVEL - - This injects a level type external interrupt into the guest context. The - interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET - is triggered. - - Only available with KVM_CAP_PPC_IRQ_LEVEL. - -Note that any value for 'irq' other than the ones stated above is invalid -and incurs unexpected behavior. - -This is an asynchronous vcpu ioctl and can be invoked from any thread. - -MIPS: - -Queues an external interrupt to be injected into the virtual CPU. A negative -interrupt number dequeues the interrupt. - -This is an asynchronous vcpu ioctl and can be invoked from any thread. - - -4.17 KVM_DEBUG_GUEST - -Capability: basic -Architectures: none -Type: vcpu ioctl -Parameters: none) -Returns: -1 on error - -Support for this has been removed. Use KVM_SET_GUEST_DEBUG instead. - - -4.18 KVM_GET_MSRS - -Capability: basic (vcpu), KVM_CAP_GET_MSR_FEATURES (system) -Architectures: x86 -Type: system ioctl, vcpu ioctl -Parameters: struct kvm_msrs (in/out) -Returns: number of msrs successfully returned; - -1 on error - -When used as a system ioctl: -Reads the values of MSR-based features that are available for the VM. This -is similar to KVM_GET_SUPPORTED_CPUID, but it returns MSR indices and values. -The list of msr-based features can be obtained using KVM_GET_MSR_FEATURE_INDEX_LIST -in a system ioctl. - -When used as a vcpu ioctl: -Reads model-specific registers from the vcpu. Supported msr indices can -be obtained using KVM_GET_MSR_INDEX_LIST in a system ioctl. - -struct kvm_msrs { - __u32 nmsrs; /* number of msrs in entries */ - __u32 pad; - - struct kvm_msr_entry entries[0]; -}; - -struct kvm_msr_entry { - __u32 index; - __u32 reserved; - __u64 data; -}; - -Application code should set the 'nmsrs' member (which indicates the -size of the entries array) and the 'index' member of each array entry. -kvm will fill in the 'data' member. - - -4.19 KVM_SET_MSRS - -Capability: basic -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_msrs (in) -Returns: 0 on success, -1 on error - -Writes model-specific registers to the vcpu. See KVM_GET_MSRS for the -data structures. - -Application code should set the 'nmsrs' member (which indicates the -size of the entries array), and the 'index' and 'data' members of each -array entry. - - -4.20 KVM_SET_CPUID - -Capability: basic -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_cpuid (in) -Returns: 0 on success, -1 on error - -Defines the vcpu responses to the cpuid instruction. Applications -should use the KVM_SET_CPUID2 ioctl if available. - - -struct kvm_cpuid_entry { - __u32 function; - __u32 eax; - __u32 ebx; - __u32 ecx; - __u32 edx; - __u32 padding; -}; - -/* for KVM_SET_CPUID */ -struct kvm_cpuid { - __u32 nent; - __u32 padding; - struct kvm_cpuid_entry entries[0]; -}; - - -4.21 KVM_SET_SIGNAL_MASK - -Capability: basic -Architectures: all -Type: vcpu ioctl -Parameters: struct kvm_signal_mask (in) -Returns: 0 on success, -1 on error - -Defines which signals are blocked during execution of KVM_RUN. This -signal mask temporarily overrides the threads signal mask. Any -unblocked signal received (except SIGKILL and SIGSTOP, which retain -their traditional behaviour) will cause KVM_RUN to return with -EINTR. - -Note the signal will only be delivered if not blocked by the original -signal mask. - -/* for KVM_SET_SIGNAL_MASK */ -struct kvm_signal_mask { - __u32 len; - __u8 sigset[0]; -}; - - -4.22 KVM_GET_FPU - -Capability: basic -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_fpu (out) -Returns: 0 on success, -1 on error - -Reads the floating point state from the vcpu. - -/* for KVM_GET_FPU and KVM_SET_FPU */ -struct kvm_fpu { - __u8 fpr[8][16]; - __u16 fcw; - __u16 fsw; - __u8 ftwx; /* in fxsave format */ - __u8 pad1; - __u16 last_opcode; - __u64 last_ip; - __u64 last_dp; - __u8 xmm[16][16]; - __u32 mxcsr; - __u32 pad2; -}; - - -4.23 KVM_SET_FPU - -Capability: basic -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_fpu (in) -Returns: 0 on success, -1 on error - -Writes the floating point state to the vcpu. - -/* for KVM_GET_FPU and KVM_SET_FPU */ -struct kvm_fpu { - __u8 fpr[8][16]; - __u16 fcw; - __u16 fsw; - __u8 ftwx; /* in fxsave format */ - __u8 pad1; - __u16 last_opcode; - __u64 last_ip; - __u64 last_dp; - __u8 xmm[16][16]; - __u32 mxcsr; - __u32 pad2; -}; - - -4.24 KVM_CREATE_IRQCHIP - -Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390) -Architectures: x86, ARM, arm64, s390 -Type: vm ioctl -Parameters: none -Returns: 0 on success, -1 on error - -Creates an interrupt controller model in the kernel. -On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up -future vcpus to have a local APIC. IRQ routing for GSIs 0-15 is set to both -PIC and IOAPIC; GSI 16-23 only go to the IOAPIC. -On ARM/arm64, a GICv2 is created. Any other GIC versions require the usage of -KVM_CREATE_DEVICE, which also supports creating a GICv2. Using -KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2. -On s390, a dummy irq routing table is created. - -Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled -before KVM_CREATE_IRQCHIP can be used. - - -4.25 KVM_IRQ_LINE - -Capability: KVM_CAP_IRQCHIP -Architectures: x86, arm, arm64 -Type: vm ioctl -Parameters: struct kvm_irq_level -Returns: 0 on success, -1 on error - -Sets the level of a GSI input to the interrupt controller model in the kernel. -On some architectures it is required that an interrupt controller model has -been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered -interrupts require the level to be set to 1 and then back to 0. - -On real hardware, interrupt pins can be active-low or active-high. This -does not matter for the level field of struct kvm_irq_level: 1 always -means active (asserted), 0 means inactive (deasserted). - -x86 allows the operating system to program the interrupt polarity -(active-low/active-high) for level-triggered interrupts, and KVM used -to consider the polarity. However, due to bitrot in the handling of -active-low interrupts, the above convention is now valid on x86 too. -This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace -should not present interrupts to the guest as active-low unless this -capability is present (or unless it is not using the in-kernel irqchip, -of course). - - -ARM/arm64 can signal an interrupt either at the CPU level, or at the -in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to -use PPIs designated for specific cpus. The irq field is interpreted -like this: - - bits: | 31 ... 24 | 23 ... 16 | 15 ... 0 | - field: | irq_type | vcpu_index | irq_id | - -The irq_type field has the following values: -- irq_type[0]: out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ -- irq_type[1]: in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.) - (the vcpu_index field is ignored) -- irq_type[2]: in-kernel GIC: PPI, irq_id between 16 and 31 (incl.) - -(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs) - -In both cases, level is used to assert/deassert the line. - -struct kvm_irq_level { - union { - __u32 irq; /* GSI */ - __s32 status; /* not used for KVM_IRQ_LEVEL */ - }; - __u32 level; /* 0 or 1 */ -}; - - -4.26 KVM_GET_IRQCHIP - -Capability: KVM_CAP_IRQCHIP -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_irqchip (in/out) -Returns: 0 on success, -1 on error - -Reads the state of a kernel interrupt controller created with -KVM_CREATE_IRQCHIP into a buffer provided by the caller. - -struct kvm_irqchip { - __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ - __u32 pad; - union { - char dummy[512]; /* reserving space */ - struct kvm_pic_state pic; - struct kvm_ioapic_state ioapic; - } chip; -}; - - -4.27 KVM_SET_IRQCHIP - -Capability: KVM_CAP_IRQCHIP -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_irqchip (in) -Returns: 0 on success, -1 on error - -Sets the state of a kernel interrupt controller created with -KVM_CREATE_IRQCHIP from a buffer provided by the caller. - -struct kvm_irqchip { - __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ - __u32 pad; - union { - char dummy[512]; /* reserving space */ - struct kvm_pic_state pic; - struct kvm_ioapic_state ioapic; - } chip; -}; - - -4.28 KVM_XEN_HVM_CONFIG - -Capability: KVM_CAP_XEN_HVM -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_xen_hvm_config (in) -Returns: 0 on success, -1 on error - -Sets the MSR that the Xen HVM guest uses to initialize its hypercall -page, and provides the starting address and size of the hypercall -blobs in userspace. When the guest writes the MSR, kvm copies one -page of a blob (32- or 64-bit, depending on the vcpu mode) to guest -memory. - -struct kvm_xen_hvm_config { - __u32 flags; - __u32 msr; - __u64 blob_addr_32; - __u64 blob_addr_64; - __u8 blob_size_32; - __u8 blob_size_64; - __u8 pad2[30]; -}; - - -4.29 KVM_GET_CLOCK - -Capability: KVM_CAP_ADJUST_CLOCK -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_clock_data (out) -Returns: 0 on success, -1 on error - -Gets the current timestamp of kvmclock as seen by the current guest. In -conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios -such as migration. - -When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the -set of bits that KVM can return in struct kvm_clock_data's flag member. - -The only flag defined now is KVM_CLOCK_TSC_STABLE. If set, the returned -value is the exact kvmclock value seen by all VCPUs at the instant -when KVM_GET_CLOCK was called. If clear, the returned value is simply -CLOCK_MONOTONIC plus a constant offset; the offset can be modified -with KVM_SET_CLOCK. KVM will try to make all VCPUs follow this clock, -but the exact value read by each VCPU could differ, because the host -TSC is not stable. - -struct kvm_clock_data { - __u64 clock; /* kvmclock current value */ - __u32 flags; - __u32 pad[9]; -}; - - -4.30 KVM_SET_CLOCK - -Capability: KVM_CAP_ADJUST_CLOCK -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_clock_data (in) -Returns: 0 on success, -1 on error - -Sets the current timestamp of kvmclock to the value specified in its parameter. -In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios -such as migration. - -struct kvm_clock_data { - __u64 clock; /* kvmclock current value */ - __u32 flags; - __u32 pad[9]; -}; - - -4.31 KVM_GET_VCPU_EVENTS - -Capability: KVM_CAP_VCPU_EVENTS -Extended by: KVM_CAP_INTR_SHADOW -Architectures: x86, arm, arm64 -Type: vcpu ioctl -Parameters: struct kvm_vcpu_event (out) -Returns: 0 on success, -1 on error - -X86: - -Gets currently pending exceptions, interrupts, and NMIs as well as related -states of the vcpu. - -struct kvm_vcpu_events { - struct { - __u8 injected; - __u8 nr; - __u8 has_error_code; - __u8 pending; - __u32 error_code; - } exception; - struct { - __u8 injected; - __u8 nr; - __u8 soft; - __u8 shadow; - } interrupt; - struct { - __u8 injected; - __u8 pending; - __u8 masked; - __u8 pad; - } nmi; - __u32 sipi_vector; - __u32 flags; - struct { - __u8 smm; - __u8 pending; - __u8 smm_inside_nmi; - __u8 latched_init; - } smi; - __u8 reserved[27]; - __u8 exception_has_payload; - __u64 exception_payload; -}; - -The following bits are defined in the flags field: - -- KVM_VCPUEVENT_VALID_SHADOW may be set to signal that - interrupt.shadow contains a valid state. - -- KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a - valid state. - -- KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the - exception_has_payload, exception_payload, and exception.pending - fields contain a valid state. This bit will be set whenever - KVM_CAP_EXCEPTION_PAYLOAD is enabled. - -ARM/ARM64: - -If the guest accesses a device that is being emulated by the host kernel in -such a way that a real device would generate a physical SError, KVM may make -a virtual SError pending for that VCPU. This system error interrupt remains -pending until the guest takes the exception by unmasking PSTATE.A. - -Running the VCPU may cause it to take a pending SError, or make an access that -causes an SError to become pending. The event's description is only valid while -the VPCU is not running. - -This API provides a way to read and write the pending 'event' state that is not -visible to the guest. To save, restore or migrate a VCPU the struct representing -the state can be read then written using this GET/SET API, along with the other -guest-visible registers. It is not possible to 'cancel' an SError that has been -made pending. - -A device being emulated in user-space may also wish to generate an SError. To do -this the events structure can be populated by user-space. The current state -should be read first, to ensure no existing SError is pending. If an existing -SError is pending, the architecture's 'Multiple SError interrupts' rules should -be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and -Serviceability (RAS) Specification"). - -SError exceptions always have an ESR value. Some CPUs have the ability to -specify what the virtual SError's ESR value should be. These systems will -advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will -always have a non-zero value when read, and the agent making an SError pending -should specify the ISS field in the lower 24 bits of exception.serror_esr. If -the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events -with exception.has_esr as zero, KVM will choose an ESR. - -Specifying exception.has_esr on a system that does not support it will return --EINVAL. Setting anything other than the lower 24bits of exception.serror_esr -will return -EINVAL. - -struct kvm_vcpu_events { - struct { - __u8 serror_pending; - __u8 serror_has_esr; - /* Align it to 8 bytes */ - __u8 pad[6]; - __u64 serror_esr; - } exception; - __u32 reserved[12]; -}; - -4.32 KVM_SET_VCPU_EVENTS - -Capability: KVM_CAP_VCPU_EVENTS -Extended by: KVM_CAP_INTR_SHADOW -Architectures: x86, arm, arm64 -Type: vcpu ioctl -Parameters: struct kvm_vcpu_event (in) -Returns: 0 on success, -1 on error - -X86: - -Set pending exceptions, interrupts, and NMIs as well as related states of the -vcpu. - -See KVM_GET_VCPU_EVENTS for the data structure. - -Fields that may be modified asynchronously by running VCPUs can be excluded -from the update. These fields are nmi.pending, sipi_vector, smi.smm, -smi.pending. Keep the corresponding bits in the flags field cleared to -suppress overwriting the current in-kernel state. The bits are: - -KVM_VCPUEVENT_VALID_NMI_PENDING - transfer nmi.pending to the kernel -KVM_VCPUEVENT_VALID_SIPI_VECTOR - transfer sipi_vector -KVM_VCPUEVENT_VALID_SMM - transfer the smi sub-struct. - -If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in -the flags field to signal that interrupt.shadow contains a valid state and -shall be written into the VCPU. - -KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. - -If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD -can be set in the flags field to signal that the -exception_has_payload, exception_payload, and exception.pending fields -contain a valid state and shall be written into the VCPU. - -ARM/ARM64: - -Set the pending SError exception state for this VCPU. It is not possible to -'cancel' an Serror that has been made pending. - -See KVM_GET_VCPU_EVENTS for the data structure. - - -4.33 KVM_GET_DEBUGREGS - -Capability: KVM_CAP_DEBUGREGS -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_debugregs (out) -Returns: 0 on success, -1 on error - -Reads debug registers from the vcpu. - -struct kvm_debugregs { - __u64 db[4]; - __u64 dr6; - __u64 dr7; - __u64 flags; - __u64 reserved[9]; -}; - - -4.34 KVM_SET_DEBUGREGS - -Capability: KVM_CAP_DEBUGREGS -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_debugregs (in) -Returns: 0 on success, -1 on error - -Writes debug registers into the vcpu. - -See KVM_GET_DEBUGREGS for the data structure. The flags field is unused -yet and must be cleared on entry. - - -4.35 KVM_SET_USER_MEMORY_REGION - -Capability: KVM_CAP_USER_MEMORY -Architectures: all -Type: vm ioctl -Parameters: struct kvm_userspace_memory_region (in) -Returns: 0 on success, -1 on error - -struct kvm_userspace_memory_region { - __u32 slot; - __u32 flags; - __u64 guest_phys_addr; - __u64 memory_size; /* bytes */ - __u64 userspace_addr; /* start of the userspace allocated memory */ -}; - -/* for kvm_memory_region::flags */ -#define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) -#define KVM_MEM_READONLY (1UL << 1) - -This ioctl allows the user to create, modify or delete a guest physical -memory slot. Bits 0-15 of "slot" specify the slot id and this value -should be less than the maximum number of user memory slots supported per -VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS. -Slots may not overlap in guest physical address space. - -If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot" -specifies the address space which is being modified. They must be -less than the value that KVM_CHECK_EXTENSION returns for the -KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces -are unrelated; the restriction on overlapping slots only applies within -each address space. - -Deleting a slot is done by passing zero for memory_size. When changing -an existing slot, it may be moved in the guest physical memory space, -or its flags may be modified, but it may not be resized. - -Memory for the region is taken starting at the address denoted by the -field userspace_addr, which must point at user addressable memory for -the entire memory slot size. Any object may back this memory, including -anonymous memory, ordinary files, and hugetlbfs. - -It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr -be identical. This allows large pages in the guest to be backed by large -pages in the host. - -The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and -KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of -writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to -use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it, -to make a new slot read-only. In this case, writes to this memory will be -posted to userspace as KVM_EXIT_MMIO exits. - -When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of -the memory region are automatically reflected into the guest. For example, an -mmap() that affects the region will be made visible immediately. Another -example is madvise(MADV_DROP). - -It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl. -The KVM_SET_MEMORY_REGION does not allow fine grained control over memory -allocation and is deprecated. - - -4.36 KVM_SET_TSS_ADDR - -Capability: KVM_CAP_SET_TSS_ADDR -Architectures: x86 -Type: vm ioctl -Parameters: unsigned long tss_address (in) -Returns: 0 on success, -1 on error - -This ioctl defines the physical address of a three-page region in the guest -physical address space. The region must be within the first 4GB of the -guest physical address space and must not conflict with any memory slot -or any mmio address. The guest may malfunction if it accesses this memory -region. - -This ioctl is required on Intel-based hosts. This is needed on Intel hardware -because of a quirk in the virtualization implementation (see the internals -documentation when it pops into existence). - - -4.37 KVM_ENABLE_CAP - -Capability: KVM_CAP_ENABLE_CAP -Architectures: mips, ppc, s390 -Type: vcpu ioctl -Parameters: struct kvm_enable_cap (in) -Returns: 0 on success; -1 on error - -Capability: KVM_CAP_ENABLE_CAP_VM -Architectures: all -Type: vcpu ioctl -Parameters: struct kvm_enable_cap (in) -Returns: 0 on success; -1 on error - -+Not all extensions are enabled by default. Using this ioctl the application -can enable an extension, making it available to the guest. - -On systems that do not support this ioctl, it always fails. On systems that -do support it, it only works for extensions that are supported for enablement. - -To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should -be used. - -struct kvm_enable_cap { - /* in */ - __u32 cap; - -The capability that is supposed to get enabled. - - __u32 flags; - -A bitfield indicating future enhancements. Has to be 0 for now. - - __u64 args[4]; - -Arguments for enabling a feature. If a feature needs initial values to -function properly, this is the place to put them. - - __u8 pad[64]; -}; - -The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl -for vm-wide capabilities. - -4.38 KVM_GET_MP_STATE - -Capability: KVM_CAP_MP_STATE -Architectures: x86, s390, arm, arm64 -Type: vcpu ioctl -Parameters: struct kvm_mp_state (out) -Returns: 0 on success; -1 on error - -struct kvm_mp_state { - __u32 mp_state; -}; - -Returns the vcpu's current "multiprocessing state" (though also valid on -uniprocessor guests). - -Possible values are: - - - KVM_MP_STATE_RUNNABLE: the vcpu is currently running [x86,arm/arm64] - - KVM_MP_STATE_UNINITIALIZED: the vcpu is an application processor (AP) - which has not yet received an INIT signal [x86] - - KVM_MP_STATE_INIT_RECEIVED: the vcpu has received an INIT signal, and is - now ready for a SIPI [x86] - - KVM_MP_STATE_HALTED: the vcpu has executed a HLT instruction and - is waiting for an interrupt [x86] - - KVM_MP_STATE_SIPI_RECEIVED: the vcpu has just received a SIPI (vector - accessible via KVM_GET_VCPU_EVENTS) [x86] - - KVM_MP_STATE_STOPPED: the vcpu is stopped [s390,arm/arm64] - - KVM_MP_STATE_CHECK_STOP: the vcpu is in a special error state [s390] - - KVM_MP_STATE_OPERATING: the vcpu is operating (running or halted) - [s390] - - KVM_MP_STATE_LOAD: the vcpu is in a special load/startup state - [s390] - -On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an -in-kernel irqchip, the multiprocessing state must be maintained by userspace on -these architectures. - -For arm/arm64: - -The only states that are valid are KVM_MP_STATE_STOPPED and -KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not. - -4.39 KVM_SET_MP_STATE - -Capability: KVM_CAP_MP_STATE -Architectures: x86, s390, arm, arm64 -Type: vcpu ioctl -Parameters: struct kvm_mp_state (in) -Returns: 0 on success; -1 on error - -Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for -arguments. - -On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an -in-kernel irqchip, the multiprocessing state must be maintained by userspace on -these architectures. - -For arm/arm64: - -The only states that are valid are KVM_MP_STATE_STOPPED and -KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not. - -4.40 KVM_SET_IDENTITY_MAP_ADDR - -Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR -Architectures: x86 -Type: vm ioctl -Parameters: unsigned long identity (in) -Returns: 0 on success, -1 on error - -This ioctl defines the physical address of a one-page region in the guest -physical address space. The region must be within the first 4GB of the -guest physical address space and must not conflict with any memory slot -or any mmio address. The guest may malfunction if it accesses this memory -region. - -Setting the address to 0 will result in resetting the address to its default -(0xfffbc000). - -This ioctl is required on Intel-based hosts. This is needed on Intel hardware -because of a quirk in the virtualization implementation (see the internals -documentation when it pops into existence). - -Fails if any VCPU has already been created. - -4.41 KVM_SET_BOOT_CPU_ID - -Capability: KVM_CAP_SET_BOOT_CPU_ID -Architectures: x86 -Type: vm ioctl -Parameters: unsigned long vcpu_id -Returns: 0 on success, -1 on error - -Define which vcpu is the Bootstrap Processor (BSP). Values are the same -as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default -is vcpu 0. - - -4.42 KVM_GET_XSAVE - -Capability: KVM_CAP_XSAVE -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_xsave (out) -Returns: 0 on success, -1 on error - -struct kvm_xsave { - __u32 region[1024]; -}; - -This ioctl would copy current vcpu's xsave struct to the userspace. - - -4.43 KVM_SET_XSAVE - -Capability: KVM_CAP_XSAVE -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_xsave (in) -Returns: 0 on success, -1 on error - -struct kvm_xsave { - __u32 region[1024]; -}; - -This ioctl would copy userspace's xsave struct to the kernel. - - -4.44 KVM_GET_XCRS - -Capability: KVM_CAP_XCRS -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_xcrs (out) -Returns: 0 on success, -1 on error - -struct kvm_xcr { - __u32 xcr; - __u32 reserved; - __u64 value; -}; - -struct kvm_xcrs { - __u32 nr_xcrs; - __u32 flags; - struct kvm_xcr xcrs[KVM_MAX_XCRS]; - __u64 padding[16]; -}; - -This ioctl would copy current vcpu's xcrs to the userspace. - - -4.45 KVM_SET_XCRS - -Capability: KVM_CAP_XCRS -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_xcrs (in) -Returns: 0 on success, -1 on error - -struct kvm_xcr { - __u32 xcr; - __u32 reserved; - __u64 value; -}; - -struct kvm_xcrs { - __u32 nr_xcrs; - __u32 flags; - struct kvm_xcr xcrs[KVM_MAX_XCRS]; - __u64 padding[16]; -}; - -This ioctl would set vcpu's xcr to the value userspace specified. - - -4.46 KVM_GET_SUPPORTED_CPUID - -Capability: KVM_CAP_EXT_CPUID -Architectures: x86 -Type: system ioctl -Parameters: struct kvm_cpuid2 (in/out) -Returns: 0 on success, -1 on error - -struct kvm_cpuid2 { - __u32 nent; - __u32 padding; - struct kvm_cpuid_entry2 entries[0]; -}; - -#define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) -#define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) -#define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) - -struct kvm_cpuid_entry2 { - __u32 function; - __u32 index; - __u32 flags; - __u32 eax; - __u32 ebx; - __u32 ecx; - __u32 edx; - __u32 padding[3]; -}; - -This ioctl returns x86 cpuid features which are supported by both the -hardware and kvm in its default configuration. Userspace can use the -information returned by this ioctl to construct cpuid information (for -KVM_SET_CPUID2) that is consistent with hardware, kernel, and -userspace capabilities, and with user requirements (for example, the -user may wish to constrain cpuid to emulate older hardware, or for -feature consistency across a cluster). - -Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may -expose cpuid features (e.g. MONITOR) which are not supported by kvm in -its default configuration. If userspace enables such capabilities, it -is responsible for modifying the results of this ioctl appropriately. - -Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure -with the 'nent' field indicating the number of entries in the variable-size -array 'entries'. If the number of entries is too low to describe the cpu -capabilities, an error (E2BIG) is returned. If the number is too high, -the 'nent' field is adjusted and an error (ENOMEM) is returned. If the -number is just right, the 'nent' field is adjusted to the number of valid -entries in the 'entries' array, which is then filled. - -The entries returned are the host cpuid as returned by the cpuid instruction, -with unknown or unsupported features masked out. Some features (for example, -x2apic), may not be present in the host cpu, but are exposed by kvm if it can -emulate them efficiently. The fields in each entry are defined as follows: - - function: the eax value used to obtain the entry - index: the ecx value used to obtain the entry (for entries that are - affected by ecx) - flags: an OR of zero or more of the following: - KVM_CPUID_FLAG_SIGNIFCANT_INDEX: - if the index field is valid - KVM_CPUID_FLAG_STATEFUL_FUNC: - if cpuid for this function returns different values for successive - invocations; there will be several entries with the same function, - all with this flag set - KVM_CPUID_FLAG_STATE_READ_NEXT: - for KVM_CPUID_FLAG_STATEFUL_FUNC entries, set if this entry is - the first entry to be read by a cpu - eax, ebx, ecx, edx: the values returned by the cpuid instruction for - this function/index combination - -The TSC deadline timer feature (CPUID leaf 1, ecx[24]) is always returned -as false, since the feature depends on KVM_CREATE_IRQCHIP for local APIC -support. Instead it is reported via - - ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER) - -if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the -feature in userspace, then you can enable the feature for KVM_SET_CPUID2. - - -4.47 KVM_PPC_GET_PVINFO - -Capability: KVM_CAP_PPC_GET_PVINFO -Architectures: ppc -Type: vm ioctl -Parameters: struct kvm_ppc_pvinfo (out) -Returns: 0 on success, !0 on error - -struct kvm_ppc_pvinfo { - __u32 flags; - __u32 hcall[4]; - __u8 pad[108]; -}; - -This ioctl fetches PV specific information that need to be passed to the guest -using the device tree or other means from vm context. - -The hcall array defines 4 instructions that make up a hypercall. - -If any additional field gets added to this structure later on, a bit for that -additional piece of information will be set in the flags bitmap. - -The flags bitmap is defined as: - - /* the host supports the ePAPR idle hcall - #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0) - -4.52 KVM_SET_GSI_ROUTING - -Capability: KVM_CAP_IRQ_ROUTING -Architectures: x86 s390 arm arm64 -Type: vm ioctl -Parameters: struct kvm_irq_routing (in) -Returns: 0 on success, -1 on error - -Sets the GSI routing table entries, overwriting any previously set entries. - -On arm/arm64, GSI routing has the following limitation: -- GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD. - -struct kvm_irq_routing { - __u32 nr; - __u32 flags; - struct kvm_irq_routing_entry entries[0]; -}; - -No flags are specified so far, the corresponding field must be set to zero. - -struct kvm_irq_routing_entry { - __u32 gsi; - __u32 type; - __u32 flags; - __u32 pad; - union { - struct kvm_irq_routing_irqchip irqchip; - struct kvm_irq_routing_msi msi; - struct kvm_irq_routing_s390_adapter adapter; - struct kvm_irq_routing_hv_sint hv_sint; - __u32 pad[8]; - } u; -}; - -/* gsi routing entry types */ -#define KVM_IRQ_ROUTING_IRQCHIP 1 -#define KVM_IRQ_ROUTING_MSI 2 -#define KVM_IRQ_ROUTING_S390_ADAPTER 3 -#define KVM_IRQ_ROUTING_HV_SINT 4 - -flags: -- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry - type, specifies that the devid field contains a valid value. The per-VM - KVM_CAP_MSI_DEVID capability advertises the requirement to provide - the device ID. If this capability is not available, userspace should - never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. -- zero otherwise - -struct kvm_irq_routing_irqchip { - __u32 irqchip; - __u32 pin; -}; - -struct kvm_irq_routing_msi { - __u32 address_lo; - __u32 address_hi; - __u32 data; - union { - __u32 pad; - __u32 devid; - }; -}; - -If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier -for the device that wrote the MSI message. For PCI, this is usually a -BFD identifier in the lower 16 bits. - -On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS -feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, -address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of -address_hi must be zero. - -struct kvm_irq_routing_s390_adapter { - __u64 ind_addr; - __u64 summary_addr; - __u64 ind_offset; - __u32 summary_offset; - __u32 adapter_id; -}; - -struct kvm_irq_routing_hv_sint { - __u32 vcpu; - __u32 sint; -}; - - -4.55 KVM_SET_TSC_KHZ - -Capability: KVM_CAP_TSC_CONTROL -Architectures: x86 -Type: vcpu ioctl -Parameters: virtual tsc_khz -Returns: 0 on success, -1 on error - -Specifies the tsc frequency for the virtual machine. The unit of the -frequency is KHz. - - -4.56 KVM_GET_TSC_KHZ - -Capability: KVM_CAP_GET_TSC_KHZ -Architectures: x86 -Type: vcpu ioctl -Parameters: none -Returns: virtual tsc-khz on success, negative value on error - -Returns the tsc frequency of the guest. The unit of the return value is -KHz. If the host has unstable tsc this ioctl returns -EIO instead as an -error. - - -4.57 KVM_GET_LAPIC - -Capability: KVM_CAP_IRQCHIP -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_lapic_state (out) -Returns: 0 on success, -1 on error - -#define KVM_APIC_REG_SIZE 0x400 -struct kvm_lapic_state { - char regs[KVM_APIC_REG_SIZE]; -}; - -Reads the Local APIC registers and copies them into the input argument. The -data format and layout are the same as documented in the architecture manual. - -If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is -enabled, then the format of APIC_ID register depends on the APIC mode -(reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in -the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID -which is stored in bits 31-24 of the APIC register, or equivalently in -byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then -be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR. - -If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state -always uses xAPIC format. - - -4.58 KVM_SET_LAPIC - -Capability: KVM_CAP_IRQCHIP -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_lapic_state (in) -Returns: 0 on success, -1 on error - -#define KVM_APIC_REG_SIZE 0x400 -struct kvm_lapic_state { - char regs[KVM_APIC_REG_SIZE]; -}; - -Copies the input argument into the Local APIC registers. The data format -and layout are the same as documented in the architecture manual. - -The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's -regs field) depends on the state of the KVM_CAP_X2APIC_API capability. -See the note in KVM_GET_LAPIC. - - -4.59 KVM_IOEVENTFD - -Capability: KVM_CAP_IOEVENTFD -Architectures: all -Type: vm ioctl -Parameters: struct kvm_ioeventfd (in) -Returns: 0 on success, !0 on error - -This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address -within the guest. A guest write in the registered address will signal the -provided event instead of triggering an exit. - -struct kvm_ioeventfd { - __u64 datamatch; - __u64 addr; /* legal pio/mmio address */ - __u32 len; /* 0, 1, 2, 4, or 8 bytes */ - __s32 fd; - __u32 flags; - __u8 pad[36]; -}; - -For the special case of virtio-ccw devices on s390, the ioevent is matched -to a subchannel/virtqueue tuple instead. - -The following flags are defined: - -#define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) -#define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) -#define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) -#define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \ - (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify) - -If datamatch flag is set, the event will be signaled only if the written value -to the registered address is equal to datamatch in struct kvm_ioeventfd. - -For virtio-ccw devices, addr contains the subchannel id and datamatch the -virtqueue index. - -With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and -the kernel will ignore the length of guest write and may get a faster vmexit. -The speedup may only apply to specific architectures, but the ioeventfd will -work anyway. - -4.60 KVM_DIRTY_TLB - -Capability: KVM_CAP_SW_TLB -Architectures: ppc -Type: vcpu ioctl -Parameters: struct kvm_dirty_tlb (in) -Returns: 0 on success, -1 on error - -struct kvm_dirty_tlb { - __u64 bitmap; - __u32 num_dirty; -}; - -This must be called whenever userspace has changed an entry in the shared -TLB, prior to calling KVM_RUN on the associated vcpu. - -The "bitmap" field is the userspace address of an array. This array -consists of a number of bits, equal to the total number of TLB entries as -determined by the last successful call to KVM_CONFIG_TLB, rounded up to the -nearest multiple of 64. - -Each bit corresponds to one TLB entry, ordered the same as in the shared TLB -array. - -The array is little-endian: the bit 0 is the least significant bit of the -first byte, bit 8 is the least significant bit of the second byte, etc. -This avoids any complications with differing word sizes. - -The "num_dirty" field is a performance hint for KVM to determine whether it -should skip processing the bitmap and just invalidate everything. It must -be set to the number of set bits in the bitmap. - - -4.62 KVM_CREATE_SPAPR_TCE - -Capability: KVM_CAP_SPAPR_TCE -Architectures: powerpc -Type: vm ioctl -Parameters: struct kvm_create_spapr_tce (in) -Returns: file descriptor for manipulating the created TCE table - -This creates a virtual TCE (translation control entry) table, which -is an IOMMU for PAPR-style virtual I/O. It is used to translate -logical addresses used in virtual I/O into guest physical addresses, -and provides a scatter/gather capability for PAPR virtual I/O. - -/* for KVM_CAP_SPAPR_TCE */ -struct kvm_create_spapr_tce { - __u64 liobn; - __u32 window_size; -}; - -The liobn field gives the logical IO bus number for which to create a -TCE table. The window_size field specifies the size of the DMA window -which this TCE table will translate - the table will contain one 64 -bit TCE entry for every 4kiB of the DMA window. - -When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE -table has been created using this ioctl(), the kernel will handle it -in real mode, updating the TCE table. H_PUT_TCE calls for other -liobns will cause a vm exit and must be handled by userspace. - -The return value is a file descriptor which can be passed to mmap(2) -to map the created TCE table into userspace. This lets userspace read -the entries written by kernel-handled H_PUT_TCE calls, and also lets -userspace update the TCE table directly which is useful in some -circumstances. - - -4.63 KVM_ALLOCATE_RMA - -Capability: KVM_CAP_PPC_RMA -Architectures: powerpc -Type: vm ioctl -Parameters: struct kvm_allocate_rma (out) -Returns: file descriptor for mapping the allocated RMA - -This allocates a Real Mode Area (RMA) from the pool allocated at boot -time by the kernel. An RMA is a physically-contiguous, aligned region -of memory used on older POWER processors to provide the memory which -will be accessed by real-mode (MMU off) accesses in a KVM guest. -POWER processors support a set of sizes for the RMA that usually -includes 64MB, 128MB, 256MB and some larger powers of two. - -/* for KVM_ALLOCATE_RMA */ -struct kvm_allocate_rma { - __u64 rma_size; -}; - -The return value is a file descriptor which can be passed to mmap(2) -to map the allocated RMA into userspace. The mapped area can then be -passed to the KVM_SET_USER_MEMORY_REGION ioctl to establish it as the -RMA for a virtual machine. The size of the RMA in bytes (which is -fixed at host kernel boot time) is returned in the rma_size field of -the argument structure. - -The KVM_CAP_PPC_RMA capability is 1 or 2 if the KVM_ALLOCATE_RMA ioctl -is supported; 2 if the processor requires all virtual machines to have -an RMA, or 1 if the processor can use an RMA but doesn't require it, -because it supports the Virtual RMA (VRMA) facility. - - -4.64 KVM_NMI - -Capability: KVM_CAP_USER_NMI -Architectures: x86 -Type: vcpu ioctl -Parameters: none -Returns: 0 on success, -1 on error - -Queues an NMI on the thread's vcpu. Note this is well defined only -when KVM_CREATE_IRQCHIP has not been called, since this is an interface -between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP -has been called, this interface is completely emulated within the kernel. - -To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the -following algorithm: - - - pause the vcpu - - read the local APIC's state (KVM_GET_LAPIC) - - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1) - - if so, issue KVM_NMI - - resume the vcpu - -Some guests configure the LINT1 NMI input to cause a panic, aiding in -debugging. - - -4.65 KVM_S390_UCAS_MAP - -Capability: KVM_CAP_S390_UCONTROL -Architectures: s390 -Type: vcpu ioctl -Parameters: struct kvm_s390_ucas_mapping (in) -Returns: 0 in case of success - -The parameter is defined like this: - struct kvm_s390_ucas_mapping { - __u64 user_addr; - __u64 vcpu_addr; - __u64 length; - }; - -This ioctl maps the memory at "user_addr" with the length "length" to -the vcpu's address space starting at "vcpu_addr". All parameters need to -be aligned by 1 megabyte. - - -4.66 KVM_S390_UCAS_UNMAP - -Capability: KVM_CAP_S390_UCONTROL -Architectures: s390 -Type: vcpu ioctl -Parameters: struct kvm_s390_ucas_mapping (in) -Returns: 0 in case of success - -The parameter is defined like this: - struct kvm_s390_ucas_mapping { - __u64 user_addr; - __u64 vcpu_addr; - __u64 length; - }; - -This ioctl unmaps the memory in the vcpu's address space starting at -"vcpu_addr" with the length "length". The field "user_addr" is ignored. -All parameters need to be aligned by 1 megabyte. - - -4.67 KVM_S390_VCPU_FAULT - -Capability: KVM_CAP_S390_UCONTROL -Architectures: s390 -Type: vcpu ioctl -Parameters: vcpu absolute address (in) -Returns: 0 in case of success - -This call creates a page table entry on the virtual cpu's address space -(for user controlled virtual machines) or the virtual machine's address -space (for regular virtual machines). This only works for minor faults, -thus it's recommended to access subject memory page via the user page -table upfront. This is useful to handle validity intercepts for user -controlled virtual machines to fault in the virtual cpu's lowcore pages -prior to calling the KVM_RUN ioctl. - - -4.68 KVM_SET_ONE_REG - -Capability: KVM_CAP_ONE_REG -Architectures: all -Type: vcpu ioctl -Parameters: struct kvm_one_reg (in) -Returns: 0 on success, negative value on failure -Errors: - ENOENT: no such register - EINVAL: invalid register ID, or no such register - EPERM: (arm64) register access not allowed before vcpu finalization -(These error codes are indicative only: do not rely on a specific error -code being returned in a specific situation.) - -struct kvm_one_reg { - __u64 id; - __u64 addr; -}; - -Using this ioctl, a single vcpu register can be set to a specific value -defined by user space with the passed in struct kvm_one_reg, where id -refers to the register identifier as described below and addr is a pointer -to a variable with the respective size. There can be architecture agnostic -and architecture specific registers. Each have their own range of operation -and their own constants and width. To keep track of the implemented -registers, find a list below: - - Arch | Register | Width (bits) - | | - PPC | KVM_REG_PPC_HIOR | 64 - PPC | KVM_REG_PPC_IAC1 | 64 - PPC | KVM_REG_PPC_IAC2 | 64 - PPC | KVM_REG_PPC_IAC3 | 64 - PPC | KVM_REG_PPC_IAC4 | 64 - PPC | KVM_REG_PPC_DAC1 | 64 - PPC | KVM_REG_PPC_DAC2 | 64 - PPC | KVM_REG_PPC_DABR | 64 - PPC | KVM_REG_PPC_DSCR | 64 - PPC | KVM_REG_PPC_PURR | 64 - PPC | KVM_REG_PPC_SPURR | 64 - PPC | KVM_REG_PPC_DAR | 64 - PPC | KVM_REG_PPC_DSISR | 32 - PPC | KVM_REG_PPC_AMR | 64 - PPC | KVM_REG_PPC_UAMOR | 64 - PPC | KVM_REG_PPC_MMCR0 | 64 - PPC | KVM_REG_PPC_MMCR1 | 64 - PPC | KVM_REG_PPC_MMCRA | 64 - PPC | KVM_REG_PPC_MMCR2 | 64 - PPC | KVM_REG_PPC_MMCRS | 64 - PPC | KVM_REG_PPC_SIAR | 64 - PPC | KVM_REG_PPC_SDAR | 64 - PPC | KVM_REG_PPC_SIER | 64 - PPC | KVM_REG_PPC_PMC1 | 32 - PPC | KVM_REG_PPC_PMC2 | 32 - PPC | KVM_REG_PPC_PMC3 | 32 - PPC | KVM_REG_PPC_PMC4 | 32 - PPC | KVM_REG_PPC_PMC5 | 32 - PPC | KVM_REG_PPC_PMC6 | 32 - PPC | KVM_REG_PPC_PMC7 | 32 - PPC | KVM_REG_PPC_PMC8 | 32 - PPC | KVM_REG_PPC_FPR0 | 64 - ... - PPC | KVM_REG_PPC_FPR31 | 64 - PPC | KVM_REG_PPC_VR0 | 128 - ... - PPC | KVM_REG_PPC_VR31 | 128 - PPC | KVM_REG_PPC_VSR0 | 128 - ... - PPC | KVM_REG_PPC_VSR31 | 128 - PPC | KVM_REG_PPC_FPSCR | 64 - PPC | KVM_REG_PPC_VSCR | 32 - PPC | KVM_REG_PPC_VPA_ADDR | 64 - PPC | KVM_REG_PPC_VPA_SLB | 128 - PPC | KVM_REG_PPC_VPA_DTL | 128 - PPC | KVM_REG_PPC_EPCR | 32 - PPC | KVM_REG_PPC_EPR | 32 - PPC | KVM_REG_PPC_TCR | 32 - PPC | KVM_REG_PPC_TSR | 32 - PPC | KVM_REG_PPC_OR_TSR | 32 - PPC | KVM_REG_PPC_CLEAR_TSR | 32 - PPC | KVM_REG_PPC_MAS0 | 32 - PPC | KVM_REG_PPC_MAS1 | 32 - PPC | KVM_REG_PPC_MAS2 | 64 - PPC | KVM_REG_PPC_MAS7_3 | 64 - PPC | KVM_REG_PPC_MAS4 | 32 - PPC | KVM_REG_PPC_MAS6 | 32 - PPC | KVM_REG_PPC_MMUCFG | 32 - PPC | KVM_REG_PPC_TLB0CFG | 32 - PPC | KVM_REG_PPC_TLB1CFG | 32 - PPC | KVM_REG_PPC_TLB2CFG | 32 - PPC | KVM_REG_PPC_TLB3CFG | 32 - PPC | KVM_REG_PPC_TLB0PS | 32 - PPC | KVM_REG_PPC_TLB1PS | 32 - PPC | KVM_REG_PPC_TLB2PS | 32 - PPC | KVM_REG_PPC_TLB3PS | 32 - PPC | KVM_REG_PPC_EPTCFG | 32 - PPC | KVM_REG_PPC_ICP_STATE | 64 - PPC | KVM_REG_PPC_VP_STATE | 128 - PPC | KVM_REG_PPC_TB_OFFSET | 64 - PPC | KVM_REG_PPC_SPMC1 | 32 - PPC | KVM_REG_PPC_SPMC2 | 32 - PPC | KVM_REG_PPC_IAMR | 64 - PPC | KVM_REG_PPC_TFHAR | 64 - PPC | KVM_REG_PPC_TFIAR | 64 - PPC | KVM_REG_PPC_TEXASR | 64 - PPC | KVM_REG_PPC_FSCR | 64 - PPC | KVM_REG_PPC_PSPB | 32 - PPC | KVM_REG_PPC_EBBHR | 64 - PPC | KVM_REG_PPC_EBBRR | 64 - PPC | KVM_REG_PPC_BESCR | 64 - PPC | KVM_REG_PPC_TAR | 64 - PPC | KVM_REG_PPC_DPDES | 64 - PPC | KVM_REG_PPC_DAWR | 64 - PPC | KVM_REG_PPC_DAWRX | 64 - PPC | KVM_REG_PPC_CIABR | 64 - PPC | KVM_REG_PPC_IC | 64 - PPC | KVM_REG_PPC_VTB | 64 - PPC | KVM_REG_PPC_CSIGR | 64 - PPC | KVM_REG_PPC_TACR | 64 - PPC | KVM_REG_PPC_TCSCR | 64 - PPC | KVM_REG_PPC_PID | 64 - PPC | KVM_REG_PPC_ACOP | 64 - PPC | KVM_REG_PPC_VRSAVE | 32 - PPC | KVM_REG_PPC_LPCR | 32 - PPC | KVM_REG_PPC_LPCR_64 | 64 - PPC | KVM_REG_PPC_PPR | 64 - PPC | KVM_REG_PPC_ARCH_COMPAT | 32 - PPC | KVM_REG_PPC_DABRX | 32 - PPC | KVM_REG_PPC_WORT | 64 - PPC | KVM_REG_PPC_SPRG9 | 64 - PPC | KVM_REG_PPC_DBSR | 32 - PPC | KVM_REG_PPC_TIDR | 64 - PPC | KVM_REG_PPC_PSSCR | 64 - PPC | KVM_REG_PPC_DEC_EXPIRY | 64 - PPC | KVM_REG_PPC_PTCR | 64 - PPC | KVM_REG_PPC_TM_GPR0 | 64 - ... - PPC | KVM_REG_PPC_TM_GPR31 | 64 - PPC | KVM_REG_PPC_TM_VSR0 | 128 - ... - PPC | KVM_REG_PPC_TM_VSR63 | 128 - PPC | KVM_REG_PPC_TM_CR | 64 - PPC | KVM_REG_PPC_TM_LR | 64 - PPC | KVM_REG_PPC_TM_CTR | 64 - PPC | KVM_REG_PPC_TM_FPSCR | 64 - PPC | KVM_REG_PPC_TM_AMR | 64 - PPC | KVM_REG_PPC_TM_PPR | 64 - PPC | KVM_REG_PPC_TM_VRSAVE | 64 - PPC | KVM_REG_PPC_TM_VSCR | 32 - PPC | KVM_REG_PPC_TM_DSCR | 64 - PPC | KVM_REG_PPC_TM_TAR | 64 - PPC | KVM_REG_PPC_TM_XER | 64 - | | - MIPS | KVM_REG_MIPS_R0 | 64 - ... - MIPS | KVM_REG_MIPS_R31 | 64 - MIPS | KVM_REG_MIPS_HI | 64 - MIPS | KVM_REG_MIPS_LO | 64 - MIPS | KVM_REG_MIPS_PC | 64 - MIPS | KVM_REG_MIPS_CP0_INDEX | 32 - MIPS | KVM_REG_MIPS_CP0_ENTRYLO0 | 64 - MIPS | KVM_REG_MIPS_CP0_ENTRYLO1 | 64 - MIPS | KVM_REG_MIPS_CP0_CONTEXT | 64 - MIPS | KVM_REG_MIPS_CP0_CONTEXTCONFIG| 32 - MIPS | KVM_REG_MIPS_CP0_USERLOCAL | 64 - MIPS | KVM_REG_MIPS_CP0_XCONTEXTCONFIG| 64 - MIPS | KVM_REG_MIPS_CP0_PAGEMASK | 32 - MIPS | KVM_REG_MIPS_CP0_PAGEGRAIN | 32 - MIPS | KVM_REG_MIPS_CP0_SEGCTL0 | 64 - MIPS | KVM_REG_MIPS_CP0_SEGCTL1 | 64 - MIPS | KVM_REG_MIPS_CP0_SEGCTL2 | 64 - MIPS | KVM_REG_MIPS_CP0_PWBASE | 64 - MIPS | KVM_REG_MIPS_CP0_PWFIELD | 64 - MIPS | KVM_REG_MIPS_CP0_PWSIZE | 64 - MIPS | KVM_REG_MIPS_CP0_WIRED | 32 - MIPS | KVM_REG_MIPS_CP0_PWCTL | 32 - MIPS | KVM_REG_MIPS_CP0_HWRENA | 32 - MIPS | KVM_REG_MIPS_CP0_BADVADDR | 64 - MIPS | KVM_REG_MIPS_CP0_BADINSTR | 32 - MIPS | KVM_REG_MIPS_CP0_BADINSTRP | 32 - MIPS | KVM_REG_MIPS_CP0_COUNT | 32 - MIPS | KVM_REG_MIPS_CP0_ENTRYHI | 64 - MIPS | KVM_REG_MIPS_CP0_COMPARE | 32 - MIPS | KVM_REG_MIPS_CP0_STATUS | 32 - MIPS | KVM_REG_MIPS_CP0_INTCTL | 32 - MIPS | KVM_REG_MIPS_CP0_CAUSE | 32 - MIPS | KVM_REG_MIPS_CP0_EPC | 64 - MIPS | KVM_REG_MIPS_CP0_PRID | 32 - MIPS | KVM_REG_MIPS_CP0_EBASE | 64 - MIPS | KVM_REG_MIPS_CP0_CONFIG | 32 - MIPS | KVM_REG_MIPS_CP0_CONFIG1 | 32 - MIPS | KVM_REG_MIPS_CP0_CONFIG2 | 32 - MIPS | KVM_REG_MIPS_CP0_CONFIG3 | 32 - MIPS | KVM_REG_MIPS_CP0_CONFIG4 | 32 - MIPS | KVM_REG_MIPS_CP0_CONFIG5 | 32 - MIPS | KVM_REG_MIPS_CP0_CONFIG7 | 32 - MIPS | KVM_REG_MIPS_CP0_XCONTEXT | 64 - MIPS | KVM_REG_MIPS_CP0_ERROREPC | 64 - MIPS | KVM_REG_MIPS_CP0_KSCRATCH1 | 64 - MIPS | KVM_REG_MIPS_CP0_KSCRATCH2 | 64 - MIPS | KVM_REG_MIPS_CP0_KSCRATCH3 | 64 - MIPS | KVM_REG_MIPS_CP0_KSCRATCH4 | 64 - MIPS | KVM_REG_MIPS_CP0_KSCRATCH5 | 64 - MIPS | KVM_REG_MIPS_CP0_KSCRATCH6 | 64 - MIPS | KVM_REG_MIPS_CP0_MAAR(0..63) | 64 - MIPS | KVM_REG_MIPS_COUNT_CTL | 64 - MIPS | KVM_REG_MIPS_COUNT_RESUME | 64 - MIPS | KVM_REG_MIPS_COUNT_HZ | 64 - MIPS | KVM_REG_MIPS_FPR_32(0..31) | 32 - MIPS | KVM_REG_MIPS_FPR_64(0..31) | 64 - MIPS | KVM_REG_MIPS_VEC_128(0..31) | 128 - MIPS | KVM_REG_MIPS_FCR_IR | 32 - MIPS | KVM_REG_MIPS_FCR_CSR | 32 - MIPS | KVM_REG_MIPS_MSA_IR | 32 - MIPS | KVM_REG_MIPS_MSA_CSR | 32 - -ARM registers are mapped using the lower 32 bits. The upper 16 of that -is the register group type, or coprocessor number: - -ARM core registers have the following id bit patterns: - 0x4020 0000 0010 <index into the kvm_regs struct:16> - -ARM 32-bit CP15 registers have the following id bit patterns: - 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3> - -ARM 64-bit CP15 registers have the following id bit patterns: - 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3> - -ARM CCSIDR registers are demultiplexed by CSSELR value: - 0x4020 0000 0011 00 <csselr:8> - -ARM 32-bit VFP control registers have the following id bit patterns: - 0x4020 0000 0012 1 <regno:12> - -ARM 64-bit FP registers have the following id bit patterns: - 0x4030 0000 0012 0 <regno:12> - -ARM firmware pseudo-registers have the following bit pattern: - 0x4030 0000 0014 <regno:16> - - -arm64 registers are mapped using the lower 32 bits. The upper 16 of -that is the register group type, or coprocessor number: - -arm64 core/FP-SIMD registers have the following id bit patterns. Note -that the size of the access is variable, as the kvm_regs structure -contains elements ranging from 32 to 128 bits. The index is a 32bit -value in the kvm_regs structure seen as a 32bit array. - 0x60x0 0000 0010 <index into the kvm_regs struct:16> - -Specifically: - Encoding Register Bits kvm_regs member ----------------------------------------------------------------- - 0x6030 0000 0010 0000 X0 64 regs.regs[0] - 0x6030 0000 0010 0002 X1 64 regs.regs[1] - ... - 0x6030 0000 0010 003c X30 64 regs.regs[30] - 0x6030 0000 0010 003e SP 64 regs.sp - 0x6030 0000 0010 0040 PC 64 regs.pc - 0x6030 0000 0010 0042 PSTATE 64 regs.pstate - 0x6030 0000 0010 0044 SP_EL1 64 sp_el1 - 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1 - 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC) - 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT] - 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND] - 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ] - 0x6060 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ] - 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] (*) - 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] (*) - ... - 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] (*) - 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr - 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr - -(*) These encodings are not accepted for SVE-enabled vcpus. See - KVM_ARM_VCPU_INIT. - - The equivalent register content can be accessed via bits [127:0] of - the corresponding SVE Zn registers instead for vcpus that have SVE - enabled (see below). - -arm64 CCSIDR registers are demultiplexed by CSSELR value: - 0x6020 0000 0011 00 <csselr:8> - -arm64 system registers have the following id bit patterns: - 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3> - -arm64 firmware pseudo-registers have the following bit pattern: - 0x6030 0000 0014 <regno:16> - -arm64 SVE registers have the following bit patterns: - 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice] - 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice] - 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice] - 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register - -Access to register IDs where 2048 * slice >= 128 * max_vq will fail with -ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit -quadwords: see (**) below. - -These registers are only accessible on vcpus for which SVE is enabled. -See KVM_ARM_VCPU_INIT for details. - -In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not -accessible until the vcpu's SVE configuration has been finalized -using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT -and KVM_ARM_VCPU_FINALIZE for more information about this procedure. - -KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector -lengths supported by the vcpu to be discovered and configured by -userspace. When transferred to or from user memory via KVM_GET_ONE_REG -or KVM_SET_ONE_REG, the value of this register is of type -__u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as -follows: - -__u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS]; - -if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX && - ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >> - ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1)) - /* Vector length vq * 16 bytes supported */ -else - /* Vector length vq * 16 bytes not supported */ - -(**) The maximum value vq for which the above condition is true is -max_vq. This is the maximum vector length available to the guest on -this vcpu, and determines which register slices are visible through -this ioctl interface. - -(See Documentation/arm64/sve.rst for an explanation of the "vq" -nomenclature.) - -KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT. -KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that -the host supports. - -Userspace may subsequently modify it if desired until the vcpu's SVE -configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). - -Apart from simply removing all vector lengths from the host set that -exceed some value, support for arbitrarily chosen sets of vector lengths -is hardware-dependent and may not be available. Attempting to configure -an invalid set of vector lengths via KVM_SET_ONE_REG will fail with -EINVAL. - -After the vcpu's SVE configuration is finalized, further attempts to -write this register will fail with EPERM. - - -MIPS registers are mapped using the lower 32 bits. The upper 16 of that is -the register group type: - -MIPS core registers (see above) have the following id bit patterns: - 0x7030 0000 0000 <reg:16> - -MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit -patterns depending on whether they're 32-bit or 64-bit registers: - 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit) - 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit) - -Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64 -versions of the EntryLo registers regardless of the word size of the host -hardware, host kernel, guest, and whether XPA is present in the guest, i.e. -with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and -the PFNX field starting at bit 30. - -MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit -patterns: - 0x7030 0000 0001 01 <reg:8> - -MIPS KVM control registers (see above) have the following id bit patterns: - 0x7030 0000 0002 <reg:16> - -MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following -id bit patterns depending on the size of the register being accessed. They are -always accessed according to the current guest FPU mode (Status.FR and -Config5.FRE), i.e. as the guest would see them, and they become unpredictable -if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector -registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they -overlap the FPU registers: - 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers) - 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers) - 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers) - -MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the -following id bit patterns: - 0x7020 0000 0003 01 <0:3> <reg:5> - -MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the -following id bit patterns: - 0x7020 0000 0003 02 <0:3> <reg:5> - - -4.69 KVM_GET_ONE_REG - -Capability: KVM_CAP_ONE_REG -Architectures: all -Type: vcpu ioctl -Parameters: struct kvm_one_reg (in and out) -Returns: 0 on success, negative value on failure -Errors include: - ENOENT: no such register - EINVAL: invalid register ID, or no such register - EPERM: (arm64) register access not allowed before vcpu finalization -(These error codes are indicative only: do not rely on a specific error -code being returned in a specific situation.) - -This ioctl allows to receive the value of a single register implemented -in a vcpu. The register to read is indicated by the "id" field of the -kvm_one_reg struct passed in. On success, the register value can be found -at the memory location pointed to by "addr". - -The list of registers accessible using this interface is identical to the -list in 4.68. - - -4.70 KVM_KVMCLOCK_CTRL - -Capability: KVM_CAP_KVMCLOCK_CTRL -Architectures: Any that implement pvclocks (currently x86 only) -Type: vcpu ioctl -Parameters: None -Returns: 0 on success, -1 on error - -This signals to the host kernel that the specified guest is being paused by -userspace. The host will set a flag in the pvclock structure that is checked -from the soft lockup watchdog. The flag is part of the pvclock structure that -is shared between guest and host, specifically the second bit of the flags -field of the pvclock_vcpu_time_info structure. It will be set exclusively by -the host and read/cleared exclusively by the guest. The guest operation of -checking and clearing the flag must an atomic operation so -load-link/store-conditional, or equivalent must be used. There are two cases -where the guest will clear the flag: when the soft lockup watchdog timer resets -itself or when a soft lockup is detected. This ioctl can be called any time -after pausing the vcpu, but before it is resumed. - - -4.71 KVM_SIGNAL_MSI - -Capability: KVM_CAP_SIGNAL_MSI -Architectures: x86 arm arm64 -Type: vm ioctl -Parameters: struct kvm_msi (in) -Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error - -Directly inject a MSI message. Only valid with in-kernel irqchip that handles -MSI messages. - -struct kvm_msi { - __u32 address_lo; - __u32 address_hi; - __u32 data; - __u32 flags; - __u32 devid; - __u8 pad[12]; -}; - -flags: KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM - KVM_CAP_MSI_DEVID capability advertises the requirement to provide - the device ID. If this capability is not available, userspace - should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. - -If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier -for the device that wrote the MSI message. For PCI, this is usually a -BFD identifier in the lower 16 bits. - -On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS -feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, -address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of -address_hi must be zero. - - -4.71 KVM_CREATE_PIT2 - -Capability: KVM_CAP_PIT2 -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_pit_config (in) -Returns: 0 on success, -1 on error - -Creates an in-kernel device model for the i8254 PIT. This call is only valid -after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following -parameters have to be passed: - -struct kvm_pit_config { - __u32 flags; - __u32 pad[15]; -}; - -Valid flags are: - -#define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */ - -PIT timer interrupts may use a per-VM kernel thread for injection. If it -exists, this thread will have a name of the following pattern: - -kvm-pit/<owner-process-pid> - -When running a guest with elevated priorities, the scheduling parameters of -this thread may have to be adjusted accordingly. - -This IOCTL replaces the obsolete KVM_CREATE_PIT. - - -4.72 KVM_GET_PIT2 - -Capability: KVM_CAP_PIT_STATE2 -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_pit_state2 (out) -Returns: 0 on success, -1 on error - -Retrieves the state of the in-kernel PIT model. Only valid after -KVM_CREATE_PIT2. The state is returned in the following structure: - -struct kvm_pit_state2 { - struct kvm_pit_channel_state channels[3]; - __u32 flags; - __u32 reserved[9]; -}; - -Valid flags are: - -/* disable PIT in HPET legacy mode */ -#define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 - -This IOCTL replaces the obsolete KVM_GET_PIT. - - -4.73 KVM_SET_PIT2 - -Capability: KVM_CAP_PIT_STATE2 -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_pit_state2 (in) -Returns: 0 on success, -1 on error - -Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. -See KVM_GET_PIT2 for details on struct kvm_pit_state2. - -This IOCTL replaces the obsolete KVM_SET_PIT. - - -4.74 KVM_PPC_GET_SMMU_INFO - -Capability: KVM_CAP_PPC_GET_SMMU_INFO -Architectures: powerpc -Type: vm ioctl -Parameters: None -Returns: 0 on success, -1 on error - -This populates and returns a structure describing the features of -the "Server" class MMU emulation supported by KVM. -This can in turn be used by userspace to generate the appropriate -device-tree properties for the guest operating system. - -The structure contains some global information, followed by an -array of supported segment page sizes: - - struct kvm_ppc_smmu_info { - __u64 flags; - __u32 slb_size; - __u32 pad; - struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ]; - }; - -The supported flags are: - - - KVM_PPC_PAGE_SIZES_REAL: - When that flag is set, guest page sizes must "fit" the backing - store page sizes. When not set, any page size in the list can - be used regardless of how they are backed by userspace. - - - KVM_PPC_1T_SEGMENTS - The emulated MMU supports 1T segments in addition to the - standard 256M ones. - - - KVM_PPC_NO_HASH - This flag indicates that HPT guests are not supported by KVM, - thus all guests must use radix MMU mode. - -The "slb_size" field indicates how many SLB entries are supported - -The "sps" array contains 8 entries indicating the supported base -page sizes for a segment in increasing order. Each entry is defined -as follow: - - struct kvm_ppc_one_seg_page_size { - __u32 page_shift; /* Base page shift of segment (or 0) */ - __u32 slb_enc; /* SLB encoding for BookS */ - struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ]; - }; - -An entry with a "page_shift" of 0 is unused. Because the array is -organized in increasing order, a lookup can stop when encoutering -such an entry. - -The "slb_enc" field provides the encoding to use in the SLB for the -page size. The bits are in positions such as the value can directly -be OR'ed into the "vsid" argument of the slbmte instruction. - -The "enc" array is a list which for each of those segment base page -size provides the list of supported actual page sizes (which can be -only larger or equal to the base page size), along with the -corresponding encoding in the hash PTE. Similarly, the array is -8 entries sorted by increasing sizes and an entry with a "0" shift -is an empty entry and a terminator: - - struct kvm_ppc_one_page_size { - __u32 page_shift; /* Page shift (or 0) */ - __u32 pte_enc; /* Encoding in the HPTE (>>12) */ - }; - -The "pte_enc" field provides a value that can OR'ed into the hash -PTE's RPN field (ie, it needs to be shifted left by 12 to OR it -into the hash PTE second double word). - -4.75 KVM_IRQFD - -Capability: KVM_CAP_IRQFD -Architectures: x86 s390 arm arm64 -Type: vm ioctl -Parameters: struct kvm_irqfd (in) -Returns: 0 on success, -1 on error - -Allows setting an eventfd to directly trigger a guest interrupt. -kvm_irqfd.fd specifies the file descriptor to use as the eventfd and -kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When -an event is triggered on the eventfd, an interrupt is injected into -the guest using the specified gsi pin. The irqfd is removed using -the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd -and kvm_irqfd.gsi. - -With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify -mechanism allowing emulation of level-triggered, irqfd-based -interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an -additional eventfd in the kvm_irqfd.resamplefd field. When operating -in resample mode, posting of an interrupt through kvm_irq.fd asserts -the specified gsi in the irqchip. When the irqchip is resampled, such -as from an EOI, the gsi is de-asserted and the user is notified via -kvm_irqfd.resamplefd. It is the user's responsibility to re-queue -the interrupt if the device making use of it still requires service. -Note that closing the resamplefd is not sufficient to disable the -irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment -and need not be specified with KVM_IRQFD_FLAG_DEASSIGN. - -On arm/arm64, gsi routing being supported, the following can happen: -- in case no routing entry is associated to this gsi, injection fails -- in case the gsi is associated to an irqchip routing entry, - irqchip.pin + 32 corresponds to the injected SPI ID. -- in case the gsi is associated to an MSI routing entry, the MSI - message and device ID are translated into an LPI (support restricted - to GICv3 ITS in-kernel emulation). - -4.76 KVM_PPC_ALLOCATE_HTAB - -Capability: KVM_CAP_PPC_ALLOC_HTAB -Architectures: powerpc -Type: vm ioctl -Parameters: Pointer to u32 containing hash table order (in/out) -Returns: 0 on success, -1 on error - -This requests the host kernel to allocate an MMU hash table for a -guest using the PAPR paravirtualization interface. This only does -anything if the kernel is configured to use the Book 3S HV style of -virtualization. Otherwise the capability doesn't exist and the ioctl -returns an ENOTTY error. The rest of this description assumes Book 3S -HV. - -There must be no vcpus running when this ioctl is called; if there -are, it will do nothing and return an EBUSY error. - -The parameter is a pointer to a 32-bit unsigned integer variable -containing the order (log base 2) of the desired size of the hash -table, which must be between 18 and 46. On successful return from the -ioctl, the value will not be changed by the kernel. - -If no hash table has been allocated when any vcpu is asked to run -(with the KVM_RUN ioctl), the host kernel will allocate a -default-sized hash table (16 MB). - -If this ioctl is called when a hash table has already been allocated, -with a different order from the existing hash table, the existing hash -table will be freed and a new one allocated. If this is ioctl is -called when a hash table has already been allocated of the same order -as specified, the kernel will clear out the existing hash table (zero -all HPTEs). In either case, if the guest is using the virtualized -real-mode area (VRMA) facility, the kernel will re-create the VMRA -HPTEs on the next KVM_RUN of any vcpu. - -4.77 KVM_S390_INTERRUPT - -Capability: basic -Architectures: s390 -Type: vm ioctl, vcpu ioctl -Parameters: struct kvm_s390_interrupt (in) -Returns: 0 on success, -1 on error - -Allows to inject an interrupt to the guest. Interrupts can be floating -(vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type. - -Interrupt parameters are passed via kvm_s390_interrupt: - -struct kvm_s390_interrupt { - __u32 type; - __u32 parm; - __u64 parm64; -}; - -type can be one of the following: - -KVM_S390_SIGP_STOP (vcpu) - sigp stop; optional flags in parm -KVM_S390_PROGRAM_INT (vcpu) - program check; code in parm -KVM_S390_SIGP_SET_PREFIX (vcpu) - sigp set prefix; prefix address in parm -KVM_S390_RESTART (vcpu) - restart -KVM_S390_INT_CLOCK_COMP (vcpu) - clock comparator interrupt -KVM_S390_INT_CPU_TIMER (vcpu) - CPU timer interrupt -KVM_S390_INT_VIRTIO (vm) - virtio external interrupt; external interrupt - parameters in parm and parm64 -KVM_S390_INT_SERVICE (vm) - sclp external interrupt; sclp parameter in parm -KVM_S390_INT_EMERGENCY (vcpu) - sigp emergency; source cpu in parm -KVM_S390_INT_EXTERNAL_CALL (vcpu) - sigp external call; source cpu in parm -KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) - compound value to indicate an - I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel); - I/O interruption parameters in parm (subchannel) and parm64 (intparm, - interruption subclass) -KVM_S390_MCHK (vm, vcpu) - machine check interrupt; cr 14 bits in parm, - machine check interrupt code in parm64 (note that - machine checks needing further payload are not - supported by this ioctl) - -This is an asynchronous vcpu ioctl and can be invoked from any thread. - -4.78 KVM_PPC_GET_HTAB_FD - -Capability: KVM_CAP_PPC_HTAB_FD -Architectures: powerpc -Type: vm ioctl -Parameters: Pointer to struct kvm_get_htab_fd (in) -Returns: file descriptor number (>= 0) on success, -1 on error - -This returns a file descriptor that can be used either to read out the -entries in the guest's hashed page table (HPT), or to write entries to -initialize the HPT. The returned fd can only be written to if the -KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and -can only be read if that bit is clear. The argument struct looks like -this: - -/* For KVM_PPC_GET_HTAB_FD */ -struct kvm_get_htab_fd { - __u64 flags; - __u64 start_index; - __u64 reserved[2]; -}; - -/* Values for kvm_get_htab_fd.flags */ -#define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1) -#define KVM_GET_HTAB_WRITE ((__u64)0x2) - -The `start_index' field gives the index in the HPT of the entry at -which to start reading. It is ignored when writing. - -Reads on the fd will initially supply information about all -"interesting" HPT entries. Interesting entries are those with the -bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise -all entries. When the end of the HPT is reached, the read() will -return. If read() is called again on the fd, it will start again from -the beginning of the HPT, but will only return HPT entries that have -changed since they were last read. - -Data read or written is structured as a header (8 bytes) followed by a -series of valid HPT entries (16 bytes) each. The header indicates how -many valid HPT entries there are and how many invalid entries follow -the valid entries. The invalid entries are not represented explicitly -in the stream. The header format is: - -struct kvm_get_htab_header { - __u32 index; - __u16 n_valid; - __u16 n_invalid; -}; - -Writes to the fd create HPT entries starting at the index given in the -header; first `n_valid' valid entries with contents from the data -written, then `n_invalid' invalid entries, invalidating any previously -valid entries found. - -4.79 KVM_CREATE_DEVICE - -Capability: KVM_CAP_DEVICE_CTRL -Type: vm ioctl -Parameters: struct kvm_create_device (in/out) -Returns: 0 on success, -1 on error -Errors: - ENODEV: The device type is unknown or unsupported - EEXIST: Device already created, and this type of device may not - be instantiated multiple times - - Other error conditions may be defined by individual device types or - have their standard meanings. - -Creates an emulated device in the kernel. The file descriptor returned -in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR. - -If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the -device type is supported (not necessarily whether it can be created -in the current vm). - -Individual devices should not define flags. Attributes should be used -for specifying any behavior that is not implied by the device type -number. - -struct kvm_create_device { - __u32 type; /* in: KVM_DEV_TYPE_xxx */ - __u32 fd; /* out: device handle */ - __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ -}; - -4.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR - -Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, - KVM_CAP_VCPU_ATTRIBUTES for vcpu device -Type: device ioctl, vm ioctl, vcpu ioctl -Parameters: struct kvm_device_attr -Returns: 0 on success, -1 on error -Errors: - ENXIO: The group or attribute is unknown/unsupported for this device - or hardware support is missing. - EPERM: The attribute cannot (currently) be accessed this way - (e.g. read-only attribute, or attribute that only makes - sense when the device is in a different state) - - Other error conditions may be defined by individual device types. - -Gets/sets a specified piece of device configuration and/or state. The -semantics are device-specific. See individual device documentation in -the "devices" directory. As with ONE_REG, the size of the data -transferred is defined by the particular attribute. - -struct kvm_device_attr { - __u32 flags; /* no flags currently defined */ - __u32 group; /* device-defined */ - __u64 attr; /* group-defined */ - __u64 addr; /* userspace address of attr data */ -}; - -4.81 KVM_HAS_DEVICE_ATTR - -Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, - KVM_CAP_VCPU_ATTRIBUTES for vcpu device -Type: device ioctl, vm ioctl, vcpu ioctl -Parameters: struct kvm_device_attr -Returns: 0 on success, -1 on error -Errors: - ENXIO: The group or attribute is unknown/unsupported for this device - or hardware support is missing. - -Tests whether a device supports a particular attribute. A successful -return indicates the attribute is implemented. It does not necessarily -indicate that the attribute can be read or written in the device's -current state. "addr" is ignored. - -4.82 KVM_ARM_VCPU_INIT - -Capability: basic -Architectures: arm, arm64 -Type: vcpu ioctl -Parameters: struct kvm_vcpu_init (in) -Returns: 0 on success; -1 on error -Errors: - EINVAL: the target is unknown, or the combination of features is invalid. - ENOENT: a features bit specified is unknown. - -This tells KVM what type of CPU to present to the guest, and what -optional features it should have. This will cause a reset of the cpu -registers to their initial values. If this is not called, KVM_RUN will -return ENOEXEC for that vcpu. - -Note that because some registers reflect machine topology, all vcpus -should be created before this ioctl is invoked. - -Userspace can call this function multiple times for a given vcpu, including -after the vcpu has been run. This will reset the vcpu to its initial -state. All calls to this function after the initial call must use the same -target and same set of feature flags, otherwise EINVAL will be returned. - -Possible features: - - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. - Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on - and execute guest code when KVM_RUN is called. - - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. - Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). - - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision - backward compatible with v0.2) for the CPU. - Depends on KVM_CAP_ARM_PSCI_0_2. - - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. - Depends on KVM_CAP_ARM_PMU_V3. - - - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication - for arm64 only. - Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. - If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are - both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and - KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be - requested. - - - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication - for arm64 only. - Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. - If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are - both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and - KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be - requested. - - - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). - Depends on KVM_CAP_ARM_SVE. - Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): - - * After KVM_ARM_VCPU_INIT: - - - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the - initial value of this pseudo-register indicates the best set of - vector lengths possible for a vcpu on this host. - - * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): - - - KVM_RUN and KVM_GET_REG_LIST are not available; - - - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access - the scalable archietctural SVE registers - KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or - KVM_REG_ARM64_SVE_FFR; - - - KVM_REG_ARM64_SVE_VLS may optionally be written using - KVM_SET_ONE_REG, to modify the set of vector lengths available - for the vcpu. - - * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): - - - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can - no longer be written using KVM_SET_ONE_REG. - -4.83 KVM_ARM_PREFERRED_TARGET - -Capability: basic -Architectures: arm, arm64 -Type: vm ioctl -Parameters: struct struct kvm_vcpu_init (out) -Returns: 0 on success; -1 on error -Errors: - ENODEV: no preferred target available for the host - -This queries KVM for preferred CPU target type which can be emulated -by KVM on underlying host. - -The ioctl returns struct kvm_vcpu_init instance containing information -about preferred CPU target type and recommended features for it. The -kvm_vcpu_init->features bitmap returned will have feature bits set if -the preferred target recommends setting these features, but this is -not mandatory. - -The information returned by this ioctl can be used to prepare an instance -of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in -in VCPU matching underlying host. - - -4.84 KVM_GET_REG_LIST - -Capability: basic -Architectures: arm, arm64, mips -Type: vcpu ioctl -Parameters: struct kvm_reg_list (in/out) -Returns: 0 on success; -1 on error -Errors: - E2BIG: the reg index list is too big to fit in the array specified by - the user (the number required will be written into n). - -struct kvm_reg_list { - __u64 n; /* number of registers in reg[] */ - __u64 reg[0]; -}; - -This ioctl returns the guest registers that are supported for the -KVM_GET_ONE_REG/KVM_SET_ONE_REG calls. - - -4.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) - -Capability: KVM_CAP_ARM_SET_DEVICE_ADDR -Architectures: arm, arm64 -Type: vm ioctl -Parameters: struct kvm_arm_device_address (in) -Returns: 0 on success, -1 on error -Errors: - ENODEV: The device id is unknown - ENXIO: Device not supported on current system - EEXIST: Address already set - E2BIG: Address outside guest physical address space - EBUSY: Address overlaps with other device range - -struct kvm_arm_device_addr { - __u64 id; - __u64 addr; -}; - -Specify a device address in the guest's physical address space where guests -can access emulated or directly exposed devices, which the host kernel needs -to know about. The id field is an architecture specific identifier for a -specific device. - -ARM/arm64 divides the id field into two parts, a device id and an -address type id specific to the individual device. - - bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 | - field: | 0x00000000 | device id | addr type id | - -ARM/arm64 currently only require this when using the in-kernel GIC -support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 -as the device id. When setting the base address for the guest's -mapping of the VGIC virtual CPU and distributor interface, the ioctl -must be called after calling KVM_CREATE_IRQCHIP, but before calling -KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the -base addresses will return -EEXIST. - -Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API -should be used instead. - - -4.86 KVM_PPC_RTAS_DEFINE_TOKEN - -Capability: KVM_CAP_PPC_RTAS -Architectures: ppc -Type: vm ioctl -Parameters: struct kvm_rtas_token_args -Returns: 0 on success, -1 on error - -Defines a token value for a RTAS (Run Time Abstraction Services) -service in order to allow it to be handled in the kernel. The -argument struct gives the name of the service, which must be the name -of a service that has a kernel-side implementation. If the token -value is non-zero, it will be associated with that service, and -subsequent RTAS calls by the guest specifying that token will be -handled by the kernel. If the token value is 0, then any token -associated with the service will be forgotten, and subsequent RTAS -calls by the guest for that service will be passed to userspace to be -handled. - -4.87 KVM_SET_GUEST_DEBUG - -Capability: KVM_CAP_SET_GUEST_DEBUG -Architectures: x86, s390, ppc, arm64 -Type: vcpu ioctl -Parameters: struct kvm_guest_debug (in) -Returns: 0 on success; -1 on error - -struct kvm_guest_debug { - __u32 control; - __u32 pad; - struct kvm_guest_debug_arch arch; -}; - -Set up the processor specific debug registers and configure vcpu for -handling guest debug events. There are two parts to the structure, the -first a control bitfield indicates the type of debug events to handle -when running. Common control bits are: - - - KVM_GUESTDBG_ENABLE: guest debugging is enabled - - KVM_GUESTDBG_SINGLESTEP: the next run should single-step - -The top 16 bits of the control field are architecture specific control -flags which can include the following: - - - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] - - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390, arm64] - - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] - - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] - - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] - -For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints -are enabled in memory so we need to ensure breakpoint exceptions are -correctly trapped and the KVM run loop exits at the breakpoint and not -running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP -we need to ensure the guest vCPUs architecture specific registers are -updated to the correct (supplied) values. - -The second part of the structure is architecture specific and -typically contains a set of debug registers. - -For arm64 the number of debug registers is implementation defined and -can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and -KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number -indicating the number of supported registers. - -When debug events exit the main run loop with the reason -KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run -structure containing architecture specific debug information. - -4.88 KVM_GET_EMULATED_CPUID - -Capability: KVM_CAP_EXT_EMUL_CPUID -Architectures: x86 -Type: system ioctl -Parameters: struct kvm_cpuid2 (in/out) -Returns: 0 on success, -1 on error - -struct kvm_cpuid2 { - __u32 nent; - __u32 flags; - struct kvm_cpuid_entry2 entries[0]; -}; - -The member 'flags' is used for passing flags from userspace. - -#define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) -#define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) -#define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) - -struct kvm_cpuid_entry2 { - __u32 function; - __u32 index; - __u32 flags; - __u32 eax; - __u32 ebx; - __u32 ecx; - __u32 edx; - __u32 padding[3]; -}; - -This ioctl returns x86 cpuid features which are emulated by -kvm.Userspace can use the information returned by this ioctl to query -which features are emulated by kvm instead of being present natively. - -Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2 -structure with the 'nent' field indicating the number of entries in -the variable-size array 'entries'. If the number of entries is too low -to describe the cpu capabilities, an error (E2BIG) is returned. If the -number is too high, the 'nent' field is adjusted and an error (ENOMEM) -is returned. If the number is just right, the 'nent' field is adjusted -to the number of valid entries in the 'entries' array, which is then -filled. - -The entries returned are the set CPUID bits of the respective features -which kvm emulates, as returned by the CPUID instruction, with unknown -or unsupported feature bits cleared. - -Features like x2apic, for example, may not be present in the host cpu -but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be -emulated efficiently and thus not included here. - -The fields in each entry are defined as follows: - - function: the eax value used to obtain the entry - index: the ecx value used to obtain the entry (for entries that are - affected by ecx) - flags: an OR of zero or more of the following: - KVM_CPUID_FLAG_SIGNIFCANT_INDEX: - if the index field is valid - KVM_CPUID_FLAG_STATEFUL_FUNC: - if cpuid for this function returns different values for successive - invocations; there will be several entries with the same function, - all with this flag set - KVM_CPUID_FLAG_STATE_READ_NEXT: - for KVM_CPUID_FLAG_STATEFUL_FUNC entries, set if this entry is - the first entry to be read by a cpu - eax, ebx, ecx, edx: the values returned by the cpuid instruction for - this function/index combination - -4.89 KVM_S390_MEM_OP - -Capability: KVM_CAP_S390_MEM_OP -Architectures: s390 -Type: vcpu ioctl -Parameters: struct kvm_s390_mem_op (in) -Returns: = 0 on success, - < 0 on generic error (e.g. -EFAULT or -ENOMEM), - > 0 if an exception occurred while walking the page tables - -Read or write data from/to the logical (virtual) memory of a VCPU. - -Parameters are specified via the following structure: - -struct kvm_s390_mem_op { - __u64 gaddr; /* the guest address */ - __u64 flags; /* flags */ - __u32 size; /* amount of bytes */ - __u32 op; /* type of operation */ - __u64 buf; /* buffer in userspace */ - __u8 ar; /* the access register number */ - __u8 reserved[31]; /* should be set to 0 */ -}; - -The type of operation is specified in the "op" field. It is either -KVM_S390_MEMOP_LOGICAL_READ for reading from logical memory space or -KVM_S390_MEMOP_LOGICAL_WRITE for writing to logical memory space. The -KVM_S390_MEMOP_F_CHECK_ONLY flag can be set in the "flags" field to check -whether the corresponding memory access would create an access exception -(without touching the data in the memory at the destination). In case an -access exception occurred while walking the MMU tables of the guest, the -ioctl returns a positive error number to indicate the type of exception. -This exception is also raised directly at the corresponding VCPU if the -flag KVM_S390_MEMOP_F_INJECT_EXCEPTION is set in the "flags" field. - -The start address of the memory region has to be specified in the "gaddr" -field, and the length of the region in the "size" field. "buf" is the buffer -supplied by the userspace application where the read data should be written -to for KVM_S390_MEMOP_LOGICAL_READ, or where the data that should be written -is stored for a KVM_S390_MEMOP_LOGICAL_WRITE. "buf" is unused and can be NULL -when KVM_S390_MEMOP_F_CHECK_ONLY is specified. "ar" designates the access -register number to be used. - -The "reserved" field is meant for future extensions. It is not used by -KVM with the currently defined set of flags. - -4.90 KVM_S390_GET_SKEYS - -Capability: KVM_CAP_S390_SKEYS -Architectures: s390 -Type: vm ioctl -Parameters: struct kvm_s390_skeys -Returns: 0 on success, KVM_S390_GET_KEYS_NONE if guest is not using storage - keys, negative value on error - -This ioctl is used to get guest storage key values on the s390 -architecture. The ioctl takes parameters via the kvm_s390_skeys struct. - -struct kvm_s390_skeys { - __u64 start_gfn; - __u64 count; - __u64 skeydata_addr; - __u32 flags; - __u32 reserved[9]; -}; - -The start_gfn field is the number of the first guest frame whose storage keys -you want to get. - -The count field is the number of consecutive frames (starting from start_gfn) -whose storage keys to get. The count field must be at least 1 and the maximum -allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range -will cause the ioctl to return -EINVAL. - -The skeydata_addr field is the address to a buffer large enough to hold count -bytes. This buffer will be filled with storage key data by the ioctl. - -4.91 KVM_S390_SET_SKEYS - -Capability: KVM_CAP_S390_SKEYS -Architectures: s390 -Type: vm ioctl -Parameters: struct kvm_s390_skeys -Returns: 0 on success, negative value on error - -This ioctl is used to set guest storage key values on the s390 -architecture. The ioctl takes parameters via the kvm_s390_skeys struct. -See section on KVM_S390_GET_SKEYS for struct definition. - -The start_gfn field is the number of the first guest frame whose storage keys -you want to set. - -The count field is the number of consecutive frames (starting from start_gfn) -whose storage keys to get. The count field must be at least 1 and the maximum -allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range -will cause the ioctl to return -EINVAL. - -The skeydata_addr field is the address to a buffer containing count bytes of -storage keys. Each byte in the buffer will be set as the storage key for a -single frame starting at start_gfn for count frames. - -Note: If any architecturally invalid key value is found in the given data then -the ioctl will return -EINVAL. - -4.92 KVM_S390_IRQ - -Capability: KVM_CAP_S390_INJECT_IRQ -Architectures: s390 -Type: vcpu ioctl -Parameters: struct kvm_s390_irq (in) -Returns: 0 on success, -1 on error -Errors: - EINVAL: interrupt type is invalid - type is KVM_S390_SIGP_STOP and flag parameter is invalid value - type is KVM_S390_INT_EXTERNAL_CALL and code is bigger - than the maximum of VCPUs - EBUSY: type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped - type is KVM_S390_SIGP_STOP and a stop irq is already pending - type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt - is already pending - -Allows to inject an interrupt to the guest. - -Using struct kvm_s390_irq as a parameter allows -to inject additional payload which is not -possible via KVM_S390_INTERRUPT. - -Interrupt parameters are passed via kvm_s390_irq: - -struct kvm_s390_irq { - __u64 type; - union { - struct kvm_s390_io_info io; - struct kvm_s390_ext_info ext; - struct kvm_s390_pgm_info pgm; - struct kvm_s390_emerg_info emerg; - struct kvm_s390_extcall_info extcall; - struct kvm_s390_prefix_info prefix; - struct kvm_s390_stop_info stop; - struct kvm_s390_mchk_info mchk; - char reserved[64]; - } u; -}; - -type can be one of the following: - -KVM_S390_SIGP_STOP - sigp stop; parameter in .stop -KVM_S390_PROGRAM_INT - program check; parameters in .pgm -KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix -KVM_S390_RESTART - restart; no parameters -KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters -KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters -KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg -KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall -KVM_S390_MCHK - machine check interrupt; parameters in .mchk - -This is an asynchronous vcpu ioctl and can be invoked from any thread. - -4.94 KVM_S390_GET_IRQ_STATE - -Capability: KVM_CAP_S390_IRQ_STATE -Architectures: s390 -Type: vcpu ioctl -Parameters: struct kvm_s390_irq_state (out) -Returns: >= number of bytes copied into buffer, - -EINVAL if buffer size is 0, - -ENOBUFS if buffer size is too small to fit all pending interrupts, - -EFAULT if the buffer address was invalid - -This ioctl allows userspace to retrieve the complete state of all currently -pending interrupts in a single buffer. Use cases include migration -and introspection. The parameter structure contains the address of a -userspace buffer and its length: - -struct kvm_s390_irq_state { - __u64 buf; - __u32 flags; /* will stay unused for compatibility reasons */ - __u32 len; - __u32 reserved[4]; /* will stay unused for compatibility reasons */ -}; - -Userspace passes in the above struct and for each pending interrupt a -struct kvm_s390_irq is copied to the provided buffer. - -The structure contains a flags and a reserved field for future extensions. As -the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and -reserved, these fields can not be used in the future without breaking -compatibility. - -If -ENOBUFS is returned the buffer provided was too small and userspace -may retry with a bigger buffer. - -4.95 KVM_S390_SET_IRQ_STATE - -Capability: KVM_CAP_S390_IRQ_STATE -Architectures: s390 -Type: vcpu ioctl -Parameters: struct kvm_s390_irq_state (in) -Returns: 0 on success, - -EFAULT if the buffer address was invalid, - -EINVAL for an invalid buffer length (see below), - -EBUSY if there were already interrupts pending, - errors occurring when actually injecting the - interrupt. See KVM_S390_IRQ. - -This ioctl allows userspace to set the complete state of all cpu-local -interrupts currently pending for the vcpu. It is intended for restoring -interrupt state after a migration. The input parameter is a userspace buffer -containing a struct kvm_s390_irq_state: - -struct kvm_s390_irq_state { - __u64 buf; - __u32 flags; /* will stay unused for compatibility reasons */ - __u32 len; - __u32 reserved[4]; /* will stay unused for compatibility reasons */ -}; - -The restrictions for flags and reserved apply as well. -(see KVM_S390_GET_IRQ_STATE) - -The userspace memory referenced by buf contains a struct kvm_s390_irq -for each interrupt to be injected into the guest. -If one of the interrupts could not be injected for some reason the -ioctl aborts. - -len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0 -and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq), -which is the maximum number of possibly pending cpu-local interrupts. - -4.96 KVM_SMI - -Capability: KVM_CAP_X86_SMM -Architectures: x86 -Type: vcpu ioctl -Parameters: none -Returns: 0 on success, -1 on error - -Queues an SMI on the thread's vcpu. - -4.97 KVM_CAP_PPC_MULTITCE - -Capability: KVM_CAP_PPC_MULTITCE -Architectures: ppc -Type: vm - -This capability means the kernel is capable of handling hypercalls -H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user -space. This significantly accelerates DMA operations for PPC KVM guests. -User space should expect that its handlers for these hypercalls -are not going to be called if user space previously registered LIOBN -in KVM (via KVM_CREATE_SPAPR_TCE or similar calls). - -In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest, -user space might have to advertise it for the guest. For example, -IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is -present in the "ibm,hypertas-functions" device-tree property. - -The hypercalls mentioned above may or may not be processed successfully -in the kernel based fast path. If they can not be handled by the kernel, -they will get passed on to user space. So user space still has to have -an implementation for these despite the in kernel acceleration. - -This capability is always enabled. - -4.98 KVM_CREATE_SPAPR_TCE_64 - -Capability: KVM_CAP_SPAPR_TCE_64 -Architectures: powerpc -Type: vm ioctl -Parameters: struct kvm_create_spapr_tce_64 (in) -Returns: file descriptor for manipulating the created TCE table - -This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit -windows, described in 4.62 KVM_CREATE_SPAPR_TCE - -This capability uses extended struct in ioctl interface: - -/* for KVM_CAP_SPAPR_TCE_64 */ -struct kvm_create_spapr_tce_64 { - __u64 liobn; - __u32 page_shift; - __u32 flags; - __u64 offset; /* in pages */ - __u64 size; /* in pages */ -}; - -The aim of extension is to support an additional bigger DMA window with -a variable page size. -KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and -a bus offset of the corresponding DMA window, @size and @offset are numbers -of IOMMU pages. - -@flags are not used at the moment. - -The rest of functionality is identical to KVM_CREATE_SPAPR_TCE. - -4.99 KVM_REINJECT_CONTROL - -Capability: KVM_CAP_REINJECT_CONTROL -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_reinject_control (in) -Returns: 0 on success, - -EFAULT if struct kvm_reinject_control cannot be read, - -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier. - -i8254 (PIT) has two modes, reinject and !reinject. The default is reinject, -where KVM queues elapsed i8254 ticks and monitors completion of interrupt from -vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its -interrupt whenever there isn't a pending interrupt from i8254. -!reinject mode injects an interrupt as soon as a tick arrives. - -struct kvm_reinject_control { - __u8 pit_reinject; - __u8 reserved[31]; -}; - -pit_reinject = 0 (!reinject mode) is recommended, unless running an old -operating system that uses the PIT for timing (e.g. Linux 2.4.x). - -4.100 KVM_PPC_CONFIGURE_V3_MMU - -Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3 -Architectures: ppc -Type: vm ioctl -Parameters: struct kvm_ppc_mmuv3_cfg (in) -Returns: 0 on success, - -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read, - -EINVAL if the configuration is invalid - -This ioctl controls whether the guest will use radix or HPT (hashed -page table) translation, and sets the pointer to the process table for -the guest. - -struct kvm_ppc_mmuv3_cfg { - __u64 flags; - __u64 process_table; -}; - -There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and -KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest -to use radix tree translation, and if clear, to use HPT translation. -KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest -to be able to use the global TLB and SLB invalidation instructions; -if clear, the guest may not use these instructions. - -The process_table field specifies the address and size of the guest -process table, which is in the guest's space. This field is formatted -as the second doubleword of the partition table entry, as defined in -the Power ISA V3.00, Book III section 5.7.6.1. - -4.101 KVM_PPC_GET_RMMU_INFO - -Capability: KVM_CAP_PPC_RADIX_MMU -Architectures: ppc -Type: vm ioctl -Parameters: struct kvm_ppc_rmmu_info (out) -Returns: 0 on success, - -EFAULT if struct kvm_ppc_rmmu_info cannot be written, - -EINVAL if no useful information can be returned - -This ioctl returns a structure containing two things: (a) a list -containing supported radix tree geometries, and (b) a list that maps -page sizes to put in the "AP" (actual page size) field for the tlbie -(TLB invalidate entry) instruction. - -struct kvm_ppc_rmmu_info { - struct kvm_ppc_radix_geom { - __u8 page_shift; - __u8 level_bits[4]; - __u8 pad[3]; - } geometries[8]; - __u32 ap_encodings[8]; -}; - -The geometries[] field gives up to 8 supported geometries for the -radix page table, in terms of the log base 2 of the smallest page -size, and the number of bits indexed at each level of the tree, from -the PTE level up to the PGD level in that order. Any unused entries -will have 0 in the page_shift field. - -The ap_encodings gives the supported page sizes and their AP field -encodings, encoded with the AP value in the top 3 bits and the log -base 2 of the page size in the bottom 6 bits. - -4.102 KVM_PPC_RESIZE_HPT_PREPARE - -Capability: KVM_CAP_SPAPR_RESIZE_HPT -Architectures: powerpc -Type: vm ioctl -Parameters: struct kvm_ppc_resize_hpt (in) -Returns: 0 on successful completion, - >0 if a new HPT is being prepared, the value is an estimated - number of milliseconds until preparation is complete - -EFAULT if struct kvm_reinject_control cannot be read, - -EINVAL if the supplied shift or flags are invalid - -ENOMEM if unable to allocate the new HPT - -ENOSPC if there was a hash collision when moving existing - HPT entries to the new HPT - -EIO on other error conditions - -Used to implement the PAPR extension for runtime resizing of a guest's -Hashed Page Table (HPT). Specifically this starts, stops or monitors -the preparation of a new potential HPT for the guest, essentially -implementing the H_RESIZE_HPT_PREPARE hypercall. - -If called with shift > 0 when there is no pending HPT for the guest, -this begins preparation of a new pending HPT of size 2^(shift) bytes. -It then returns a positive integer with the estimated number of -milliseconds until preparation is complete. - -If called when there is a pending HPT whose size does not match that -requested in the parameters, discards the existing pending HPT and -creates a new one as above. - -If called when there is a pending HPT of the size requested, will: - * If preparation of the pending HPT is already complete, return 0 - * If preparation of the pending HPT has failed, return an error - code, then discard the pending HPT. - * If preparation of the pending HPT is still in progress, return an - estimated number of milliseconds until preparation is complete. - -If called with shift == 0, discards any currently pending HPT and -returns 0 (i.e. cancels any in-progress preparation). - -flags is reserved for future expansion, currently setting any bits in -flags will result in an -EINVAL. - -Normally this will be called repeatedly with the same parameters until -it returns <= 0. The first call will initiate preparation, subsequent -ones will monitor preparation until it completes or fails. - -struct kvm_ppc_resize_hpt { - __u64 flags; - __u32 shift; - __u32 pad; -}; - -4.103 KVM_PPC_RESIZE_HPT_COMMIT - -Capability: KVM_CAP_SPAPR_RESIZE_HPT -Architectures: powerpc -Type: vm ioctl -Parameters: struct kvm_ppc_resize_hpt (in) -Returns: 0 on successful completion, - -EFAULT if struct kvm_reinject_control cannot be read, - -EINVAL if the supplied shift or flags are invalid - -ENXIO is there is no pending HPT, or the pending HPT doesn't - have the requested size - -EBUSY if the pending HPT is not fully prepared - -ENOSPC if there was a hash collision when moving existing - HPT entries to the new HPT - -EIO on other error conditions - -Used to implement the PAPR extension for runtime resizing of a guest's -Hashed Page Table (HPT). Specifically this requests that the guest be -transferred to working with the new HPT, essentially implementing the -H_RESIZE_HPT_COMMIT hypercall. - -This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has -returned 0 with the same parameters. In other cases -KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or --EBUSY, though others may be possible if the preparation was started, -but failed). - -This will have undefined effects on the guest if it has not already -placed itself in a quiescent state where no vcpu will make MMU enabled -memory accesses. - -On succsful completion, the pending HPT will become the guest's active -HPT and the previous HPT will be discarded. - -On failure, the guest will still be operating on its previous HPT. - -struct kvm_ppc_resize_hpt { - __u64 flags; - __u32 shift; - __u32 pad; -}; - -4.104 KVM_X86_GET_MCE_CAP_SUPPORTED - -Capability: KVM_CAP_MCE -Architectures: x86 -Type: system ioctl -Parameters: u64 mce_cap (out) -Returns: 0 on success, -1 on error - -Returns supported MCE capabilities. The u64 mce_cap parameter -has the same format as the MSR_IA32_MCG_CAP register. Supported -capabilities will have the corresponding bits set. - -4.105 KVM_X86_SETUP_MCE - -Capability: KVM_CAP_MCE -Architectures: x86 -Type: vcpu ioctl -Parameters: u64 mcg_cap (in) -Returns: 0 on success, - -EFAULT if u64 mcg_cap cannot be read, - -EINVAL if the requested number of banks is invalid, - -EINVAL if requested MCE capability is not supported. - -Initializes MCE support for use. The u64 mcg_cap parameter -has the same format as the MSR_IA32_MCG_CAP register and -specifies which capabilities should be enabled. The maximum -supported number of error-reporting banks can be retrieved when -checking for KVM_CAP_MCE. The supported capabilities can be -retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED. - -4.106 KVM_X86_SET_MCE - -Capability: KVM_CAP_MCE -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_x86_mce (in) -Returns: 0 on success, - -EFAULT if struct kvm_x86_mce cannot be read, - -EINVAL if the bank number is invalid, - -EINVAL if VAL bit is not set in status field. - -Inject a machine check error (MCE) into the guest. The input -parameter is: - -struct kvm_x86_mce { - __u64 status; - __u64 addr; - __u64 misc; - __u64 mcg_status; - __u8 bank; - __u8 pad1[7]; - __u64 pad2[3]; -}; - -If the MCE being reported is an uncorrected error, KVM will -inject it as an MCE exception into the guest. If the guest -MCG_STATUS register reports that an MCE is in progress, KVM -causes an KVM_EXIT_SHUTDOWN vmexit. - -Otherwise, if the MCE is a corrected error, KVM will just -store it in the corresponding bank (provided this bank is -not holding a previously reported uncorrected error). - -4.107 KVM_S390_GET_CMMA_BITS - -Capability: KVM_CAP_S390_CMMA_MIGRATION -Architectures: s390 -Type: vm ioctl -Parameters: struct kvm_s390_cmma_log (in, out) -Returns: 0 on success, a negative value on error - -This ioctl is used to get the values of the CMMA bits on the s390 -architecture. It is meant to be used in two scenarios: -- During live migration to save the CMMA values. Live migration needs - to be enabled via the KVM_REQ_START_MIGRATION VM property. -- To non-destructively peek at the CMMA values, with the flag - KVM_S390_CMMA_PEEK set. - -The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired -values are written to a buffer whose location is indicated via the "values" -member in the kvm_s390_cmma_log struct. The values in the input struct are -also updated as needed. -Each CMMA value takes up one byte. - -struct kvm_s390_cmma_log { - __u64 start_gfn; - __u32 count; - __u32 flags; - union { - __u64 remaining; - __u64 mask; - }; - __u64 values; -}; - -start_gfn is the number of the first guest frame whose CMMA values are -to be retrieved, - -count is the length of the buffer in bytes, - -values points to the buffer where the result will be written to. - -If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be -KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with -other ioctls. - -The result is written in the buffer pointed to by the field values, and -the values of the input parameter are updated as follows. - -Depending on the flags, different actions are performed. The only -supported flag so far is KVM_S390_CMMA_PEEK. - -The default behaviour if KVM_S390_CMMA_PEEK is not set is: -start_gfn will indicate the first page frame whose CMMA bits were dirty. -It is not necessarily the same as the one passed as input, as clean pages -are skipped. - -count will indicate the number of bytes actually written in the buffer. -It can (and very often will) be smaller than the input value, since the -buffer is only filled until 16 bytes of clean values are found (which -are then not copied in the buffer). Since a CMMA migration block needs -the base address and the length, for a total of 16 bytes, we will send -back some clean data if there is some dirty data afterwards, as long as -the size of the clean data does not exceed the size of the header. This -allows to minimize the amount of data to be saved or transferred over -the network at the expense of more roundtrips to userspace. The next -invocation of the ioctl will skip over all the clean values, saving -potentially more than just the 16 bytes we found. - -If KVM_S390_CMMA_PEEK is set: -the existing storage attributes are read even when not in migration -mode, and no other action is performed; - -the output start_gfn will be equal to the input start_gfn, - -the output count will be equal to the input count, except if the end of -memory has been reached. - -In both cases: -the field "remaining" will indicate the total number of dirty CMMA values -still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is -not enabled. - -mask is unused. - -values points to the userspace buffer where the result will be stored. - -This ioctl can fail with -ENOMEM if not enough memory can be allocated to -complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if -KVM_S390_CMMA_PEEK is not set but migration mode was not enabled, with --EFAULT if the userspace address is invalid or if no page table is -present for the addresses (e.g. when using hugepages). - -4.108 KVM_S390_SET_CMMA_BITS - -Capability: KVM_CAP_S390_CMMA_MIGRATION -Architectures: s390 -Type: vm ioctl -Parameters: struct kvm_s390_cmma_log (in) -Returns: 0 on success, a negative value on error - -This ioctl is used to set the values of the CMMA bits on the s390 -architecture. It is meant to be used during live migration to restore -the CMMA values, but there are no restrictions on its use. -The ioctl takes parameters via the kvm_s390_cmma_values struct. -Each CMMA value takes up one byte. - -struct kvm_s390_cmma_log { - __u64 start_gfn; - __u32 count; - __u32 flags; - union { - __u64 remaining; - __u64 mask; - }; - __u64 values; -}; - -start_gfn indicates the starting guest frame number, - -count indicates how many values are to be considered in the buffer, - -flags is not used and must be 0. - -mask indicates which PGSTE bits are to be considered. - -remaining is not used. - -values points to the buffer in userspace where to store the values. - -This ioctl can fail with -ENOMEM if not enough memory can be allocated to -complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if -the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or -if the flags field was not 0, with -EFAULT if the userspace address is -invalid, if invalid pages are written to (e.g. after the end of memory) -or if no page table is present for the addresses (e.g. when using -hugepages). - -4.109 KVM_PPC_GET_CPU_CHAR - -Capability: KVM_CAP_PPC_GET_CPU_CHAR -Architectures: powerpc -Type: vm ioctl -Parameters: struct kvm_ppc_cpu_char (out) -Returns: 0 on successful completion - -EFAULT if struct kvm_ppc_cpu_char cannot be written - -This ioctl gives userspace information about certain characteristics -of the CPU relating to speculative execution of instructions and -possible information leakage resulting from speculative execution (see -CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is -returned in struct kvm_ppc_cpu_char, which looks like this: - -struct kvm_ppc_cpu_char { - __u64 character; /* characteristics of the CPU */ - __u64 behaviour; /* recommended software behaviour */ - __u64 character_mask; /* valid bits in character */ - __u64 behaviour_mask; /* valid bits in behaviour */ -}; - -For extensibility, the character_mask and behaviour_mask fields -indicate which bits of character and behaviour have been filled in by -the kernel. If the set of defined bits is extended in future then -userspace will be able to tell whether it is running on a kernel that -knows about the new bits. - -The character field describes attributes of the CPU which can help -with preventing inadvertent information disclosure - specifically, -whether there is an instruction to flash-invalidate the L1 data cache -(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set -to a mode where entries can only be used by the thread that created -them, whether the bcctr[l] instruction prevents speculation, and -whether a speculation barrier instruction (ori 31,31,0) is provided. - -The behaviour field describes actions that software should take to -prevent inadvertent information disclosure, and thus describes which -vulnerabilities the hardware is subject to; specifically whether the -L1 data cache should be flushed when returning to user mode from the -kernel, and whether a speculation barrier should be placed between an -array bounds check and the array access. - -These fields use the same bit definitions as the new -H_GET_CPU_CHARACTERISTICS hypercall. - -4.110 KVM_MEMORY_ENCRYPT_OP - -Capability: basic -Architectures: x86 -Type: system -Parameters: an opaque platform specific structure (in/out) -Returns: 0 on success; -1 on error - -If the platform supports creating encrypted VMs then this ioctl can be used -for issuing platform-specific memory encryption commands to manage those -encrypted VMs. - -Currently, this ioctl is used for issuing Secure Encrypted Virtualization -(SEV) commands on AMD Processors. The SEV commands are defined in -Documentation/virtual/kvm/amd-memory-encryption.rst. - -4.111 KVM_MEMORY_ENCRYPT_REG_REGION - -Capability: basic -Architectures: x86 -Type: system -Parameters: struct kvm_enc_region (in) -Returns: 0 on success; -1 on error - -This ioctl can be used to register a guest memory region which may -contain encrypted data (e.g. guest RAM, SMRAM etc). - -It is used in the SEV-enabled guest. When encryption is enabled, a guest -memory region may contain encrypted data. The SEV memory encryption -engine uses a tweak such that two identical plaintext pages, each at -different locations will have differing ciphertexts. So swapping or -moving ciphertext of those pages will not result in plaintext being -swapped. So relocating (or migrating) physical backing pages for the SEV -guest will require some additional steps. - -Note: The current SEV key management spec does not provide commands to -swap or migrate (move) ciphertext pages. Hence, for now we pin the guest -memory region registered with the ioctl. - -4.112 KVM_MEMORY_ENCRYPT_UNREG_REGION - -Capability: basic -Architectures: x86 -Type: system -Parameters: struct kvm_enc_region (in) -Returns: 0 on success; -1 on error - -This ioctl can be used to unregister the guest memory region registered -with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above. - -4.113 KVM_HYPERV_EVENTFD - -Capability: KVM_CAP_HYPERV_EVENTFD -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_hyperv_eventfd (in) - -This ioctl (un)registers an eventfd to receive notifications from the guest on -the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without -causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number -(bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit. - -struct kvm_hyperv_eventfd { - __u32 conn_id; - __s32 fd; - __u32 flags; - __u32 padding[3]; -}; - -The conn_id field should fit within 24 bits: - -#define KVM_HYPERV_CONN_ID_MASK 0x00ffffff - -The acceptable values for the flags field are: - -#define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) - -Returns: 0 on success, - -EINVAL if conn_id or flags is outside the allowed range - -ENOENT on deassign if the conn_id isn't registered - -EEXIST on assign if the conn_id is already registered - -4.114 KVM_GET_NESTED_STATE - -Capability: KVM_CAP_NESTED_STATE -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_nested_state (in/out) -Returns: 0 on success, -1 on error -Errors: - E2BIG: the total state size exceeds the value of 'size' specified by - the user; the size required will be written into size. - -struct kvm_nested_state { - __u16 flags; - __u16 format; - __u32 size; - - union { - struct kvm_vmx_nested_state_hdr vmx; - struct kvm_svm_nested_state_hdr svm; - - /* Pad the header to 128 bytes. */ - __u8 pad[120]; - } hdr; - - union { - struct kvm_vmx_nested_state_data vmx[0]; - struct kvm_svm_nested_state_data svm[0]; - } data; -}; - -#define KVM_STATE_NESTED_GUEST_MODE 0x00000001 -#define KVM_STATE_NESTED_RUN_PENDING 0x00000002 -#define KVM_STATE_NESTED_EVMCS 0x00000004 - -#define KVM_STATE_NESTED_FORMAT_VMX 0 -#define KVM_STATE_NESTED_FORMAT_SVM 1 - -#define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000 - -#define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001 -#define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002 - -struct kvm_vmx_nested_state_hdr { - __u64 vmxon_pa; - __u64 vmcs12_pa; - - struct { - __u16 flags; - } smm; -}; - -struct kvm_vmx_nested_state_data { - __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; - __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; -}; - -This ioctl copies the vcpu's nested virtualization state from the kernel to -userspace. - -The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE -to the KVM_CHECK_EXTENSION ioctl(). - -4.115 KVM_SET_NESTED_STATE - -Capability: KVM_CAP_NESTED_STATE -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_nested_state (in) -Returns: 0 on success, -1 on error - -This copies the vcpu's kvm_nested_state struct from userspace to the kernel. -For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE. - -4.116 KVM_(UN)REGISTER_COALESCED_MMIO - -Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio) - KVM_CAP_COALESCED_PIO (for coalesced pio) -Architectures: all -Type: vm ioctl -Parameters: struct kvm_coalesced_mmio_zone -Returns: 0 on success, < 0 on error - -Coalesced I/O is a performance optimization that defers hardware -register write emulation so that userspace exits are avoided. It is -typically used to reduce the overhead of emulating frequently accessed -hardware registers. - -When a hardware register is configured for coalesced I/O, write accesses -do not exit to userspace and their value is recorded in a ring buffer -that is shared between kernel and userspace. - -Coalesced I/O is used if one or more write accesses to a hardware -register can be deferred until a read or a write to another hardware -register on the same device. This last access will cause a vmexit and -userspace will process accesses from the ring buffer before emulating -it. That will avoid exiting to userspace on repeated writes. - -Coalesced pio is based on coalesced mmio. There is little difference -between coalesced mmio and pio except that coalesced pio records accesses -to I/O ports. - -4.117 KVM_CLEAR_DIRTY_LOG (vm ioctl) - -Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 -Architectures: x86, arm, arm64, mips -Type: vm ioctl -Parameters: struct kvm_dirty_log (in) -Returns: 0 on success, -1 on error - -/* for KVM_CLEAR_DIRTY_LOG */ -struct kvm_clear_dirty_log { - __u32 slot; - __u32 num_pages; - __u64 first_page; - union { - void __user *dirty_bitmap; /* one bit per page */ - __u64 padding; - }; -}; - -The ioctl clears the dirty status of pages in a memory slot, according to -the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap -field. Bit 0 of the bitmap corresponds to page "first_page" in the -memory slot, and num_pages is the size in bits of the input bitmap. -first_page must be a multiple of 64; num_pages must also be a multiple of -64 unless first_page + num_pages is the size of the memory slot. For each -bit that is set in the input bitmap, the corresponding page is marked "clean" -in KVM's dirty bitmap, and dirty tracking is re-enabled for that page -(for example via write-protection, or by clearing the dirty bit in -a page table entry). - -If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 specifies -the address space for which you want to return the dirty bitmap. -They must be less than the value that KVM_CHECK_EXTENSION returns for -the KVM_CAP_MULTI_ADDRESS_SPACE capability. - -This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 -is enabled; for more information, see the description of the capability. -However, it can always be used as long as KVM_CHECK_EXTENSION confirms -that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. - -4.118 KVM_GET_SUPPORTED_HV_CPUID - -Capability: KVM_CAP_HYPERV_CPUID -Architectures: x86 -Type: vcpu ioctl -Parameters: struct kvm_cpuid2 (in/out) -Returns: 0 on success, -1 on error - -struct kvm_cpuid2 { - __u32 nent; - __u32 padding; - struct kvm_cpuid_entry2 entries[0]; -}; - -struct kvm_cpuid_entry2 { - __u32 function; - __u32 index; - __u32 flags; - __u32 eax; - __u32 ebx; - __u32 ecx; - __u32 edx; - __u32 padding[3]; -}; - -This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in -KVM. Userspace can use the information returned by this ioctl to construct -cpuid information presented to guests consuming Hyper-V enlightenments (e.g. -Windows or Hyper-V guests). - -CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level -Functional Specification (TLFS). These leaves can't be obtained with -KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature -leaves (0x40000000, 0x40000001). - -Currently, the following list of CPUID leaves are returned: - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS - HYPERV_CPUID_INTERFACE - HYPERV_CPUID_VERSION - HYPERV_CPUID_FEATURES - HYPERV_CPUID_ENLIGHTMENT_INFO - HYPERV_CPUID_IMPLEMENT_LIMITS - HYPERV_CPUID_NESTED_FEATURES - -HYPERV_CPUID_NESTED_FEATURES leaf is only exposed when Enlightened VMCS was -enabled on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). - -Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure -with the 'nent' field indicating the number of entries in the variable-size -array 'entries'. If the number of entries is too low to describe all Hyper-V -feature leaves, an error (E2BIG) is returned. If the number is more or equal -to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the -number of valid entries in the 'entries' array, which is then filled. - -'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, -userspace should not expect to get any particular value there. - -4.119 KVM_ARM_VCPU_FINALIZE - -Architectures: arm, arm64 -Type: vcpu ioctl -Parameters: int feature (in) -Returns: 0 on success, -1 on error -Errors: - EPERM: feature not enabled, needs configuration, or already finalized - EINVAL: feature unknown or not present - -Recognised values for feature: - arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE) - -Finalizes the configuration of the specified vcpu feature. - -The vcpu must already have been initialised, enabling the affected feature, by -means of a successful KVM_ARM_VCPU_INIT call with the appropriate flag set in -features[]. - -For affected vcpu features, this is a mandatory step that must be performed -before the vcpu is fully usable. - -Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be -configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration -that should be performaned and how to do it are feature-dependent. - -Other calls that depend on a particular feature being finalized, such as -KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with --EPERM unless the feature has already been finalized by means of a -KVM_ARM_VCPU_FINALIZE call. - -See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization -using this ioctl. - -4.120 KVM_SET_PMU_EVENT_FILTER - -Capability: KVM_CAP_PMU_EVENT_FILTER -Architectures: x86 -Type: vm ioctl -Parameters: struct kvm_pmu_event_filter (in) -Returns: 0 on success, -1 on error - -struct kvm_pmu_event_filter { - __u32 action; - __u32 nevents; - __u32 fixed_counter_bitmap; - __u32 flags; - __u32 pad[4]; - __u64 events[0]; -}; - -This ioctl restricts the set of PMU events that the guest can program. -The argument holds a list of events which will be allowed or denied. -The eventsel+umask of each event the guest attempts to program is compared -against the events field to determine whether the guest should have access. -The events field only controls general purpose counters; fixed purpose -counters are controlled by the fixed_counter_bitmap. - -No flags are defined yet, the field must be zero. - -Valid values for 'action': -#define KVM_PMU_EVENT_ALLOW 0 -#define KVM_PMU_EVENT_DENY 1 - - -5. The kvm_run structure ------------------------- - -Application code obtains a pointer to the kvm_run structure by -mmap()ing a vcpu fd. From that point, application code can control -execution by changing fields in kvm_run prior to calling the KVM_RUN -ioctl, and obtain information about the reason KVM_RUN returned by -looking up structure members. - -struct kvm_run { - /* in */ - __u8 request_interrupt_window; - -Request that KVM_RUN return when it becomes possible to inject external -interrupts into the guest. Useful in conjunction with KVM_INTERRUPT. - - __u8 immediate_exit; - -This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN -exits immediately, returning -EINTR. In the common scenario where a -signal is used to "kick" a VCPU out of KVM_RUN, this field can be used -to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability. -Rather than blocking the signal outside KVM_RUN, userspace can set up -a signal handler that sets run->immediate_exit to a non-zero value. - -This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available. - - __u8 padding1[6]; - - /* out */ - __u32 exit_reason; - -When KVM_RUN has returned successfully (return value 0), this informs -application code why KVM_RUN has returned. Allowable values for this -field are detailed below. - - __u8 ready_for_interrupt_injection; - -If request_interrupt_window has been specified, this field indicates -an interrupt can be injected now with KVM_INTERRUPT. - - __u8 if_flag; - -The value of the current interrupt flag. Only valid if in-kernel -local APIC is not used. - - __u16 flags; - -More architecture-specific flags detailing state of the VCPU that may -affect the device's behavior. The only currently defined flag is -KVM_RUN_X86_SMM, which is valid on x86 machines and is set if the -VCPU is in system management mode. - - /* in (pre_kvm_run), out (post_kvm_run) */ - __u64 cr8; - -The value of the cr8 register. Only valid if in-kernel local APIC is -not used. Both input and output. - - __u64 apic_base; - -The value of the APIC BASE msr. Only valid if in-kernel local -APIC is not used. Both input and output. - - union { - /* KVM_EXIT_UNKNOWN */ - struct { - __u64 hardware_exit_reason; - } hw; - -If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown -reasons. Further architecture-specific information is available in -hardware_exit_reason. - - /* KVM_EXIT_FAIL_ENTRY */ - struct { - __u64 hardware_entry_failure_reason; - } fail_entry; - -If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due -to unknown reasons. Further architecture-specific information is -available in hardware_entry_failure_reason. - - /* KVM_EXIT_EXCEPTION */ - struct { - __u32 exception; - __u32 error_code; - } ex; - -Unused. - - /* KVM_EXIT_IO */ - struct { -#define KVM_EXIT_IO_IN 0 -#define KVM_EXIT_IO_OUT 1 - __u8 direction; - __u8 size; /* bytes */ - __u16 port; - __u32 count; - __u64 data_offset; /* relative to kvm_run start */ - } io; - -If exit_reason is KVM_EXIT_IO, then the vcpu has -executed a port I/O instruction which could not be satisfied by kvm. -data_offset describes where the data is located (KVM_EXIT_IO_OUT) or -where kvm expects application code to place the data for the next -KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. - - /* KVM_EXIT_DEBUG */ - struct { - struct kvm_debug_exit_arch arch; - } debug; - -If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event -for which architecture specific information is returned. - - /* KVM_EXIT_MMIO */ - struct { - __u64 phys_addr; - __u8 data[8]; - __u32 len; - __u8 is_write; - } mmio; - -If exit_reason is KVM_EXIT_MMIO, then the vcpu has -executed a memory-mapped I/O instruction which could not be satisfied -by kvm. The 'data' member contains the written data if 'is_write' is -true, and should be filled by application code otherwise. - -The 'data' member contains, in its first 'len' bytes, the value as it would -appear if the VCPU performed a load or store of the appropriate width directly -to the byte array. - -NOTE: For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR and - KVM_EXIT_EPR the corresponding -operations are complete (and guest state is consistent) only after userspace -has re-entered the kernel with KVM_RUN. The kernel side will first finish -incomplete operations and then check for pending signals. Userspace -can re-enter the guest with an unmasked signal pending to complete -pending operations. - - /* KVM_EXIT_HYPERCALL */ - struct { - __u64 nr; - __u64 args[6]; - __u64 ret; - __u32 longmode; - __u32 pad; - } hypercall; - -Unused. This was once used for 'hypercall to userspace'. To implement -such functionality, use KVM_EXIT_IO (x86) or KVM_EXIT_MMIO (all except s390). -Note KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO. - - /* KVM_EXIT_TPR_ACCESS */ - struct { - __u64 rip; - __u32 is_write; - __u32 pad; - } tpr_access; - -To be documented (KVM_TPR_ACCESS_REPORTING). - - /* KVM_EXIT_S390_SIEIC */ - struct { - __u8 icptcode; - __u64 mask; /* psw upper half */ - __u64 addr; /* psw lower half */ - __u16 ipa; - __u32 ipb; - } s390_sieic; - -s390 specific. - - /* KVM_EXIT_S390_RESET */ -#define KVM_S390_RESET_POR 1 -#define KVM_S390_RESET_CLEAR 2 -#define KVM_S390_RESET_SUBSYSTEM 4 -#define KVM_S390_RESET_CPU_INIT 8 -#define KVM_S390_RESET_IPL 16 - __u64 s390_reset_flags; - -s390 specific. - - /* KVM_EXIT_S390_UCONTROL */ - struct { - __u64 trans_exc_code; - __u32 pgm_code; - } s390_ucontrol; - -s390 specific. A page fault has occurred for a user controlled virtual -machine (KVM_VM_S390_UNCONTROL) on it's host page table that cannot be -resolved by the kernel. -The program code and the translation exception code that were placed -in the cpu's lowcore are presented here as defined by the z Architecture -Principles of Operation Book in the Chapter for Dynamic Address Translation -(DAT) - - /* KVM_EXIT_DCR */ - struct { - __u32 dcrn; - __u32 data; - __u8 is_write; - } dcr; - -Deprecated - was used for 440 KVM. - - /* KVM_EXIT_OSI */ - struct { - __u64 gprs[32]; - } osi; - -MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch -hypercalls and exit with this exit struct that contains all the guest gprs. - -If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall. -Userspace can now handle the hypercall and when it's done modify the gprs as -necessary. Upon guest entry all guest GPRs will then be replaced by the values -in this struct. - - /* KVM_EXIT_PAPR_HCALL */ - struct { - __u64 nr; - __u64 ret; - __u64 args[9]; - } papr_hcall; - -This is used on 64-bit PowerPC when emulating a pSeries partition, -e.g. with the 'pseries' machine type in qemu. It occurs when the -guest does a hypercall using the 'sc 1' instruction. The 'nr' field -contains the hypercall number (from the guest R3), and 'args' contains -the arguments (from the guest R4 - R12). Userspace should put the -return code in 'ret' and any extra returned values in args[]. -The possible hypercalls are defined in the Power Architecture Platform -Requirements (PAPR) document available from www.power.org (free -developer registration required to access it). - - /* KVM_EXIT_S390_TSCH */ - struct { - __u16 subchannel_id; - __u16 subchannel_nr; - __u32 io_int_parm; - __u32 io_int_word; - __u32 ipb; - __u8 dequeued; - } s390_tsch; - -s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled -and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O -interrupt for the target subchannel has been dequeued and subchannel_id, -subchannel_nr, io_int_parm and io_int_word contain the parameters for that -interrupt. ipb is needed for instruction parameter decoding. - - /* KVM_EXIT_EPR */ - struct { - __u32 epr; - } epr; - -On FSL BookE PowerPC chips, the interrupt controller has a fast patch -interrupt acknowledge path to the core. When the core successfully -delivers an interrupt, it automatically populates the EPR register with -the interrupt vector number and acknowledges the interrupt inside -the interrupt controller. - -In case the interrupt controller lives in user space, we need to do -the interrupt acknowledge cycle through it to fetch the next to be -delivered interrupt vector using this exit. - -It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an -external interrupt has just been delivered into the guest. User space -should put the acknowledged interrupt vector into the 'epr' field. - - /* KVM_EXIT_SYSTEM_EVENT */ - struct { -#define KVM_SYSTEM_EVENT_SHUTDOWN 1 -#define KVM_SYSTEM_EVENT_RESET 2 -#define KVM_SYSTEM_EVENT_CRASH 3 - __u32 type; - __u64 flags; - } system_event; - -If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered -a system-level event using some architecture specific mechanism (hypercall -or some special instruction). In case of ARM/ARM64, this is triggered using -HVC instruction based PSCI call from the vcpu. The 'type' field describes -the system-level event type. The 'flags' field describes architecture -specific flags for the system-level event. - -Valid values for 'type' are: - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the - VM. Userspace is not obliged to honour this, and if it does honour - this does not need to destroy the VM synchronously (ie it may call - KVM_RUN again before shutdown finally occurs). - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. - As with SHUTDOWN, userspace can choose to ignore the request, or - to schedule the reset to occur in the future and may call KVM_RUN again. - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest - has requested a crash condition maintenance. Userspace can choose - to ignore the request, or to gather VM memory core dump and/or - reset/shutdown of the VM. - - /* KVM_EXIT_IOAPIC_EOI */ - struct { - __u8 vector; - } eoi; - -Indicates that the VCPU's in-kernel local APIC received an EOI for a -level-triggered IOAPIC interrupt. This exit only triggers when the -IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled); -the userspace IOAPIC should process the EOI and retrigger the interrupt if -it is still asserted. Vector is the LAPIC interrupt vector for which the -EOI was received. - - struct kvm_hyperv_exit { -#define KVM_EXIT_HYPERV_SYNIC 1 -#define KVM_EXIT_HYPERV_HCALL 2 - __u32 type; - union { - struct { - __u32 msr; - __u64 control; - __u64 evt_page; - __u64 msg_page; - } synic; - struct { - __u64 input; - __u64 result; - __u64 params[2]; - } hcall; - } u; - }; - /* KVM_EXIT_HYPERV */ - struct kvm_hyperv_exit hyperv; -Indicates that the VCPU exits into userspace to process some tasks -related to Hyper-V emulation. -Valid values for 'type' are: - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about -Hyper-V SynIC state change. Notification is used to remap SynIC -event/message pages and to enable/disable SynIC messages/events processing -in userspace. - - /* Fix the size of the union. */ - char padding[256]; - }; - - /* - * shared registers between kvm and userspace. - * kvm_valid_regs specifies the register classes set by the host - * kvm_dirty_regs specified the register classes dirtied by userspace - * struct kvm_sync_regs is architecture specific, as well as the - * bits for kvm_valid_regs and kvm_dirty_regs - */ - __u64 kvm_valid_regs; - __u64 kvm_dirty_regs; - union { - struct kvm_sync_regs regs; - char padding[SYNC_REGS_SIZE_BYTES]; - } s; - -If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access -certain guest registers without having to call SET/GET_*REGS. Thus we can -avoid some system call overhead if userspace has to handle the exit. -Userspace can query the validity of the structure by checking -kvm_valid_regs for specific bits. These bits are architecture specific -and usually define the validity of a groups of registers. (e.g. one bit - for general purpose registers) - -Please note that the kernel is allowed to use the kvm_run structure as the -primary storage for certain register types. Therefore, the kernel may use the -values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set. - -}; - - - -6. Capabilities that can be enabled on vCPUs --------------------------------------------- - -There are certain capabilities that change the behavior of the virtual CPU or -the virtual machine when enabled. To enable them, please see section 4.37. -Below you can find a list of capabilities and what their effect on the vCPU or -the virtual machine is when enabling them. - -The following information is provided along with the description: - - Architectures: which instruction set architectures provide this ioctl. - x86 includes both i386 and x86_64. - - Target: whether this is a per-vcpu or per-vm capability. - - Parameters: what parameters are accepted by the capability. - - Returns: the return value. General error numbers (EBADF, ENOMEM, EINVAL) - are not detailed, but errors with specific meanings are. - - -6.1 KVM_CAP_PPC_OSI - -Architectures: ppc -Target: vcpu -Parameters: none -Returns: 0 on success; -1 on error - -This capability enables interception of OSI hypercalls that otherwise would -be treated as normal system calls to be injected into the guest. OSI hypercalls -were invented by Mac-on-Linux to have a standardized communication mechanism -between the guest and the host. - -When this capability is enabled, KVM_EXIT_OSI can occur. - - -6.2 KVM_CAP_PPC_PAPR - -Architectures: ppc -Target: vcpu -Parameters: none -Returns: 0 on success; -1 on error - -This capability enables interception of PAPR hypercalls. PAPR hypercalls are -done using the hypercall instruction "sc 1". - -It also sets the guest privilege level to "supervisor" mode. Usually the guest -runs in "hypervisor" privilege mode with a few missing features. - -In addition to the above, it changes the semantics of SDR1. In this mode, the -HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the -HTAB invisible to the guest. - -When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. - - -6.3 KVM_CAP_SW_TLB - -Architectures: ppc -Target: vcpu -Parameters: args[0] is the address of a struct kvm_config_tlb -Returns: 0 on success; -1 on error - -struct kvm_config_tlb { - __u64 params; - __u64 array; - __u32 mmu_type; - __u32 array_len; -}; - -Configures the virtual CPU's TLB array, establishing a shared memory area -between userspace and KVM. The "params" and "array" fields are userspace -addresses of mmu-type-specific data structures. The "array_len" field is an -safety mechanism, and should be set to the size in bytes of the memory that -userspace has reserved for the array. It must be at least the size dictated -by "mmu_type" and "params". - -While KVM_RUN is active, the shared region is under control of KVM. Its -contents are undefined, and any modification by userspace results in -boundedly undefined behavior. - -On return from KVM_RUN, the shared region will reflect the current state of -the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB -to tell KVM which entries have been changed, prior to calling KVM_RUN again -on this vcpu. - -For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV: - - The "params" field is of type "struct kvm_book3e_206_tlb_params". - - The "array" field points to an array of type "struct - kvm_book3e_206_tlb_entry". - - The array consists of all entries in the first TLB, followed by all - entries in the second TLB. - - Within a TLB, entries are ordered first by increasing set number. Within a - set, entries are ordered by way (increasing ESEL). - - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1) - where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value. - - The tsize field of mas1 shall be set to 4K on TLB0, even though the - hardware ignores this value for TLB0. - -6.4 KVM_CAP_S390_CSS_SUPPORT - -Architectures: s390 -Target: vcpu -Parameters: none -Returns: 0 on success; -1 on error - -This capability enables support for handling of channel I/O instructions. - -TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are -handled in-kernel, while the other I/O instructions are passed to userspace. - -When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST -SUBCHANNEL intercepts. - -Note that even though this capability is enabled per-vcpu, the complete -virtual machine is affected. - -6.5 KVM_CAP_PPC_EPR - -Architectures: ppc -Target: vcpu -Parameters: args[0] defines whether the proxy facility is active -Returns: 0 on success; -1 on error - -This capability enables or disables the delivery of interrupts through the -external proxy facility. - -When enabled (args[0] != 0), every time the guest gets an external interrupt -delivered, it automatically exits into user space with a KVM_EXIT_EPR exit -to receive the topmost interrupt vector. - -When disabled (args[0] == 0), behavior is as if this facility is unsupported. - -When this capability is enabled, KVM_EXIT_EPR can occur. - -6.6 KVM_CAP_IRQ_MPIC - -Architectures: ppc -Parameters: args[0] is the MPIC device fd - args[1] is the MPIC CPU number for this vcpu - -This capability connects the vcpu to an in-kernel MPIC device. - -6.7 KVM_CAP_IRQ_XICS - -Architectures: ppc -Target: vcpu -Parameters: args[0] is the XICS device fd - args[1] is the XICS CPU number (server ID) for this vcpu - -This capability connects the vcpu to an in-kernel XICS device. - -6.8 KVM_CAP_S390_IRQCHIP - -Architectures: s390 -Target: vm -Parameters: none - -This capability enables the in-kernel irqchip for s390. Please refer to -"4.24 KVM_CREATE_IRQCHIP" for details. - -6.9 KVM_CAP_MIPS_FPU - -Architectures: mips -Target: vcpu -Parameters: args[0] is reserved for future use (should be 0). - -This capability allows the use of the host Floating Point Unit by the guest. It -allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is -done the KVM_REG_MIPS_FPR_* and KVM_REG_MIPS_FCR_* registers can be accessed -(depending on the current guest FPU register mode), and the Status.FR, -Config5.FRE bits are accessible via the KVM API and also from the guest, -depending on them being supported by the FPU. - -6.10 KVM_CAP_MIPS_MSA - -Architectures: mips -Target: vcpu -Parameters: args[0] is reserved for future use (should be 0). - -This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. -It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. -Once this is done the KVM_REG_MIPS_VEC_* and KVM_REG_MIPS_MSA_* registers can be -accessed, and the Config5.MSAEn bit is accessible via the KVM API and also from -the guest. - -6.74 KVM_CAP_SYNC_REGS -Architectures: s390, x86 -Target: s390: always enabled, x86: vcpu -Parameters: none -Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register -sets are supported (bitfields defined in arch/x86/include/uapi/asm/kvm.h). - -As described above in the kvm_sync_regs struct info in section 5 (kvm_run): -KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers -without having to call SET/GET_*REGS". This reduces overhead by eliminating -repeated ioctl calls for setting and/or getting register values. This is -particularly important when userspace is making synchronous guest state -modifications, e.g. when emulating and/or intercepting instructions in -userspace. - -For s390 specifics, please refer to the source code. - -For x86: -- the register sets to be copied out to kvm_run are selectable - by userspace (rather that all sets being copied out for every exit). -- vcpu_events are available in addition to regs and sregs. - -For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to -function as an input bit-array field set by userspace to indicate the -specific register sets to be copied out on the next exit. - -To indicate when userspace has modified values that should be copied into -the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set. -This is done using the same bitflags as for the 'kvm_valid_regs' field. -If the dirty bit is not set, then the register set values will not be copied -into the vCPU even if they've been modified. - -Unused bitfields in the bitarrays must be set to zero. - -struct kvm_sync_regs { - struct kvm_regs regs; - struct kvm_sregs sregs; - struct kvm_vcpu_events events; -}; - -6.75 KVM_CAP_PPC_IRQ_XIVE - -Architectures: ppc -Target: vcpu -Parameters: args[0] is the XIVE device fd - args[1] is the XIVE CPU number (server ID) for this vcpu - -This capability connects the vcpu to an in-kernel XIVE device. - -7. Capabilities that can be enabled on VMs ------------------------------------------- - -There are certain capabilities that change the behavior of the virtual -machine when enabled. To enable them, please see section 4.37. Below -you can find a list of capabilities and what their effect on the VM -is when enabling them. - -The following information is provided along with the description: - - Architectures: which instruction set architectures provide this ioctl. - x86 includes both i386 and x86_64. - - Parameters: what parameters are accepted by the capability. - - Returns: the return value. General error numbers (EBADF, ENOMEM, EINVAL) - are not detailed, but errors with specific meanings are. - - -7.1 KVM_CAP_PPC_ENABLE_HCALL - -Architectures: ppc -Parameters: args[0] is the sPAPR hcall number - args[1] is 0 to disable, 1 to enable in-kernel handling - -This capability controls whether individual sPAPR hypercalls (hcalls) -get handled by the kernel or not. Enabling or disabling in-kernel -handling of an hcall is effective across the VM. On creation, an -initial set of hcalls are enabled for in-kernel handling, which -consists of those hcalls for which in-kernel handlers were implemented -before this capability was implemented. If disabled, the kernel will -not to attempt to handle the hcall, but will always exit to userspace -to handle it. Note that it may not make sense to enable some and -disable others of a group of related hcalls, but KVM does not prevent -userspace from doing that. - -If the hcall number specified is not one that has an in-kernel -implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL -error. - -7.2 KVM_CAP_S390_USER_SIGP - -Architectures: s390 -Parameters: none - -This capability controls which SIGP orders will be handled completely in user -space. With this capability enabled, all fast orders will be handled completely -in the kernel: -- SENSE -- SENSE RUNNING -- EXTERNAL CALL -- EMERGENCY SIGNAL -- CONDITIONAL EMERGENCY SIGNAL - -All other orders will be handled completely in user space. - -Only privileged operation exceptions will be checked for in the kernel (or even -in the hardware prior to interception). If this capability is not enabled, the -old way of handling SIGP orders is used (partially in kernel and user space). - -7.3 KVM_CAP_S390_VECTOR_REGISTERS - -Architectures: s390 -Parameters: none -Returns: 0 on success, negative value on error - -Allows use of the vector registers introduced with z13 processor, and -provides for the synchronization between host and user space. Will -return -EINVAL if the machine does not support vectors. - -7.4 KVM_CAP_S390_USER_STSI - -Architectures: s390 -Parameters: none - -This capability allows post-handlers for the STSI instruction. After -initial handling in the kernel, KVM exits to user space with -KVM_EXIT_S390_STSI to allow user space to insert further data. - -Before exiting to userspace, kvm handlers should fill in s390_stsi field of -vcpu->run: -struct { - __u64 addr; - __u8 ar; - __u8 reserved; - __u8 fc; - __u8 sel1; - __u16 sel2; -} s390_stsi; - -@addr - guest address of STSI SYSIB -@fc - function code -@sel1 - selector 1 -@sel2 - selector 2 -@ar - access register number - -KVM handlers should exit to userspace with rc = -EREMOTE. - -7.5 KVM_CAP_SPLIT_IRQCHIP - -Architectures: x86 -Parameters: args[0] - number of routes reserved for userspace IOAPICs -Returns: 0 on success, -1 on error - -Create a local apic for each processor in the kernel. This can be used -instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the -IOAPIC and PIC (and also the PIT, even though this has to be enabled -separately). - -This capability also enables in kernel routing of interrupt requests; -when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are -used in the IRQ routing table. The first args[0] MSI routes are reserved -for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes, -a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace. - -Fails if VCPU has already been created, or if the irqchip is already in the -kernel (i.e. KVM_CREATE_IRQCHIP has already been called). - -7.6 KVM_CAP_S390_RI - -Architectures: s390 -Parameters: none - -Allows use of runtime-instrumentation introduced with zEC12 processor. -Will return -EINVAL if the machine does not support runtime-instrumentation. -Will return -EBUSY if a VCPU has already been created. - -7.7 KVM_CAP_X2APIC_API - -Architectures: x86 -Parameters: args[0] - features that should be enabled -Returns: 0 on success, -EINVAL when args[0] contains invalid features - -Valid feature flags in args[0] are - -#define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) -#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) - -Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of -KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, -allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their -respective sections. - -KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work -in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff -as a broadcast even in x2APIC mode in order to support physical x2APIC -without interrupt remapping. This is undesirable in logical mode, -where 0xff represents CPUs 0-7 in cluster 0. - -7.8 KVM_CAP_S390_USER_INSTR0 - -Architectures: s390 -Parameters: none - -With this capability enabled, all illegal instructions 0x0000 (2 bytes) will -be intercepted and forwarded to user space. User space can use this -mechanism e.g. to realize 2-byte software breakpoints. The kernel will -not inject an operating exception for these instructions, user space has -to take care of that. - -This capability can be enabled dynamically even if VCPUs were already -created and are running. - -7.9 KVM_CAP_S390_GS - -Architectures: s390 -Parameters: none -Returns: 0 on success; -EINVAL if the machine does not support - guarded storage; -EBUSY if a VCPU has already been created. - -Allows use of guarded storage for the KVM guest. - -7.10 KVM_CAP_S390_AIS - -Architectures: s390 -Parameters: none - -Allow use of adapter-interruption suppression. -Returns: 0 on success; -EBUSY if a VCPU has already been created. - -7.11 KVM_CAP_PPC_SMT - -Architectures: ppc -Parameters: vsmt_mode, flags - -Enabling this capability on a VM provides userspace with a way to set -the desired virtual SMT mode (i.e. the number of virtual CPUs per -virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2 -between 1 and 8. On POWER8, vsmt_mode must also be no greater than -the number of threads per subcore for the host. Currently flags must -be 0. A successful call to enable this capability will result in -vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is -subsequently queried for the VM. This capability is only supported by -HV KVM, and can only be set before any VCPUs have been created. -The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT -modes are available. - -7.12 KVM_CAP_PPC_FWNMI - -Architectures: ppc -Parameters: none - -With this capability a machine check exception in the guest address -space will cause KVM to exit the guest with NMI exit reason. This -enables QEMU to build error log and branch to guest kernel registered -machine check handling routine. Without this capability KVM will -branch to guests' 0x200 interrupt vector. - -7.13 KVM_CAP_X86_DISABLE_EXITS - -Architectures: x86 -Parameters: args[0] defines which exits are disabled -Returns: 0 on success, -EINVAL when args[0] contains invalid exits - -Valid bits in args[0] are - -#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) -#define KVM_X86_DISABLE_EXITS_HLT (1 << 1) -#define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) -#define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3) - -Enabling this capability on a VM provides userspace with a way to no -longer intercept some instructions for improved latency in some -workloads, and is suggested when vCPUs are associated to dedicated -physical CPUs. More bits can be added in the future; userspace can -just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable -all such vmexits. - -Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. - -7.14 KVM_CAP_S390_HPAGE_1M - -Architectures: s390 -Parameters: none -Returns: 0 on success, -EINVAL if hpage module parameter was not set - or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL - flag set - -With this capability the KVM support for memory backing with 1m pages -through hugetlbfs can be enabled for a VM. After the capability is -enabled, cmma can't be enabled anymore and pfmfi and the storage key -interpretation are disabled. If cmma has already been enabled or the -hpage module parameter is not set to 1, -EINVAL is returned. - -While it is generally possible to create a huge page backed VM without -this capability, the VM will not be able to run. - -7.15 KVM_CAP_MSR_PLATFORM_INFO - -Architectures: x86 -Parameters: args[0] whether feature should be enabled or not - -With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise, -a #GP would be raised when the guest tries to access. Currently, this -capability does not enable write permissions of this MSR for the guest. - -7.16 KVM_CAP_PPC_NESTED_HV - -Architectures: ppc -Parameters: none -Returns: 0 on success, -EINVAL when the implementation doesn't support - nested-HV virtualization. - -HV-KVM on POWER9 and later systems allows for "nested-HV" -virtualization, which provides a way for a guest VM to run guests that -can run using the CPU's supervisor mode (privileged non-hypervisor -state). Enabling this capability on a VM depends on the CPU having -the necessary functionality and on the facility being enabled with a -kvm-hv module parameter. - -7.17 KVM_CAP_EXCEPTION_PAYLOAD - -Architectures: x86 -Parameters: args[0] whether feature should be enabled or not - -With this capability enabled, CR2 will not be modified prior to the -emulated VM-exit when L1 intercepts a #PF exception that occurs in -L2. Similarly, for kvm-intel only, DR6 will not be modified prior to -the emulated VM-exit when L1 intercepts a #DB exception that occurs in -L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or -#DB) exception for L2, exception.has_payload will be set and the -faulting address (or the new DR6 bits*) will be reported in the -exception_payload field. Similarly, when userspace injects a #PF (or -#DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set -exception.has_payload and to put the faulting address (or the new DR6 -bits*) in the exception_payload field. - -This capability also enables exception.pending in struct -kvm_vcpu_events, which allows userspace to distinguish between pending -and injected exceptions. - - -* For the new DR6 bits, note that bit 16 is set iff the #DB exception - will clear DR6.RTM. - -7.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 - -Architectures: x86, arm, arm64, mips -Parameters: args[0] whether feature should be enabled or not - -With this capability enabled, KVM_GET_DIRTY_LOG will not automatically -clear and write-protect all pages that are returned as dirty. -Rather, userspace will have to do this operation separately using -KVM_CLEAR_DIRTY_LOG. - -At the cost of a slightly more complicated operation, this provides better -scalability and responsiveness for two reasons. First, -KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather -than requiring to sync a full memslot; this ensures that KVM does not -take spinlocks for an extended period of time. Second, in some cases a -large amount of time can pass between a call to KVM_GET_DIRTY_LOG and -userspace actually using the data in the page. Pages can be modified -during this time, which is inefficint for both the guest and userspace: -the guest will incur a higher penalty due to write protection faults, -while userspace can see false reports of dirty pages. Manual reprotection -helps reducing this time, improving guest performance and reducing the -number of dirty log false positives. - -KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name -KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make -it hard or impossible to use it correctly. The availability of -KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed. -Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT. - -8. Other capabilities. ----------------------- - -This section lists capabilities that give information about other -features of the KVM implementation. - -8.1 KVM_CAP_PPC_HWRNG - -Architectures: ppc - -This capability, if KVM_CHECK_EXTENSION indicates that it is -available, means that that the kernel has an implementation of the -H_RANDOM hypercall backed by a hardware random-number generator. -If present, the kernel H_RANDOM handler can be enabled for guest use -with the KVM_CAP_PPC_ENABLE_HCALL capability. - -8.2 KVM_CAP_HYPERV_SYNIC - -Architectures: x86 -This capability, if KVM_CHECK_EXTENSION indicates that it is -available, means that that the kernel has an implementation of the -Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is -used to support Windows Hyper-V based guest paravirt drivers(VMBus). - -In order to use SynIC, it has to be activated by setting this -capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this -will disable the use of APIC hardware virtualization even if supported -by the CPU, as it's incompatible with SynIC auto-EOI behavior. - -8.3 KVM_CAP_PPC_RADIX_MMU - -Architectures: ppc - -This capability, if KVM_CHECK_EXTENSION indicates that it is -available, means that that the kernel can support guests using the -radix MMU defined in Power ISA V3.00 (as implemented in the POWER9 -processor). - -8.4 KVM_CAP_PPC_HASH_MMU_V3 - -Architectures: ppc - -This capability, if KVM_CHECK_EXTENSION indicates that it is -available, means that that the kernel can support guests using the -hashed page table MMU defined in Power ISA V3.00 (as implemented in -the POWER9 processor), including in-memory segment tables. - -8.5 KVM_CAP_MIPS_VZ - -Architectures: mips - -This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that -it is available, means that full hardware assisted virtualization capabilities -of the hardware are available for use through KVM. An appropriate -KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which -utilises it. - -If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is -available, it means that the VM is using full hardware assisted virtualization -capabilities of the hardware. This is useful to check after creating a VM with -KVM_VM_MIPS_DEFAULT. - -The value returned by KVM_CHECK_EXTENSION should be compared against known -values (see below). All other values are reserved. This is to allow for the -possibility of other hardware assisted virtualization implementations which -may be incompatible with the MIPS VZ ASE. - - 0: The trap & emulate implementation is in use to run guest code in user - mode. Guest virtual memory segments are rearranged to fit the guest in the - user mode address space. - - 1: The MIPS VZ ASE is in use, providing full hardware assisted - virtualization, including standard guest virtual memory segments. - -8.6 KVM_CAP_MIPS_TE - -Architectures: mips - -This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that -it is available, means that the trap & emulate implementation is available to -run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware -assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed -to KVM_CREATE_VM to create a VM which utilises it. - -If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is -available, it means that the VM is using trap & emulate. - -8.7 KVM_CAP_MIPS_64BIT - -Architectures: mips - -This capability indicates the supported architecture type of the guest, i.e. the -supported register and address width. - -The values returned when this capability is checked by KVM_CHECK_EXTENSION on a -kvm VM handle correspond roughly to the CP0_Config.AT register field, and should -be checked specifically against known values (see below). All other values are -reserved. - - 0: MIPS32 or microMIPS32. - Both registers and addresses are 32-bits wide. - It will only be possible to run 32-bit guest code. - - 1: MIPS64 or microMIPS64 with access only to 32-bit compatibility segments. - Registers are 64-bits wide, but addresses are 32-bits wide. - 64-bit guest code may run but cannot access MIPS64 memory segments. - It will also be possible to run 32-bit guest code. - - 2: MIPS64 or microMIPS64 with access to all address segments. - Both registers and addresses are 64-bits wide. - It will be possible to run 64-bit or 32-bit guest code. - -8.9 KVM_CAP_ARM_USER_IRQ - -Architectures: arm, arm64 -This capability, if KVM_CHECK_EXTENSION indicates that it is available, means -that if userspace creates a VM without an in-kernel interrupt controller, it -will be notified of changes to the output level of in-kernel emulated devices, -which can generate virtual interrupts, presented to the VM. -For such VMs, on every return to userspace, the kernel -updates the vcpu's run->s.regs.device_irq_level field to represent the actual -output level of the device. - -Whenever kvm detects a change in the device output level, kvm guarantees at -least one return to userspace before running the VM. This exit could either -be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way, -userspace can always sample the device output level and re-compute the state of -the userspace interrupt controller. Userspace should always check the state -of run->s.regs.device_irq_level on every kvm exit. -The value in run->s.regs.device_irq_level can represent both level and edge -triggered interrupt signals, depending on the device. Edge triggered interrupt -signals will exit to userspace with the bit in run->s.regs.device_irq_level -set exactly once per edge signal. - -The field run->s.regs.device_irq_level is available independent of -run->kvm_valid_regs or run->kvm_dirty_regs bits. - -If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a -number larger than 0 indicating the version of this capability is implemented -and thereby which bits in in run->s.regs.device_irq_level can signal values. - -Currently the following bits are defined for the device_irq_level bitmap: - - KVM_CAP_ARM_USER_IRQ >= 1: - - KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer - KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer - KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal - -Future versions of kvm may implement additional events. These will get -indicated by returning a higher number from KVM_CHECK_EXTENSION and will be -listed above. - -8.10 KVM_CAP_PPC_SMT_POSSIBLE - -Architectures: ppc - -Querying this capability returns a bitmap indicating the possible -virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N -(counting from the right) is set, then a virtual SMT mode of 2^N is -available. - -8.11 KVM_CAP_HYPERV_SYNIC2 - -Architectures: x86 - -This capability enables a newer version of Hyper-V Synthetic interrupt -controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM -doesn't clear SynIC message and event flags pages when they are enabled by -writing to the respective MSRs. - -8.12 KVM_CAP_HYPERV_VP_INDEX - -Architectures: x86 - -This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its -value is used to denote the target vcpu for a SynIC interrupt. For -compatibilty, KVM initializes this msr to KVM's internal vcpu index. When this -capability is absent, userspace can still query this msr's value. - -8.13 KVM_CAP_S390_AIS_MIGRATION - -Architectures: s390 -Parameters: none - -This capability indicates if the flic device will be able to get/set the -AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows -to discover this without having to create a flic device. - -8.14 KVM_CAP_S390_PSW - -Architectures: s390 - -This capability indicates that the PSW is exposed via the kvm_run structure. - -8.15 KVM_CAP_S390_GMAP - -Architectures: s390 - -This capability indicates that the user space memory used as guest mapping can -be anywhere in the user memory address space, as long as the memory slots are -aligned and sized to a segment (1MB) boundary. - -8.16 KVM_CAP_S390_COW - -Architectures: s390 - -This capability indicates that the user space memory used as guest mapping can -use copy-on-write semantics as well as dirty pages tracking via read-only page -tables. - -8.17 KVM_CAP_S390_BPB - -Architectures: s390 - -This capability indicates that kvm will implement the interfaces to handle -reset, migration and nested KVM for branch prediction blocking. The stfle -facility 82 should not be provided to the guest without this capability. - -8.18 KVM_CAP_HYPERV_TLBFLUSH - -Architectures: x86 - -This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush -hypercalls: -HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, -HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. - -8.19 KVM_CAP_ARM_INJECT_SERROR_ESR - -Architectures: arm, arm64 - -This capability indicates that userspace can specify (via the -KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it -takes a virtual SError interrupt exception. -If KVM advertises this capability, userspace can only specify the ISS field for -the ESR syndrome. Other parts of the ESR, such as the EC are generated by the -CPU when the exception is taken. If this virtual SError is taken to EL1 using -AArch64, this value will be reported in the ISS field of ESR_ELx. - -See KVM_CAP_VCPU_EVENTS for more details. -8.20 KVM_CAP_HYPERV_SEND_IPI - -Architectures: x86 - -This capability indicates that KVM supports paravirtualized Hyper-V IPI send -hypercalls: -HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. |