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diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt new file mode 100644 index 00000000..42542eb8 --- /dev/null +++ b/Documentation/virtual/kvm/api.txt @@ -0,0 +1,1479 @@ +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). + + Only run VM ioctls 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. + + Only run vcpu ioctls from the same thread that was used to create the + vcpu. + +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 ioctl on a VM fd will create a virtual cpu +and return a file descriptor pointing to it. Finally, ioctls on a vcpu +fd can be used to control the vcpu, including 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. The only supported use is one virtual machine per process, +and one vcpu per thread. + +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 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), or a KVM_CAP_xyz constant, which + means availability needs to be checked with KVM_CHECK_EXTENSION + (see section 4.4). + + 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: none +Returns: a VM fd that can be used to control the new virtual machine. + +The new VM has no virtual cpus and no memory. An mmap() of a VM fd +will access the virtual machine's physical address space; offset zero +corresponds to guest physical address zero. Use of mmap() on a VM fd +is discouraged if userspace memory allocation (KVM_CAP_USER_MEMORY) is +available. + +4.3 KVM_GET_MSR_INDEX_LIST + +Capability: basic +Architectures: x86 +Type: system +Parameters: struct kvm_msr_list (in/out) +Returns: 0 on success; -1 on error +Errors: + 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]; +}; + +This ioctl returns the guest msrs that are supported. The list varies +by kvm version and host processor, but does not change otherwise. 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. + +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. + +4.4 KVM_CHECK_EXTENSION + +Capability: basic +Architectures: all +Type: system 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. + +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. The vcpu id is a small integer +in the range [0, max_vcpus). You can use KVM_CAP_NR_VCPUS of the +KVM_CHECK_EXTENSION ioctl() to determine the value for max_vcpus at run-time. +If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 +cpus max. + +4.8 KVM_GET_DIRTY_LOG (vm ioctl) + +Capability: basic +Architectures: x86 +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. + +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 +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; +}; + +4.12 KVM_SET_REGS + +Capability: basic +Architectures: all +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/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 +Type: vcpu ioctl +Parameters: struct kvm_interrupt (in) +Returns: 0 on success, -1 on error + +Queues a hardware interrupt vector to be injected. This is only +useful if in-kernel local APIC or equivalent is not used. + +/* for KVM_INTERRUPT */ +struct kvm_interrupt { + /* in */ + __u32 irq; +}; + +X86: + +Note 'irq' is an interrupt vector, not an interrupt pin or line. + +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. + +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 +Architectures: x86 +Type: vcpu ioctl +Parameters: struct kvm_msrs (in/out) +Returns: 0 on success, -1 on error + +Reads model-specific registers from the vcpu. Supported msr indices can +be obtained using KVM_GET_MSR_INDEX_LIST. + +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: x86 +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 +Architectures: x86, ia64 +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 ia64, a IOSAPIC is created. + +4.25 KVM_IRQ_LINE + +Capability: KVM_CAP_IRQCHIP +Architectures: x86, ia64 +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. +Requires 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. + +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, ia64 +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, ia64 +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. + +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 +Type: vm ioctl +Parameters: struct kvm_vcpu_event (out) +Returns: 0 on success, -1 on error + +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 pad; + __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; +}; + +KVM_VCPUEVENT_VALID_SHADOW may be set in the flags field to signal that +interrupt.shadow contains a valid state. Otherwise, this field is undefined. + +4.32 KVM_SET_VCPU_EVENTS + +Capability: KVM_CAP_VCPU_EVENTS +Extended by: KVM_CAP_INTR_SHADOW +Architectures: x86 +Type: vm ioctl +Parameters: struct kvm_vcpu_event (in) +Returns: 0 on success, -1 on error + +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 and sipi_vector. 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 + +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. + +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_MEM +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 + +This ioctl allows the user to create or modify a guest physical memory +slot. When changing an existing slot, it may be moved in the guest +physical memory space, or its flags may be modified. It may not be +resized. Slots may not overlap in guest physical address space. + +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 just one flag, KVM_MEM_LOG_DIRTY_PAGES, which +instructs kvm to keep track of writes to memory within the slot. See +the KVM_GET_DIRTY_LOG ioctl. + +When the KVM_CAP_SYNC_MMU capability, 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: ppc +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]; +}; + +4.38 KVM_GET_MP_STATE + +Capability: KVM_CAP_MP_STATE +Architectures: x86, ia64 +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 + - KVM_MP_STATE_UNINITIALIZED: the vcpu is an application processor (AP) + which has not yet received an INIT signal + - KVM_MP_STATE_INIT_RECEIVED: the vcpu has received an INIT signal, and is + now ready for a SIPI + - KVM_MP_STATE_HALTED: the vcpu has executed a HLT instruction and + is waiting for an interrupt + - KVM_MP_STATE_SIPI_RECEIVED: the vcpu has just received a SIPI (vector + accessible via KVM_GET_VCPU_EVENTS) + +This ioctl is only useful after KVM_CREATE_IRQCHIP. Without an in-kernel +irqchip, the multiprocessing state must be maintained by userspace. + +4.39 KVM_SET_MP_STATE + +Capability: KVM_CAP_MP_STATE +Architectures: x86, ia64 +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. + +This ioctl is only useful after KVM_CREATE_IRQCHIP. Without an in-kernel +irqchip, the multiprocessing state must be maintained by userspace. + +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. + +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). + +4.41 KVM_SET_BOOT_CPU_ID + +Capability: KVM_CAP_SET_BOOT_CPU_ID +Architectures: x86, ia64 +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 1 +#define KVM_CPUID_FLAG_STATEFUL_FUNC 2 +#define KVM_CPUID_FLAG_STATE_READ_NEXT 4 + +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. 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). + +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 + +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. + +For now the only implemented piece of information distributed here is an array +of 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. + +4.48 KVM_ASSIGN_PCI_DEVICE + +Capability: KVM_CAP_DEVICE_ASSIGNMENT +Architectures: x86 ia64 +Type: vm ioctl +Parameters: struct kvm_assigned_pci_dev (in) +Returns: 0 on success, -1 on error + +Assigns a host PCI device to the VM. + +struct kvm_assigned_pci_dev { + __u32 assigned_dev_id; + __u32 busnr; + __u32 devfn; + __u32 flags; + __u32 segnr; + union { + __u32 reserved[11]; + }; +}; + +The PCI device is specified by the triple segnr, busnr, and devfn. +Identification in succeeding service requests is done via assigned_dev_id. The +following flags are specified: + +/* Depends on KVM_CAP_IOMMU */ +#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) + +4.49 KVM_DEASSIGN_PCI_DEVICE + +Capability: KVM_CAP_DEVICE_DEASSIGNMENT +Architectures: x86 ia64 +Type: vm ioctl +Parameters: struct kvm_assigned_pci_dev (in) +Returns: 0 on success, -1 on error + +Ends PCI device assignment, releasing all associated resources. + +See KVM_CAP_DEVICE_ASSIGNMENT for the data structure. Only assigned_dev_id is +used in kvm_assigned_pci_dev to identify the device. + +4.50 KVM_ASSIGN_DEV_IRQ + +Capability: KVM_CAP_ASSIGN_DEV_IRQ +Architectures: x86 ia64 +Type: vm ioctl +Parameters: struct kvm_assigned_irq (in) +Returns: 0 on success, -1 on error + +Assigns an IRQ to a passed-through device. + +struct kvm_assigned_irq { + __u32 assigned_dev_id; + __u32 host_irq; + __u32 guest_irq; + __u32 flags; + union { + struct { + __u32 addr_lo; + __u32 addr_hi; + __u32 data; + } guest_msi; + __u32 reserved[12]; + }; +}; + +The following flags are defined: + +#define KVM_DEV_IRQ_HOST_INTX (1 << 0) +#define KVM_DEV_IRQ_HOST_MSI (1 << 1) +#define KVM_DEV_IRQ_HOST_MSIX (1 << 2) + +#define KVM_DEV_IRQ_GUEST_INTX (1 << 8) +#define KVM_DEV_IRQ_GUEST_MSI (1 << 9) +#define KVM_DEV_IRQ_GUEST_MSIX (1 << 10) + +It is not valid to specify multiple types per host or guest IRQ. However, the +IRQ type of host and guest can differ or can even be null. + +4.51 KVM_DEASSIGN_DEV_IRQ + +Capability: KVM_CAP_ASSIGN_DEV_IRQ +Architectures: x86 ia64 +Type: vm ioctl +Parameters: struct kvm_assigned_irq (in) +Returns: 0 on success, -1 on error + +Ends an IRQ assignment to a passed-through device. + +See KVM_ASSIGN_DEV_IRQ for the data structure. The target device is specified +by assigned_dev_id, flags must correspond to the IRQ type specified on +KVM_ASSIGN_DEV_IRQ. Partial deassignment of host or guest IRQ is allowed. + +4.52 KVM_SET_GSI_ROUTING + +Capability: KVM_CAP_IRQ_ROUTING +Architectures: x86 ia64 +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. + +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; + __u32 pad[8]; + } u; +}; + +/* gsi routing entry types */ +#define KVM_IRQ_ROUTING_IRQCHIP 1 +#define KVM_IRQ_ROUTING_MSI 2 + +No flags are specified so far, the corresponding field must be set to zero. + +struct kvm_irq_routing_irqchip { + __u32 irqchip; + __u32 pin; +}; + +struct kvm_irq_routing_msi { + __u32 address_lo; + __u32 address_hi; + __u32 data; + __u32 pad; +}; + +4.53 KVM_ASSIGN_SET_MSIX_NR + +Capability: KVM_CAP_DEVICE_MSIX +Architectures: x86 ia64 +Type: vm ioctl +Parameters: struct kvm_assigned_msix_nr (in) +Returns: 0 on success, -1 on error + +Set the number of MSI-X interrupts for an assigned device. This service can +only be called once in the lifetime of an assigned device. + +struct kvm_assigned_msix_nr { + __u32 assigned_dev_id; + __u16 entry_nr; + __u16 padding; +}; + +#define KVM_MAX_MSIX_PER_DEV 256 + +4.54 KVM_ASSIGN_SET_MSIX_ENTRY + +Capability: KVM_CAP_DEVICE_MSIX +Architectures: x86 ia64 +Type: vm ioctl +Parameters: struct kvm_assigned_msix_entry (in) +Returns: 0 on success, -1 on error + +Specifies the routing of an MSI-X assigned device interrupt to a GSI. Setting +the GSI vector to zero means disabling the interrupt. + +struct kvm_assigned_msix_entry { + __u32 assigned_dev_id; + __u32 gsi; + __u16 entry; /* The index of entry in the MSI-X table */ + __u16 padding[3]; +}; + +4.54 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. + +4.55 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. + +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 padding1[7]; + + /* 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. + + __u8 padding2[2]; + + /* 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. + + struct { + struct kvm_debug_exit_arch arch; + } debug; + +Unused. + + /* 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. + +NOTE: For KVM_EXIT_IO, KVM_EXIT_MMIO and KVM_EXIT_OSI, 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_DCR */ + struct { + __u32 dcrn; + __u32 data; + __u8 is_write; + } dcr; + +powerpc specific. + + /* 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. + + /* Fix the size of the union. */ + char padding[256]; + }; +}; |