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Diffstat (limited to 'Documentation/kvm/api.txt')
| -rw-r--r-- | Documentation/kvm/api.txt | 428 |
1 files changed, 386 insertions, 42 deletions
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt index 2811e452f756..5f5b64982b1a 100644 --- a/Documentation/kvm/api.txt +++ b/Documentation/kvm/api.txt @@ -23,12 +23,12 @@ of a virtual machine. The ioctls belong to three classes Only run vcpu ioctls from the same thread that was used to create the vcpu. -2. File descritpors +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 descripror which can be used to issue VM +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 @@ -126,6 +126,10 @@ 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 @@ -160,29 +164,7 @@ Type: vm ioctl Parameters: struct kvm_memory_region (in) Returns: 0 on success, -1 on error -struct kvm_memory_region { - __u32 slot; - __u32 flags; - __u64 guest_phys_addr; - __u64 memory_size; /* bytes */ -}; - -/* 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. - -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. - -It is recommended to use the KVM_SET_USER_MEMORY_REGION ioctl instead -of this API, if available. This newer API allows placing guest memory -at specified locations in the host address space, yielding better -control and easy access. +This ioctl is obsolete and has been removed. 4.6 KVM_CREATE_VCPU @@ -226,17 +208,7 @@ Type: vm ioctl Parameters: struct kvm_memory_alias (in) Returns: 0 (success), -1 (error) -struct kvm_memory_alias { - __u32 slot; /* this has a different namespace than memory slots */ - __u32 flags; - __u64 guest_phys_addr; - __u64 memory_size; - __u64 target_phys_addr; -}; - -Defines a guest physical address space region as an alias to another -region. Useful for aliased address, for example the VGA low memory -window. Should not be used with userspace memory. +This ioctl is obsolete and has been removed. 4.9 KVM_RUN @@ -643,7 +615,7 @@ Type: vm ioctl Parameters: struct kvm_clock_data (in) Returns: 0 on success, -1 on error -Sets the current timestamp of kvmclock to the valued specific in its parameter. +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. @@ -656,6 +628,7 @@ struct kvm_clock_data { 4.29 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) @@ -676,7 +649,7 @@ struct kvm_vcpu_events { __u8 injected; __u8 nr; __u8 soft; - __u8 pad; + __u8 shadow; } interrupt; struct { __u8 injected; @@ -688,9 +661,13 @@ struct kvm_vcpu_events { __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. + 4.30 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) @@ -709,6 +686,351 @@ 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. + +4.32 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]; +}; + +4.33 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. + +4.34 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. + +4.35 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). + +4.36 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]; +}; + +4.37 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 + accesible 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. + +4.38 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. + +4.39 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). + +4.40 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. + +4.41 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. + +4.42 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. + +4.43 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. + +4.44 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. + +4.45 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. 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 5. The kvm_run structure @@ -795,11 +1117,11 @@ Unused. __u64 data_offset; /* relative to kvm_run start */ } io; -If exit_reason is KVM_EXIT_IO_IN or KVM_EXIT_IO_OUT, then the vcpu has +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 patcked array. +KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. struct { struct kvm_debug_exit_arch arch; @@ -815,11 +1137,18 @@ Unused. __u8 is_write; } mmio; -If exit_reason is KVM_EXIT_MMIO or KVM_EXIT_IO_OUT, then the vcpu has +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; @@ -829,7 +1158,9 @@ true, and should be filled by application code otherwise. __u32 pad; } hypercall; -Unused. +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 { @@ -870,6 +1201,19 @@ s390 specific. 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]; }; |