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Diffstat (limited to 'Documentation/kvm/api.txt')
| -rw-r--r-- | Documentation/kvm/api.txt | 220 |
1 files changed, 212 insertions, 8 deletions
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt index 2811e452f756..a237518e51b9 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 @@ -643,7 +643,7 @@ 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 +656,7 @@ 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 +677,7 @@ struct kvm_vcpu_events { __u8 injected; __u8 nr; __u8 soft; - __u8 pad; + __u8 shadow; } interrupt; struct { __u8 injected; @@ -688,9 +689,13 @@ 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 +714,183 @@ 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. 5. The kvm_run structure @@ -795,11 +977,11 @@ 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 +997,18 @@ 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 +1018,9 @@ 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 +1061,19 @@ 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]; }; |