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author | Jan Kiszka <jan.kiszka@siemens.com> | 2012-04-24 18:40:15 +0400 |
---|---|---|
committer | Marcelo Tosatti <mtosatti@redhat.com> | 2012-04-28 02:40:28 +0400 |
commit | 414fa985f91bdf61fe2baf8111c0ddbdb94808ea (patch) | |
tree | da6a3d6b54295515134fc4a926fe47565e5e5b08 /Documentation/virtual | |
parent | 38e8a2ddc9ada5dd1f2def95bebb733bf619bbef (diff) | |
download | linux-414fa985f91bdf61fe2baf8111c0ddbdb94808ea.tar.xz |
KVM: Improve readability of KVM API doc
This helps to identify sections and it also fixes the numbering from
4.54 to 4.61.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r-- | Documentation/virtual/kvm/api.txt | 99 |
1 files changed, 92 insertions, 7 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index a1552210b16d..b48f92786ab3 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2,6 +2,7 @@ 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 @@ -23,7 +24,9 @@ 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 descriptors +------------------- The kvm API is centered around file descriptors. An initial open("/dev/kvm") obtains a handle to the kvm subsystem; this handle @@ -41,7 +44,9 @@ 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 @@ -53,7 +58,9 @@ 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 @@ -75,6 +82,7 @@ description: 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 @@ -90,6 +98,7 @@ 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 @@ -109,6 +118,7 @@ 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). + 4.3 KVM_GET_MSR_INDEX_LIST Capability: basic @@ -135,6 +145,7 @@ 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 @@ -149,6 +160,7 @@ 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 @@ -161,6 +173,7 @@ 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 @@ -171,6 +184,7 @@ Returns: 0 on success, -1 on error This ioctl is obsolete and has been removed. + 4.7 KVM_CREATE_VCPU Capability: basic @@ -223,6 +237,7 @@ 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 @@ -246,6 +261,7 @@ 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 @@ -256,6 +272,7 @@ Returns: 0 (success), -1 (error) This ioctl is obsolete and has been removed. + 4.10 KVM_RUN Capability: basic @@ -272,6 +289,7 @@ 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 @@ -292,6 +310,7 @@ struct kvm_regs { __u64 rip, rflags; }; + 4.12 KVM_SET_REGS Capability: basic @@ -304,6 +323,7 @@ Writes the general purpose registers into the vcpu. See KVM_GET_REGS for the data structure. + 4.13 KVM_GET_SREGS Capability: basic @@ -331,6 +351,7 @@ 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 @@ -342,6 +363,7 @@ 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 @@ -365,6 +387,7 @@ struct kvm_translation { __u8 pad[5]; }; + 4.16 KVM_INTERRUPT Capability: basic @@ -413,6 +436,7 @@ c) KVM_INTERRUPT_SET_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 @@ -423,6 +447,7 @@ Returns: -1 on error Support for this has been removed. Use KVM_SET_GUEST_DEBUG instead. + 4.18 KVM_GET_MSRS Capability: basic @@ -451,6 +476,7 @@ 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 @@ -466,6 +492,7 @@ 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 @@ -494,6 +521,7 @@ struct kvm_cpuid { struct kvm_cpuid_entry entries[0]; }; + 4.21 KVM_SET_SIGNAL_MASK Capability: basic @@ -516,6 +544,7 @@ struct kvm_signal_mask { __u8 sigset[0]; }; + 4.22 KVM_GET_FPU Capability: basic @@ -541,6 +570,7 @@ struct kvm_fpu { __u32 pad2; }; + 4.23 KVM_SET_FPU Capability: basic @@ -566,6 +596,7 @@ struct kvm_fpu { __u32 pad2; }; + 4.24 KVM_CREATE_IRQCHIP Capability: KVM_CAP_IRQCHIP @@ -579,6 +610,7 @@ 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 @@ -600,6 +632,7 @@ struct kvm_irq_level { __u32 level; /* 0 or 1 */ }; + 4.26 KVM_GET_IRQCHIP Capability: KVM_CAP_IRQCHIP @@ -621,6 +654,7 @@ struct kvm_irqchip { } chip; }; + 4.27 KVM_SET_IRQCHIP Capability: KVM_CAP_IRQCHIP @@ -642,6 +676,7 @@ struct kvm_irqchip { } chip; }; + 4.28 KVM_XEN_HVM_CONFIG Capability: KVM_CAP_XEN_HVM @@ -666,6 +701,7 @@ struct kvm_xen_hvm_config { __u8 pad2[30]; }; + 4.29 KVM_GET_CLOCK Capability: KVM_CAP_ADJUST_CLOCK @@ -684,6 +720,7 @@ struct kvm_clock_data { __u32 pad[9]; }; + 4.30 KVM_SET_CLOCK Capability: KVM_CAP_ADJUST_CLOCK @@ -702,6 +739,7 @@ struct kvm_clock_data { __u32 pad[9]; }; + 4.31 KVM_GET_VCPU_EVENTS Capability: KVM_CAP_VCPU_EVENTS @@ -741,6 +779,7 @@ struct kvm_vcpu_events { 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 @@ -767,6 +806,7 @@ 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 @@ -785,6 +825,7 @@ struct kvm_debugregs { __u64 reserved[9]; }; + 4.34 KVM_SET_DEBUGREGS Capability: KVM_CAP_DEBUGREGS @@ -798,6 +839,7 @@ 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 @@ -844,6 +886,7 @@ 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 @@ -862,6 +905,7 @@ 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 @@ -897,6 +941,7 @@ function properly, this is the place to put them. __u8 pad[64]; }; + 4.38 KVM_GET_MP_STATE Capability: KVM_CAP_MP_STATE @@ -927,6 +972,7 @@ Possible values are: 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 @@ -941,6 +987,7 @@ 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 @@ -959,6 +1006,7 @@ 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 @@ -971,6 +1019,7 @@ 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 @@ -985,6 +1034,7 @@ struct kvm_xsave { This ioctl would copy current vcpu's xsave struct to the userspace. + 4.43 KVM_SET_XSAVE Capability: KVM_CAP_XSAVE @@ -999,6 +1049,7 @@ struct kvm_xsave { This ioctl would copy userspace's xsave struct to the kernel. + 4.44 KVM_GET_XCRS Capability: KVM_CAP_XCRS @@ -1022,6 +1073,7 @@ struct kvm_xcrs { This ioctl would copy current vcpu's xcrs to the userspace. + 4.45 KVM_SET_XCRS Capability: KVM_CAP_XCRS @@ -1045,6 +1097,7 @@ struct kvm_xcrs { This ioctl would set vcpu's xcr to the value userspace specified. + 4.46 KVM_GET_SUPPORTED_CPUID Capability: KVM_CAP_EXT_CPUID @@ -1119,6 +1172,7 @@ support. Instead it is reported via 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 @@ -1142,6 +1196,7 @@ 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 @@ -1185,6 +1240,7 @@ Only PCI header type 0 devices with PCI BAR resources are supported by device assignment. The user requesting this ioctl must have read/write access to the PCI sysfs resource files associated with the device. + 4.49 KVM_DEASSIGN_PCI_DEVICE Capability: KVM_CAP_DEVICE_DEASSIGNMENT @@ -1198,6 +1254,7 @@ 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 @@ -1231,6 +1288,7 @@ The following flags are defined: 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 @@ -1245,6 +1303,7 @@ 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 @@ -1293,6 +1352,7 @@ struct kvm_irq_routing_msi { __u32 pad; }; + 4.53 KVM_ASSIGN_SET_MSIX_NR Capability: KVM_CAP_DEVICE_MSIX @@ -1314,6 +1374,7 @@ struct kvm_assigned_msix_nr { #define KVM_MAX_MSIX_PER_DEV 256 + 4.54 KVM_ASSIGN_SET_MSIX_ENTRY Capability: KVM_CAP_DEVICE_MSIX @@ -1332,7 +1393,8 @@ struct kvm_assigned_msix_entry { __u16 padding[3]; }; -4.54 KVM_SET_TSC_KHZ + +4.55 KVM_SET_TSC_KHZ Capability: KVM_CAP_TSC_CONTROL Architectures: x86 @@ -1343,7 +1405,8 @@ 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 + +4.56 KVM_GET_TSC_KHZ Capability: KVM_CAP_GET_TSC_KHZ Architectures: x86 @@ -1355,7 +1418,8 @@ 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. -4.56 KVM_GET_LAPIC + +4.57 KVM_GET_LAPIC Capability: KVM_CAP_IRQCHIP Architectures: x86 @@ -1371,7 +1435,8 @@ struct kvm_lapic_state { 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. -4.57 KVM_SET_LAPIC + +4.58 KVM_SET_LAPIC Capability: KVM_CAP_IRQCHIP Architectures: x86 @@ -1387,7 +1452,8 @@ struct kvm_lapic_state { Copies the input argument into the the Local APIC registers. The data format and layout are the same as documented in the architecture manual. -4.58 KVM_IOEVENTFD + +4.59 KVM_IOEVENTFD Capability: KVM_CAP_IOEVENTFD Architectures: all @@ -1417,7 +1483,8 @@ The following flags are defined: 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. -4.59 KVM_DIRTY_TLB + +4.60 KVM_DIRTY_TLB Capability: KVM_CAP_SW_TLB Architectures: ppc @@ -1449,7 +1516,8 @@ 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. -4.60 KVM_ASSIGN_SET_INTX_MASK + +4.61 KVM_ASSIGN_SET_INTX_MASK Capability: KVM_CAP_PCI_2_3 Architectures: x86 @@ -1482,6 +1550,7 @@ See KVM_ASSIGN_DEV_IRQ for the data structure. The target device is specified by assigned_dev_id. In the flags field, only KVM_DEV_ASSIGN_MASK_INTX is evaluated. + 4.62 KVM_CREATE_SPAPR_TCE Capability: KVM_CAP_SPAPR_TCE @@ -1517,6 +1586,7 @@ 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 @@ -1549,6 +1619,7 @@ 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 @@ -1574,6 +1645,7 @@ following algorithm: 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 @@ -1593,6 +1665,7 @@ 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 alligned by 1 megabyte. + 4.66 KVM_S390_UCAS_UNMAP Capability: KVM_CAP_S390_UCONTROL @@ -1612,6 +1685,7 @@ 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 alligned by 1 megabyte. + 4.67 KVM_S390_VCPU_FAULT Capability: KVM_CAP_S390_UCONTROL @@ -1628,6 +1702,7 @@ 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 @@ -1653,6 +1728,7 @@ registers, find a list below: | | PPC | KVM_REG_PPC_HIOR | 64 + 4.69 KVM_GET_ONE_REG Capability: KVM_CAP_ONE_REG @@ -1669,6 +1745,7 @@ at the memory location pointed to by "addr". The list of registers accessible using this interface is identical to the list in 4.64. + 4.70 KVM_KVMCLOCK_CTRL Capability: KVM_CAP_KVMCLOCK_CTRL @@ -1689,6 +1766,7 @@ 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 @@ -1710,7 +1788,9 @@ struct kvm_msi { No flags are defined so far. The corresponding field must be 0. + 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 @@ -1951,7 +2031,9 @@ and usually define the validity of a groups of registers. (e.g. one bit }; + 6. Capabilities that can be enabled +----------------------------------- There are certain capabilities that change the behavior of the virtual CPU when enabled. To enable them, please see section 4.37. Below you can find a list of @@ -1967,6 +2049,7 @@ The following information is provided along with the description: 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 @@ -1980,6 +2063,7 @@ between the guest and the host. When this capability is enabled, KVM_EXIT_OSI can occur. + 6.2 KVM_CAP_PPC_PAPR Architectures: ppc @@ -1998,6 +2082,7 @@ HTAB invisible to the guest. When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. + 6.3 KVM_CAP_SW_TLB Architectures: ppc |