diff options
Diffstat (limited to 'Documentation/virt/kvm')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 356 | ||||
| -rw-r--r-- | Documentation/virt/kvm/cpuid.rst | 7 | ||||
| -rw-r--r-- | Documentation/virt/kvm/hypercalls.rst | 21 | ||||
| -rw-r--r-- | Documentation/virt/kvm/locking.rst | 5 | ||||
| -rw-r--r-- | Documentation/virt/kvm/mmu.rst | 7 | ||||
| -rw-r--r-- | Documentation/virt/kvm/msr.rst | 13 |
6 files changed, 401 insertions, 8 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 7fcb2fd38f42..b9ddce5638f5 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -688,9 +688,14 @@ MSRs that have been set successfully. Defines the vcpu responses to the cpuid instruction. Applications should use the KVM_SET_CPUID2 ioctl if available. -Note, when this IOCTL fails, KVM gives no guarantees that previous valid CPUID -configuration (if there is) is not corrupted. Userspace can get a copy of the -resulting CPUID configuration through KVM_GET_CPUID2 in case. +Caveat emptor: + - If this IOCTL fails, KVM gives no guarantees that previous valid CPUID + configuration (if there is) is not corrupted. Userspace can get a copy + of the resulting CPUID configuration through KVM_GET_CPUID2 in case. + - Using KVM_SET_CPUID{,2} after KVM_RUN, i.e. changing the guest vCPU model + after running the guest, may cause guest instability. + - Using heterogeneous CPUID configurations, modulo APIC IDs, topology, etc... + may cause guest instability. :: @@ -5034,6 +5039,260 @@ see KVM_XEN_VCPU_SET_ATTR above. The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used with the KVM_XEN_VCPU_GET_ATTR ioctl. +4.130 KVM_ARM_MTE_COPY_TAGS +--------------------------- + +:Capability: KVM_CAP_ARM_MTE +:Architectures: arm64 +:Type: vm ioctl +:Parameters: struct kvm_arm_copy_mte_tags +:Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect + arguments, -EFAULT if memory cannot be accessed). + +:: + + struct kvm_arm_copy_mte_tags { + __u64 guest_ipa; + __u64 length; + void __user *addr; + __u64 flags; + __u64 reserved[2]; + }; + +Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The +``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. The ``addr`` +field must point to a buffer which the tags will be copied to or from. + +``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or +``KVM_ARM_TAGS_FROM_GUEST``. + +The size of the buffer to store the tags is ``(length / 16)`` bytes +(granules in MTE are 16 bytes long). Each byte contains a single tag +value. This matches the format of ``PTRACE_PEEKMTETAGS`` and +``PTRACE_POKEMTETAGS``. + +If an error occurs before any data is copied then a negative error code is +returned. If some tags have been copied before an error occurs then the number +of bytes successfully copied is returned. If the call completes successfully +then ``length`` is returned. + +4.131 KVM_GET_SREGS2 +------------------ + +:Capability: KVM_CAP_SREGS2 +:Architectures: x86 +:Type: vcpu ioctl +:Parameters: struct kvm_sregs2 (out) +:Returns: 0 on success, -1 on error + +Reads special registers from the vcpu. +This ioctl (when supported) replaces the KVM_GET_SREGS. + +:: + +struct kvm_sregs2 { + /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ + 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 flags; + __u64 pdptrs[4]; +}; + +flags values for ``kvm_sregs2``: + +``KVM_SREGS2_FLAGS_PDPTRS_VALID`` + + Indicates thats the struct contain valid PDPTR values. + + +4.132 KVM_SET_SREGS2 +------------------ + +:Capability: KVM_CAP_SREGS2 +:Architectures: x86 +:Type: vcpu ioctl +:Parameters: struct kvm_sregs2 (in) +:Returns: 0 on success, -1 on error + +Writes special registers into the vcpu. +See KVM_GET_SREGS2 for the data structures. +This ioctl (when supported) replaces the KVM_SET_SREGS. + +4.133 KVM_GET_STATS_FD +---------------------- + +:Capability: KVM_CAP_STATS_BINARY_FD +:Architectures: all +:Type: vm ioctl, vcpu ioctl +:Parameters: none +:Returns: statistics file descriptor on success, < 0 on error + +Errors: + + ====== ====================================================== + ENOMEM if the fd could not be created due to lack of memory + EMFILE if the number of opened files exceeds the limit + ====== ====================================================== + +The returned file descriptor can be used to read VM/vCPU statistics data in +binary format. The data in the file descriptor consists of four blocks +organized as follows: + ++-------------+ +| Header | ++-------------+ +| id string | ++-------------+ +| Descriptors | ++-------------+ +| Stats Data | ++-------------+ + +Apart from the header starting at offset 0, please be aware that it is +not guaranteed that the four blocks are adjacent or in the above order; +the offsets of the id, descriptors and data blocks are found in the +header. However, all four blocks are aligned to 64 bit offsets in the +file and they do not overlap. + +All blocks except the data block are immutable. Userspace can read them +only one time after retrieving the file descriptor, and then use ``pread`` or +``lseek`` to read the statistics repeatedly. + +All data is in system endianness. + +The format of the header is as follows:: + + struct kvm_stats_header { + __u32 flags; + __u32 name_size; + __u32 num_desc; + __u32 id_offset; + __u32 desc_offset; + __u32 data_offset; + }; + +The ``flags`` field is not used at the moment. It is always read as 0. + +The ``name_size`` field is the size (in byte) of the statistics name string +(including trailing '\0') which is contained in the "id string" block and +appended at the end of every descriptor. + +The ``num_desc`` field is the number of descriptors that are included in the +descriptor block. (The actual number of values in the data block may be +larger, since each descriptor may comprise more than one value). + +The ``id_offset`` field is the offset of the id string from the start of the +file indicated by the file descriptor. It is a multiple of 8. + +The ``desc_offset`` field is the offset of the Descriptors block from the start +of the file indicated by the file descriptor. It is a multiple of 8. + +The ``data_offset`` field is the offset of the Stats Data block from the start +of the file indicated by the file descriptor. It is a multiple of 8. + +The id string block contains a string which identifies the file descriptor on +which KVM_GET_STATS_FD was invoked. The size of the block, including the +trailing ``'\0'``, is indicated by the ``name_size`` field in the header. + +The descriptors block is only needed to be read once for the lifetime of the +file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed +by a string of size ``name_size``. + + #define KVM_STATS_TYPE_SHIFT 0 + #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT) + #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT) + #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT) + #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT) + + #define KVM_STATS_UNIT_SHIFT 4 + #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT) + #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT) + #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) + #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) + #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) + + #define KVM_STATS_BASE_SHIFT 8 + #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT) + #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT) + #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT) + + struct kvm_stats_desc { + __u32 flags; + __s16 exponent; + __u16 size; + __u32 offset; + __u32 unused; + char name[]; + }; + +The ``flags`` field contains the type and unit of the statistics data described +by this descriptor. Its endianness is CPU native. +The following flags are supported: + +Bits 0-3 of ``flags`` encode the type: + * ``KVM_STATS_TYPE_CUMULATIVE`` + The statistics data is cumulative. The value of data can only be increased. + Most of the counters used in KVM are of this type. + The corresponding ``size`` field for this type is always 1. + All cumulative statistics data are read/write. + * ``KVM_STATS_TYPE_INSTANT`` + The statistics data is instantaneous. Its value can be increased or + decreased. This type is usually used as a measurement of some resources, + like the number of dirty pages, the number of large pages, etc. + All instant statistics are read only. + The corresponding ``size`` field for this type is always 1. + * ``KVM_STATS_TYPE_PEAK`` + The statistics data is peak. The value of data can only be increased, and + represents a peak value for a measurement, for example the maximum number + of items in a hash table bucket, the longest time waited and so on. + The corresponding ``size`` field for this type is always 1. + +Bits 4-7 of ``flags`` encode the unit: + * ``KVM_STATS_UNIT_NONE`` + There is no unit for the value of statistics data. This usually means that + the value is a simple counter of an event. + * ``KVM_STATS_UNIT_BYTES`` + It indicates that the statistics data is used to measure memory size, in the + unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is + determined by the ``exponent`` field in the descriptor. + * ``KVM_STATS_UNIT_SECONDS`` + It indicates that the statistics data is used to measure time or latency. + * ``KVM_STATS_UNIT_CYCLES`` + It indicates that the statistics data is used to measure CPU clock cycles. + +Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the +unit: + * ``KVM_STATS_BASE_POW10`` + The scale is based on power of 10. It is used for measurement of time and + CPU clock cycles. For example, an exponent of -9 can be used with + ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds. + * ``KVM_STATS_BASE_POW2`` + The scale is based on power of 2. It is used for measurement of memory size. + For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to + express that the unit is MiB. + +The ``size`` field is the number of values of this statistics data. Its +value is usually 1 for most of simple statistics. 1 means it contains an +unsigned 64bit data. + +The ``offset`` field is the offset from the start of Data Block to the start of +the corresponding statistics data. + +The ``unused`` field is reserved for future support for other types of +statistics data, like log/linear histogram. Its value is always 0 for the types +defined above. + +The ``name`` field is the name string of the statistics data. The name string +starts at the end of ``struct kvm_stats_desc``. The maximum length including +the trailing ``'\0'``, is indicated by ``name_size`` in the header. + +The Stats Data block contains an array of 64-bit values in the same order +as the descriptors in Descriptors block. + 5. The kvm_run structure ======================== @@ -6323,6 +6582,7 @@ KVM_RUN_BUS_LOCK flag is used to distinguish between them. This capability can be used to check / enable 2nd DAWR feature provided by POWER10 processor. + 7.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM ------------------------------------- @@ -6362,6 +6622,66 @@ default. See Documentation/x86/sgx/2.Kernel-internals.rst for more details. +7.26 KVM_CAP_PPC_RPT_INVALIDATE +------------------------------- + +:Capability: KVM_CAP_PPC_RPT_INVALIDATE +:Architectures: ppc +:Type: vm + +This capability indicates that the kernel is capable of handling +H_RPT_INVALIDATE hcall. + +In order to enable the use of H_RPT_INVALIDATE in the guest, +user space might have to advertise it for the guest. For example, +IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is +present in the "ibm,hypertas-functions" device-tree property. + +This capability is enabled for hypervisors on platforms like POWER9 +that support radix MMU. + +7.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE +-------------------------------------- + +:Architectures: x86 +:Parameters: args[0] whether the feature should be enabled or not + +When this capability is enabled, an emulation failure will result in an exit +to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked +to handle a VMware backdoor instruction). Furthermore, KVM will now provide up +to 15 instruction bytes for any exit to userspace resulting from an emulation +failure. When these exits to userspace occur use the emulation_failure struct +instead of the internal struct. They both have the same layout, but the +emulation_failure struct matches the content better. It also explicitly +defines the 'flags' field which is used to describe the fields in the struct +that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is +set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data +in them.) + +7.28 KVM_CAP_ARM_MTE +-------------------- + +:Architectures: arm64 +:Parameters: none + +This capability indicates that KVM (and the hardware) supports exposing the +Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the +VMM before creating any VCPUs to allow the guest access. Note that MTE is only +available to a guest running in AArch64 mode and enabling this capability will +cause attempts to create AArch32 VCPUs to fail. + +When enabled the guest is able to access tags associated with any memory given +to the guest. KVM will ensure that the tags are maintained during swap or +hibernation of the host; however the VMM needs to manually save/restore the +tags as appropriate if the VM is migrated. + +When this capability is enabled all memory in memslots must be mapped as +not-shareable (no MAP_SHARED), attempts to create a memslot with a +MAP_SHARED mmap will result in an -EINVAL return. + +When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to +perform a bulk copy of tags to/from the guest. + 8. Other capabilities. ====================== @@ -6891,3 +7211,33 @@ This capability is always enabled. This capability indicates that the KVM virtual PTP service is supported in the host. A VMM can check whether the service is available to the guest on migration. + +8.33 KVM_CAP_HYPERV_ENFORCE_CPUID +----------------------------- + +Architectures: x86 + +When enabled, KVM will disable emulated Hyper-V features provided to the +guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all +currently implmented Hyper-V features are provided unconditionally when +Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001) +leaf. + +8.34 KVM_CAP_EXIT_HYPERCALL +--------------------------- + +:Capability: KVM_CAP_EXIT_HYPERCALL +:Architectures: x86 +:Type: vm + +This capability, if enabled, will cause KVM to exit to userspace +with KVM_EXIT_HYPERCALL exit reason to process some hypercalls. + +Calling KVM_CHECK_EXTENSION for this capability will return a bitmask +of hypercalls that can be configured to exit to userspace. +Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE. + +The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset +of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace +the hypercalls whose corresponding bit is in the argument, and return +ENOSYS for the others. diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst index cf62162d4be2..bda3e3e737d7 100644 --- a/Documentation/virt/kvm/cpuid.rst +++ b/Documentation/virt/kvm/cpuid.rst @@ -96,6 +96,13 @@ KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit before using extended destination ID bits in MSI address bits 11-5. +KVM_FEATURE_HC_MAP_GPA_RANGE 16 guest checks this feature bit before + using the map gpa range hypercall + to notify the page state change + +KVM_FEATURE_MIGRATION_CONTROL 17 guest checks this feature bit before + using MSR_KVM_MIGRATION_CONTROL + KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side per-cpu warps are expected in kvmclock diff --git a/Documentation/virt/kvm/hypercalls.rst b/Documentation/virt/kvm/hypercalls.rst index ed4fddd364ea..e56fa8b9cfca 100644 --- a/Documentation/virt/kvm/hypercalls.rst +++ b/Documentation/virt/kvm/hypercalls.rst @@ -169,3 +169,24 @@ a0: destination APIC ID :Usage example: When sending a call-function IPI-many to vCPUs, yield if any of the IPI target vCPUs was preempted. + +8. KVM_HC_MAP_GPA_RANGE +------------------------- +:Architecture: x86 +:Status: active +:Purpose: Request KVM to map a GPA range with the specified attributes. + +a0: the guest physical address of the start page +a1: the number of (4kb) pages (must be contiguous in GPA space) +a2: attributes + + Where 'attributes' : + * bits 3:0 - preferred page size encoding 0 = 4kb, 1 = 2mb, 2 = 1gb, etc... + * bit 4 - plaintext = 0, encrypted = 1 + * bits 63:5 - reserved (must be zero) + +**Implementation note**: this hypercall is implemented in userspace via +the KVM_CAP_EXIT_HYPERCALL capability. Userspace must enable that capability +before advertising KVM_FEATURE_HC_MAP_GPA_RANGE in the guest CPUID. In +addition, if the guest supports KVM_FEATURE_MIGRATION_CONTROL, userspace +must also set up an MSR filter to process writes to MSR_KVM_MIGRATION_CONTROL. diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst index 1fc860c007a3..35eca377543d 100644 --- a/Documentation/virt/kvm/locking.rst +++ b/Documentation/virt/kvm/locking.rst @@ -16,6 +16,11 @@ The acquisition orders for mutexes are as follows: - kvm->slots_lock is taken outside kvm->irq_lock, though acquiring them together is quite rare. +- Unlike kvm->slots_lock, kvm->slots_arch_lock is released before + synchronize_srcu(&kvm->srcu). Therefore kvm->slots_arch_lock + can be taken inside a kvm->srcu read-side critical section, + while kvm->slots_lock cannot. + On x86: - vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock diff --git a/Documentation/virt/kvm/mmu.rst b/Documentation/virt/kvm/mmu.rst index 20d85daed395..f60f5488e121 100644 --- a/Documentation/virt/kvm/mmu.rst +++ b/Documentation/virt/kvm/mmu.rst @@ -180,8 +180,8 @@ Shadow pages contain the following information: role.gpte_is_8_bytes: Reflects the size of the guest PTE for which the page is valid, i.e. '1' if 64-bit gptes are in use, '0' if 32-bit gptes are in use. - role.nxe: - Contains the value of efer.nxe for which the page is valid. + role.efer_nx: + Contains the value of efer.nx for which the page is valid. role.cr0_wp: Contains the value of cr0.wp for which the page is valid. role.smep_andnot_wp: @@ -192,9 +192,6 @@ Shadow pages contain the following information: Contains the value of cr4.smap && !cr0.wp for which the page is valid (pages for which this is true are different from other pages; see the treatment of cr0.wp=0 below). - role.ept_sp: - This is a virtual flag to denote a shadowed nested EPT page. ept_sp - is true if "cr0_wp && smap_andnot_wp", an otherwise invalid combination. role.smm: Is 1 if the page is valid in system management mode. This field determines which of the kvm_memslots array was used to build this diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst index e37a14c323d2..9315fc385fb0 100644 --- a/Documentation/virt/kvm/msr.rst +++ b/Documentation/virt/kvm/msr.rst @@ -376,3 +376,16 @@ data: write '1' to bit 0 of the MSR, this causes the host to re-scan its queue and check if there are more notifications pending. The MSR is available if KVM_FEATURE_ASYNC_PF_INT is present in CPUID. + +MSR_KVM_MIGRATION_CONTROL: + 0x4b564d08 + +data: + This MSR is available if KVM_FEATURE_MIGRATION_CONTROL is present in + CPUID. Bit 0 represents whether live migration of the guest is allowed. + + When a guest is started, bit 0 will be 0 if the guest has encrypted + memory and 1 if the guest does not have encrypted memory. If the + guest is communicating page encryption status to the host using the + ``KVM_HC_MAP_GPA_RANGE`` hypercall, it can set bit 0 in this MSR to + allow live migration of the guest. |