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Diffstat (limited to 'Documentation/virt/kvm/api.rst')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 6aa40ee05a4a..57061fa29e6a 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -1229,6 +1229,9 @@ It is not possible to read back a pending external abort (injected via KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered directly to the virtual CPU). +Calling this ioctl on a vCPU that hasn't been initialized will return +-ENOEXEC. + :: struct kvm_vcpu_events { @@ -1309,6 +1312,8 @@ exceptions by manipulating individual registers using the KVM_SET_ONE_REG API. See KVM_GET_VCPU_EVENTS for the data structure. +Calling this ioctl on a vCPU that hasn't been initialized will return +-ENOEXEC. 4.33 KVM_GET_DEBUGREGS ---------------------- @@ -2908,6 +2913,16 @@ such as set vcpu counter or reset vcpu, and they have the following id bit patte 0x9030 0000 0002 <reg:16> +x86 MSR registers have the following id bit patterns:: + 0x2030 0002 <msr number:32> + +Following are the KVM-defined registers for x86: + +======================= ========= ============================================= + Encoding Register Description +======================= ========= ============================================= + 0x2030 0003 0000 0000 SSP Shadow Stack Pointer +======================= ========= ============================================= 4.69 KVM_GET_ONE_REG -------------------- @@ -3075,6 +3090,12 @@ This IOCTL replaces the obsolete KVM_GET_PIT. Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. See KVM_GET_PIT2 for details on struct kvm_pit_state2. +.. Tip:: + ``KVM_SET_PIT2`` strictly adheres to the spec of Intel 8254 PIT. For example, + a ``count`` value of 0 in ``struct kvm_pit_channel_state`` is interpreted as + 65536, which is the maximum count value. Refer to `Intel 8254 programmable + interval timer <https://www.scs.stanford.edu/10wi-cs140/pintos/specs/8254.pdf>`_. + This IOCTL replaces the obsolete KVM_SET_PIT. @@ -3582,7 +3603,7 @@ VCPU matching underlying host. --------------------- :Capability: basic -:Architectures: arm64, mips, riscv +:Architectures: arm64, mips, riscv, x86 (if KVM_CAP_ONE_REG) :Type: vcpu ioctl :Parameters: struct kvm_reg_list (in/out) :Returns: 0 on success; -1 on error @@ -3625,6 +3646,8 @@ Note that s390 does not support KVM_GET_REG_LIST for historical reasons - KVM_REG_S390_GBEA +Note, for x86, all MSRs enumerated by KVM_GET_MSR_INDEX_LIST are supported as +type KVM_X86_REG_TYPE_MSR, but are NOT enumerated via KVM_GET_REG_LIST. 4.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) ----------------------------------------- @@ -6414,6 +6437,24 @@ most one mapping per page, i.e. binding multiple memory regions to a single guest_memfd range is not allowed (any number of memory regions can be bound to a single guest_memfd file, but the bound ranges must not overlap). +The capability KVM_CAP_GUEST_MEMFD_FLAGS enumerates the `flags` that can be +specified via KVM_CREATE_GUEST_MEMFD. Currently defined flags: + + ============================ ================================================ + GUEST_MEMFD_FLAG_MMAP Enable using mmap() on the guest_memfd file + descriptor. + GUEST_MEMFD_FLAG_INIT_SHARED Make all memory in the file shared during + KVM_CREATE_GUEST_MEMFD (memory files created + without INIT_SHARED will be marked private). + Shared memory can be faulted into host userspace + page tables. Private memory cannot. + ============================ ================================================ + +When the KVM MMU performs a PFN lookup to service a guest fault and the backing +guest_memfd has the GUEST_MEMFD_FLAG_MMAP set, then the fault will always be +consumed from guest_memfd, regardless of whether it is a shared or a private +fault. + See KVM_SET_USER_MEMORY_REGION2 for additional details. 4.143 KVM_PRE_FAULT_MEMORY |