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| author | Aaron Lewis <aaronlewis@google.com> | 2021-05-10 17:48:33 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-06-25 01:00:48 +0300 |
| commit | 19238e75bd8ed8ffe784bf5b37586e77b2093742 (patch) | |
| tree | 13d0d58c59af12f70c7ae7b3f83a4c6a0e755a29 /Documentation | |
| parent | 27de925044e18eb056d6157305c841b1408621b5 (diff) | |
| download | linux-19238e75bd8ed8ffe784bf5b37586e77b2093742.tar.xz | |
kvm: x86: Allow userspace to handle emulation errors
Add a fallback mechanism to the in-kernel instruction emulator that
allows userspace the opportunity to process an instruction the emulator
was unable to. When the in-kernel instruction emulator fails to process
an instruction it will either inject a #UD into the guest or exit to
userspace with exit reason KVM_INTERNAL_ERROR. This is because it does
not know how to proceed in an appropriate manner. This feature lets
userspace get involved to see if it can figure out a better path
forward.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20210510144834.658457-2-aaronlewis@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 5d8db4922df6..3b6e3b1628b4 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6546,6 +6546,7 @@ 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 ------------------------------------- @@ -6603,6 +6604,25 @@ 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.) + + 8. Other capabilities. ====================== |