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| author | Sean Christopherson <seanjc@google.com> | 2022-06-08 22:45:12 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-06-20 11:50:42 -0400 |
| commit | bfbcc81bb82cbbad8bf4e40cea274f42b50674e2 (patch) | |
| tree | 644d8901c84e9720c22a819b706773951201e31c /arch/x86/include/uapi | |
| parent | ff81a90f45ce6b818167c590f7625b3b573defc9 (diff) | |
| download | lwn-bfbcc81bb82cbbad8bf4e40cea274f42b50674e2.tar.gz lwn-bfbcc81bb82cbbad8bf4e40cea274f42b50674e2.zip | |
KVM: x86: Add a quirk for KVM's "MONITOR/MWAIT are NOPs!" behavior
Add a quirk for KVM's behavior of emulating intercepted MONITOR/MWAIT
instructions a NOPs regardless of whether or not they are supported in
guest CPUID. KVM's current behavior was likely motiviated by a certain
fruity operating system that expects MONITOR/MWAIT to be supported
unconditionally and blindly executes MONITOR/MWAIT without first checking
CPUID. And because KVM does NOT advertise MONITOR/MWAIT to userspace,
that's effectively the default setup for any VMM that regurgitates
KVM_GET_SUPPORTED_CPUID to KVM_SET_CPUID2.
Note, this quirk interacts with KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT. The
behavior is actually desirable, as userspace VMMs that want to
unconditionally hide MONITOR/MWAIT from the guest can leave the
MISC_ENABLE quirk enabled.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220608224516.3788274-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/uapi')
| -rw-r--r-- | arch/x86/include/uapi/asm/kvm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 50a4e787d5e6..ee3896416c68 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -439,6 +439,7 @@ struct kvm_sync_regs { #define KVM_X86_QUIRK_OUT_7E_INC_RIP (1 << 3) #define KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT (1 << 4) #define KVM_X86_QUIRK_FIX_HYPERCALL_INSN (1 << 5) +#define KVM_X86_QUIRK_MWAIT_NEVER_FAULTS (1 << 6) #define KVM_STATE_NESTED_FORMAT_VMX 0 #define KVM_STATE_NESTED_FORMAT_SVM 1 |