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| author | Kyle Huey <me@kylehuey.com> | 2017-03-20 01:16:28 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-04-21 12:50:06 +0200 |
| commit | db2336a80489e7c3c7728cefd9be58fac5ecfb39 (patch) | |
| tree | 2a462ecee35d68dea1b931ba5ee226933e663cd0 /arch/x86/kvm/cpuid.c | |
| parent | bd17117bb2af60d4bc44e0f9c859e800a3d99722 (diff) | |
| download | lwn-db2336a80489e7c3c7728cefd9be58fac5ecfb39.tar.gz lwn-db2336a80489e7c3c7728cefd9be58fac5ecfb39.zip | |
KVM: x86: virtualize cpuid faulting
Hardware support for faulting on the cpuid instruction is not required to
emulate it, because cpuid triggers a VM exit anyways. KVM handles the relevant
MSRs (MSR_PLATFORM_INFO and MSR_MISC_FEATURES_ENABLE) and upon a
cpuid-induced VM exit checks the cpuid faulting state and the CPL.
kvm_require_cpl is even kind enough to inject the GP fault for us.
Signed-off-by: Kyle Huey <khuey@kylehuey.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[Return "1" from kvm_emulate_cpuid, it's not void. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index efde6cc50875..a181ae76c71c 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -876,6 +876,9 @@ int kvm_emulate_cpuid(struct kvm_vcpu *vcpu) { u32 eax, ebx, ecx, edx; + if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0)) + return 1; + eax = kvm_register_read(vcpu, VCPU_REGS_RAX); ecx = kvm_register_read(vcpu, VCPU_REGS_RCX); kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx); |