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| author | Wanpeng Li <wanpengli@tencent.com> | 2019-05-21 14:06:54 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-06-04 19:29:09 +0200 |
| commit | 511a8556e3342af6a46eb9477936b29aa983f154 (patch) | |
| tree | 59eb52e1ebf9eef6051629cfe9db3fd347693849 /arch/x86/kvm/cpuid.c | |
| parent | b51700632e0e53254733ff706e5bdca22d19dbe5 (diff) | |
| download | linux-511a8556e3342af6a46eb9477936b29aa983f154.tar.bz2 | |
KVM: X86: Emulate MSR_IA32_MISC_ENABLE MWAIT bit
MSR IA32_MISC_ENABLE bit 18, according to SDM:
| When this bit is set to 0, the MONITOR feature flag is not set (CPUID.01H:ECX[bit 3] = 0).
| This indicates that MONITOR/MWAIT are not supported.
|
| Software attempts to execute MONITOR/MWAIT will cause #UD when this bit is 0.
|
| When this bit is set to 1 (default), MONITOR/MWAIT are supported (CPUID.01H:ECX[bit 3] = 1).
The CPUID.01H:ECX[bit 3] ought to mirror the value of the MSR bit,
CPUID.01H:ECX[bit 3] is a better guard than kvm_mwait_in_guest().
kvm_mwait_in_guest() affects the behavior of MONITOR/MWAIT, not its
guest visibility.
This patch implements toggling of the CPUID bit based on guest writes
to the MSR.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
[Fixes for backwards compatibility - 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 | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index e18a9f9f65b5..60f87ba2ccca 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -137,6 +137,16 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu) (best->eax & (1 << KVM_FEATURE_PV_UNHALT))) best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT); + if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT)) { + best = kvm_find_cpuid_entry(vcpu, 0x1, 0); + if (best) { + if (vcpu->arch.ia32_misc_enable_msr & MSR_IA32_MISC_ENABLE_MWAIT) + best->ecx |= F(MWAIT); + else + best->ecx &= ~F(MWAIT); + } + } + /* Update physical-address width */ vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu); kvm_mmu_reset_context(vcpu); |