On Thu, Dec 16, 2021, Vitaly Kuznetsov wrote: > Sean Christopherson <seanjc@xxxxxxxxxx> writes: > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 85127b3e3690..65e297875405 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -3424,7 +3424,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > > > > if (!msr_info->host_initiated) > > return 1; > > - if (guest_cpuid_has(vcpu, X86_FEATURE_PDCM) && kvm_get_msr_feature(&msr_ent)) > > + if (kvm_get_msr_feature(&msr_ent)) > > return 1; > > if (data & ~msr_ent.data) > > return 1; > > This looks OK. > > > @@ -3779,14 +3779,12 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > > msr_info->data = vcpu->arch.microcode_version; > > break; > > case MSR_IA32_ARCH_CAPABILITIES: > > - if (!msr_info->host_initiated && > > - !guest_cpuid_has(vcpu, X86_FEATURE_ARCH_CAPABILITIES)) > > + if (!msr_info->host_initiated) > > return 1; > > msr_info->data = vcpu->arch.arch_capabilities; > > break; > > case MSR_IA32_PERF_CAPABILITIES: > > - if (!msr_info->host_initiated && > > - !guest_cpuid_has(vcpu, X86_FEATURE_PDCM)) > > + if (!msr_info->host_initiated) > > return 1; > > msr_info->data = vcpu->arch.perf_capabilities; > > break; > > > > Hm, this change will unconditionally forbid reading > MSR_IA32_ARCH_CAPABILITIES/MSR_IA32_PERF_CAPABILITIES from the guest. Is > this what we want? No, I completely misread the code. The kvm_set_msr_common() goof seems to be the only bug, and that would also explain the selftest's bad testcase.
