> -----Original Message----- > From: Sean Christopherson <seanjc@xxxxxxxxxx> > Sent: Wednesday, December 30, 2020 10:08 AM > To: Borislav Petkov <bp@xxxxxxxxx> > Cc: Moger, Babu <Babu.Moger@xxxxxxx>; pbonzini@xxxxxxxxxx; > tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; fenghua.yu@xxxxxxxxx; > tony.luck@xxxxxxxxx; wanpengli@xxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; > Lendacky, Thomas <Thomas.Lendacky@xxxxxxx>; peterz@xxxxxxxxxxxxx; > joro@xxxxxxxxxx; x86@xxxxxxxxxx; kyung.min.park@xxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; krish.sadhukhan@xxxxxxxxxx; hpa@xxxxxxxxx; > mgross@xxxxxxxxxxxxxxx; vkuznets@xxxxxxxxxx; Phillips, Kim > <kim.phillips@xxxxxxx>; Huang2, Wei <Wei.Huang2@xxxxxxx>; > jmattson@xxxxxxxxxx > Subject: Re: [PATCH v2 2/2] KVM: SVM: Add support for Virtual SPEC_CTRL > > On Wed, Dec 30, 2020, Borislav Petkov wrote: > > On Tue, Dec 22, 2020 at 04:31:55PM -0600, Babu Moger wrote: > > > @@ -2549,7 +2559,10 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, > struct msr_data *msr_info) > > > !guest_cpuid_has(vcpu, X86_FEATURE_AMD_SSBD)) > > > return 1; > > > > > > - msr_info->data = svm->spec_ctrl; > > > + if (static_cpu_has(X86_FEATURE_V_SPEC_CTRL)) > > > + msr_info->data = svm->vmcb->save.spec_ctrl; > > > + else > > > + msr_info->data = svm->spec_ctrl; > > > break; > > > case MSR_AMD64_VIRT_SPEC_CTRL: > > > if (!msr_info->host_initiated && > > > @@ -2640,6 +2653,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, > struct msr_data *msr) > > > return 1; > > > > > > svm->spec_ctrl = data; > > > + if (static_cpu_has(X86_FEATURE_V_SPEC_CTRL)) > > > + svm->vmcb->save.spec_ctrl = data; > > > if (!data) > > > break; > > > > > > > Are the get/set_msr() accessors such a fast path that they need > > static_cpu_has() ? > > Nope, they can definitely use boot_cpu_has(). With Tom's latest comment, this change may not be required. I will remove these changes. Thanks Babu
