Messages in this thread | | | Subject | RE: [PATCH v2 2/2] KVM: SVM: Add support for Virtual SPEC_CTRL | From | Babu Moger <> | Date | Mon, 4 Jan 2021 12:37:13 -0600 |
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> -----Original Message----- > From: Sean Christopherson <seanjc@google.com> > Sent: Wednesday, December 30, 2020 10:08 AM > To: Borislav Petkov <bp@alien8.de> > Cc: Moger, Babu <Babu.Moger@amd.com>; pbonzini@redhat.com; > tglx@linutronix.de; mingo@redhat.com; fenghua.yu@intel.com; > tony.luck@intel.com; wanpengli@tencent.com; kvm@vger.kernel.org; > Lendacky, Thomas <Thomas.Lendacky@amd.com>; peterz@infradead.org; > joro@8bytes.org; x86@kernel.org; kyung.min.park@intel.com; linux- > kernel@vger.kernel.org; krish.sadhukhan@oracle.com; hpa@zytor.com; > mgross@linux.intel.com; vkuznets@redhat.com; Phillips, Kim > <kim.phillips@amd.com>; Huang2, Wei <Wei.Huang2@amd.com>; > jmattson@google.com > 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
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