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Date: Fri, 8 Jan 2021 09:37:03 +0800 From: Like Xu <like.xu@...ux.intel.com> To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>, Vitaly Kuznetsov <vkuznets@...hat.com>, Wanpeng Li <wanpengli@...cent.com>, Jim Mattson <jmattson@...gle.com>, Joerg Roedel <joro@...tes.org> Cc: Ingo Molnar <mingo@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>, "H . Peter Anvin" <hpa@...or.com>, ak@...ux.intel.com, wei.w.wang@...el.com, kan.liang@...el.com, x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [RESEND v13 09/10] KVM: vmx/pmu: Expose LBR_FMT in the MSR_IA32_PERF_CAPABILITIES Userspace could enable guest LBR feature when the exactly supported LBR format value is initialized to the MSR_IA32_PERF_CAPABILITIES and the LBR is also compatible with vPMU version and host cpu model. Signed-off-by: Like Xu <like.xu@...ux.intel.com> Reviewed-by: Andi Kleen <ak@...ux.intel.com> --- arch/x86/kvm/vmx/capabilities.h | 9 ++++++++- arch/x86/kvm/vmx/vmx.c | 7 +++++++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h index 57b940c613ab..a9a7c4d1b634 100644 --- a/arch/x86/kvm/vmx/capabilities.h +++ b/arch/x86/kvm/vmx/capabilities.h @@ -378,7 +378,14 @@ static inline u64 vmx_get_perf_capabilities(void) * Since counters are virtualized, KVM would support full * width counting unconditionally, even if the host lacks it. */ - return PMU_CAP_FW_WRITES; + u64 perf_cap = PMU_CAP_FW_WRITES; + + if (boot_cpu_has(X86_FEATURE_PDCM)) + rdmsrl(MSR_IA32_PERF_CAPABILITIES, perf_cap); + + perf_cap |= perf_cap & PMU_CAP_LBR_FMT; + + return perf_cap; } static inline u64 vmx_supported_debugctl(void) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index ad3b079f6700..9cb5b1e4fc27 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2229,6 +2229,13 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_IA32_PERF_CAPABILITIES: if (data && !vcpu_to_pmu(vcpu)->version) return 1; + if (data & PMU_CAP_LBR_FMT) { + if ((data & PMU_CAP_LBR_FMT) != + (vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT)) + return 1; + if (!intel_pmu_lbr_is_compatible(vcpu)) + return 1; + } ret = kvm_set_msr_common(vcpu, msr_info); break; -- 2.29.2
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