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Message-ID: <7e3be98e-d0c0-634b-fbb3-0096976a89bf@gmail.com>
Date: Fri, 14 Oct 2022 17:25:58 +0800
From: Like Xu <like.xu.linux@...il.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [PATCH v5 5/8] KVM: x86: Track supported PERF_CAPABILITIES in
kvm_caps
On 6/10/2022 8:03 am, Sean Christopherson wrote:
> Track KVM's supported PERF_CAPABILITIES in kvm_caps instead of computing
> the supported capabilities on the fly every time. Using kvm_caps will
> also allow for future cleanups as the kvm_caps values can be used
> directly in common x86 code.
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
A similar change was made to one of my git branches. Please move forward.
Acked-by: Like Xu <likexu@...cent.com>
> ---
> arch/x86/kvm/svm/svm.c | 2 ++
> arch/x86/kvm/vmx/capabilities.h | 25 ------------------------
> arch/x86/kvm/vmx/pmu_intel.c | 2 +-
> arch/x86/kvm/vmx/vmx.c | 34 +++++++++++++++++++++++++++++----
> arch/x86/kvm/x86.h | 1 +
> 5 files changed, 34 insertions(+), 30 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 58f0077d9357..6b680b249975 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -2715,6 +2715,7 @@ static int svm_get_msr_feature(struct kvm_msr_entry *msr)
> msr->data |= MSR_F10H_DECFG_LFENCE_SERIALIZE;
> break;
> case MSR_IA32_PERF_CAPABILITIES:
> + msr->data = kvm_caps.supported_perf_cap;
> return 0;
> default:
> return KVM_MSR_RET_INVALID;
> @@ -4898,6 +4899,7 @@ static __init void svm_set_cpu_caps(void)
> {
> kvm_set_cpu_caps();
>
> + kvm_caps.supported_perf_cap = 0;
> kvm_caps.supported_xss = 0;
>
> /* CPUID 0x80000001 and 0x8000000A (SVM features) */
> diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
> index 479124e49bbd..cd2ac9536c99 100644
> --- a/arch/x86/kvm/vmx/capabilities.h
> +++ b/arch/x86/kvm/vmx/capabilities.h
> @@ -395,31 +395,6 @@ static inline bool vmx_pebs_supported(void)
> return boot_cpu_has(X86_FEATURE_PEBS) && kvm_pmu_cap.pebs_ept;
> }
>
> -static inline u64 vmx_get_perf_capabilities(void)
> -{
> - u64 perf_cap = PMU_CAP_FW_WRITES;
> - struct x86_pmu_lbr lbr;
> - u64 host_perf_cap = 0;
> -
> - if (!enable_pmu)
> - return 0;
> -
> - if (boot_cpu_has(X86_FEATURE_PDCM))
> - rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
> -
> - x86_perf_get_lbr(&lbr);
> - if (lbr.nr)
> - perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
> -
> - if (vmx_pebs_supported()) {
> - perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
> - if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
> - perf_cap &= ~PERF_CAP_PEBS_BASELINE;
> - }
> -
> - return perf_cap;
> -}
> -
> static inline bool cpu_has_notify_vmexit(void)
> {
> return vmcs_config.cpu_based_2nd_exec_ctrl &
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index 25b70a85bef5..24f4c22691f8 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -631,7 +631,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
> pmu->fixed_counters[i].current_config = 0;
> }
>
> - vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
> + vcpu->arch.perf_capabilities = kvm_caps.supported_perf_cap;
> lbr_desc->records.nr = 0;
> lbr_desc->event = NULL;
> lbr_desc->msr_passthrough = false;
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index e70ac91cd2fb..850ff6e683d1 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1850,7 +1850,7 @@ static int vmx_get_msr_feature(struct kvm_msr_entry *msr)
> return 1;
> return vmx_get_vmx_msr(&vmcs_config.nested, msr->index, &msr->data);
> case MSR_IA32_PERF_CAPABILITIES:
> - msr->data = vmx_get_perf_capabilities();
> + msr->data = kvm_caps.supported_perf_cap;
> return 0;
> default:
> return KVM_MSR_RET_INVALID;
> @@ -2029,7 +2029,7 @@ static u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated
> (host_initiated || guest_cpuid_has(vcpu, X86_FEATURE_BUS_LOCK_DETECT)))
> debugctl |= DEBUGCTLMSR_BUS_LOCK_DETECT;
>
> - if ((vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT) &&
> + if ((kvm_caps.supported_perf_cap & PMU_CAP_LBR_FMT) &&
> (host_initiated || intel_pmu_lbr_is_enabled(vcpu)))
> debugctl |= DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI;
>
> @@ -2342,14 +2342,14 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> return 1;
> if (data & PMU_CAP_LBR_FMT) {
> if ((data & PMU_CAP_LBR_FMT) !=
> - (vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT))
> + (kvm_caps.supported_perf_cap & PMU_CAP_LBR_FMT))
> return 1;
> if (!cpuid_model_is_consistent(vcpu))
> return 1;
> }
> if (data & PERF_CAP_PEBS_FORMAT) {
> if ((data & PERF_CAP_PEBS_MASK) !=
> - (vmx_get_perf_capabilities() & PERF_CAP_PEBS_MASK))
> + (kvm_caps.supported_perf_cap & PERF_CAP_PEBS_MASK))
> return 1;
> if (!guest_cpuid_has(vcpu, X86_FEATURE_DS))
> return 1;
> @@ -7669,6 +7669,31 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> vmx_update_exception_bitmap(vcpu);
> }
>
> +static u64 vmx_get_perf_capabilities(void)
> +{
> + u64 perf_cap = PMU_CAP_FW_WRITES;
> + struct x86_pmu_lbr lbr;
> + u64 host_perf_cap = 0;
> +
> + if (!enable_pmu)
> + return 0;
> +
> + if (boot_cpu_has(X86_FEATURE_PDCM))
> + rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
> +
> + x86_perf_get_lbr(&lbr);
> + if (lbr.nr)
> + perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
> +
> + if (vmx_pebs_supported()) {
> + perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
> + if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
> + perf_cap &= ~PERF_CAP_PEBS_BASELINE;
> + }
> +
> + return perf_cap;
> +}
> +
> static __init void vmx_set_cpu_caps(void)
> {
> kvm_set_cpu_caps();
> @@ -7691,6 +7716,7 @@ static __init void vmx_set_cpu_caps(void)
>
> if (!enable_pmu)
> kvm_cpu_cap_clear(X86_FEATURE_PDCM);
> + kvm_caps.supported_perf_cap = vmx_get_perf_capabilities();
>
> if (!enable_sgx) {
> kvm_cpu_cap_clear(X86_FEATURE_SGX);
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 829d3134c1eb..9de72586f406 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -27,6 +27,7 @@ struct kvm_caps {
> u64 supported_mce_cap;
> u64 supported_xcr0;
> u64 supported_xss;
> + u64 supported_perf_cap;
> };
>
> void kvm_spurious_fault(void);
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