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X-CSE-ConnectionGUID: r5d1FcBmSbax/VCa7Tpy0g== X-CSE-MsgGUID: r9QEkc0CTW+I4tvwSqhBhQ== X-IronPort-AV: E=McAfee;i="6800,10657,11832"; a="94091096" X-IronPort-AV: E=Sophos;i="6.24,233,1774335600"; d="scan'208";a="94091096" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jun 2026 19:23:32 -0700 X-CSE-ConnectionGUID: DJVaWLCpT8i4pMUAo1nv3g== X-CSE-MsgGUID: YfgxEhF1QkeF10euEZXQFw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,233,1774335600"; d="scan'208";a="249489339" Received: from dapengmi-mobl1.ccr.corp.intel.com (HELO [10.124.232.65]) ([10.124.232.65]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jun 2026 19:23:29 -0700 Message-ID: <7cce9e44-3cc6-4265-8e83-0a49f1e7c2f5@linux.intel.com> Date: Tue, 30 Jun 2026 10:23:27 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 7/8] KVM: x86/pmu: Emulate RDPMC on performance metrics To: Zide Chen , Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Mingwei Zhang , Das Sandipan , Shukla Manali , Falcon Thomas , Xudong Hao References: <20260629231938.15129-1-zide.chen@intel.com> <20260629231938.15129-8-zide.chen@intel.com> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: <20260629231938.15129-8-zide.chen@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Reviewed-by: Dapeng Mi On 6/30/2026 7:19 AM, Zide Chen wrote: > If the host has the PERF_METRICS capability but it's not present on > the guest, RDPMC interception must be enabled and KVM should inject > an #GP when the guest attempts a PERF_METRICS RDPMC. > > If the guest has PERF_METRICS but RDPMC interception is enabled for > other reasons, KVM needs to emulate RDPMC with type 2000H. > > For simplicity, Metrics Clear Mode is not supported. > > Signed-off-by: Zide Chen > --- > v6: > - Merge kvm_pmu_rdpmc_metrics() into intel_emulate_rdpmc(). > - Reject non-zero index. > v5: > - new patch. > --- > arch/x86/kvm/pmu.c | 7 +++++++ > arch/x86/kvm/vmx/pmu_intel.c | 14 ++++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c > index 8ef2d4761790..04b9c840f218 100644 > --- a/arch/x86/kvm/pmu.c > +++ b/arch/x86/kvm/pmu.c > @@ -806,6 +806,12 @@ bool kvm_need_perf_global_ctrl_intercept(struct kvm_vcpu *vcpu) > } > EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_need_perf_global_ctrl_intercept); > > +static bool kvm_need_perf_metrics_intercept(struct kvm_vcpu *vcpu) > +{ > + return (kvm_host.perf_capabilities & PERF_CAP_PERF_METRICS) && > + !kvm_vcpu_has_perf_metrics(vcpu); > +} > + > bool kvm_need_rdpmc_intercept(struct kvm_vcpu *vcpu) > { > struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); > @@ -818,6 +824,7 @@ bool kvm_need_rdpmc_intercept(struct kvm_vcpu *vcpu) > return true; > > return kvm_need_any_pmc_intercept(vcpu) || > + kvm_need_perf_metrics_intercept(vcpu) || > pmu->counter_bitmask[KVM_PMC_GP] != (BIT_ULL(kvm_host_pmu.bit_width_gp) - 1) || > pmu->counter_bitmask[KVM_PMC_FIXED] != (BIT_ULL(kvm_host_pmu.bit_width_fixed) - 1); > } > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c > index 080677372c9b..93b5a8360377 100644 > --- a/arch/x86/kvm/vmx/pmu_intel.c > +++ b/arch/x86/kvm/vmx/pmu_intel.c > @@ -30,6 +30,7 @@ > */ > #define INTEL_RDPMC_GP 0 > #define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE > +#define INTEL_RDPMC_METRICS INTEL_PMC_FIXED_RDPMC_METRICS > > #define INTEL_RDPMC_TYPE_MASK GENMASK(31, 16) > #define INTEL_RDPMC_INDEX_MASK GENMASK(15, 0) > @@ -124,6 +125,19 @@ static int intel_emulate_rdpmc(struct kvm_vcpu *vcpu, unsigned int idx, > counters = pmu->gp_counters; > num_counters = pmu->nr_arch_gp_counters; > break; > + case INTEL_RDPMC_METRICS: > + if (!kvm_vcpu_has_perf_metrics(vcpu)) > + return 1; > + > + /* > + * The index in ECX[15:0] is implementation specific, but no > + * platform currently supports a non-zero index. > + */ > + if (idx) > + return 1; > + > + *data = pmu->perf_metrics; > + return 0; > default: > return 1; > }