From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39BE53BFE38; Mon, 15 Jun 2026 23:10:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781565017; cv=none; b=GeScB5ccGku25GnezJtTFSzBAHXpeqTWsrygOnO5EL3Z0HnJO6mq2+Vg3OEQzfsbWdXQhd77FbJ7RJqF4LqdcXeSRZwP/tEkXX2zMCxjFAn9Iy33YHrstZ7AQ22RFqhuMdhTsh2Bp6qjaiMnjll60dZAilY0EUiXtmt7bFUNuPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781565017; c=relaxed/simple; bh=mObAXzgzVSj2g/0GQmnGJbz/wiNhfxgB7FVTxDAhup8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TzAg4UbyJnt4f/rBS5hA3hzvA2jMkXmhljlN8+6jPdnBBUZYXbS1EOTAXeBIHmhc8xkSbPXjSom/Wpa+UokdqAQ/aHNVWoeL4Pq3tWv6VN2psHN3a/K6kaZNBWivaolcQezTHbzijw+TZ1QpqoI1PhRvomWj3wPV0FC3j5IQf7E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=KkXG382W; arc=none smtp.client-ip=198.175.65.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="KkXG382W" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1781565012; x=1813101012; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mObAXzgzVSj2g/0GQmnGJbz/wiNhfxgB7FVTxDAhup8=; b=KkXG382Wrvg6CfThaYnafIbUwONhO0wQfvxxrkMeIscjeYddhJqwzCOd JB85tig3IbK52CWB9jhcoBTKIBZEJME2GmDA808oMKsedplKdGCSaVm0H b/I2+ZVHrnxo5wwbkbQa8A120n+23ibXGBdpObB6w1jz0TyZA6lrdfkTy /VRuLNyvoJCqFePEGmM7kxscp6Uw+avQSOn/qerbfClgLhFikwydxBfoU 5K/YHW7edKarzJAUolwPbbZGkpouYGT5eTX1OErUtwZrhWsbc6XJaQaPv C3Ie5sg35vP4TUI6P6PExyGeILv1zf6WCa4q6vRgnIcoRxpxZXXn0PcOn g==; X-CSE-ConnectionGUID: a0Y9gODnSRuguMIJXq4kDg== X-CSE-MsgGUID: odb7gGGjQRevcN9D4zeeHA== X-IronPort-AV: E=McAfee;i="6800,10657,11818"; a="99738603" X-IronPort-AV: E=Sophos;i="6.24,207,1774335600"; d="scan'208";a="99738603" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2026 16:10:08 -0700 X-CSE-ConnectionGUID: U9BGZOccQRyMD1JqWS5O+g== X-CSE-MsgGUID: wFCCThigQJWnbgtE0BANRw== X-ExtLoop1: 1 Received: from 9cc2c43eec6b.jf.intel.com ([10.54.77.29]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2026 16:10:07 -0700 From: Zide Chen To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Mingwei Zhang , Zide Chen , Das Sandipan , Shukla Manali , Dapeng Mi , Falcon Thomas , Xudong Hao Subject: [PATCH V3 3/4] KVM: x86/pmu: Support PERF_METRICS MSR in mediated vPMU Date: Mon, 15 Jun 2026 16:01:17 -0700 Message-ID: <20260615230118.50718-4-zide.chen@intel.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260615230118.50718-1-zide.chen@intel.com> References: <20260615230118.50718-1-zide.chen@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Dapeng Mi Bit 15 in IA32_PERF_CAPABILITIES indicates that the CPU provides built-in support for Topdown Microarchitecture Analysis (TMA) L1 metrics via the IA32_PERF_METRICS MSR. Expose this capability only when mediated vPMU is enabled, as emulating IA32_PERF_METRICS in the legacy vPMU model is impractical. Pass IA32_PERF_METRICS through to the guest only when mediated vPMU is enabled and bit 15 is set in guest IA32_PERF_CAPABILITIES. Allow kvm_pmu_{get,set}_msr() to handle this MSR for host accesses. Save and restore this MSR on host/guest PMU context switches so that host PMU activity does not clobber the guest value, and guest state is not leaked into the host. Signed-off-by: Dapeng Mi Signed-off-by: Zide Chen --- v3: - Replace WARN_ON() with WARN_ON_ONCE(). (Dapeng) - Add comments to explain why don't validate writes on PERF_METRICS. --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/include/asm/msr-index.h | 1 + arch/x86/include/asm/perf_event.h | 1 + arch/x86/kvm/vmx/pmu_intel.c | 36 +++++++++++++++++++++++++++++++ arch/x86/kvm/vmx/pmu_intel.h | 5 +++++ arch/x86/kvm/vmx/vmx.c | 6 ++++++ arch/x86/kvm/x86.c | 6 +++++- 7 files changed, 55 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 754103e7ab4d..9b03475843f3 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -597,6 +597,7 @@ struct kvm_pmu { u64 global_status_rsvd; u64 reserved_bits; u64 raw_event_mask; + u64 perf_metrics; struct kvm_pmc gp_counters[KVM_MAX_NR_GP_COUNTERS]; struct kvm_pmc fixed_counters[KVM_MAX_NR_FIXED_COUNTERS]; diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 18c4be75e927..fdcaeb6c8352 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -331,6 +331,7 @@ #define PERF_CAP_PEBS_FORMAT 0xf00 #define PERF_CAP_FW_WRITES BIT_ULL(13) #define PERF_CAP_PEBS_BASELINE BIT_ULL(14) +#define PERF_CAP_PERF_METRICS BIT_ULL(15) #define PERF_CAP_PEBS_TIMING_INFO BIT_ULL(17) #define PERF_CAP_PEBS_MASK (PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \ PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE | \ diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 1eb13673e889..bc2e1cbcd9b9 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -447,6 +447,7 @@ static inline bool is_topdown_idx(int idx) #define GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT 54 #define GLOBAL_STATUS_ARCH_PEBS_THRESHOLD BIT_ULL(GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT) #define GLOBAL_STATUS_PERF_METRICS_OVF_BIT 48 +#define GLOBAL_STATUS_PERF_METRICS_OVF BIT_ULL(GLOBAL_STATUS_PERF_METRICS_OVF_BIT) #define GLOBAL_CTRL_EN_PERF_METRICS BIT_ULL(48) /* diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 59b7a90c79e1..19daee29b731 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -188,6 +188,8 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) switch (msr) { case MSR_CORE_PERF_FIXED_CTR_CTRL: return kvm_pmu_has_perf_global_ctrl(pmu); + case MSR_PERF_METRICS: + return vcpu_has_perf_metrics(vcpu); case MSR_IA32_PEBS_ENABLE: ret = vcpu_get_perf_capabilities(vcpu) & PERF_CAP_PEBS_FORMAT; break; @@ -345,6 +347,10 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_CORE_PERF_FIXED_CTR_CTRL: msr_info->data = pmu->fixed_ctr_ctrl; break; + case MSR_PERF_METRICS: + WARN_ON_ONCE(!msr_info->host_initiated); + msr_info->data = pmu->perf_metrics; + break; case MSR_IA32_PEBS_ENABLE: msr_info->data = pmu->pebs_enable; break; @@ -394,6 +400,15 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (pmu->fixed_ctr_ctrl != data) reprogram_fixed_counters(pmu, data); break; + case MSR_PERF_METRICS: + WARN_ON_ONCE(!msr_info->host_initiated); + + /* + * If TMA level 2 is not supported, bits [63:32] are reserved + * and ignored on write, so no validation is needed here. + */ + pmu->perf_metrics = data; + break; case MSR_IA32_PEBS_ENABLE: if (data & pmu->pebs_enable_rsvd) return 1; @@ -589,6 +604,11 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->global_status_rsvd &= ~MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI; + if (perf_capabilities & PERF_CAP_PERF_METRICS) { + pmu->global_ctrl_rsvd &= ~GLOBAL_CTRL_EN_PERF_METRICS; + pmu->global_status_rsvd &= ~GLOBAL_STATUS_PERF_METRICS_OVF; + } + if (perf_capabilities & PERF_CAP_PEBS_FORMAT) { if (perf_capabilities & PERF_CAP_PEBS_BASELINE) { pmu->pebs_enable_rsvd = counter_rsvd; @@ -632,6 +652,9 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu) static void intel_pmu_reset(struct kvm_vcpu *vcpu) { + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + + pmu->perf_metrics = 0; intel_pmu_release_guest_lbr_event(vcpu); } @@ -803,6 +826,13 @@ static void intel_mediated_pmu_load(struct kvm_vcpu *vcpu) struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); u64 global_status, toggle; + /* + * PERF_METRICS MSR must be restored closely after fixed counter 3 + * (kvm_pmu_load_guest_pmcs()). + */ + if (vcpu_has_perf_metrics(vcpu)) + wrmsrq(MSR_PERF_METRICS, pmu->perf_metrics); + rdmsrq(MSR_CORE_PERF_GLOBAL_STATUS, global_status); toggle = pmu->global_status ^ global_status; if (global_status & toggle) @@ -831,6 +861,12 @@ static void intel_mediated_pmu_put(struct kvm_vcpu *vcpu) */ if (pmu->fixed_ctr_ctrl_hw) wrmsrq(MSR_CORE_PERF_FIXED_CTR_CTRL, 0); + + if (vcpu_has_perf_metrics(vcpu)) { + pmu->perf_metrics = rdpmc(INTEL_PMC_FIXED_RDPMC_METRICS); + if (pmu->perf_metrics) + wrmsrq(MSR_PERF_METRICS, 0); + } } struct kvm_pmu_ops intel_pmu_ops __initdata = { diff --git a/arch/x86/kvm/vmx/pmu_intel.h b/arch/x86/kvm/vmx/pmu_intel.h index 5d9357640aa1..2ec547223b09 100644 --- a/arch/x86/kvm/vmx/pmu_intel.h +++ b/arch/x86/kvm/vmx/pmu_intel.h @@ -40,4 +40,9 @@ struct lbr_desc { extern struct x86_pmu_lbr vmx_lbr_caps; +static inline bool vcpu_has_perf_metrics(struct kvm_vcpu *vcpu) +{ + return !!(vcpu_get_perf_capabilities(vcpu) & PERF_CAP_PERF_METRICS); +} + #endif /* __KVM_X86_VMX_PMU_INTEL_H */ diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index c548f22375ad..7cffe1619a1f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4264,6 +4264,9 @@ static void vmx_recalc_pmu_msr_intercepts(struct kvm_vcpu *vcpu) MSR_TYPE_RW, intercept); vmx_set_intercept_for_msr(vcpu, MSR_CORE_PERF_GLOBAL_OVF_CTRL, MSR_TYPE_RW, intercept); + + vmx_set_intercept_for_msr(vcpu, MSR_PERF_METRICS, MSR_TYPE_RW, + !vcpu_has_perf_metrics(vcpu)); } static void vmx_recalc_msr_intercepts(struct kvm_vcpu *vcpu) @@ -8088,6 +8091,9 @@ static __init u64 vmx_get_perf_capabilities(void) perf_cap &= ~PERF_CAP_PEBS_BASELINE; } + if (enable_mediated_pmu) + perf_cap |= host_perf_cap & PERF_CAP_PERF_METRICS; + return perf_cap; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b9cca855bc10..2ac297ba3598 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -352,7 +352,7 @@ static const u32 msrs_to_save_pmu[] = { MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1, MSR_ARCH_PERFMON_FIXED_CTR2, MSR_ARCH_PERFMON_FIXED_CTR3, MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS, - MSR_CORE_PERF_GLOBAL_CTRL, + MSR_CORE_PERF_GLOBAL_CTRL, MSR_PERF_METRICS, MSR_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA, MSR_PEBS_DATA_CFG, /* This part of MSRs should match KVM_MAX_NR_INTEL_GP_COUNTERS. */ @@ -7679,6 +7679,10 @@ static void kvm_probe_msr_to_save(u32 msr_index) intel_pt_validate_hw_cap(PT_CAP_num_address_ranges) * 2)) return; break; + case MSR_PERF_METRICS: + if (!(kvm_caps.supported_perf_cap & PERF_CAP_PERF_METRICS)) + return; + break; case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR0 + KVM_MAX_NR_GP_COUNTERS - 1: if (msr_index - MSR_ARCH_PERFMON_PERFCTR0 >= -- 2.54.0