From patchwork Fri May 6 03:32:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Yang, Weijiang" X-Patchwork-Id: 12840528 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61B02C433F5 for ; Fri, 6 May 2022 03:34:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1388854AbiEFDiE (ORCPT ); Thu, 5 May 2022 23:38:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238889AbiEFDhP (ORCPT ); Thu, 5 May 2022 23:37:15 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4856064706; Thu, 5 May 2022 20:33:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651808013; x=1683344013; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=+3gk55q3Ad3Of360G/YnCWmNKXfCtFp62GgwqT7dhvk=; b=dX8gaI61Ig0HsSR0bvIgKUFHZwW+h2NP7K62wavnLRDrUaefUXOtoQhD 5hCPAHQpqi5ZmExQDELDlTVTsDF33JF4RClsXLLaCgJgV9SuWHyvJmQcT mNGVTAcCRBGdeHOxDVLDisJXgJh1saHEDzStarmG+nEWON71dg1cLeA+N wLAQnyCvtpLLdod7ihJY/s+tBXwEAKM3LSrX37IQ3PTvL1mcrR0Y3Og4p N81D1YZ4UMKoqo7d5L2fRRTfyED1JRE6PH8rZWBgWImnsOifTIUUveZvf WF16CrI+yxfPK5Z9LdlZsZ5dXf9L0R+HoqXYTF30KDGST0M+g7sdOLpA6 w==; X-IronPort-AV: E=McAfee;i="6400,9594,10338"; a="248241431" X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="248241431" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2022 20:33:33 -0700 X-IronPort-AV: E=Sophos;i="5.91,203,1647327600"; d="scan'208";a="632745172" Received: from embargo.jf.intel.com ([10.165.9.183]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2022 20:33:32 -0700 From: Yang Weijiang To: pbonzini@redhat.com, jmattson@google.com, seanjc@google.com, kan.liang@linux.intel.com, like.xu.linux@gmail.com, vkuznets@redhat.com, wei.w.wang@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Like Xu , Yang Weijiang Subject: [PATCH v11 06/16] KVM: vmx/pmu: Emulate MSR_ARCH_LBR_DEPTH for guest Arch LBR Date: Thu, 5 May 2022 23:32:55 -0400 Message-Id: <20220506033305.5135-7-weijiang.yang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220506033305.5135-1-weijiang.yang@intel.com> References: <20220506033305.5135-1-weijiang.yang@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Like Xu The number of Arch LBR entries available is determined by the value in host MSR_ARCH_LBR_DEPTH.DEPTH. The supported LBR depth values are enumerated in CPUID.(EAX=01CH, ECX=0):EAX[7:0]. For each bit "n" set in this field, the MSR_ARCH_LBR_DEPTH.DEPTH value of "8*(n+1)" is supported. In the first generation of Arch LBR, max entry size is 32, host configures the max size and guest always honors the setting. Write to MSR_ARCH_LBR_DEPTH has side-effect, all LBR entries are reset to 0. Kernel PMU driver can leverage this effect to do fask reset to LBR record MSRs. KVM allows guest to achieve it when Arch LBR records MSRs are passed through to the guest. Signed-off-by: Like Xu Co-developed-by: Yang Weijiang Signed-off-by: Yang Weijiang Reviewed-by: Kan Liang --- arch/x86/include/asm/kvm_host.h | 3 ++ arch/x86/kvm/vmx/pmu_intel.c | 50 ++++++++++++++++++++++++++++++++- 2 files changed, 52 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4ff36610af6a..753e3ecac1a1 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -534,6 +534,9 @@ struct kvm_pmu { * redundant check before cleanup if guest don't use vPMU at all. */ u8 event_count; + + /* Guest arch lbr depth supported by KVM. */ + u64 kvm_arch_lbr_depth; }; struct kvm_pmu_ops; diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index b82b6709d7a8..e2b5fc1f4f1a 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -192,6 +192,12 @@ static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index) if (!intel_pmu_lbr_is_enabled(vcpu)) return ret; + if (index == MSR_ARCH_LBR_DEPTH) { + if (kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR)) + ret = guest_cpuid_has(vcpu, X86_FEATURE_ARCH_LBR); + return ret; + } + ret = (index == MSR_LBR_SELECT) || (index == MSR_LBR_TOS) || (index >= records->from && index < records->from + records->nr) || (index >= records->to && index < records->to + records->nr); @@ -205,7 +211,7 @@ static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index) static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); - int ret; + int ret = 0; switch (msr) { case MSR_CORE_PERF_FIXED_CTR_CTRL: @@ -342,10 +348,26 @@ static bool intel_pmu_handle_lbr_msrs_access(struct kvm_vcpu *vcpu, return true; } +/* + * Check if the requested depth value the same as that of host. + * When guest/host depth are different, the handling would be tricky, + * so now only max depth is supported for both host and guest. + */ +static bool arch_lbr_depth_is_valid(struct kvm_vcpu *vcpu, u64 depth) +{ + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + + if (!kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR)) + return false; + + return (depth == pmu->kvm_arch_lbr_depth); +} + static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; + struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu); u32 msr = msr_info->index; switch (msr) { @@ -361,6 +383,9 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_CORE_PERF_GLOBAL_OVF_CTRL: msr_info->data = 0; return 0; + case MSR_ARCH_LBR_DEPTH: + msr_info->data = lbr_desc->records.nr; + return 0; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) { @@ -387,6 +412,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; + struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu); u32 msr = msr_info->index; u64 data = msr_info->data; u64 reserved_bits; @@ -421,6 +447,16 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 0; } break; + case MSR_ARCH_LBR_DEPTH: + if (!arch_lbr_depth_is_valid(vcpu, data)) + return 1; + lbr_desc->records.nr = data; + /* + * Writing depth MSR from guest could either setting the + * MSR or resetting the LBR records with the side-effect. + */ + wrmsrl(MSR_ARCH_LBR_DEPTH, lbr_desc->records.nr); + return 0; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) { @@ -555,6 +591,18 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) if (lbr_desc->records.nr) bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1); + + if (!kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR)) + return; + + entry = kvm_find_cpuid_entry(vcpu, 28, 0); + if (entry) { + /* + * The depth mask in CPUID is fixed to host supported + * value when userspace sets guest CPUID. + */ + pmu->kvm_arch_lbr_depth = fls(entry->eax & 0xff) * 8; + } } static void intel_pmu_init(struct kvm_vcpu *vcpu)