From patchwork Fri Apr 22 07:54:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Yang, Weijiang" X-Patchwork-Id: 12823010 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 7742AC433F5 for ; Fri, 22 Apr 2022 07:55:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1445256AbiDVH6i (ORCPT ); Fri, 22 Apr 2022 03:58:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1445192AbiDVH62 (ORCPT ); Fri, 22 Apr 2022 03:58:28 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 172A637AA1; Fri, 22 Apr 2022 00:55:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1650614135; x=1682150135; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jFrqc5UcEsylDQP6ebLwaY8xYtycN2QaRC0TSCH2CSM=; b=Er8Py8KwpeQD8ph5s6ie33OmWJ+bt6agilvaaogUqilJGmYL9XExKHmc YgnOnuw4hEIquFZXA4SwB9+YCuI9ECE7qcN+sV9I6zl20fiZJxM8XQOuD 7Vwow4236UzQ0JYxBs98LvaBebJid9GWBqz6NWTwJ5EpCB5EfuTgnGYkj G5FLugp7RTEYpUsgjW1vQszjyc9P92niOiTNPmH44VN2kfkrcAr/cfFAm 8we8zMU+nsBSbfGztI0vtehLXhxGxcefKsivMTnqka8s0VlDM0WtLCTQH LgRFYb6DVSmhOuEagIWIlX3Cl6ZoQig/gUdoUT0sCPTKwv6vOXWLIMW+i Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10324"; a="264384830" X-IronPort-AV: E=Sophos;i="5.90,281,1643702400"; d="scan'208";a="264384830" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2022 00:55:30 -0700 X-IronPort-AV: E=Sophos;i="5.90,281,1643702400"; d="scan'208";a="577741332" Received: from embargo.jf.intel.com ([10.165.9.183]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2022 00:55:30 -0700 From: Yang Weijiang To: pbonzini@redhat.com, jmattson@google.com, seanjc@google.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 v10 06/16] KVM: vmx/pmu: Emulate MSR_ARCH_LBR_DEPTH for guest Arch LBR Date: Fri, 22 Apr 2022 03:54:59 -0400 Message-Id: <20220422075509.353942-7-weijiang.yang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220422075509.353942-1-weijiang.yang@intel.com> References: <20220422075509.353942-1-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 --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/vmx/pmu_intel.c | 48 ++++++++++++++++++++++++++++++++- 2 files changed, 50 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index d23e80a56eb8..d067a382e914 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 bc3f8512bb64..c8e6c1e1e00c 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -205,7 +205,7 @@ 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: @@ -214,6 +214,10 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) case MSR_CORE_PERF_GLOBAL_OVF_CTRL: ret = pmu->version > 1; break; + case MSR_ARCH_LBR_DEPTH: + if (kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR)) + ret = guest_cpuid_has(vcpu, X86_FEATURE_ARCH_LBR); + break; default: ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) || get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) || @@ -342,10 +346,26 @@ 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 +381,9 @@ 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 +410,7 @@ 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 +445,16 @@ 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))) { @@ -559,6 +593,18 @@ 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)