From patchwork Fri Jul 16 08:53:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhu, Lingshan" X-Patchwork-Id: 12381775 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B245C636CA for ; Fri, 16 Jul 2021 08:54:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04946613E8 for ; Fri, 16 Jul 2021 08:54:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239293AbhGPI5j (ORCPT ); Fri, 16 Jul 2021 04:57:39 -0400 Received: from mga07.intel.com ([134.134.136.100]:48015 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239193AbhGPI5c (ORCPT ); Fri, 16 Jul 2021 04:57:32 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10046"; a="274526376" X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="274526376" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2021 01:54:38 -0700 X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="495983986" Received: from vmm_a4_icx.sh.intel.com (HELO localhost.localdomain) ([10.239.53.245]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2021 01:54:32 -0700 From: Zhu Lingshan To: peterz@infradead.org, pbonzini@redhat.com Cc: bp@alien8.de, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, kan.liang@linux.intel.com, ak@linux.intel.com, wei.w.wang@intel.com, eranian@google.com, liuxiangdong5@huawei.com, linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, like.xu.linux@gmail.com, boris.ostrvsky@oracle.com, Like Xu , Zhu Lingshan Subject: [PATCH V8 09/18] KVM: x86/pmu: Reprogram PEBS event to emulate guest PEBS counter Date: Fri, 16 Jul 2021 16:53:16 +0800 Message-Id: <20210716085325.10300-10-lingshan.zhu@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210716085325.10300-1-lingshan.zhu@intel.com> References: <20210716085325.10300-1-lingshan.zhu@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Like Xu When a guest counter is configured as a PEBS counter through IA32_PEBS_ENABLE, a guest PEBS event will be reprogrammed by configuring a non-zero precision level in the perf_event_attr. The guest PEBS overflow PMI bit would be set in the guest GLOBAL_STATUS MSR when PEBS facility generates a PEBS overflow PMI based on guest IA32_DS_AREA MSR. Even with the same counter index and the same event code and mask, guest PEBS events will not be reused for non-PEBS events. Originally-by: Andi Kleen Co-developed-by: Kan Liang Signed-off-by: Kan Liang Signed-off-by: Like Xu Signed-off-by: Zhu Lingshan --- arch/x86/kvm/pmu.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 2dcbd1b30004..d76b0a5d80d7 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -74,11 +74,21 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event, { struct kvm_pmc *pmc = perf_event->overflow_handler_context; struct kvm_pmu *pmu = pmc_to_pmu(pmc); + bool skip_pmi = false; if (!test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) { - __set_bit(pmc->idx, (unsigned long *)&pmu->global_status); + if (perf_event->attr.precise_ip) { + /* Indicate PEBS overflow PMI to guest. */ + skip_pmi = __test_and_set_bit(GLOBAL_STATUS_BUFFER_OVF_BIT, + (unsigned long *)&pmu->global_status); + } else { + __set_bit(pmc->idx, (unsigned long *)&pmu->global_status); + } kvm_make_request(KVM_REQ_PMU, pmc->vcpu); + if (skip_pmi) + return; + /* * Inject PMI. If vcpu was in a guest mode during NMI PMI * can be ejected on a guest mode re-entry. Otherwise we can't @@ -99,6 +109,7 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, bool exclude_kernel, bool intr, bool in_tx, bool in_tx_cp) { + struct kvm_pmu *pmu = vcpu_to_pmu(pmc->vcpu); struct perf_event *event; struct perf_event_attr attr = { .type = type, @@ -110,6 +121,8 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, .exclude_kernel = exclude_kernel, .config = config, }; + bool pebs = test_bit(pmc->idx, (unsigned long *)&pmu->pebs_enable); + perf_overflow_handler_t ovf = kvm_perf_overflow; attr.sample_period = get_sample_period(pmc, pmc->counter); @@ -124,10 +137,27 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, attr.sample_period = 0; attr.config |= HSW_IN_TX_CHECKPOINTED; } + if (pebs) { + /* + * The non-zero precision level of guest event makes the ordinary + * guest event becomes a guest PEBS event and triggers the host + * PEBS PMI handler to determine whether the PEBS overflow PMI + * comes from the host counters or the guest. + * + * For most PEBS hardware events, the difference in the software + * precision levels of guest and host PEBS events will not affect + * the accuracy of the PEBS profiling result, because the "event IP" + * in the PEBS record is calibrated on the guest side. + * + * On Icelake everything is fine. Other hardware (GLC+, TNT+) that + * could possibly care here is unsupported and needs changes. + */ + attr.precise_ip = 1; + } + if (pebs || intr) + ovf = kvm_perf_overflow_intr; - event = perf_event_create_kernel_counter(&attr, -1, current, - intr ? kvm_perf_overflow_intr : - kvm_perf_overflow, pmc); + event = perf_event_create_kernel_counter(&attr, -1, current, ovf, pmc); if (IS_ERR(event)) { pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n", PTR_ERR(event), pmc->idx); @@ -161,6 +191,10 @@ static bool pmc_resume_counter(struct kvm_pmc *pmc) get_sample_period(pmc, pmc->counter))) return false; + if (!test_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->pebs_enable) && + pmc->perf_event->attr.precise_ip) + return false; + /* reuse perf_event to serve as pmc_reprogram_counter() does*/ perf_event_enable(pmc->perf_event);