From patchwork Fri Jul 16 08:53:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhu, Lingshan" X-Patchwork-Id: 12381763 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=unavailable 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 A8E7FC12002 for ; Fri, 16 Jul 2021 08:54:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 90ADD613EE for ; Fri, 16 Jul 2021 08:54:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238879AbhGPI5M (ORCPT ); Fri, 16 Jul 2021 04:57:12 -0400 Received: from mga07.intel.com ([134.134.136.100]:47963 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238546AbhGPI5L (ORCPT ); Fri, 16 Jul 2021 04:57:11 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10046"; a="274526307" X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="274526307" 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 01:54:11 -0700 X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="495983892" 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 01:54:07 -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 03/18] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Date: Fri, 16 Jul 2021 16:53:10 +0800 Message-Id: <20210716085325.10300-4-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 With PEBS virtualization, the guest PEBS records get delivered to the guest DS, and the host pmi handler uses perf_guest_cbs->is_in_guest() to distinguish whether the PMI comes from the guest code like Intel PT. No matter how many guest PEBS counters are overflowed, only triggering one fake event is enough. The fake event causes the KVM PMI callback to be called, thereby injecting the PEBS overflow PMI into the guest. KVM may inject the PMI with BUFFER_OVF set, even if the guest DS is empty. That should really be harmless. Thus guest PEBS handler would retrieve the correct information from its own PEBS records buffer. 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/events/intel/core.c | 45 ++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index da835f5a37e2..2eceb73cd303 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2783,6 +2783,50 @@ static void intel_pmu_reset(void) } DECLARE_STATIC_CALL(x86_guest_handle_intel_pt_intr, *(perf_guest_cbs->handle_intel_pt_intr)); +DECLARE_STATIC_CALL(x86_guest_state, *(perf_guest_cbs->state)); + +/* + * We may be running with guest PEBS events created by KVM, and the + * PEBS records are logged into the guest's DS and invisible to host. + * + * In the case of guest PEBS overflow, we only trigger a fake event + * to emulate the PEBS overflow PMI for guest PBES counters in KVM. + * The guest will then vm-entry and check the guest DS area to read + * the guest PEBS records. + * + * The contents and other behavior of the guest event do not matter. + */ +static void x86_pmu_handle_guest_pebs(struct pt_regs *regs, + struct perf_sample_data *data) +{ + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + u64 guest_pebs_idxs = cpuc->pebs_enabled & ~cpuc->intel_ctrl_host_mask; + struct perf_event *event = NULL; + unsigned int guest = 0; + int bit; + + guest = static_call(x86_guest_state)(); + if (!(guest & PERF_GUEST_ACTIVE)) + return; + + if (!x86_pmu.pebs_vmx || !x86_pmu.pebs_active || + !(cpuc->pebs_enabled & ~cpuc->intel_ctrl_host_mask)) + return; + + for_each_set_bit(bit, (unsigned long *)&guest_pebs_idxs, + INTEL_PMC_IDX_FIXED + x86_pmu.num_counters_fixed) { + event = cpuc->events[bit]; + if (!event->attr.precise_ip) + continue; + + perf_sample_data_init(data, 0, event->hw.last_period); + if (perf_event_overflow(event, data, regs)) + x86_pmu_stop(event, 0); + + /* Inject one fake event is enough. */ + break; + } +} static int handle_pmi_common(struct pt_regs *regs, u64 status) { @@ -2835,6 +2879,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) u64 pebs_enabled = cpuc->pebs_enabled; handled++; + x86_pmu_handle_guest_pebs(regs, &data); x86_pmu.drain_pebs(regs, &data); status &= intel_ctrl | GLOBAL_STATUS_TRACE_TOPAPMI;