From patchwork Thu Sep 20 10:05:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Wei W" X-Patchwork-Id: 10607387 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C689314BD for ; Thu, 20 Sep 2018 10:37:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B6A542CCD9 for ; Thu, 20 Sep 2018 10:37:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AAA4D2CCFB; Thu, 20 Sep 2018 10:37:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4D9502CCD9 for ; Thu, 20 Sep 2018 10:37:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731487AbeITQT5 (ORCPT ); Thu, 20 Sep 2018 12:19:57 -0400 Received: from mga12.intel.com ([192.55.52.136]:59584 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726177AbeITQT5 (ORCPT ); Thu, 20 Sep 2018 12:19:57 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Sep 2018 03:37:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,398,1531810800"; d="scan'208";a="74796067" Received: from devel-ww.sh.intel.com ([10.239.48.110]) by orsmga008.jf.intel.com with ESMTP; 20 Sep 2018 03:36:30 -0700 From: Wei Wang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, ak@linux.intel.com Cc: kan.liang@intel.com, peterz@infradead.org, mingo@redhat.com, rkrcmar@redhat.com, like.xu@intel.com, wei.w.wang@intel.com, jannh@google.com, arei.gonglei@huawei.com Subject: [PATCH v3 0/5] Guest LBR Enabling Date: Thu, 20 Sep 2018 18:05:54 +0800 Message-Id: <1537437959-8751-1-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Last Branch Recording (LBR) is a performance monitor unit (PMU) feature on Intel CPUs that captures branch related info. This patch series enables this feature to KVM guests. Here is a conclusion of the fundamental methods that we use: 1) the LBR feature is enabled per guest via QEMU setting of KVM_CAP_X86_GUEST_LBR; 2) the LBR stack is passed through to the guest for direct accesses after the guest's first access to any of the lbr related MSRs; 3) When the guest uses the LBR feature with the user callstack mode, the host will help save/resotre the LBR stack when the vCPU is scheduled out/in. ChangeLog: v2->v3: - replaces the pv approach with a lazy save approach to saving the lbr stack on vCPU switching; - destroy the host side perf event if the guest is torn down; - remove the unnecessary event->pmu->stop() before calling perf_event_release_kernel(). v1->v2: - add the per guest LBR capability, KVM_CAP_X86_GUEST_LBR; - save/restore the LBR stack conditionally on the vCPU thread context switching, instead of on VMX transitions; - expose MSR_IA32_PERF_CAPABILITIES to the guest. Like Xu (1): KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Wei Wang (4): perf/x86: add a function to get the lbr stack KVM/x86: KVM_CAP_X86_GUEST_LBR KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest KVM/x86/lbr: lazy save the guest lbr stack arch/x86/events/intel/lbr.c | 49 ++++++++++++- arch/x86/events/perf_event.h | 1 + arch/x86/include/asm/kvm_host.h | 7 ++ arch/x86/include/asm/perf_event.h | 22 ++++++ arch/x86/kvm/cpuid.c | 2 +- arch/x86/kvm/pmu.h | 8 +++ arch/x86/kvm/pmu_intel.c | 41 +++++++++++ arch/x86/kvm/vmx.c | 144 ++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 10 +++ include/uapi/linux/kvm.h | 1 + 10 files changed, 281 insertions(+), 4 deletions(-)