From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C5476C433E0 for ; Thu, 4 Mar 2021 03:04:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 863A264E7C for ; Thu, 4 Mar 2021 03:04:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232041AbhCDDD0 (ORCPT ); Wed, 3 Mar 2021 22:03:26 -0500 Received: from mga14.intel.com ([192.55.52.115]:17919 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232102AbhCDDDK (ORCPT ); Wed, 3 Mar 2021 22:03:10 -0500 IronPort-SDR: dvQBDC9pkS5tMZJA4Ns29E66bzQIqGTGF42ixSx5E2eQgyKPGzbYsUaB8xmk2PLKi1Mz+JauIw 8VMYfn6y1K1A== X-IronPort-AV: E=McAfee;i="6000,8403,9912"; a="186674934" X-IronPort-AV: E=Sophos;i="5.81,221,1610438400"; d="scan'208";a="186674934" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2021 19:02:29 -0800 IronPort-SDR: Cfmd6zW4Klj1dIlCxFCLxjPUOXywJAhceDtM7lI6c6/ciDnBy44aUlHYVa4arFRrwaMmoD83Oe XLDjK2QQix+g== X-IronPort-AV: E=Sophos;i="5.81,221,1610438400"; d="scan'208";a="400284153" Received: from likexu-mobl1.ccr.corp.intel.com (HELO [10.238.4.93]) ([10.238.4.93]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2021 19:02:25 -0800 Subject: Re: [PATCH v3 7/9] KVM: vmx/pmu: Add Arch LBR emulation and its VMCS field To: Sean Christopherson Cc: Peter Zijlstra , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Kan Liang , Dave Hansen , wei.w.wang@intel.com, Borislav Petkov , kvm@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Like Xu References: <20210303135756.1546253-1-like.xu@linux.intel.com> <20210303135756.1546253-8-like.xu@linux.intel.com> From: "Xu, Like" Message-ID: <267c408c-6999-649b-d733-8d64f9cf0594@intel.com> Date: Thu, 4 Mar 2021 11:02:24 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/3/4 1:26, Sean Christopherson wrote: > On Wed, Mar 03, 2021, Like Xu wrote: >> New VMX controls bits for Arch LBR are added. When bit 21 in vmentry_ctrl >> is set, VM entry will write the value from the "Guest IA32_LBR_CTL" guest >> state field to IA32_LBR_CTL. When bit 26 in vmexit_ctrl is set, VM exit >> will clear IA32_LBR_CTL after the value has been saved to the "Guest >> IA32_LBR_CTL" guest state field. > ... > >> @@ -2529,7 +2532,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf, >> VM_EXIT_LOAD_IA32_EFER | >> VM_EXIT_CLEAR_BNDCFGS | >> VM_EXIT_PT_CONCEAL_PIP | >> - VM_EXIT_CLEAR_IA32_RTIT_CTL; >> + VM_EXIT_CLEAR_IA32_RTIT_CTL | >> + VM_EXIT_CLEAR_IA32_LBR_CTL; > So, how does MSR_ARCH_LBR_CTL get restored on the host? What if the host wants > to keep _its_ LBR recording active while the guest is running? Thank you! I will add "host_lbrctlmsr" field to "struct vcpu_vmx" and repeat the update/get_debugctlmsr() stuff. >> if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_EXIT_CTLS, >> &_vmexit_control) < 0) >> return -EIO; >> @@ -2553,7 +2557,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf, >> VM_ENTRY_LOAD_IA32_EFER | >> VM_ENTRY_LOAD_BNDCFGS | >> VM_ENTRY_PT_CONCEAL_PIP | >> - VM_ENTRY_LOAD_IA32_RTIT_CTL; >> + VM_ENTRY_LOAD_IA32_RTIT_CTL | >> + VM_ENTRY_LOAD_IA32_LBR_CTL; >> if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_ENTRY_CTLS, >> &_vmentry_control) < 0) >> return -EIO; >> -- >> 2.29.2 >>