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=-7.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5D15BC433DB for ; Fri, 5 Feb 2021 11:05:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1020964F9D for ; Fri, 5 Feb 2021 11:05:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231919AbhBELFa (ORCPT ); Fri, 5 Feb 2021 06:05:30 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:36918 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231965AbhBELCc (ORCPT ); Fri, 5 Feb 2021 06:02:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612522864; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hlQHxvz68herj6uUlAqo6cNNlISG8mBPX3iyJA1YfgY=; b=U2R7dq0veCLLFAVwqOxvVea3BPvYdvokhPTfULuAhI6A4XeySy63DjAVyJcnCbRVrkR6zX Wpn5bRZyNzi+n8f6hFmcNpvvdV3YNIGn1/hNYjea7bwdvNBMVohSoXQmT8Fiv/NzsjcCn4 xvWmheoU8pNCX+B64VpCHF2LcEveh0E= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-199-XMZ3BsibNCmkIiYAPxHyiQ-1; Fri, 05 Feb 2021 06:01:03 -0500 X-MC-Unique: XMZ3BsibNCmkIiYAPxHyiQ-1 Received: by mail-ej1-f69.google.com with SMTP id n25so6711746ejd.5 for ; Fri, 05 Feb 2021 03:01:02 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=hlQHxvz68herj6uUlAqo6cNNlISG8mBPX3iyJA1YfgY=; b=lxkhUIjkllwQXWxcJMg4WIdgJWMifQNFnc/wuDjp0H+ZQPHMCWcpO1pEZTackOk78X NUoi/fBaXNJs8G8dsInU21UcNDAH5KrXM/g5K0/VtA+F0UsL2MAo9SyfK4Frm38piu47 n4ej+zv5OQ++kNyaomuEoIJ17Pnv472FUJJgB4JO+a0LjzNp0jYK9aSggJ5khAopNtiY 0kyA41A1eNA6rE2fsBEW0IT+oruURUDlI6hWB57JhExvxmFoFJaB6U7xw5oUd7YFoj8d WcjcNTfQwo3sjS8O4swYo6x2HPgFUeLkzh0J9M1oqFOGjrqeHq5pjN7AW14mq0LLkM9W mPcQ== X-Gm-Message-State: AOAM5339wWStsAeCo0+E6IFQNlxce6IS1qXgd9yCOBQrvuSYCYJzEJm7 zw2JSYf+r5Cm8fTynjmfijPxlUKgDttwtS9pWgw8OMQFjRPrsfOSymN/fX50lgPO9Q5EDRFy1l6 BNfSmq8NkdYvA5PySl9BM1w3X X-Received: by 2002:a17:906:d84:: with SMTP id m4mr3483451eji.437.1612522861723; Fri, 05 Feb 2021 03:01:01 -0800 (PST) X-Google-Smtp-Source: ABdhPJy4F1t/R+DPSOQFVqV3fjaYushABxmKmxDzt7PERmONeplKqUD5cGkaLMtwig78BxPe+5fXxw== X-Received: by 2002:a17:906:d84:: with SMTP id m4mr3483425eji.437.1612522861540; Fri, 05 Feb 2021 03:01:01 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id x25sm3802377edv.65.2021.02.05.03.00.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 05 Feb 2021 03:01:00 -0800 (PST) Subject: Re: [PATCH v2 4/4] KVM: x86: Expose Architectural LBR CPUID and its XSAVES bit To: "Xu, Like" , Sean Christopherson Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Like Xu References: <20210203135714.318356-1-like.xu@linux.intel.com> <20210203135714.318356-5-like.xu@linux.intel.com> <8321d54b-173b-722b-ddce-df2f9bd7abc4@redhat.com> <219d869b-0eeb-9e52-ea99-3444c6ab16a3@intel.com> From: Paolo Bonzini Message-ID: <7698fd6c-94da-e352-193f-e09e002a8961@redhat.com> Date: Fri, 5 Feb 2021 12:00:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/02/21 09:16, Xu, Like wrote: > Hi Paolo, > > I am wondering if it is acceptable for you to > review the minor Architecture LBR patch set without XSAVES for v5.12 ? > > As far as I know, the guest Arch LBR  can still work without XSAVES > support. I dopn't think it can work. You could have two guests on the same physical CPU and the MSRs would be corrupted if the guests write to the MSR but they do not enable the LBRs. Paolo