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=-8.3 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=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 8D851C433E3 for ; Tue, 18 Aug 2020 07:15:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65388204FD for ; Tue, 18 Aug 2020 07:15:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MgsXpBMt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726823AbgHRHPP (ORCPT ); Tue, 18 Aug 2020 03:15:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:27148 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726476AbgHRHPG (ORCPT ); Tue, 18 Aug 2020 03:15:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597734905; 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=VnkZLMte3116urPzW5jKDlxRd4vsRM7I0r+mSa2q174=; b=MgsXpBMtXmMOJ0hyIw7fG34i/pFZBlY/c3tPAgPL3QDlViBcKKKXvymJatVimXD/Sa3yuZ fIY0XO9CKD1blC5EmSqH2r+ON5e1tuQIstWc9og2P+C7xaeZTetcE4MJ2UUfo6NxmaZjvR vgs/WBIJaCVNkEXDA2FxHm2J+zjrybI= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-200-Xy10gfRmMWWXdyFdRV1i0Q-1; Tue, 18 Aug 2020 03:15:02 -0400 X-MC-Unique: Xy10gfRmMWWXdyFdRV1i0Q-1 Received: by mail-wm1-f71.google.com with SMTP id q15so7030789wmj.6 for ; Tue, 18 Aug 2020 00:15:01 -0700 (PDT) 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=VnkZLMte3116urPzW5jKDlxRd4vsRM7I0r+mSa2q174=; b=UOCnanfXTZq6IBIssE7kT3EHu7oDiu0zwfytKam+n3IBQr84Xwv75MPJ1bWb8MGy3a jQgb6QGfzfJwXRrK+Uryk2bInr4nni0vajVIxEq4EeTCLnwhLgXZWadURIW3Rl3mDnDF Z2o/uboKGZZitt1sFoRV4EJSQv2H0c5cjk3mt/4Q72+7yVf4nATx2KhVRjH/+ZYvBvi9 tyC0X7/RzcGwVbKI5Yv8tGECHXOUOSWA0BiNSJyO2krfJ1c/6HlvZ85KUYG/qy7l2iLO aYIMkaLr5y5hS7Gh01FoR6HPLJaVClalJV5bu5MoDGk+Hx3MX5EkCFtH9GFdoFFD9Q5B Fnig== X-Gm-Message-State: AOAM532S5+jY63qQs8LGVEcPA3bJh5izFnN4grU3kjNvpXbxBLIeCDcN +5kqtiD/P6gWf+yw1fW+94g+rWyIx+q59WZ4/CjSXFKsyTiR4/3KkeSTlTARvqiF8lTPHiDCnN/ 4kmw5yAyAPQn6zkdh6OlsbfVv X-Received: by 2002:adf:b312:: with SMTP id j18mr19499391wrd.142.1597734900805; Tue, 18 Aug 2020 00:15:00 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxxDBVc6FNobMFPmLaQ8JBtEJ0j8nc00thHTm7+HAm5Z27/zTChbr9Q9OWX0Of8Uc7BLJHy1Q== X-Received: by 2002:adf:b312:: with SMTP id j18mr19499363wrd.142.1597734900475; Tue, 18 Aug 2020 00:15:00 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id t14sm32631227wrv.14.2020.08.18.00.14.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 18 Aug 2020 00:14:59 -0700 (PDT) Subject: Re: [PATCH v2 1/4] x86/cpufeatures: Add enumeration for SERIALIZE instruction To: Thomas Gleixner , Ricardo Neri , Andy Lutomirski Cc: Cathy Zhang , kvm list , LKML , X86 ML , "Christopherson, Sean J" , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Kyung Min Park , Josh Poimboeuf , Greg KH , Andi Kleen , Dave Hansen , Tony Luck , "Ravi V. Shankar" , fenghua.yu@intel.com References: <1594088183-7187-1-git-send-email-cathy.zhang@intel.com> <1594088183-7187-2-git-send-email-cathy.zhang@intel.com> <20200708022102.GA25016@ranerica-svr.sc.intel.com> <87eep3ywz0.fsf@nanos.tec.linutronix.de> From: Paolo Bonzini Message-ID: Date: Tue, 18 Aug 2020 09:14:58 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <87eep3ywz0.fsf@nanos.tec.linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/07/20 01:02, Thomas Gleixner wrote: >> I am cc'ing Fenghua, who has volunteered to work on this. Addind support >> for SERIALIZE in sync_core() should not block merging these patches, >> correct? > Come on. We are not serving KVM first before making this usable on bare > metal. This in the end was merged in 5.9, but: why not? It is just an instruction with no other support code needed in the kernel (or KVM for that matter except for marking the CPUID bit as supported). It is common to run hosts with an older kernel than the guests, and by this line of reasoning, we should not even have enabled support for FSGSBASE in KVM. Paolo