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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 64029C04FF3 for ; Mon, 24 May 2021 22:21:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 413CF6109F for ; Mon, 24 May 2021 22:21:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230033AbhEXWXL (ORCPT ); Mon, 24 May 2021 18:23:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229762AbhEXWXC (ORCPT ); Mon, 24 May 2021 18:23:02 -0400 Received: from mail-ot1-x331.google.com (mail-ot1-x331.google.com [IPv6:2607:f8b0:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6121EC061574 for ; Mon, 24 May 2021 15:21:32 -0700 (PDT) Received: by mail-ot1-x331.google.com with SMTP id v19-20020a0568301413b0290304f00e3d88so26706130otp.4 for ; Mon, 24 May 2021 15:21:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GDIQ9fX7lLs/gbyWNEU6V6HWzQKvLmHPZGiIasFlfRM=; b=oXVIQseLDoeABV/dp53lRn0giiPNZMb1SK5CpIaX74y8d+rhVsMtH4iNDvzelsXt3R MOphmVil/Eff+qNgr1AJf2R9XVwwslGTbNk4ZImOHcinCwCR/lQbNHoSex6Shrotkaqx UTRdl+JWDMyCfW4qxcBOfccdBPJm/3r3iM4M4PfqO3/z9nZf5YGj1a7+qA7nxXltUgpj CdP8U3jellankNmbaUC44RGRdP3EJo8OIzpfiB2nrzllD2u8PXBi3978tk9cD0cRNUM4 67MJHJmxgqiHetnAA1coICZMbqJABK+RHME5mkwNzAl3q0s7XdhFEzs4sbP4A4/A4zcw hz9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=GDIQ9fX7lLs/gbyWNEU6V6HWzQKvLmHPZGiIasFlfRM=; b=Cw/I6I5dg41+hfLrCN70wQ2UGrva00D08vpgBJ8nPjRNeLSDuaMLDeju9OORr9bDc9 Fh7a/04aa0c1mBAowIA9oxwoWV7JEiLjFwJwiHGj0ZTnWKtPFtGXDJDzL49Hj+linLIM DGOLrZFsTzJflc6R93kwkqPM+W2Plnbl9LDww5Q8AU3PvLkT3G9eYvn2NBo5sF35LNuS hz3avixyDE9KiQcuF28jMHYxlGA5Jrag4AAFy9rqgnQR4iHS5ixcN0v8nfP3TaXuHL8H yyV9wdg63+6cBJf9SHsdeOXw/nlFx5F3e82/xvze6EfYizftuQ68JhEZYbC6Ib6MGg7l jU+w== X-Gm-Message-State: AOAM532btXctgx0uZsTHMGFv23nRnk3sNvKqmPO7+FAfm2HTVB7R2BJb KlJjDuBZWpuofmm+BFsE2ccN5kzFoK3jR/eDAP9Wog== X-Google-Smtp-Source: ABdhPJziySXZk11WNjyzRJ6zXrXwgIiDyYvJ5+F9SVg/TMDZkrwooR7ggFmvjnEhHj4wAhfq3lTsk2Unh3rxK7khctU= X-Received: by 2002:a9d:5786:: with SMTP id q6mr20800952oth.56.1621894891564; Mon, 24 May 2021 15:21:31 -0700 (PDT) MIME-Version: 1.0 References: <20210424004645.3950558-1-seanjc@google.com> <20210424004645.3950558-43-seanjc@google.com> In-Reply-To: From: Jim Mattson Date: Mon, 24 May 2021 15:21:20 -0700 Message-ID: Subject: Re: [PATCH 42/43] KVM: VMX: Drop VMWRITEs to zero fields at vCPU RESET To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Joerg Roedel , kvm list , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, May 24, 2021 at 2:15 PM Paolo Bonzini wrote: > > On 24/04/21 02:46, Sean Christopherson wrote: > > Don't waste time writing zeros via VMWRITE during vCPU RESET, the VMCS > > is zero allocated. > > Is this guaranteed to be valid, or could the VMCS in principle use some > weird encoding? (Like it does for the access rights, even though this > does not matter for this patch). I see nothing in the SDM that would indicate that zero must be encoded as zero.