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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS 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 8BA2DECDE32 for ; Wed, 17 Oct 2018 08:21:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 463CC21526 for ; Wed, 17 Oct 2018 08:21:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dVel2bXx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 463CC21526 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727330AbeJQQQJ (ORCPT ); Wed, 17 Oct 2018 12:16:09 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:43107 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726957AbeJQQQJ (ORCPT ); Wed, 17 Oct 2018 12:16:09 -0400 Received: by mail-ed1-f66.google.com with SMTP id y20-v6so23974037eds.10; Wed, 17 Oct 2018 01:21:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Ms9d1niz/4VScBsJqzALxhkeGS1pF6S1ndIf0eoHiuw=; b=dVel2bXxIbVpddElkux8ISXLJCh5Hzfz9TCd1Ydq6ym3hvbjVaWTBEatnwX3HGz/Ea 6OdMqC7oP/JKNK4ClX7MizVrFWZtZQPk7F/SeLiq2AIpP1lRABsSpaD8ri6MGM9jJ0iz EaTQRGHsKbIq3k+RI7Q0+/GRCsHG38J0+cYfJICKrAe8qyibSGwWY8cNjisfojDZ2v5w PCCtDuKfsbxBoTILFEd2mCrarZYuxjKWbPrXJxWP3JbPesLXuMGXyHhfkwkhBT6/jwUi RLee8/zefaagqlNknN9XpSJi0J0oK2eWfRSXbIPxzKNpzt55Bt6p5s7SAbK1OAl/rHgw gxGQ== 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=Ms9d1niz/4VScBsJqzALxhkeGS1pF6S1ndIf0eoHiuw=; b=jHXG+bII87cBw69XgLw3yj4GBI50YbkiRjxizLtMzlbpGwFnXiHf1GHUXpdKNUSyuV LlezT5XiYZEb3pwvH3U5AHrFlPILraDqBWAqjhGm9CV4CRK8oSbqHAGVmDaUjdhFQLe5 Wb3eiArMmRhhvSy1vsn0rq7zk9lzSyzu6OJlaP+oMA2M623kfogehJSzWEO9/daaIAyv 5IMln2lfTeP8DVt4rNRK0UBMreLaPhJ+0YtOCDoKq/iwEpecc72PUwQstIy5UqW+Iyd4 ptLT5aYHw1SjFHUYbNDN2frJLuuEpLLKZfzSUTZDckiLBWxlLgHAyhhqvUw0hRbfLRK2 gdCw== X-Gm-Message-State: ABuFfohCNA6kw+ADnPPj4uhrv0IJOLBoDGEs9wfPnM1CfrwxSdGhK73S wsTYZqA4QYUg7esyG553epE18TdT8UV5thsrd1K9DYWb X-Google-Smtp-Source: ACcGV615iXG64pXDkewjaqV0xQ0OWlAt5gdzs2sPc0/OsjTSxdWLuUEeI93PW+sjkvuq1PdyFF2tSddpHhhNvXtbb7w= X-Received: by 2002:a17:906:731d:: with SMTP id d29-v6mr26413049ejl.26.1539764495098; Wed, 17 Oct 2018 01:21:35 -0700 (PDT) MIME-Version: 1.0 References: <20181016225522.13077-1-pbonzini@redhat.com> In-Reply-To: <20181016225522.13077-1-pbonzini@redhat.com> From: Wincy Van Date: Wed, 17 Oct 2018 16:21:23 +0800 Message-ID: Subject: Re: [PATCH] KVM: VMX: enable nested virtualization by default To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Liran Alon , Jim Mattson Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 17, 2018 at 6:57 AM Paolo Bonzini wrote: > > With live migration support and finally a good solution for CR2/DR6 > exception payloads, nested VMX should finally be ready for having a stable > userspace ABI. The results of syzkaller fuzzing are not perfect but not > horrible either (and might be partially due to running on GCE, so that > effectively we're testing three-level nesting on a fork of upstream KVM!). > Enabling it by default seems like a nice way to conclude the 4.20 > pull request. :) > > Unfortunately, enabling nested SVM in 2009 was a bit premature. However, > until live migration support is in place we can reasonably expect that > it does not offer much in terms of ABI guarantees. Therefore we are > still in time to break things and conform as much as possible to the > interface used for VMX. > > Suggested-by: Jim Mattson > Suggested-by: Liran Alon > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/vmx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index e665aa7167cf..89fc2a744d7f 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -107,7 +107,7 @@ module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO); > * VMX and be a hypervisor for its own guests. If nested=0, guests may not > * use VMX instructions. > */ > -static bool __read_mostly nested = 0; > +static bool __read_mostly nested = 1; > module_param(nested, bool, S_IRUGO); > > static u64 __read_mostly host_xss; > -- > 2.17.1 > bravo! :-) Thanks, Wincy