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 5D5D9C5ACC6 for ; Wed, 17 Oct 2018 00:44:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20B88214C3 for ; Wed, 17 Oct 2018 00:44:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hHMA8OU6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20B88214C3 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 S1727621AbeJQIhv (ORCPT ); Wed, 17 Oct 2018 04:37:51 -0400 Received: from mail-oi1-f196.google.com ([209.85.167.196]:38475 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727348AbeJQIhv (ORCPT ); Wed, 17 Oct 2018 04:37:51 -0400 Received: by mail-oi1-f196.google.com with SMTP id u197-v6so19680408oif.5; Tue, 16 Oct 2018 17:44:48 -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=sj9uAqGJ4tTJnDwumO/ai2exba+qRiidOuUmCPe67C8=; b=hHMA8OU6Exxd3GuURYwHgi+7AaPNWTd8PGrzPx9BmKNTxltR6EFRTf8JVKXNXgwAOG xzNjsNSU9yiefM5FuWx3G2Ew7zkHAoBt1Dq6Ag6EKhKZBHNK9OBn8s7LHKU3INqNPnqP GOnxu51SZM1SNL9wPoIOogv4lZNeaMIaPOun9sOMtMvwHLwfplbldargX1ZON1Yp6XSQ t9qvxS2WCFbdt34TRe4z0AXFGZrE71K4e3uXameQNyEPMgeeOSUHj7HHXrt3GcJF5ZFT PdpUu0eWZXGA7/+lsef2z8M8eI+GMGNQhji32Xnd4vgyNOLSwhsNs7qe5vscUVnXN1X9 6KrA== 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=sj9uAqGJ4tTJnDwumO/ai2exba+qRiidOuUmCPe67C8=; b=kYtDp39DQFk3aEqTpYejuHMqlAgMqxpIN4H1od3FhNJx9UWRI62oSI+/NLQ/X/QIlD Jx578vgcOACVP2Yiju7YnUmOBRve0xBz3ubUeY8wvYYJYOLvDXGuDW5iJJfHdXMX0Zfp +XvqzNtDPYYh7vawPSVJUR4CzM17AGjRo31TvTymV++5Ew2Sf27nSZ/ohiIKbzvqi9Jn ctdkOMcixqpF40ef6dj11zSsESg1QxJap0+dD0oPeRSwn+h+vU+eSRHX6L7HxCIuOKjw FBMHh7E141ltO15WZpl6gRRrsalSYBlQygp1NN40h5jX19UHqp6hqS8LM5vM+0fePeLJ dT3g== X-Gm-Message-State: ABuFfohBfm+LVWUOmSMYqeVTVz5e400GPEsMU+7e78zqzqQGaDJ9duqH EHiOkdTy9iO6qvrcNgF9Jf1qeWrfRYXhg1V+DYc= X-Google-Smtp-Source: ACcGV63eUVtJJKDOjOZfKI1uzzl61WwImkNHTg3zHkJImClc/Erz74lSBBVSQ1fTxHknI2+pJJi/3zAke8LGQ6N/vaA= X-Received: by 2002:aca:a896:: with SMTP id r144-v6mr12121420oie.317.1539737088210; Tue, 16 Oct 2018 17:44:48 -0700 (PDT) MIME-Version: 1.0 References: <20181016225522.13077-1-pbonzini@redhat.com> In-Reply-To: <20181016225522.13077-1-pbonzini@redhat.com> From: Wanpeng Li Date: Wed, 17 Oct 2018 08:44:47 +0800 Message-ID: Subject: Re: [PATCH] KVM: VMX: enable nested virtualization by default To: Paolo Bonzini Cc: LKML , kvm , 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, 17 Oct 2018 at 06:57, 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; Really cool, a milestone for nested. :) Regards, Wanpeng Li