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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 53C8FC5ACCC for ; Tue, 16 Oct 2018 23:13:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4FE62147C for ; Tue, 16 Oct 2018 23:13:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="rz/rV4hY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4FE62147C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.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 S1727219AbeJQHGF (ORCPT ); Wed, 17 Oct 2018 03:06:05 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:42030 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726703AbeJQHGF (ORCPT ); Wed, 17 Oct 2018 03:06:05 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9GN8fJb032730; Tue, 16 Oct 2018 23:13:20 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2018-07-02; bh=gv/y8dToplbRvPfHS/sW1iB01Tc15hwyMkc6bXTSz0M=; b=rz/rV4hYxt3usAmbwd24daX0Eg/YgU8nG+iq85vcAR0uGfZlCcf4Vxm/j+S7Iz1+tGYv MtKmkazpGKMQpiLpsTBgedlaCr3Eap1iTLsjoW8hBjD29HZp14khgSVHclQDrk/Lbal+ rB87TjIkAhyGvfrTRv/wa8daI8mUTAS6u4hf8NgKooymljvWjxTtzG02Xfy2VUdJiMAS sJnqVAqvGR8fZ+1fkhTZ0hQeDhwr0R45iv5HtNFek0EYNgjR5/uIxClbE+D3pY5hQLaQ wKHuMAjwOUwtfFdiqCE+nUQb/l4N1cXu97G5eniodMZergeu20pSScNlazoAItYKRo6G qg== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2120.oracle.com with ESMTP id 2n39brbm7u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Oct 2018 23:13:20 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w9GNDIOB014522 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Oct 2018 23:13:19 GMT Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w9GNDIwH007222; Tue, 16 Oct 2018 23:13:18 GMT Received: from [192.168.14.112] (/79.181.251.57) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 16 Oct 2018 16:13:18 -0700 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.1 \(3445.4.7\)) Subject: Re: [PATCH] KVM: VMX: enable nested virtualization by default From: Liran Alon In-Reply-To: <20181016225522.13077-1-pbonzini@redhat.com> Date: Wed, 17 Oct 2018 02:13:15 +0300 Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, jmattson@google.com Content-Transfer-Encoding: quoted-printable Message-Id: <1CB58AE6-8057-4D76-8EA5-C219326F3432@oracle.com> References: <20181016225522.13077-1-pbonzini@redhat.com> To: Paolo Bonzini X-Mailer: Apple Mail (2.3445.4.7) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9048 signatures=668706 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810160193 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On 17 Oct 2018, at 1:55, Paolo Bonzini wrote: >=20 > With live migration support and finally a good solution for CR2/DR6 > exception payloads, nested VMX should finally be ready for having a = stable And good solution for setting/getting vCPU events from userspace with = correct pending/injected state. > 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. :) >=20 > Unfortunately, enabling nested SVM in 2009 was a bit premature. = However, Don=E2=80=99t you wish to mention commit which enabled it? > 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. >=20 > 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(-) >=20 > 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=3D0, guests = may not > * use VMX instructions. > */ > -static bool __read_mostly nested =3D 0; > +static bool __read_mostly nested =3D 1; > module_param(nested, bool, S_IRUGO); >=20 > static u64 __read_mostly host_xss; > --=20 > 2.17.1 >=20 Woohoo! :) Reviewed-by: Liran Alon