From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: drop -enable-nesting Date: Mon, 30 May 2011 18:19:14 +0300 Message-ID: <4DE3B572.6030105@redhat.com> References: <4DDAD5CF.5050805@redhat.com> <4DE0B4B1.1000407@web.de> <20110530081847.GC27062@amd.com> <4DE3A3EC.80201@siemens.com> <20110530143846.GA2957@fermat.math.technion.ac.il> <4DE3B1E2.7020006@siemens.com> <20110530151020.GB7855@amd.com> <4DE3B4A5.6050509@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "Roedel, Joerg" , "Nadav Har'El" , john cooper , "qemu-devel@nongnu.org" , Anthony Liguori , kvm To: Jan Kiszka , "Daniel P. Berrange" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42223 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757223Ab1E3PT2 (ORCPT ); Mon, 30 May 2011 11:19:28 -0400 In-Reply-To: <4DE3B4A5.6050509@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05/30/2011 06:15 PM, Jan Kiszka wrote: > On 2011-05-30 17:10, Roedel, Joerg wrote: > > On Mon, May 30, 2011 at 11:04:02AM -0400, Jan Kiszka wrote: > >> On 2011-05-30 16:38, Nadav Har'El wrote: > >>> On Mon, May 30, 2011, Jan Kiszka wrote about "drop -enable-nesti= ng (was: [PATCH 3/7] cpu model bug fixes and definition corrections...)= ": > >>>> On 2011-05-30 10:18, Roedel, Joerg wrote: > >>>>> On Sat, May 28, 2011 at 04:39:13AM -0400, Jan Kiszka wrote: > >>>>> > >>>>>> J=EF=BF=BDrg, how to deal with -enable-nesting in qemu-kvm to= align behavior > >>>>>> with upstream? > >>>>> > >>>>> My personal preference is to just remove it. In upstream-qemu = it is > >>>>> enabled/disabled by +/-svm. -enable-nesting is just a historic= thing > >>>>> which can be wiped out. > >>> > >>> "-enable-nesting" could remain as a synonym for enabling either = VMX or SVM > >>> in the guest, depending on what was available in the host (becau= se KVM now > >>> supports both nested SVM and nested VMX, but not SVM-on-VMX or v= ice versa). > >> > >> Why? Once nesting is stable (I think SVM already is), there is no= reason > >> for an explicit enable. And you can always mask it out via -cpu. > >> > >> BTW, what are the defaults for SVM right now in qemu-kvm and upst= ream? > >> Enable if the modeled CPU supports it? > > > > qemu-kvm still needs -enable-nesting, otherwise it is disabled. Up= stream > > qemu should enable it unconditionally (can be disabled with -cpu ,= -svm). > > Then let's start with aligning qemu-kvm defaults to upstream? I guess > that's what the diff I was citing yesterday is responsible for. > > In the same run, -enable-nesting could dump a warning on the console > that this switch is obsolete and will be removed from future versions= =2E I think it's safe to drop -enable-nesting immediately. Dan, does=20 libvirt make use of it? > For VMX, I would suggest to keep it off by default until it matured, > asking the user to issue -cpu ...,+vmx. We should do that for svm as well (except for -cpu host or -cpu=20 something-with-svm). vmx will be kept disabled by the module option,=20 until it is deemed fit for general consumption. --=20 error compiling committee.c: too many arguments to function