From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH 3/9] change order of kvm_init call. Date: Mon, 27 Jul 2009 15:38:57 -0300 Message-ID: <20090727183857.GI4776@poweredge.glommer> References: <1248131416-11272-2-git-send-email-glommer@redhat.com> <1248131416-11272-3-git-send-email-glommer@redhat.com> <1248131416-11272-4-git-send-email-glommer@redhat.com> <4A6CA7A0.8020901@web.de> <20090727173851.GC4776@poweredge.glommer> <4A6DE892.7050801@us.ibm.com> <20090727180003.GE4776@poweredge.glommer> <4A6DED90.3010200@web.de> <20090727182008.GH4776@poweredge.glommer> <20090727182817.GB15020@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kiszka , Anthony Liguori , kvm@vger.kernel.org, avi@redhat.com, markmc@redhat.com To: "Daniel P. Berrange" Return-path: Received: from mx2.redhat.com ([66.187.237.31]:49103 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752735AbZG0ScA (ORCPT ); Mon, 27 Jul 2009 14:32:00 -0400 Content-Disposition: inline In-Reply-To: <20090727182817.GB15020@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Jul 27, 2009 at 07:28:17PM +0100, Daniel P. Berrange wrote: > On Mon, Jul 27, 2009 at 03:20:08PM -0300, Glauber Costa wrote: > > On Mon, Jul 27, 2009 at 08:10:24PM +0200, Jan Kiszka wrote: > > > > > > I think we should simply resolves this the way upstream does: Do not > > > start if modules are missing and -no-kvm is omitted - or even switch > > > over to -enable-kvm as I think you already suggested in some other > > > thread. Then we can either fail or succeed, but not fall back more or > > > less silently. This falling back of qemu-kvm to tcg is a constant source > > > of confusion anyway. > > > > switching to --enable-kvm would be my preferred solution, but guys from > > mgmt tools may not like it. > > Totally agree that it should never ever fallback to a different mode than > the one requested, since falling back from KVM to QEMU simply means the > user doesn't discover the problem till their VM install has wasted an > hour of their time. Personally I would vote for --accelmode qemu|kvm|kqemu > since it is more future proof, but I'm not too bothered if people prefer > to have --enable-kvm on the grounds that kqemu is being killed off. > libvirt just needs a reliable way to request one of qemu, kvm, or kqemu, > and either get an error message, or have the requested mode work. The big problem here is that in qemu-kvm.git, kvm happens without any user request. That would be the advantage of --enable-kvm or --accelmode, or whatever. Simply changing the default to kill the VM if we fail to initialize KVM is cumbersome, because it would mean that users of pure tcg would have to add an option for a basic VM to work.