From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel P. Berrange" Subject: Re: [PATCH 3/9] change order of kvm_init call. Date: Mon, 27 Jul 2009 19:44:27 +0100 Message-ID: <20090727184427.GC15020@redhat.com> References: <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> <20090727183857.GI4776@poweredge.glommer> Reply-To: "Daniel P. Berrange" 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: Glauber Costa Return-path: Received: from mx1.redhat.com ([66.187.233.31]:35647 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750959AbZG0Soc (ORCPT ); Mon, 27 Jul 2009 14:44:32 -0400 Content-Disposition: inline In-Reply-To: <20090727183857.GI4776@poweredge.glommer> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Jul 27, 2009 at 03:38:57PM -0300, Glauber Costa wrote: > 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. Well, we could go for logic like: * No arg given => try kvm, try kqemu, try tcg * --accelmode arg given => try $arg, and fail if unavailable then libvirt would simply always supply --accelmode for all VMs, while people running qemu manually would get best available Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|