From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH] exit if we fail to initialize kvm Date: Wed, 29 Jul 2009 12:50:44 -0300 Message-ID: <20090729155044.GE4776@poweredge.glommer> References: <1248814374-7953-1-git-send-email-glommer@redhat.com> <20090728212852.GY4776@poweredge.glommer> <4A7021AC.80403@siemens.com> <4A703767.6050301@redhat.com> <4A70406B.3050000@suse.de> <4A705FFF.5060503@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexander Graf , Avi Kivity , "kvm@vger.kernel.org" To: Jan Kiszka Return-path: Received: from mx2.redhat.com ([66.187.237.31]:48891 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751039AbZG2Psu (ORCPT ); Wed, 29 Jul 2009 11:48:50 -0400 Content-Disposition: inline In-Reply-To: <4A705FFF.5060503@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Jul 29, 2009 at 04:43:11PM +0200, Jan Kiszka wrote: > Alexander Graf wrote: > > Avi Kivity wrote: > >> On 07/29/2009 01:17 PM, Jan Kiszka wrote: > >>> I just wonder now if/when qemu-kvm will switch over to the > >>> kvm-by-default-off policy of upstream? > >>> > >> That will surely inconvenience/surprise a lot of users. > >> > >> A migration path could be: > >> > >> - add -accel > >> - start warning when -accel is not used, encouraging people to use -accel > >> - time passes > >> - switch default to tcg (maybe unless invoked with kvm in argv[0]) > >> - time passes > >> - remove warning > >> > > > > I would prefer: > > > > - add -accel (default to kvm) > > - give a message to use -accel tcg when the user wants tcg > > - make -accel go kvm,kqemu,tcg in qemu upstream > > Upstream just dropped the behavior '-accel kqemu,tcg', so I'm not sure > if this is desired to return (though I'm surely not comparing kvm to > kqemu here). > > > - have distros / management tools decide which accel they like > > That's likely the key: explicit -accel. While I do understand the value of backwards compatibility, we did change behaviour of a number of things in the past. Example: "qemu" would print a help message, and now it runs without any disks. It changed people's script already. It should probably be okay to drop all kvm,kqemu,whatever-related options in favour of accel if we are doing this in a release boundary.