From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48838) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dVJOu-0000ru-P6 for qemu-devel@nongnu.org; Wed, 12 Jul 2017 11:18:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dVJOs-0001EZ-3C for qemu-devel@nongnu.org; Wed, 12 Jul 2017 11:18:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48824) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dVJOr-0001EE-Pd for qemu-devel@nongnu.org; Wed, 12 Jul 2017 11:18:02 -0400 Date: Wed, 12 Jul 2017 12:17:52 -0300 From: Eduardo Habkost Message-ID: <20170712151752.GG6020@localhost.localdomain> References: <20170707180358.GA12152@localhost.localdomain> <626ce419-8418-a4a2-88d3-b61bf20bbb32@redhat.com> <20170710135943.GG12152@localhost.localdomain> <20170710194345-mutt-send-email-mst@kernel.org> <20170710174730.GL12152@localhost.localdomain> <063778b8-d517-dcac-3c83-95076604a16c@redhat.com> <1499760785.8257.5.camel@redhat.com> <20170711144215.GI4335@noname.str.redhat.com> <1cc3488e-d40b-ac73-9087-f2bf64f2cd1c@redhat.com> <8d6ed662-63e5-fe49-f41e-05f80a52bc20@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8d6ed662-63e5-fe49-f41e-05f80a52bc20@redhat.com> Subject: Re: [Qemu-devel] change x86 default machine type to Q35? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcel Apfelbaum Cc: Paolo Bonzini , Kevin Wolf , Gerd Hoffmann , "Tian, Kevin" , "Michael S. Tsirkin" , libvir-list@redhat.com, Thomas Huth , qemu-devel@nongnu.org, Chao Peng , Laszlo Ersek On Wed, Jul 12, 2017 at 09:39:39AM +0300, Marcel Apfelbaum wrote: > On 11/07/2017 17:47, Paolo Bonzini wrote: > > On 11/07/2017 16:42, Kevin Wolf wrote: > > > > > Concerning QEMU, could we maybe simply emit a warning a la > > > > > > > > > > "you did not specify a machine type with the -M option, so you are > > > > > currently running the the 'pc' machine type. Please note that > > > > > future > > > > > versions of QEMU might use the 'q35' machine type instead. If you > > > > > require the 'pc' machine type for your setting, then please specify > > > > > it with the -M option." > > > > Warnings tend to get ignored until things are actually break, so I > > > > don't think this helps much. I think simply not having a default > > > > machine type (as already suggested elsewhere in this thread) is the > > > > best way to deal with this. > > > I would absolutely hate this. One of the nice things about qemu has > > > always been that 'qemu disk.img' is enough to start a simple VM. You > > > only need to touch any other options for things you care about. I > > > wouldn't want to give this up. > > > > I agree. Don't change anything, leave "-M pc" aside, and let libosinfo > > pick q35 for newer guests. > > > > Hi Paolo, > > While I do think it would be a good step moving forward, I am not > convinced is "enough" to get more users using it. More so, a low > level bug in upper layers (e.g. Open stack) will lead to difficulty > to debug and result in the same "The machine is not steady enough, > it doesn't worth the effort, let's move back to pc", or even > frustration of the people that really need Q35. I guess not being enough depends on which users we want to affect. People who run QEMU from the command-line don't get a virtio drive or a modern CPU model chosen by default, either. Is the choice of machine-type different? Why? > [...] -- Eduardo