From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51341) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQEPA-0006Rl-FS for qemu-devel@nongnu.org; Tue, 05 Jun 2018 12:01:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQEP7-00010n-Cl for qemu-devel@nongnu.org; Tue, 05 Jun 2018 12:01:52 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:52654 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fQEP7-000101-87 for qemu-devel@nongnu.org; Tue, 05 Jun 2018 12:01:49 -0400 Date: Tue, 5 Jun 2018 17:01:45 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20180605160145.GS32286@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20180603092749.107476-1-marcel.apfelbaum@gmail.com> <20180604042928-mutt-send-email-mst@kernel.org> <23040757-b561-e0bf-a41d-38d3c44555ee@gmail.com> <20180605072746.v6xxabsbewiuw7ka@sirius.home.kraxel.org> <20180605084300.GF32286@redhat.com> <53c37321-52d2-732c-19fb-8f6a9542c714@gmail.com> <20180605132948.GH32286@redhat.com> <0952e6da-a75f-914a-857e-40a6704cad33@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <0952e6da-a75f-914a-857e-40a6704cad33@gmail.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH RFC] hw/pc: set q35 as the default x86 machine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcel Apfelbaum Cc: Gerd Hoffmann , pbonzini@redhat.com, rth@twiddle.net, qemu-devel@nongnu.org, ehabkost@redhat.com, "Michael S. Tsirkin" , Laszlo Ersek On Tue, Jun 05, 2018 at 06:56:09PM +0300, Marcel Apfelbaum wrote: >=20 >=20 > On 06/05/2018 04:29 PM, Daniel P. Berrang=C3=A9 wrote: > > On Tue, Jun 05, 2018 at 04:20:46PM +0300, Marcel Apfelbaum wrote: > > >=20 > > > On 06/05/2018 11:43 AM, Daniel P. Berrang=C3=A9 wrote: > > > > On Tue, Jun 05, 2018 at 09:27:46AM +0200, Gerd Hoffmann wrote: > > > > > Hi, > > > > >=20 > > > > > > > Add to that shortcuts like -cdrom > > > > > > > stop working, > > > > > > Maybe is fixable. > > > > > Already fixed for ages. > > > > >=20 > > > > > > I see marking Q35 as the default machine a first step. > > > > > Maybe the better option is to go the arm route: Just don't def= ine a > > > > > default, so users have to specify pc or q35. That will make th= em notice > > > > > there is a world beside 'pc', and we also avoid breaking things > > > > > silently. > > > It can work, sure. And we can add user hints: "Use q35 for ...., se= lect pc > > > if..." > > >=20 > > > > If QEMU removes the default, then libvirt will have to hardcode > > > > 'pc' as the default to maintain back compatibility, so I don't > > > > think that ends up as a net win > > > Can't libvirt preserve 'pc' for existing domains, while defaulting = to q35 > > > the creation of new domains ? This way it aligns with Gerd's propos= al of no > > > default x86 machine. > > Existing domains wasn't the case I was concerned about. Consider you = have > > libvirt 4.4.0 intsalled and you deploy a *new* domain from a prebuilt > > disk image "foo". >=20 > Using Laszlo idea (I think): > =C2=A01) disk image "foo"/no info -> use 'pc' machine. > =C2=A02) no prebuild image (clean install?) ->=C2=A0 use q35 and add th= is info to xml NB there's no reliable distinction of "new" from "old" guest install from libvirt's POV. When we receive XML from an application we've no way of knowing if this is a brand new guest about to be installed or a previously installed guest. Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :|