From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42002) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6eD3-0003cl-T8 for qemu-devel@nongnu.org; Tue, 06 Aug 2013 06:09:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V6eCz-0002WF-01 for qemu-devel@nongnu.org; Tue, 06 Aug 2013 06:09:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:19069) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6eCy-0002W9-NK for qemu-devel@nongnu.org; Tue, 06 Aug 2013 06:09:40 -0400 Date: Tue, 6 Aug 2013 13:11:16 +0300 From: "Michael S. Tsirkin" Message-ID: <20130806101116.GA13680@redhat.com> References: <20130805151723.GF877@redhat.com> <1970367422.9695773.1375718517492.JavaMail.root@redhat.com> <20130805161833.GA4244@redhat.com> <51FFD6CE.5090302@redhat.com> <20130805182628.GC4244@redhat.com> <20130806072152.GK10891@redhat.com> <20130806083309.GA11051@redhat.com> <20130806083625.GF8218@redhat.com> <5200B78D.2060708@suse.de> <871u67p2h0.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <871u67p2h0.fsf@blackfin.pond.sub.org> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [SeaBIOS] [PATCH] don't expose pvpanic device in the UI List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Gleb Natapov , Marcel Apfelbaum , seabios@seabios.org, qemu-devel@nongnu.org, Gerd Hoffmann , Paolo Bonzini , Andreas =?iso-8859-1?Q?F=E4rber?= On Tue, Aug 06, 2013 at 11:56:11AM +0200, Markus Armbruster wrote: > Andreas F=E4rber writes: >=20 > > Am 06.08.2013 10:36, schrieb Gleb Natapov: > >> On Tue, Aug 06, 2013 at 11:33:10AM +0300, Michael S. Tsirkin wrote: > >>> On Tue, Aug 06, 2013 at 10:21:52AM +0300, Gleb Natapov wrote: > >>>>> If you see a mouse in a room, how likely is it that there's > >>>>> a single mouse there? > >>>>> > >>>>> This is a PV technology which to me looks like it was > >>>>> rushed through and not only set on by default, but > >>>>> without a way to disable it - apparently on the assumption > >>>>> there's 0 chance it can cause any damage. Now that > >>>>> we do know the chance it's not there, why not go back > >>>>> to the standard interface, and why not give > >>>>> users a chance to enable/disable it? > >>>> You should be able to disable it with: -device pvpanic,ioport=3D0 > >>> > >>> Doesn't work for me. > >> Bug that should be fixed. With this command line _STA should return > >> zero. > >>=20 > >>> Besides, both -device pvpanic and use of ioport=3D0 to disable it > >>> are completely undocumented. > >>> > >> Not the only undocumented thing in QEMU command line :) > > [snip] > > > > I disagree: -device adds a device, not removes one. It will still be > > present. > > > > I am neutral as to whether qemu-system-x86_64 should have it enabled = by > > default or not. >=20 > Me too. In general, me neither. But we have -device to add a device, it's nicely self-documenting, We don't have -nodevice to remove a device except the big -nodefaults, and -nodefaults is not self-documenting, and it's not clear how it can be made self-documenting.