From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40409) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6fyy-00031W-5r for qemu-devel@nongnu.org; Tue, 06 Aug 2013 08:03:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V6fyr-0006Bw-Nn for qemu-devel@nongnu.org; Tue, 06 Aug 2013 08:03:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15352) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6fyr-0006BW-GU for qemu-devel@nongnu.org; Tue, 06 Aug 2013 08:03:13 -0400 Date: Tue, 6 Aug 2013 15:03:10 +0300 From: Gleb Natapov Message-ID: <20130806120310.GX8218@redhat.com> References: <20130806072152.GK10891@redhat.com> <20130806083309.GA11051@redhat.com> <20130806083625.GF8218@redhat.com> <20130806092148.GC11051@redhat.com> <20130806093247.GL8218@redhat.com> <20130806101953.GC13680@redhat.com> <20130806104442.GR8218@redhat.com> <5200D806.5030509@suse.de> <20130806111637.GU8218@redhat.com> <87r4e7doqm.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <87r4e7doqm.fsf@blackfin.pond.sub.org> 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: "Michael S. Tsirkin" , seabios@seabios.org, qemu-devel@nongnu.org, Gerd Hoffmann , Anthony Liguori , Paolo Bonzini , Marcel Apfelbaum , Andreas =?utf-8?Q?F=C3=A4rber?= On Tue, Aug 06, 2013 at 01:48:17PM +0200, Markus Armbruster wrote: > Gleb Natapov writes: >=20 > > On Tue, Aug 06, 2013 at 01:03:34PM +0200, Andreas F=C3=A4rber wrote: > >> Am 06.08.2013 12:44, schrieb Gleb Natapov: > >> > On Tue, Aug 06, 2013 at 01:19:53PM +0300, Michael S. Tsirkin wrote: > >> >>>> It's a QEMU issue, devices that are added with -device are > >> >>>> documented in -device help and removed by dropping them from > >> >>>> command line. Devices added by default have no way to > >> >>>> be dropped from QOM except -nodefaults. > >> >>>> > >> >>> Are you saying that because pvpanic is added automatically QEMU -d= evice > >> >>> help does not print help about it? Why not fix that? What QEMU --h= elp > >> >>> issues has to do with deciding which devices should or should not = be > >> >>> present by default? > >> >> > >> >> No, I'm saying what I said: that there's no way to remove a device > >> >> added by default except -nodefaults, and no way to > >> >> find out what does -nodefaults exclude so you > >> >> can add things you need back selectively. > >> >> > >> > And what are the rules that govern device exclusion from -nodefaults > >> > list? Why -nodefaults does not create empty machine? > >>=20 > >> We have -M none to create an empty machine. > >>=20 > >> FWIW -M q35 does not create all Q35 devices, there's -readconfig > >> docs/q35-chipset.cfg for the rest. The criteria certainly is not > >> migratability, since ICH9 AHCI (part of -M q35) is unmigratable, > >> unfortunately. > >> One practical reason not to create everything via config is that we > >> cannot create SysBusDevices via -device when they require MMIO mapping > >> or IRQ setup. >=20 > Support wiring up a machine without board code, just configuration has > been the ever-distant goal of the qdev effort. >=20 > >> For ISADevices such as pvpanic that's not a problem. > >> Anthony has proposed QOM'ifying MemoryRegions and qemu_irq as solution > >> to do the wiring-up from command line or config file, but those attemp= ts > >> got stuck a long time ago. > >>=20 > > But -M creates not only things that cannot be created from a command > > line, it includes some default set of devices, so what is the criteria > > for those? >=20 > I'm not aware of defined, coherent criteria. >=20 > I can give you descriptive rather than prescriptive, though. Used to be > "whatever anyone felt users would want". It's now "whatever has always > been there, plus whatever survives interminable bikeshedding^W^Wvigorous > debate. No need to for ^W! It is like disputes in court: whoever has more money wins. In out case whoever has more times wins and I am going on vocation, so... :) -- Gleb.