From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58562) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dGccl-0000MM-Kv for qemu-devel@nongnu.org; Thu, 01 Jun 2017 22:47:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dGcck-0003iy-GG for qemu-devel@nongnu.org; Thu, 01 Jun 2017 22:47:39 -0400 Date: Fri, 2 Jun 2017 12:00:07 +1000 From: David Gibson Message-ID: <20170602020007.GH13397@umbus.fritz.box> References: <20170526052319.28096-1-david@gibson.dropbear.id.au> <20170530011416.01eea576@bahia.ttt.fr.ibm.com> <20170530061852.GE12163@umbus.fritz.box> <20170530100136.680ce96f@bahia.ttt.fr.ibm.com> <20170531025748.GG12163@umbus.fritz.box> <20170531105857.62a25a84@bahia.ttt.fr.ibm.com> <20170601065233.GD13397@umbus.fritz.box> <20170601150915.2bb628f5@bahia.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ewQ5hdP4CtoTt3oD" Content-Disposition: inline In-Reply-To: <20170601150915.2bb628f5@bahia.lan> Subject: Re: [Qemu-devel] [PATCHv4 0/5] Clean up compatibility mode handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz Cc: =?iso-8859-1?Q?C=E9dric?= Le Goater , aik@ozlabs.ru, mdroth@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, agraf@suse.de, abologna@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, qemu-ppc@nongnu.org, quintela@redhat.com, dgilbert@redhat.com, sursingh@redhat.com, sbobroff@redhat.com --ewQ5hdP4CtoTt3oD Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 01, 2017 at 03:09:15PM +0200, Greg Kurz wrote: > On Thu, 1 Jun 2017 13:59:14 +0200 > C=E9dric Le Goater wrote: >=20 > > On 06/01/2017 08:52 AM, David Gibson wrote: > > > On Wed, May 31, 2017 at 10:58:57AM +0200, Greg Kurz wrote: =20 > > >> On Wed, 31 May 2017 12:57:48 +1000 > > >> David Gibson wrote: =20 > > >>> [...] =20 > > >>>> All old non-pseries machine types already complain when started wi= th > > >>>> a POWER7 or newer CPU. Providing the extra error message looks wei= rd: > > >>>> > > >>>> qemu-system-ppc64 -machine ppce500 \ > > >>>> -cpu POWER7,compat=3Dpower6 > > >>>> qemu-system-ppc64: CPU 'compat' property is deprecated and has no = effect; > > >>>> use max-cpu-compat machine property instead > > >>>> MMU model 983043 not supported by this machine. > > >>>> > > >>>> but I guess it's better than crashing. :) =20 > > >>> > > >>> Well, sure POWER7 doesn't make sense for an e500 machine for other > > >>> reasons. But POWER7 or POWER8 _would_ make sense for powernv, where > > >>> compat=3D doesn't. > > >>> =20 > > >> > > >> The powernv machine type doesn't even support CPU features at all: > > >> > > >> chip_typename =3D g_strdup_printf(TYPE_PNV_CHIP "-%s", machine->= cpu_model); > > >> if (!object_class_by_name(chip_typename)) { > > >> error_report("invalid CPU model '%s' for %s machine", > > >> machine->cpu_model, MACHINE_GET_CLASS(machine)-= >name); > > >> exit(1); > > >> } =20 > > >=20 > > > Ah, well, that's another bug, but not one that's in scope for this > > > series. =20 > >=20 > > PowerNV is still work in progress. I would not worry about it too much. > >=20 >=20 > Of course and this isn't the purpose of the discussion actually. We were > talking about CPU features being relevant or not depending on the machine > type. >=20 > But I'm not even sure that CPU features are useful at all for ppc, not to > say very confusing (otherwise this series wouldn't be needed for example). >=20 > Speaking of PowerNV, just as an example, I guess the fix would be to > forbid machine->cpu_model if it contains features. And probably the same > for all other machine types, except pseries for backward compatibility > reasons. I don't think that's correct in principle. I can imagine CPU properties it might make sense to really set on the cpu, regardless of machine type. A quick look says we don't have any such at the moment, but I don't think it's something we should prevent as a matter of policy. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --ewQ5hdP4CtoTt3oD Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJZMManAAoJEGw4ysog2bOS60gQALkaViouWONg/Uw8dPN/VJKK cH9YTMyN8twqpnpxZMTg+agEOgM4sExaaxP6kfA5J05u0Uj/z7Urp0qqa4K17IxQ ZiEX2tcE7wL3xeS6WCFVxq3yCLv2PsGwmxFmzDcDxEtBmwde6wIRGAWR86WK9NWA fRrHDQXfM7ykJRdof2d1RIaI3Hzzgj/8mtanzGQi2u9044Y7MPFg2R3k0aKJvZnx yjPNp/0MMuTg5OkndZjBTzO3DmR/RiRjjgYuLabi3WEALfZzli9BPEAmrIDvRgbb od8wLs5MyS+9UqWub9jq/BzBj1TqYuITdlqijff47/tTywuFtCKhmHno0IUaayzD vJfZhkVeIaQPX8zK/0QyGh/Mr5iguSIAkBdDHxpSOET7nwI9TjxD7mqW2Jbf0uwv 5OC1Phb0ELGxZ7IAtPu4W+ZtqIfybTvLaH5XZgjwtYUQ3V2iMeay6aW2B8Ho3lyf 3DN7gYnyLZc+QE85Z8aaNOQt4EFKlFL6ksd5YhS2fgukzct4KhKzLJ0neCE01Kbl vMDbzd+lqYogXowfyohlI6KsKgP99UWUdYFoK+Pp2IBkEFYMqvbTTWGZPfMUQhc9 ICu8CRwZOhw03qX2sUMeT5xIteIcdgWrE3fZ1c7vY6jORRDfRVyK8GtWjT3tl7qP XV09PtzC9ivw7Shpsgwj =Kf/t -----END PGP SIGNATURE----- --ewQ5hdP4CtoTt3oD--