From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47952) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VA02f-00072g-DW for qemu-devel@nongnu.org; Thu, 15 Aug 2013 12:04:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VA02Z-0004l7-EG for qemu-devel@nongnu.org; Thu, 15 Aug 2013 12:04:53 -0400 Received: from mail-ob0-f179.google.com ([209.85.214.179]:42543) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VA02Z-0004kt-9l for qemu-devel@nongnu.org; Thu, 15 Aug 2013 12:04:47 -0400 Received: by mail-ob0-f179.google.com with SMTP id fb19so1037726obc.38 for ; Thu, 15 Aug 2013 09:04:46 -0700 (PDT) From: Anthony Liguori In-Reply-To: <520CEFAC.6090500@suse.de> References: <1376537732-29300-1-git-send-email-aik@ozlabs.ru> <283AA2CE-F23C-4218-B28A-3779D6BA549B@suse.de> <520C6AC6.6010708@ozlabs.ru> <25583D8C-4023-4E78-9B5E-2E3970FB301E@suse.de> <1376548221.4255.103.camel@pasglop> <87vc37qerm.fsf@codemonkey.ws> <520CEFAC.6090500@suse.de> Date: Thu, 15 Aug 2013 11:04:43 -0500 Message-ID: <87haer549w.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC PATCH] powerpc: add PVR mask support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andreas =?utf-8?Q?F=C3=A4rber?= Cc: Alexey Kardashevskiy , Alexander Graf , "qemu-devel@nongnu.org" , "qemu-ppc@nongnu.org" , Paul Mackerras Andreas F=C3=A4rber writes: > Am 15.08.2013 15:12, schrieb Anthony Liguori: >> Everyone is talking past each other and no one is addressing the real >> problem. There are two distinct issues here: >>=20 >> 1) We have two ABIs that cannot be changed unless there's a very good >> reason to. Alexey's original patch breaks both. The guest ABI >> cannot change given a fixed command line. >>=20 >> IOW, the exposed PVR value for -cpu POWER7 cannot change across >> versions of QEMU or when running on different hardware. This breaks >> live migration and save/resume. >>=20 >> We also cannot break the command line interface. If the last version >> of QEMU supported -cpu POWER7_v2.1, then we must continue to support >> that. > > 1a) How should -cpu 0xDEADBEEF or -cpu DEADBEEF behave. > > I expect it to error out as before Correct although that can't be guaranteed. Maybe there is a 'DEADBEEF' cpu model in the future. This is the architecture of the ripvanwinkle and eieio instructions after all :-) > rather than applying the same fuzz/mask that -cpu host might. Fuzzing CPU models sounds like an awful idea to me. Regards, Anthony Liguori > That would let us implement our own fuzz logic in kvm.c, > operating on a GSList of ObjectClasses to handle multiple matches. > > Regards, > Andreas