From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40785) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYDoI-0005dI-Sv for qemu-devel@nongnu.org; Thu, 10 Apr 2014 08:10:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WYDoC-0004NK-DJ for qemu-devel@nongnu.org; Thu, 10 Apr 2014 08:10:26 -0400 Message-ID: <53468A29.50404@suse.de> Date: Thu, 10 Apr 2014 14:10:17 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1395888071-28677-1-git-send-email-aik@ozlabs.ru> <53341B8F.7040904@suse.de> <53341E41.7050101@ozlabs.ru> <533422AB.7080106@ozlabs.ru> <53435036.9020901@ozlabs.ru> In-Reply-To: <53435036.9020901@ozlabs.ru> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH] target-ppc: Add @cpu_dt_id into migration stream List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexey Kardashevskiy , Peter Maydell Cc: "qemu-ppc@nongnu.org" , =?UTF-8?B?QW5kcmVhcyBGw6Q=?= =?UTF-8?B?cmJlcg==?= , QEMU Developers On 08.04.14 03:26, Alexey Kardashevskiy wrote: > On 03/28/2014 12:07 AM, Alexey Kardashevskiy wrote: >> On 03/27/2014 11:57 PM, Peter Maydell wrote: >>> On 27 March 2014 12:49, Alexey Kardashevskiy wrote: >>>> On 03/27/2014 11:37 PM, Andreas F=C3=A4rber wrote: >>>>> Am 27.03.2014 03:41, schrieb Alexey Kardashevskiy: >>>>>> This should prevent the destination guest from misbehaving when >>>>>> the threads number is different in "-smp" command. >>>>> Sorry, I don't understand. When migrating, surely -smp needs to be = the >>>>> same on source and destination, so how can they differ? >>>> >>>> The idea is that "-smp" does not migrate and if we run source and >>>> destination guests with different numbers in -smp, we end up with we= ird >>>> machine >>> Yes, so don't do that. As I understand it: >>> (1) if you don't run QEMU with the exact same command line >>> and config at both ends then migration won't work >>> (2) we don't guarantee to detect and cleanly fail if you >>> don't do (1) >>> >>> It would probably be nice if we did detect config mismatches, >> Yep, we do not send the device tree (as libvirt does). Pure command li= ne >> matching won't work. >> >>> but that seems to me like a problem we should be addressing >>> more globally than just for one particular config item for >>> one particular target... > > Ok. So. Let's assume I want to implement migration of "-smp" parameters= . > What would be the correct way of doing this in terms of the current QOM > principles? Thanks. You don't. The migration protocol doesn't migrate configuration. If you=20 want to start to transfer VM configuration (which I'd be all in for), do=20 it properly and transfer _all_ configuration. Alex