From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1NCaGE-0001vu-LE
	for qemu-devel@nongnu.org; Mon, 23 Nov 2009 09:51:26 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1NCaGA-0001sj-0s
	for qemu-devel@nongnu.org; Mon, 23 Nov 2009 09:51:26 -0500
Received: from [199.232.76.173] (port=36791 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1NCaG9-0001sc-P5
	for qemu-devel@nongnu.org; Mon, 23 Nov 2009 09:51:21 -0500
Received: from qw-out-1920.google.com ([74.125.92.146]:6975)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <anthony@codemonkey.ws>) id 1NCaG9-0005R3-41
	for qemu-devel@nongnu.org; Mon, 23 Nov 2009 09:51:21 -0500
Received: by qw-out-1920.google.com with SMTP id 5so1103727qwc.4
	for <qemu-devel@nongnu.org>; Mon, 23 Nov 2009 06:51:20 -0800 (PST)
Message-ID: <4B0AA165.60900@codemonkey.ws>
Date: Mon, 23 Nov 2009 08:51:17 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
MIME-Version: 1.0
References: <4B0952C9.9010803@redhat.com> <4B095D86.700@codemonkey.ws>
	<hec6i6$j3r$1@ger.gmane.org> <4B09F0CA.3060705@codemonkey.ws>
	<20091123082659.GC2999@redhat.com> <m3iqd14edf.fsf@neno.neno>
	<20091123123640.GL2999@redhat.com> <m3r5rpwcww.fsf@neno.neno>
	<20091123143242.GO2999@redhat.com>
In-Reply-To: <20091123143242.GO2999@redhat.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: Live migration protocol, device features,
	ABIs and   other beasts
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Juan Quintela <quintela@trasno.org>, qemu-devel@nongnu.org

Gleb Natapov wrote:
>>>> My problem implementing optional features/sections/... is not the
>>>> savevm/VMState bits.  At the end, implementing that is easy.  What is
>>>> more dificult is once that a device have 5 features, what are the valid
>>>> combinations.  i.e. if you have pci and msix features, msix requires
>>>> pci.  In this case, the dependency is trivial, but in others that
>>>> hasen't to be so obvious.
>>>>         
>>> It doesn't matter what device support and how it is configured. This can
>>> be handled by each device separately. i.e if destination detects that
>>> source had MSIX enabled for the device but destination hasn't it will
>>> signal an error.
>>>       
>> And guess what, with current code migration is going to "suceed" on the
>> source host and fail on the target host.
>>     
> Then current code is buggy. It should be possible to abort migration in
> the middle if device can't understand the data it received.
>   

It can, post_load() can error which will terminate the migration.  This 
can be used to validate fields beyond whether they fit into the type 
specified.

Regards,

Anthony Liguori
> --
> 			Gleb.
>