From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1Mbtjk-0007pp-40
	for qemu-devel@nongnu.org; Fri, 14 Aug 2009 06:10:16 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1Mbtjc-0007lp-Re
	for qemu-devel@nongnu.org; Fri, 14 Aug 2009 06:10:15 -0400
Received: from [199.232.76.173] (port=33091 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Mbtjc-0007lk-Ip
	for qemu-devel@nongnu.org; Fri, 14 Aug 2009 06:10:08 -0400
Received: from mx2.redhat.com ([66.187.237.31]:33063)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <kraxel@redhat.com>) id 1Mbtjc-0002ej-3F
	for qemu-devel@nongnu.org; Fri, 14 Aug 2009 06:10:08 -0400
Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26])
	by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n7EAA6mp022134
	for <qemu-devel@nongnu.org>; Fri, 14 Aug 2009 06:10:06 -0400
Message-ID: <4A8537FA.9090404@redhat.com>
Date: Fri, 14 Aug 2009 12:10:02 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] [PATCH] switch balloon initialization to -device.
References: <1250238862-1408-1-git-send-email-kraxel@redhat.com>
	<87tz0alogm.fsf@pike.pond.sub.org>
In-Reply-To: <87tz0alogm.fsf@pike.pond.sub.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
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: Markus Armbruster <armbru@redhat.com>
Cc: qemu-devel@nongnu.org

On 08/14/09 11:44, Markus Armbruster wrote:
> Gerd Hoffmann<kraxel@redhat.com>  writes:
>
>> With that patch applied "-balloon virtio,args" becomes a shortcut for
>> "-device virtio-balloon-pci,args".
>>
>> Side effects:
>>   - ballon device gains support for id=<tag>.
>>   - ballon device is off by default now.
>>   - initialization order changes, which may in different pci slot
>>     assignment depending on the VM configuration.
>>
>> Signed-off-by: Gerd Hoffmann<kraxel@redhat.com>
>
> Looks good on quick inspection (gotta run), just one question: what
> happens when I (stupidly) do -balloon virtio,driver=e1000 ?  Question
> might apply to plain -device before this patch as well.

QemuOpts allows overwriting, so who is written last will win.
Write order is undefined, so don't try that at home ;)

Behavior of the current code:

   -balloon virtio,driver=e1000 will give you a balloon device.
   -device virtio-blk-pci,driver=e1000 will give you a e1000.

cheers,
   Gerd