From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1NAODU-0007tG-RS
	for qemu-devel@nongnu.org; Tue, 17 Nov 2009 08:35:32 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1NAODP-0007qU-SV
	for qemu-devel@nongnu.org; Tue, 17 Nov 2009 08:35:32 -0500
Received: from [199.232.76.173] (port=36893 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1NAODP-0007qM-KB
	for qemu-devel@nongnu.org; Tue, 17 Nov 2009 08:35:27 -0500
Received: from mx20.gnu.org ([199.232.41.8]:2841)
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <paul@codesourcery.com>)
	id 1NAODP-0004Mb-6m
	for qemu-devel@nongnu.org; Tue, 17 Nov 2009 08:35:27 -0500
Received: from mail.codesourcery.com ([38.113.113.100])
	by mx20.gnu.org with esmtp (Exim 4.60)
	(envelope-from <paul@codesourcery.com>) id 1NAODN-0001y3-6k
	for qemu-devel@nongnu.org; Tue, 17 Nov 2009 08:35:25 -0500
From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH 0/2] extboot reloaded.
Date: Tue, 17 Nov 2009 13:35:22 +0000
References: <1258394678-8634-1-git-send-email-kraxel@redhat.com>
	<200911171236.03478.paul@codesourcery.com>
	<4B029E9D.3050003@redhat.com>
In-Reply-To: <4B029E9D.3050003@redhat.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-Id: <200911171335.22727.paul@codesourcery.com>
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: qemu-devel@nongnu.org
Cc: Kevin O'Connor <kevin@koconnor.net>, Gerd Hoffmann <kraxel@redhat.com>

On Tuesday 17 November 2009, Gerd Hoffmann wrote:
> On 11/17/09 13:36, Paul Brook wrote:
> >>> In fact I'd much prefer to see extboot rewritten to just virtio-block.
> >>
> >> Hmm, I'd prefer something which is *not* used by the guest OS, so it is
> >> a pure bootloader thing.  When using it to boot from scsi you don't want
> >> to have the disk show up twice (as virtio and scsi) in the guest.
> >
> > You're assuming noone ever writes OS support for extboot...
> 
> Which would be almost as silly as writing OS support for bios-int13 ...

Not entirely. int13 is a software interface, extboot is a hardware interface.
Look at it the other way round: If I already have my low performance boot 
device exposed via extboot (on an otherwise diskless client), why should I 
have to also expose it via virtio-blk just so that the guest can access it for 
installing kernel upgrades.

Paul