Re: [Xen-devel] [PATCH] Extboot support for Xen

Daniel P. Berrange
Tue, 15 Jan 2008 21:44:13 -0000

On Tue, Jan 15, 2008 at 02:02:24PM -0600, Anthony Liguori
wrote:
> This patch adds extboot to Xen.  It should be pretty harmless as the moment
> because it''s never enabled.  extboot allows arbitrary block
devices to
> be used
> to boot guests including SCSI and PV disks.  I''ve tested it with
both
> Windows
> and Linux guests in QEMU.
>
> The version of QEMU in Xen is a bit old so I couldn''t complete the
plumbing.
> The main problem is that Xen provides no way of exposing SCSI disks
> right now
> and PV disks aren''t actually accessible within QEMU.  I''m
hoping someone
> else
> can pick that up though as I''m pretty overcommitted at the moment.
The
> extboot infrastructure is there though so it''s just a matter of
> initializing it
> with the appropriate BlockDriverState.

We really badly need the ''-drive'' patch from QEMU 0.9.1 in
Xen. We currently
hack this horribly by passing disks via xenstore, while all other args to
QEMU are regular command line args. If we had the -drive patch another large
chunk of Xen specific patches would go away which has to be a good thing.

If there aren''t already plans to rebase to QEMU 0.9.1 in Xen 3.3.x
series
I''d recommend back-porting the ''-drive'' patch to
Xen''s QEMU 0.9.0

Dan.
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