Re: [Qemu-devel] [PATCH] Remove hardcoded xen-platform device initialization

From: Paul Durrant <Paul.Durrant@citrix.com>
To: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [Qemu-devel] [PATCH] Remove hardcoded xen-platform device initialization
Date: Fri, 14 Jun 2013 08:50:14 +0000	[thread overview]
Message-ID: <9AAE0902D5BC7E449B7C8E4E778ABCD0039278@LONPEX01CL01.citrite.net> (raw)
In-Reply-To: <alpine.DEB.2.02.1306131830560.4548@kaball.uk.xensource.com>

> -----Original Message-----
> From: Stefano Stabellini [mailto:stefano.stabellini@eu.citrix.com]
> Sent: 13 June 2013 18:33
> To: Paul Durrant
> Cc: qemu-devel@nongnu.org; xen-devel@lists.xen.org
> Subject: Re: [Qemu-devel] [PATCH] Remove hardcoded xen-platform device
> initialization
> 
> On Thu, 13 Jun 2013, Paul Durrant wrote:
> > The xen-platform device should be initialized by the Xen toolstack by
> > passing the appropriate -device argument on the command line.
> >
> > Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> 
> This patch is problematic because we can't know for sure the version of
> upstream QEMU that is going to be used with Xen.
> If we apply this patch and QEMU 1.5 is going to be used with Xen 4.2,
> guests won't be able to use PV drivers.
> 

Is there not a compatibility matrix? The hardcoded init. is just blatantly the wrong thing to be doing and it needs to go.

Could my accompanying toolstack patch not be backported to the next 4.2 release as mitigation?

  Paul