From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Levon <levon@movementarian.org>
Subject: Re: bimodal PAE and compatibility
Date: Mon, 8 Jan 2007 15:16:09 +0000
Message-ID: <20070108151609.GD1557@totally.trollied.org.uk>
References: <20070108144932.GA1557@totally.trollied.org.uk>
	<45A25DC0.1040401@suse.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Return-path: <xen-devel-bounces@lists.xensource.com>
Content-Disposition: inline
In-Reply-To: <45A25DC0.1040401@suse.de>
List-Unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Gerd Hoffmann <kraxel@suse.de>
Cc: xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

On Mon, Jan 08, 2007 at 04:05:36PM +0100, Gerd Hoffmann wrote:

> > We currently ship a PAE 32-bit domU that we can trivially make bimodal,
> > except that if we set it to "bimodal", then older Xens will default to
> > thinking the domU is not PAE:
> > 
> > 353     dsi->pae_kernel = PAEKERN_no;
> > 354     if ( dsi->__elfnote_section )
> > 355     {
> > 356         p = xen_elfnote_string(dsi, XEN_ELFNOTE_PAE_MODE);
> > 357         if ( p != NULL && strncmp(p, "yes", 3) == 0 )
> > 358             dsi->pae_kernel = PAEKERN_extended_cr3;
> > 
> > Could we have a new note instead?
> 
> I don't think it improves the situation, for older Xens you need two
> kernels anyway, even if the only difference is the content of the
> pae_mode elf note ...

What do you mean? Are you saying that Xen complains about an ELF note it
doesn't understand? That would be unfortunate.

john