From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [Planning for Xen-4.6] Migration v2
Date: Thu, 27 Nov 2014 08:46:36 +0000
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To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Juergen Gross <JGross@suse.com>, Wei Liu <wei.liu2@citrix.com>, Tim Deegan <tim@xen.org>, Ian Jackson <Ian.Jackson@eu.citrix.com>, Xen-devel List <xen-devel@lists.xen.org>, Ross Lagerwall <ross.lagerwall@citrix.com>, David Vrabel <david.vrabel@citrix.com>, Jan Beulich <JBeulich@suse.com>, Shriram Rajagopalan <rshriram@cs.ubc.ca>, Hongyang Yang <yanghy@cn.fujitsu.com>
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On Wed, 2014-11-26 at 17:39 +0000, Andrew Cooper wrote:
> > IMHO this is fine. It essentially means that for xl users there is some
> > delayed gratification wrt the promise of migration between non-alike
> > dom0s. The migration from 4.5(legacy)->4.6(v2) won't support such
> > migrations, but the next step from 4.6(v2)->4.7(v2) will.
> 
> Two options exist.
> 
> 1) Assume that the sending bitness is the same as the receiving
> bitness.  This is already the status quo, and will require that the two
> dom0s are the same width.

As I said above I think this is absolutely acceptable as a transitional
step.

> 2) Allow the administrator to specify the bitness of the sending side. 
> In this case, xl 4.5(legacy)->4.6(v2) works even cross-bitness.

If this is trivial to plumb in and you are motivated to do so then this
seems like a reasonable enough "stretch goal".

Ian.