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Date: Wed, 16 Feb 2011 20:09:35 +0530
From: Amit Shah <amit.shah@redhat.com>
Subject: Re: [Qemu-devel] KVM call minutes for Feb 15
Message-ID: <20110216143934.GB5770@amit-x200.redhat.com>
References: <20110215162629.GN21720@x200.localdomain>
	<4D5B0889.4030303@codemonkey.ws>
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Chris Wright <chrisw@redhat.com>, qemu-devel@nongnu.org, kvm@vger.kernel.org

On (Tue) 15 Feb 2011 [17:13:13], Anthony Liguori wrote:
> On 02/15/2011 10:26 AM, Chris Wright wrote:
> >
> >revisit new ->  old migration
> >- Amit offers virtio-serial patches and some legwork
> 
> So, to me, migration correctness trumps compatibility.  I don't
> think compatibility is useful if it means that a guest may fail
> during migration.  We have subsections as a way to support the cases
> where it's safe to migrate to an old version only if a feature is
> not being used or a corner case is not currently happening.  This is
> the best way to approach the problem.
> 
> If a subsection won't work, that means you want to migrate when
> you're completely sure that migrating will break a guest.  That
> doesn't seem reasonable at all to me.
> 
> I think in the last discussion on Amit's patches, I had suggested
> that subsections could be used to allow migration when there wasn't
> any queued data.  I think this is the best we can do while
> preserving correctness.

The only problem is that virtio hasn't been converted over to vmstate,
which is necessary for subsections.

		Amit