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Date: Fri, 01 Jul 2011 08:10:22 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 1/4] add support for machine models to
 specify their migration format
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org

On 06/30/2011 08:11 PM, Michael S. Tsirkin wrote:
> >  Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
>
> Should not machine describe guest behaviour?
> It seems that a flag to the migrate/save command to control format
> would be better - this way the same machine can
> migrate to different formats.

I thought about it, but there is no savevm state variable (only 
migration state, but it's unused for snapshotting).  So it seemed too 
much work for an RFC series I wanted to push out fast.

Besides, you need to store a default somewhere, and the default must be 
the old format for versioned machine models; perhaps not from QEMU where 
new->old migration is a wild bet anyway, but for downstream it must. 
Then I think that you are suggesting a superset of this patch. I'm not 
even sure it is necessary to have it though: it is a correctness fix, it 
should be on for everyone.

Paolo