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Date: Thu, 14 May 2015 12:04:05 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH RFC 1/1] virtio: migrate config_vector
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>, borntraeger@de.ibm.com, qemu-devel@nongnu.org, jjherne@linux.vnet.ibm.com



On 14/05/2015 11:56, Michael S. Tsirkin wrote:
> > That's expected.  Subsections break compatibility because sometimes
> > breaking migration is better than leaving a broken guest after migration.
> 
> Right, and what happens is that some devices work kind of okay without
> config interrupts? Christian - is this why you are trying to preserve
> the broken behaviour for cross-version migration?

If you really want that, the hook should be in the virtio device class.
Keying on the machine type is almost never the answer, at least upstream.

Distros can always override it if they know what they're getting into.

Paolo