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Date: Wed, 10 Sep 2014 15:20:09 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for
	save/restore
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: amit.shah@redhat.com, dgilbert@redhat.com, qemu-devel@nongnu.org, Pavel.Dovgaluk@ispras.ru, quintela@redhat.com

On Wed, Sep 10, 2014 at 12:59:35PM +0200, Paolo Bonzini wrote:
> Il 10/09/2014 14:02, Michael S. Tsirkin ha scritto:
> > That's not too hard: we need two types that only
> > differ in the vmstate.
> > Use the correct one to create the device depending
> > on the pc type.
> > 
> > Put in that light, we definitely did create new
> > devices while keeping old ones around for
> > compatibility.
> 
> Do you have an example?  I can think of one that we did in RHEL (hda)
> but it was never upstream.
> 
> Paolo

Well the whole PC machine is exactly like this, isn't it?

Also, xen plans to do something similar for igd passthrough,
and I plan to do something similar for virtio 1.0.
stdvga is somewhat similar.

-- 
MST