Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore

[Paolo Bonzini]

Il 10/09/2014 14:20, Michael S. Tsirkin ha scritto:
> > Do you have an example?  I can think of one that we did in RHEL (hda)
> > but it was never upstream.
> 
> Well the whole PC machine is exactly like this, isn't it?

Sorry, I cannot parse.

You proposed creating two versions of pcspk that only differ in the
vmstate.  We never did that in upstream QEMU, and all precedents are in
the other direction.

Furthermore, for a downstream that cares about backwards migration the
simplest thing to do would be to just revert this patch.  It would
really be overkill.

> 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.

This has nothing to do with migration though.  I understand the
technicalities of how it would be done.  I just think that upstream
policy so far hasn't been to do this.

Paolo