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