[libvirt] [Qemu-devel] Configuring pflash devices for OVMF firmware

[Gerd Hoffmann]

  Hi,

> > (Migration compat is left as an exercise for the reader :-))
> 
> It's not just migration compatibility, it's also guest ABI: "the guest
> can tell the difference".

Is that actually the case on x86?  I don't think so.

Note: arm is different, because the flash is listed in the device tree
which is guest visible.

> So, old machine types continue to get two flash devices, and new
> machine types get one.  In other words, we're stuck maintaining (a)
> even if we decide to switch to (b).

I think that'll be true nevertheless for live migration compatibility.

cheers,
  Gerd