Re: [Qemu-devel] [Xen-devel] [PATCH] Add Xen platform PCI device version 2.

[Tim Deegan]

At 07:47 +0000 on 20 Jun (1371714432), Paul Durrant wrote:
> > > I agree. If this is really the only solution, we would need to have
> > > both versions presented to the guest so that old drivers continue to
> > > work without any intervention.
> > 
> > I suspect that if we expose both, both sets of drivers try to run the
> > same PV connections, and hilarity ensues.
> > 
> 
> Actually I think I can make that work, and it is the conclusion I came
> to after Alex's comment.

Ah, nice!  In that case, I'm a lot less worried -- we can just expose
both versions/devices by default and there's no need for a visible
control knob tied to driver version (except maybe for debugging).

It means an 'unsupported' device appearing on other/older OSes, which is
unfortunate, but ISTR only Windows really complains visibly about that.

Tim.