On Fri, 16 Feb 2007, Zachary Amsden wrote:

Yes, but that is just because the Xen hooks happens to be near the last part
of the merge.  VMI required some special hooks, as do both Xen and lhype (I
think ... Rusty can correct me if lhype's puppy's have precluded the addition
of new hooks).  Xen page table handling is very different, mostly it is trap
and emulate so writable page tables can work, which means they don't always
issue hypercalls for PTE updates, although they do have that option, should
the hypervisor MMU model change, or performance concerns prompt a different
model (or perhaps, migration?)

Well looks like there are still some major design issues to be ironed out. 
What is proposed here is to make paravirt_ops a fake generic 
API and then tunnel through it to vendor specific kernel mods.