On Thu, 13 Sep 2012, Dave Martin wrote:

Do you think it's feasible to standardise on some interoperable ABI for
kvm and Xen?  This sounds pretty optimistic, but I'm not aware of all
the technicalities, or what possible third-party hypervisors are out
there.

If we could do it, it would be good.  But I have my doubts about the
feasibility and the benefits.  If different hypervisors are significantly
imcompatible, then having a common low-level ABI doesn't help all that
much.

It is not really possible because each hypervisor offers a different set
of hypercalls and has a different calling convention, so there is very
little we can do to unify them.

For example many of the current Xen hypercalls are to deal with the grant
table and event channels, that are Xen specific concepts completely
missing in KVM.