On the contrary. Xen already has a hypercall interface, and we need to
keep supporting it. If we were to also support a vmm-independent
interface (aka "kvm interface"), then we need to be able to do that in
parallel. If we have a cpuid leaf clash, then its impossible to do so;
if we define the new interface to be disjoint from other current users
of cpuid, then we can support them concurrently.
J
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