RE: [kvm-devel] [PATCH] Refactor hypercall infrastructure

From: Nakajima, Jun
Date: Fri Sep 14 2007 - 21:04:27 EST


Jeremy Fitzhardinge wrote:
> Nakajima, Jun wrote:
> > Today, 3 CPUID leaves starting from 0x4000_0000 are defined in a
generic
> > fashion (hypervisor detection, version, and hypercall page), and
those
> > are the ones used by Xen today. We should extend those leaves (e.g.
> > starting from 0x4000_0003) for the vmm-independent features as well.
> >
> > If Xen needs additional Xen-specific features, we need to allocate
some
> > leaves for those (e.g. 0x4000_1000)
>
> But the signature is "XenVMMXenVMM", which isn't very generic. If
we're
> presenting a generic interface, it needs to have a generic signature,
> otherwise guests will need to have a list of all hypervisor signatures
> supporting their interface. Since 0x40000000 has already been
> established as the base leaf of the hypervisor-specific interfaces,
the
> generic interface will have to be elsewhere.

The hypervisor detection machanism is generic, and the signature
returned is implentation specific. Having a list of all hypervisor
signatures sounds fine to me as we are detecting vendor-specific
processor(s) in the native. And I don't expect the list is large.

>
> J

Jun
---
Intel Open Source Technology Center
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