Messages in this thread | | | Date | Mon, 29 Sep 2008 10:58:41 -0700 | From | "H. Peter Anvin" <> | Subject | Re: Use CPUID to communicate with the hypervisor. |
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Alok Kataria wrote: >> Shouldn't you check the hypervisor signature here? > > Nope the whole idea of not checking the hypervisor signature is that we > should keep this interface generic.
Unfortunately, given current evidence this is entirely unrealistic.
> So for instance right now, VMware has defined 40000010 leaf, if either > kvm/xen think it could be useful they could just define that leaf to > return nonzero value and the kernel will start using it for them. > Likewise, if in future either kvm/xen come up with a need to define a > new CPUID leaf they can define the semantics for that leaf, and the > corresponding kernel side stuff. If VMware, think that this new leaf is > useful, we can then support that leaf in our hypervisor or return zero > otherwise.
This is only true if you can also except M$ and other hypervisor vendors to stick to it. So far, hypervisor vendors have hardly shown any inclination toward standardization.
Hence I really don't think it is sane.
-hpa
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