Re: [RFC] CPUID usage for interaction between Hypervisorsand Linux.

[Alok Kataria]

On Wed, 2008-10-01 at 11:06 -0700, Jeremy Fitzhardinge wrote:
> Alok Kataria wrote:
> > Its not a user who has to do anything special here.
> > There are *intelligent* VM developers out there who can export a
> > different CPUid interface depending on the guest OS type. And this is
> > what most of the hypervisors do (not necessarily for CPUID, but for
> > other things right now).
> >
> 
> No, that's always a terrible idea.  Sure, its necessary to deal with
> some backward-compatibility issues, but we should even consider a new
> interface which assumes this kind of thing.  We want properly enumerable
> interfaces.

The reason we still have to do this is because, Microsoft has already
defined a CPUID format which is way different than what you or I are
proposing ( with the current case of 256 leafs being available). And I
doubt they would change the way they deal with it on their OS. 
Any proposal that we go with, we will have to export different CPUID
interface from the hypervisor for the 2 OS in question. 

So i think this is something that we anyways will have to do and not
worth binging about in the discussion.

--
Alok

>     J

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/