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RE: [Xen-devel] [RFC] Hypercalls from HVM guests


On Sun, 2006-04-09 at 06:56 -0700, Nakajima, Jun wrote:

> If we really need to tell if we are running on a hypervisor at a very
> early point or even in user-mode, I think CPUID with "an unused index"
> would be the simplest, but so far I haven't seen any usage models that
> really require that. If we want to add virtualization hints for
> processor architectures (e.g. MMU) in guests, it would be needed. 

If you want it for MMU setup right at the earliest stages, prior to
entering 32-bit mode, you can probably already get this today by
searching for "HVMAssist" in the rombios, and the same information is
visible from 32-bit supervisor mode (but not from user space unless the
OS decides to export it.)


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