Re: [RFC, PATCH 1/24] i386 Vmi documentation

Chris Wright
2006-03-22T21:35:09Z

* Andi Kleen (ak@suse.de) wrote:
> On Monday 13 March 2006 18:59, Zachary Amsden wrote:
>
> > + The general mechanism for providing customized features and
> > + capabilities is to provide notification of these feature through
> > + the CPUID call,
>
> How should that work since CPUID cannot be intercepted by
> a Hypervisor (without VMX/SVM)?

Yeah, it requires guest kernel cooperation/modification.

> > + The net result of these choices is that most of the calls are very
> > + easy to make from C-code, and calls that are likely to be required in
> > + low level trap handling code are easy to call from assembler. Most
> > + of these calls are also very easily implemented by the hypervisor
> > + vendor in C code, and only the performance critical calls from
> > + assembler paths require custom assembly implementations.
> > +
> > + CORE INTERFACE CALLS
>
> Did I miss it or do you never describe how to find these entry points?

It's the ROM interface. For native they are emitted directly inline.
For non-native, they are emitted as call stubs, which call to the ROM.
I don't recall if it's in this doc, but the inline patch has all the
gory details.

thanks,
-chris