Re: [Qemu-devel] [PATCH] i386: wire up MSR_IA32_MISC_ENABLE

[Avi Kivity]

On 10/04/2011 07:24 PM, Jan Kiszka wrote:
> >>
> >>  Given that, when in conflict, we rather model after AMD than Intel for
> >>  TCG, I would hesitate to expose this by default. Or are there
> >>  precedences already?
> >
> >  Practically all MSRs.  i486 doesn't have any, IIRC, for example.
>
> Pre-Pentiums don't have instructions to access them as well, so that
> doesn't cause any harm.

kvm doesn't detect this; does tcg?  In any case, MSR availability varies 
widely with processor model.

> >
> >  (and given this MSR has no effect, the only difference it makes to
> >  guests is the #GP we take or not; still it may be worthwhile to
> >  construct some table-driven thing to allow or reject MSR accesses, both
> >  for kvm and qemu)
>
> Right. If this MSR is not the first bogus one on AMD, we can do this
> later. If it is, it should be done first.

It's certainly not the first - they practically all are, depending on 
exact model.

--
error compiling committee.c: too many arguments to function