Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage

Andi Kleen
2014-04-23T20:00:25Z

> > Acked-by: Borislav Petkov <bp@suse.de>
>
> Brown-Paper-Bag-Worn-By: Venkatesh Srinivas <venkateshs@google.com>

Again the bug is really in KVM. We wouldn't need all this crap
if KVM didn't throw the bogus #GPs. I'm sure you missed plenty
of MSR accesses elsewhere, and it's a ticking time bomb.

If the VM lies to the kernel with the family-model you need to at
least limit the consequences. KVM is spectacularly failing
to do that by throwing bogus #GPs.

The brown paper bad needs to be employed on the KVM code
(or better the bug be fixed there, by defaulting to not #GP
on unknown MSRs)

-Andi

--
ak@linux.intel.com -- Speaking for myself only