Re: GPF in intel_pmu_lbr_reset() with qemu -cpu host

Andi Kleen
2014-03-21T21:51:14Z

"H. Peter Anvin" <hpa@zytor.com> writes:
>
> That's why at least to some extent The Right Thing is not to try to
> pretend to be a CPU you don't even know how to emulate.
>
> But again, that has its own issues, too, mostly with userspace
> optimization, and making the Linux code more resilient wouldn't hurt.
> In that sense #GP(0) is *much* better than 0: it unambiguously gives an
> error to work with.

That means we could just throw rdmsr() away and it would be completely
replaced with rdmsr_safe(). But then that will likely cause all kinds
of problems with how to handle these errors and where and how to handle
these exceptions.

I much prefer just to fix KVM. I cannot think of any case
where 0 would cause a major issue.

After all it's virtualization not "rewrite complete kernel for it"

-Andi

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