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

From: Andi Kleen
Date: Fri Mar 21 2014 - 17:51:48 EST

"H. Peter Anvin" <hpa@xxxxxxxxx> 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"


ak@xxxxxxxxxxxxxxx -- Speaking for myself only
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at