Re: [PATCH] perf/x86/intel: Use rdmsrl_safe when initializing RAPL PMU.

Andi Kleen
2014-03-14T16:17:50Z

> The Intel ISR section for RDMSR seems to say: "Specifying a reserved
> or unimplemented
> MSR address in ECX will also cause a general protection exception".
>
> From a guest's perspective, MSR_RAPL_POWER_UNIT is unimplemented; kvm matches
> this behavior.

MSRs are model specific and defined per model number. If you report a model
number you're expected to implement the MSRs defined for that model number.

AFAIK Xen just reports 0 for unknown MSRs (and I'm surprised KVM doesn't too)

I would suggest to fix KVM.

-Andi