Re: [PATCH v1 0/4] Enable LBR for the guest

[Andi Kleen]

> On the other side, it seems that the (guest) kernel driver also works
> without
> the above being supported, should we change it to report error and stop
> using the PMU features when the check of the above two fails (at
> intel_pmu_init())?

You could add the extra check for the LBR code yes, although it already checks
if the LBR MSRs work, so in practice it's likely already covered.

-Andi