Re: KVM PMU virtualization

Peter Zijlstra
2010-02-26T14:49:11Z

On Fri, 2010-02-26 at 15:30 +0200, Avi Kivity wrote:
>
> Even if there were no security considerations, if the guest can observe
> host data in the pmu, it means the pmu is inaccurate. We should expose
> guest data only in the guest pmu. That's not difficult to do, you stop
> the pmu on exit and swap the counters on context switches.

That's not enough, memory node wide counters are impossible to isolate
like that, the same for core wide (ANY flag) counters.