Re: [RFC 3/3] KVM: arm64: pmu: Enforce PMEVTYPER evtCount size

From: Will Deacon
Date: Thu Dec 05 2019 - 04:02:40 EST


On Wed, Dec 04, 2019 at 09:44:26PM +0100, Eric Auger wrote:
> ARMv8.1-PMU supports 16-bit evtCount whereas 8.0 only supports
> 10 bits.
>
> On Seatlle which has an 8.0 PMU implementation, evtCount[15:10]
> are not read as 0, as expected. Fix that by applying a mask on
> the selected event that depends on the PMU version.

Are you sure about that? These bits are RES0 in 8.0 afaict, so this would be
a CPU erratum. Have you checked the SDEN document (I haven't)?

Will