Re: [PATCH v4 12/16] KVM: arm64: PMU: Allow ID_DFR0_EL1.PerfMon to be set from userspace

2022-11-19 Thread Marc Zyngier
On 2022-11-19 05:52, Reiji Watanabe wrote: Hi Marc, On Sun, Nov 13, 2022 at 8:46 AM Marc Zyngier wrote: Allow userspace to write ID_DFR0_EL1, on the condition that only the PerfMon field can be altered and be something that is compatible with what was computed for the AArch64 view of the

Re: [PATCH v4 09/16] KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits

2022-11-19 Thread Marc Zyngier
On 2022-11-18 07:45, Reiji Watanabe wrote: Hi Marc, On Sun, Nov 13, 2022 at 8:38 AM Marc Zyngier wrote: Even when using PMUv3p5 (which implies 64bit counters), there is no way for AArch32 to write to the top 32 bits of the counters. The only way to influence these bits (other than by