Hi Andrew, On 12/06/2019 20:04, Andrew Murray wrote: > We currently use pmc->bitmask to determine the width of the pmc - however > it's superfluous as the pmc index already describes if the pmc is a cycle > counter or event counter. The architecture clearly describes the widths of > these counters. > > Let's remove the bitmask to simplify the code. > > Signed-off-by: Andrew Murray <[email protected]> > --- > include/kvm/arm_pmu.h | 1 - > virt/kvm/arm/pmu.c | 19 +++++++++---------- > 2 files changed, 9 insertions(+), 11 deletions(-) > > diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h > index b73f31baca52..2f0e28dc5a9e 100644 > --- a/include/kvm/arm_pmu.h > +++ b/include/kvm/arm_pmu.h > @@ -28,7 +28,6 @@ > struct kvm_pmc { > u8 idx; /* index into the pmu->pmc array */ > struct perf_event *perf_event; > - u64 bitmask; > }; > > struct kvm_pmu { > diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c > index ae1e886d4a1a..88ce24ae0b45 100644 > --- a/virt/kvm/arm/pmu.c > +++ b/virt/kvm/arm/pmu.c > @@ -47,7 +47,10 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 > select_idx) > counter += perf_event_read_value(pmc->perf_event, &enabled, > &running); > > - return counter & pmc->bitmask; > + if (select_idx != ARMV8_PMU_CYCLE_IDX) > + counter = lower_32_bits(counter);
Shouldn't this depend on PMCR.LC as well? If PMCR.LC is clear we only want the lower 32bits of the cycle counter. Cheers, -- Julien Thierry _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
