diff options
| author | Oliver Upton <oliver.upton@linux.dev> | 2025-03-05 12:30:21 -0800 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2025-03-11 12:54:30 -0700 |
| commit | 1b92e65f5006da55c8779b86f052855a49ecdd97 (patch) | |
| tree | e0532bf585648c1ca7ae1c8e213fba3a39418ab4 | |
| parent | 2d00cab849be5e4c1b2ba82d4fdcfa0af48c340f (diff) | |
KVM: arm64: Provide 1 event counter on IMPDEF hardware
PMUv3 requires that all programmable event counters are capable of
counting any event. The Apple M* PMU is quite a bit different, and
events have affinities for particular PMCs.
Expose 1 event counter on IMPDEF hardware, allowing the guest to do
something useful with its PMU while also upholding the requirements of
the architecture.
Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305203021.428366-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
| -rw-r--r-- | arch/arm64/kvm/pmu-emul.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 5f4e9be8aa8b..51fb47e0bf89 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -1039,6 +1039,13 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm) struct arm_pmu *arm_pmu = kvm->arch.arm_pmu; /* + * PMUv3 requires that all event counters are capable of counting any + * event, though the same may not be true of non-PMUv3 hardware. + */ + if (cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS)) + return 1; + + /* * The arm_pmu->cntr_mask considers the fixed counter(s) as well. * Ignore those and return only the general-purpose counters. */ |