[RFC PATCH 13/14] KVM: arm64: Advertise 0 event counters for IMPDEF PMU

[Oliver Upton]

The programmable event counters on Apple M* parts are quite different
from what's available in PMUv3, as the event counters aren't fungible
(some events only work on specific counters) and the event ID space
doesn't match the architecture.

Signed-off-by: Oliver Upton <oliver.upton at linux.dev>
---
 arch/arm64/kvm/pmu-emul.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 34d9c08af209..8ac4eee781c9 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -1044,6 +1044,9 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
 {
 	struct arm_pmu *arm_pmu = kvm->arch.arm_pmu;
 
+	if (cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS))
+		return 0;
+
 	/*
 	 * The arm_pmu->cntr_mask considers the fixed counter(s) as well.
 	 * Ignore those and return only the general-purpose counters.
-- 
2.39.5