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

Message ID 20241203193220.1070811-14-oliver.upton@linux.dev (mailing list archive)
State New
Headers show
Series KVM: arm64: Support FEAT_PMUv3 on Apple hardware | expand

Commit Message

Oliver Upton Dec. 3, 2024, 7:32 p.m. UTC 
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@linux.dev>
---
 arch/arm64/kvm/pmu-emul.c | 3 +++
 1 file changed, 3 insertions(+)
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Patch

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.