[PATCH 4/4] KVM: arm64: Only apply PMCR_EL0.P to the guest range of counters

[Oliver Upton <oliver.upton@linux.dev>]

An important distinction from other registers affected by HPMN is that
PMCR_EL0 only affects the guest range of counters, regardless of the EL
from which it is accessed. Ensure that PMCR_EL0.P is always applied to
'guest' counters by manually computing the mask rather than deriving it
from the current context.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/pmu-emul.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index c6423782a8aa..6c5950b9ceac 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -617,8 +617,14 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
 		kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0);
 
 	if (val & ARMV8_PMU_PMCR_P) {
-		unsigned long mask = kvm_pmu_accessible_counter_mask(vcpu);
-		mask &= ~BIT(ARMV8_PMU_CYCLE_IDX);
+		/*
+		 * Unlike other PMU sysregs, the controls in PMCR_EL0 always apply
+		 * to the 'guest' range of counters and never the 'hyp' range.
+		 */
+		unsigned long mask = kvm_pmu_implemented_counter_mask(vcpu) &
+				     ~kvm_pmu_hyp_counter_mask(vcpu) &
+				     ~BIT(ARMV8_PMU_CYCLE_IDX);
+
 		for_each_set_bit(i, &mask, 32)
 			kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true);
 	}
-- 
2.39.5