From: Marc Zyngier <maz@kernel.org>
Date: Sun, 13 Nov 2022 16:38:22 +0000 (+0000)
Subject: KVM: arm64: PMU: Only narrow counters that are not 64bit wide
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0f1e172b54f7574ca6aa46b851b332896add955f;p=linux.git

KVM: arm64: PMU: Only narrow counters that are not 64bit wide

The current PMU emulation sometimes narrows counters to 32bit
if the counter isn't the cycle counter. As this is going to
change with PMUv3p5 where the counters are all 64bit, fix
the couple of cases where this happens unconditionally.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Link: https://lore.kernel.org/r/20221113163832.3154370-7-maz@kernel.org
---

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 9e6bc7edc4de0..1fab889dbc74f 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -151,20 +151,17 @@ static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc)
  */
 static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
 {
-	u64 counter, reg, val;
+	u64 reg, val;
 
 	if (!pmc->perf_event)
 		return;
 
-	counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
+	val = kvm_pmu_get_counter_value(vcpu, pmc->idx);
 
-	if (pmc->idx == ARMV8_PMU_CYCLE_IDX) {
+	if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
 		reg = PMCCNTR_EL0;
-		val = counter;
-	} else {
+	else
 		reg = PMEVCNTR0_EL0 + pmc->idx;
-		val = lower_32_bits(counter);
-	}
 
 	__vcpu_sys_reg(vcpu, reg) = val;
 
@@ -414,7 +411,8 @@ static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
 
 		/* Increment this counter */
 		reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
-		reg = lower_32_bits(reg);
+		if (!kvm_pmu_idx_is_64bit(vcpu, i))
+			reg = lower_32_bits(reg);
 		__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
 
 		/* No overflow? move on */