diff mbox series

[v4,06/16] KVM: arm64: PMU: Only narrow counters that are not 64bit wide

Message ID 20221113163832.3154370-7-maz@kernel.org (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: PMU: Fixing chained events, and PMUv3p5 support | expand

Commit Message

Marc Zyngier Nov. 13, 2022, 4:38 p.m. UTC 
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>
---
 arch/arm64/kvm/pmu-emul.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

Comments

Reiji Watanabe Nov. 17, 2022, 6:54 a.m. UTC | #1 
On Sun, Nov 13, 2022 at 8:38 AM Marc Zyngier <maz@kernel.org> wrote:
>
> 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>
diff mbox series

Patch

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 9e6bc7edc4de..1fab889dbc74 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 */