diff mbox series

[v4,03/16] KVM: arm64: PMU: Always advertise the CHAIN event

Message ID 20221113163832.3154370-4-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 
Even when the underlying HW doesn't offer the CHAIN event
(which happens with QEMU), we can always support it as we're
in control of the counter overflow.

Always advertise the event via PMCEID0_EL0.

Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/pmu-emul.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 57765be69bea..69b67ab3c4bf 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -701,6 +701,8 @@  u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
 
 	if (!pmceid1) {
 		val = read_sysreg(pmceid0_el0);
+		/* always support CHAIN */
+		val |= BIT(ARMV8_PMUV3_PERFCTR_CHAIN);
 		base = 0;
 	} else {
 		val = read_sysreg(pmceid1_el0);