Thread (1 message) 1 message, 1 author, 2025-05-05

[PATCH AUTOSEL 6.14 289/642] perf: arm_pmuv3: Call kvm_vcpu_pmu_resync_el0() before enabling counters

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STALE416d REVIEWED: 4 (3M)

From: Sasha Levin <sashal@kernel.org>
Date: 2025-05-05 22:25:56
Also in: linux-perf-users, lkml, stable
Subsystem: arm pmu profiling and debugging, the rest · Maintainers: Will Deacon, Mark Rutland, Linus Torvalds

2 review trailers.

From: "Rob Herring (Arm)" <robh@kernel.org>

[ Upstream commit 04bd15c4cbc3f7bd2399d1baab958c5e738dbfc9 ]

Counting events related to setup of the PMU is not desired, but
kvm_vcpu_pmu_resync_el0() is called just after the PMU counters have
been enabled. Move the call to before enabling the counters.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Anshuman Khandual <redacted>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250218-arm-brbe-v19-v20-1-4e9922fc2e8e@kernel.org (local)
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/perf/arm_pmuv3.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 0e360feb3432e..9ebc950559c0a 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -825,10 +825,10 @@ static void armv8pmu_start(struct arm_pmu *cpu_pmu)
 	else
 		armv8pmu_disable_user_access();
 
+	kvm_vcpu_pmu_resync_el0();
+
 	/* Enable all counters */
 	armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E);
-
-	kvm_vcpu_pmu_resync_el0();
 }
 
 static void armv8pmu_stop(struct arm_pmu *cpu_pmu)
-- 
2.39.5

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