A hypervisor will typically mask the overflow interrupt before
forwarding it to Guest Linux hence we need to re-enable the overflow
interrupt after clearing it in Guest Linux. Also, this re-enabling
of overflow interrupt does not harm in non-virtualized scenarios.
Signed-off-by: Pranavkumar Sawargaonkar <pranavku...@linaro.org>
Signed-off-by: Anup Patel <anup.pa...@linaro.org>
---
arch/arm/kernel/perf_event_v7.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index 1d37568..581cca5 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -1355,6 +1355,14 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void
*dev)
if (!armv7_pmnc_counter_has_overflowed(pmnc, idx))
continue;
+ /*
+ * If we are running under a hypervisor such as KVM then
+ * hypervisor will mask the interrupt before forwarding
+ * it to Guest Linux hence re-enable interrupt for the
+ * overflowed counter.
+ */
+ armv7_pmnc_enable_intens(idx);
+
hwc = &event->hw;
armpmu_event_update(event);
perf_sample_data_init(&data, 0, hwc->last_period);
--
1.7.9.5
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