[RFC PATCH 3/6] ARM: perf: Re-enable overflow interrupt from interrupt handler
From: Anup Patel <hidden>
Date: 2014-08-05 09:24:12
Also in:
kvm
Subsystem:
arm pmu profiling and debugging, arm port, performance events subsystem, the rest · Maintainers:
Will Deacon, Mark Rutland, Russell King, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
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 <redacted> Signed-off-by: Anup Patel <redacted> --- 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