VisionFive2 Linux kernel

author: Wei Huang <wei@redhat.com> 2017-05-30 11:56:22 +0100 committer: Catalin Marinas <catalin.marinas@arm.com> 2017-05-30 12:40:03 +0100 commit: 477c50e8dc1c7b5004e099b8b74ca8b70be2f4fd parent: 717902cc93118119a6fce7765da6cf2786987418

Commit Summary:

drivers/perf: arm_pmu_acpi: avoid perf IRQ init when guest PMU is off

Diffstat:

1 file changed, 10 insertions, 0 deletions

diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index 34c862f213c7..0a9b78705ee8 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -29,6 +29,17 @@ static int arm_pmu_acpi_register_irq(int cpu)
 		return -EINVAL;
 
 	gsi = gicc->performance_interrupt;
+
+	/*
+	 * Per the ACPI spec, the MADT cannot describe a PMU that doesn't
+	 * have an interrupt. QEMU advertises this by using a GSI of zero,
+	 * which is not known to be valid on any hardware despite being
+	 * valid per the spec. Take the pragmatic approach and reject a
+	 * GSI of zero for now.
+	 */
+	if (!gsi)
+		return 0;
+
 	if (gicc->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE)
 		trigger = ACPI_EDGE_SENSITIVE;
 	else