Arm CCA assigns the physical PMU device to the guest running in realm
world, however the IRQs are routed via the host. To enter a realm guest
while a PMU IRQ is pending it is necessary to block the physical IRQ to
prevent an immediate exit. Provide a mechanism in the PMU driver for KVM
to control the physical IRQ.

Signed-off-by: Steven Price <steven.price@arm.com>
---
v3: Add a dummy function for the !CONFIG_ARM_PMU case.
---
 drivers/perf/arm_pmu.c       | 15 +++++++++++++++
 include/linux/perf/arm_pmu.h |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 398cce3d76fc..2cdcdda8f638 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -735,6 +735,21 @@ static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node)
 	return 0;
 }
 
+void arm_pmu_set_phys_irq(bool enable)
+{
+	int cpu = get_cpu();
+	struct arm_pmu *pmu = per_cpu(cpu_armpmu, cpu);
+	int irq;
+
+	irq = armpmu_get_cpu_irq(pmu, cpu);
+	if (irq && !enable)
+		per_cpu(cpu_irq_ops, cpu)->disable_pmuirq(irq);
+	else if (irq && enable)
+		per_cpu(cpu_irq_ops, cpu)->enable_pmuirq(irq);
+
+	put_cpu();
+}
+
 #ifdef CONFIG_CPU_PM
 static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
 {
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 4b5b83677e3f..6c2631e2cbd7 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -172,6 +172,7 @@ void kvm_host_pmu_init(struct arm_pmu *pmu);
 #endif
 
 bool arm_pmu_irq_is_nmi(void);
+void arm_pmu_set_phys_irq(bool enable);
 
 /* Internal functions only for core arm_pmu code */
 struct arm_pmu *armpmu_alloc(void);
@@ -182,6 +183,10 @@ void armpmu_free_irq(int irq, int cpu);
 
 #define ARMV8_PMU_PDEV_NAME "armv8-pmu"
 
+#else /* CONFIG_ARM_PMU */
+
+static inline void arm_pmu_set_phys_irq(bool enable) {}
+
 #endif /* CONFIG_ARM_PMU */
 
 #define ARMV8_SPE_PDEV_NAME "arm,spe-v1"
-- 
2.34.1