linux-kernel - [PATCH v2 32/43] arm_pmu: Provide a mechanism for disabling the physical IRQ

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Date: Fri, 12 Apr 2024 09:42:58 +0100
From: Steven Price <steven.price@....com>
To: kvm@...r.kernel.org,
	kvmarm@...ts.linux.dev
Cc: Steven Price <steven.price@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Marc Zyngier <maz@...nel.org>,
	Will Deacon <will@...nel.org>,
	James Morse <james.morse@....com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Joey Gouly <joey.gouly@....com>,
	Alexandru Elisei <alexandru.elisei@....com>,
	Christoffer Dall <christoffer.dall@....com>,
	Fuad Tabba <tabba@...gle.com>,
	linux-coco@...ts.linux.dev,
	Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>
Subject: [PATCH v2 32/43] arm_pmu: Provide a mechanism for disabling the physical IRQ

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@....com>
---
 drivers/perf/arm_pmu.c       | 15 +++++++++++++++
 include/linux/perf/arm_pmu.h |  1 +
 2 files changed, 16 insertions(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 8458fe2cebb4..1e024acc98bb 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 b3b34f6670cf..fd5e2e63b7fb 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -168,6 +168,7 @@ 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);
-- 
2.34.1