Make it mandatory to use the architected PPI when running a GICv5
guest. Attempts to set anything other than the architected PPI (23)
are rejected.

Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
---
 arch/arm64/kvm/pmu-emul.c | 14 ++++++++++++--
 include/kvm/arm_pmu.h     |  5 ++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 0baf8e0fe23bd..9925f10aa4fce 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -961,8 +961,13 @@ static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
 		if (!vgic_initialized(vcpu->kvm))
 			return -ENODEV;
 
-		if (!kvm_arm_pmu_irq_initialized(vcpu))
-			return -ENXIO;
+		if (!kvm_arm_pmu_irq_initialized(vcpu)) {
+			/* Use the architected irq number for GICv5. */
+			if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V5)
+				vcpu->arch.pmu.irq_num = KVM_ARMV8_PMU_GICV5_IRQ;
+			else
+				return -ENXIO;
+		}
 
 		ret = kvm_vgic_set_owner(vcpu, vcpu->arch.pmu.irq_num,
 					 &vcpu->arch.pmu);
@@ -987,6 +992,11 @@ static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
 	unsigned long i;
 	struct kvm_vcpu *vcpu;
 
+	/* On GICv5, the PMUIRQ is architecturally mandated to be PPI 23 */
+	if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V5 &&
+	    irq != KVM_ARMV8_PMU_GICV5_IRQ)
+		return false;
+
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		if (!kvm_arm_pmu_irq_initialized(vcpu))
 			continue;
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 96754b51b4116..0a36a3d5c8944 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -12,6 +12,9 @@
 
 #define KVM_ARMV8_PMU_MAX_COUNTERS	32
 
+/* PPI #23 - architecturally specified for GICv5 */
+#define KVM_ARMV8_PMU_GICV5_IRQ		0x20000017
+
 #if IS_ENABLED(CONFIG_HW_PERF_EVENTS) && IS_ENABLED(CONFIG_KVM)
 struct kvm_pmc {
 	u8 idx;	/* index into the pmu->pmc array */
@@ -38,7 +41,7 @@ struct arm_pmu_entry {
 };
 
 bool kvm_supports_guest_pmuv3(void);
-#define kvm_arm_pmu_irq_initialized(v)	((v)->arch.pmu.irq_num >= VGIC_NR_SGIS)
+#define kvm_arm_pmu_irq_initialized(v)	((v)->arch.pmu.irq_num != 0)
 u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
 void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val);
 void kvm_pmu_set_counter_value_user(struct kvm_vcpu *vcpu, u64 select_idx, u64 val);
-- 
2.34.1