[PATCH v3 51/59] KVM: arm/arm64: GICv4: Add doorbell interrupt handling

[Marc Zyngier]

When a vPE is not running, a VLPI being made pending results in a
doorbell interrupt being delivered. Let's handle this interrupt
and update the pending_last flag that indicates that VLPIs are
pending. The corresponding vcpu is also kicked into action.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 virt/kvm/arm/vgic/vgic-v4.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
index 534d3051a078..6af3cde6d7d4 100644
--- a/virt/kvm/arm/vgic/vgic-v4.c
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -21,6 +21,19 @@
 
 #include "vgic.h"
 
+static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
+{
+	struct kvm_vcpu *vcpu = info;
+
+	if (!kvm_vgic_vcpu_pending_irq(vcpu)) {
+		vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
+		kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+		kvm_vcpu_kick(vcpu);
+	}
+
+	return IRQ_HANDLED;
+}
+
 int vgic_v4_init(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
@@ -57,16 +70,37 @@ int vgic_v4_init(struct kvm *kvm)
 		return ret;
 	}
 
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		int irq = dist->its_vm.vpes[i]->irq;
+
+		ret = request_irq(irq, vgic_v4_doorbell_handler,
+				  0, "vcpu", vcpu);
+		if (ret) {
+			kvm_err("failed to allocate vcpu IRQ%d\n", irq);
+			dist->its_vm.nr_vpes = i;
+			break;
+		}
+	}
+
+	if (ret)
+		vgic_v4_teardown(kvm);
+
 	return ret;
 }
 
 void vgic_v4_teardown(struct kvm *kvm)
 {
 	struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
+	int i;
 
 	if (!its_vm->vpes)
 		return;
 
+	for (i = 0; i < its_vm->nr_vpes; i++) {
+		struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i);
+		free_irq(its_vm->vpes[i]->irq, vcpu);
+	}
+
 	its_free_vcpu_irqs(its_vm);
 	kfree(its_vm->vpes);
 	its_vm->nr_vpes = 0;
-- 
2.11.0