KVM: arm/arm64: prepare GICv2 emulation to be handled by kvm_io_bus

Using the framework provided by the recent vgic.c changes we register
a kvm_io_bus device when initializing the virtual GICv2.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

include/kvm/arm_vgic.h

@@ -251,6 +251,7 @@ struct vgic_dist {
 	unsigned long		*irq_active_on_cpu;
 
 	struct vgic_vm_ops	vm_ops;
+	struct vgic_io_device	dist_iodev;
 };
 
 struct vgic_v2_cpu_if {

virt/kvm/arm/vgic-v2-emul.c

@@ -506,6 +506,7 @@ static bool vgic_v2_queue_sgi(struct kvm_vcpu *vcpu, int irq)
 static int vgic_v2_map_resources(struct kvm *kvm,
 				 const struct vgic_params *params)
 {
+	struct vgic_dist *dist = &kvm->arch.vgic;
 	int ret = 0;
 
 	if (!irqchip_in_kernel(kvm))
@@ -516,13 +517,17 @@ static int vgic_v2_map_resources(struct kvm *kvm,
 	if (vgic_ready(kvm))
 		goto out;
 
-	if (IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_dist_base) ||
-	    IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_cpu_base)) {
+	if (IS_VGIC_ADDR_UNDEF(dist->vgic_dist_base) ||
+	    IS_VGIC_ADDR_UNDEF(dist->vgic_cpu_base)) {
 		kvm_err("Need to set vgic cpu and dist addresses first\n");
 		ret = -ENXIO;
 		goto out;
 	}
 
+	vgic_register_kvm_io_dev(kvm, dist->vgic_dist_base,
+				 KVM_VGIC_V2_DIST_SIZE,
+				 vgic_dist_ranges, -1, &dist->dist_iodev);
+
 	/*
 	 * Initialize the vgic if this hasn't already been done on demand by
 	 * accessing the vgic state from userspace.
@@ -530,18 +535,23 @@ static int vgic_v2_map_resources(struct kvm *kvm,
 	ret = vgic_init(kvm);
 	if (ret) {
 		kvm_err("Unable to allocate maps\n");
-		goto out;
+		goto out_unregister;
 	}
 
-	ret = kvm_phys_addr_ioremap(kvm, kvm->arch.vgic.vgic_cpu_base,
+	ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
 				    params->vcpu_base, KVM_VGIC_V2_CPU_SIZE,
 				    true);
 	if (ret) {
 		kvm_err("Unable to remap VGIC CPU to VCPU\n");
-		goto out;
+		goto out_unregister;
 	}
 
-	kvm->arch.vgic.ready = true;
+	dist->ready = true;
+	goto out;
+
+out_unregister:
+	kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &dist->dist_iodev.dev);
+
 out:
 	if (ret)
 		kvm_vgic_destroy(kvm);