KVM: arm64: vgic-its: Enable ITS emulation as a virtual MSI controller

Now that all ITS emulation functionality is in place, we advertise
MSI functionality to userland and also the ITS device to the guest - if
userland has configured that.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 535e713..01a60dc 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -258,6 +258,9 @@
 	if (ret)
 		goto out;
 
+	if (vgic_has_its(kvm))
+		dist->msis_require_devid = true;
+
 	kvm_for_each_vcpu(i, vcpu, kvm)
 		kvm_vgic_vcpu_init(vcpu);