KVM: PPC: Move xics_debugfs_init out of create

As we are about to hold the kvm->lock during the create operation on KVM
devices, we should move the call to xics_debugfs_init into its own
function, since holding a mutex over extended amounts of time might not
be a good idea.

Introduce an init operation on the kvm_device_ops struct which cannot
fail and call this, if configured, after the device has been created.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index a75ba38..f2def8e 100644
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -1341,8 +1341,6 @@
 		return ret;
 	}
 
-	xics_debugfs_init(xics);
-
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
 		/* Enable real mode support */
@@ -1354,9 +1352,17 @@
 	return 0;
 }
 
+static void kvmppc_xics_init(struct kvm_device *dev)
+{
+	struct kvmppc_xics *xics = (struct kvmppc_xics *)dev->private;
+
+	xics_debugfs_init(xics);
+}
+
 struct kvm_device_ops kvm_xics_ops = {
 	.name = "kvm-xics",
 	.create = kvmppc_xics_create,
+	.init = kvmppc_xics_init,
 	.destroy = kvmppc_xics_free,
 	.set_attr = xics_set_attr,
 	.get_attr = xics_get_attr,