[PATCH v5 01/15] KVM: s390: unregister debug feature on failing arch init

[Michael Mueller <mimu@linux.ibm.com>]

Make sure the debug feature and its allocated resources get
released upon unsuccessful architecture initialization.

A related indication of the issue will be reported as kernel
message.

Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20181130143215.69496-2-mimu@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 Documentation/kmsg/s390/kvm | 12 ++++++++++++
 arch/s390/kvm/kvm-s390.c    | 17 ++++++++++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/kmsg/s390/kvm

diff --git a/Documentation/kmsg/s390/kvm b/Documentation/kmsg/s390/kvm
new file mode 100644
index 000000000000..76ffe2012254
--- /dev/null
+++ b/Documentation/kmsg/s390/kvm
@@ -0,0 +1,12 @@
+/*?
+ * Text: "Failed to register FLIC rc=%d\n"
+ * Severity: Error
+ * Parameter:
+ *   @1: return code of the FLIC registration call
+ * Description:
+ * The registration of the FLIC (Floating Interrupt Controller Interface)
+ * was not successful.
+ * User action:
+ * If this problem persists after a reload of the kvm kernel module, gather
+ * Linux debug data and contact your support organization.
+ */
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index fe24150ff666..d8d8e0788157 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -417,19 +417,30 @@ static void kvm_s390_cpu_feat_init(void)
 
 int kvm_arch_init(void *opaque)
 {
+	int rc;
+
 	kvm_s390_dbf = debug_register("kvm-trace", 32, 1, 7 * sizeof(long));
 	if (!kvm_s390_dbf)
 		return -ENOMEM;
 
 	if (debug_register_view(kvm_s390_dbf, &debug_sprintf_view)) {
-		debug_unregister(kvm_s390_dbf);
-		return -ENOMEM;
+		rc = -ENOMEM;
+		goto out_debug_unreg;
 	}
 
 	kvm_s390_cpu_feat_init();
 
 	/* Register floating interrupt controller interface. */
-	return kvm_register_device_ops(&kvm_flic_ops, KVM_DEV_TYPE_FLIC);
+	rc = kvm_register_device_ops(&kvm_flic_ops, KVM_DEV_TYPE_FLIC);
+	if (rc) {
+		pr_err("Failed to register FLIC rc=%d\n", rc);
+		goto out_debug_unreg;
+	}
+	return 0;
+
+out_debug_unreg:
+	debug_unregister(kvm_s390_dbf);
+	return rc;
 }
 
 void kvm_arch_exit(void)
-- 
2.13.4