KVM: Fix coalesced interrupt reporting in IOAPIC

commit 65a82211 upstream.

This bug was introduced by b4a2f5e7.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

virt/kvm/ioapic.c

@@ -188,6 +188,8 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
 			if ((edge && old_irr != ioapic->irr) ||
 			    (!edge && !entry.fields.remote_irr))
 				ret = ioapic_service(ioapic, irq);
+			else
+				ret = 0; /* report coalesced interrupt */
 		}
 	}
 	return ret;