return 0;
        }
 
-       if (irq_domain_is_hierarchy(domain)) {
-               virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, irq_data);
-               return virq <= 0 ? 0 : virq;
-       }
-
        /* If domain has no translation, then we assume interrupt line */
        if (domain->ops->xlate == NULL)
                hwirq = irq_data->args[0];
                        return 0;
        }
 
-       /* Create mapping */
-       virq = irq_create_mapping(domain, hwirq);
-       if (!virq)
-               return virq;
+       if (irq_domain_is_hierarchy(domain)) {
+               /*
+                * If we've already configured this interrupt,
+                * don't do it again, or hell will break loose.
+                */
+               virq = irq_find_mapping(domain, hwirq);
+               if (virq)
+                       return virq;
+
+               virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, irq_data);
+               if (virq <= 0)
+                       return 0;
+       } else {
+               /* Create mapping */
+               virq = irq_create_mapping(domain, hwirq);
+               if (!virq)
+                       return virq;
+       }
 
        /* Set type if specified and different than the current one */
        if (type != IRQ_TYPE_NONE &&