diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 906f29c05c546b0e1dd69856c0fb219041f5e2cd..bfc6211e5422ef17b6e0bb0d24b926fa653354d9 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -1376,7 +1376,7 @@ struct mpic * __init mpic_alloc(struct device_node *node,
 	mpic->isu_mask = (1 << mpic->isu_shift) - 1;
 
 	mpic->irqhost = irq_domain_add_linear(mpic->node,
-				       last_irq + 1,
+				       intvec_top,
 				       &mpic_host_ops, mpic);
 
 	/*