diff --git a/hw/spapr.c b/hw/spapr.c
index ad3f0ea7fc..eafee0313d 100644
--- a/hw/spapr.c
+++ b/hw/spapr.c
@@ -801,7 +801,7 @@ static void ppc_spapr_init(QEMUMachineInitArgs *args)
 
     /* Set up Interrupt Controller */
     spapr->icp = xics_system_init(XICS_IRQS);
-    spapr->next_irq = 16;
+    spapr->next_irq = XICS_IRQ_BASE;
 
     /* Set up EPOW events infrastructure */
     spapr_events_init(spapr);
diff --git a/hw/xics.c b/hw/xics.c
index edf58339c0..b8887cd9c7 100644
--- a/hw/xics.c
+++ b/hw/xics.c
@@ -549,7 +549,7 @@ struct icp_state *xics_system_init(int nr_irqs)
 
     ics = g_malloc0(sizeof(*ics));
     ics->nr_irqs = nr_irqs;
-    ics->offset = 16;
+    ics->offset = XICS_IRQ_BASE;
     ics->irqs = g_malloc0(nr_irqs * sizeof(struct ics_irq_state));
 
     icp->ics = ics;
diff --git a/hw/xics.h b/hw/xics.h
index 6817268697..c3bf0083e2 100644
--- a/hw/xics.h
+++ b/hw/xics.h
@@ -28,6 +28,7 @@
 #define __XICS_H__
 
 #define XICS_IPI        0x2
+#define XICS_IRQ_BASE   0x10
 
 struct icp_state;