diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 042c13cdbc..abfcfe4d2b 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -92,13 +92,10 @@ static void piix_intx_routing_notifier_xen(PCIDevice *dev)
 {
     int i;
 
-    /* Scan for updates to PCI link routes (0x60-0x63). */
+    /* Scan for updates to PCI link routes. */
     for (i = 0; i < PIIX_NUM_PIRQS; i++) {
-        uint8_t v = dev->config_read(dev, PIIX_PIRQCA + i, 1);
-        if (v & 0x80) {
-            v = 0;
-        }
-        v &= 0xf;
+        const PCIINTxRoute route = pci_device_route_intx_to_irq(dev, i);
+        const uint8_t v = route.mode == PCI_INTX_ENABLED ? route.irq : 0;
         xen_set_pci_link_route(i, v);
     }
 }