diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
index 9c79c9677b3c..6e9434129dcd 100644
--- a/hw/isa/piix4.c
+++ b/hw/isa/piix4.c
@@ -79,31 +79,6 @@ static void piix4_set_irq(void *opaque, int irq_num, int level)
     }
 }
 
-static int pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num)
-{
-    int slot;
-
-    slot = PCI_SLOT(pci_dev->devfn);
-
-    switch (slot) {
-    /* PIIX4 USB */
-    case 10:
-        return 3;
-    /* AMD 79C973 Ethernet */
-    case 11:
-        return 1;
-    /* Crystal 4281 Sound */
-    case 12:
-        return 2;
-    /* PCI slot 1 to 4 */
-    case 18 ... 21:
-        return ((slot - 18) + irq_num) & 0x03;
-    /* Unknown device, don't do any translation */
-    default:
-        return irq_num;
-    }
-}
-
 static void piix4_isa_reset(DeviceState *dev)
 {
     PIIX4State *d = PIIX4_PCI_DEVICE(dev);
@@ -272,7 +247,6 @@ static void piix4_realize(PCIDevice *dev, Error **errp)
     qdev_connect_gpio_out(DEVICE(&s->pm), 0, s->isa[9]);
 
     pci_bus_irqs(pci_bus, piix4_set_irq, s, PIIX_NUM_PIRQS);
-    pci_bus_map_irqs(pci_bus, pci_slot_get_pirq);
 }
 
 static void piix4_init(Object *obj)
diff --git a/hw/mips/malta.c b/hw/mips/malta.c
index 8bf2e2ff5f7c..ec172b111ae4 100644
--- a/hw/mips/malta.c
+++ b/hw/mips/malta.c
@@ -39,6 +39,7 @@
 #include "hw/mips/bootloader.h"
 #include "hw/mips/cpudevs.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
 #include "qemu/log.h"
 #include "hw/mips/bios.h"
 #include "hw/ide/pci.h"
@@ -993,6 +994,31 @@ static void malta_mips_config(MIPSCPU *cpu)
     }
 }
 
+static int malta_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num)
+{
+    int slot;
+
+    slot = PCI_SLOT(pci_dev->devfn);
+
+    switch (slot) {
+    /* PIIX4 USB */
+    case 10:
+        return 3;
+    /* AMD 79C973 Ethernet */
+    case 11:
+        return 1;
+    /* Crystal 4281 Sound */
+    case 12:
+        return 2;
+    /* PCI slot 1 to 4 */
+    case 18 ... 21:
+        return ((slot - 18) + irq_num) & 0x03;
+    /* Unknown device, don't do any translation */
+    default:
+        return irq_num;
+    }
+}
+
 static void main_cpu_reset(void *opaque)
 {
     MIPSCPU *cpu = opaque;
@@ -1225,6 +1251,7 @@ void mips_malta_init(MachineState *machine)
     qdev_prop_set_bit(dev, "cpu-little-endian", !be);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
     pci_bus = PCI_BUS(qdev_get_child_bus(dev, "pci"));
+    pci_bus_map_irqs(pci_bus, malta_pci_slot_get_pirq);
 
     /* Southbridge */
     piix4 = pci_create_simple_multifunction(pci_bus, PIIX4_PCI_DEVFN, true,