diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index cdd6f775a1483e0e3ffd3364aabd30006ba09004..4f75c873e267734f5aa26a9cd2665d5e0ef27457 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -496,8 +496,7 @@ static const MemoryRegionOps acpi_pcihp_io_ops = {
 };
 
 void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
-                     MemoryRegion *address_space_io,
-                     uint16_t io_base)
+                     MemoryRegion *io, uint16_t io_base)
 {
     s->io_len = ACPI_PCIHP_SIZE;
     s->io_base = io_base;
@@ -506,7 +505,7 @@ void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
 
     memory_region_init_io(&s->io, owner, &acpi_pcihp_io_ops, s,
                           "acpi-pci-hotplug", s->io_len);
-    memory_region_add_subregion(address_space_io, s->io_base, &s->io);
+    memory_region_add_subregion(io, s->io_base, &s->io);
 
     object_property_add_uint16_ptr(owner, ACPI_PCIHP_IO_BASE_PROP, &s->io_base,
                                    OBJ_PROP_FLAG_READ);
diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
index ef59810c17f63ac24044abcfcec2dbcd637a8a90..ac21a95913c49a2284886ec27a70e4f7defb6bdc 100644
--- a/include/hw/acpi/pcihp.h
+++ b/include/hw/acpi/pcihp.h
@@ -56,7 +56,7 @@ typedef struct AcpiPciHpState {
 } AcpiPciHpState;
 
 void acpi_pcihp_init(Object *owner, AcpiPciHpState *, PCIBus *root,
-                     MemoryRegion *address_space_io, uint16_t io_base);
+                     MemoryRegion *io, uint16_t io_base);
 
 bool acpi_pcihp_is_hotpluggbale_bus(AcpiPciHpState *s, BusState *bus);
 void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,