diff --git a/hw/pci-host/uninorth.c b/hw/pci-host/uninorth.c
index e2278fd0f0..3a29a4410e 100644
--- a/hw/pci-host/uninorth.c
+++ b/hw/pci-host/uninorth.c
@@ -127,7 +127,7 @@ static void pci_unin_main_realize(DeviceState *dev, Error **errp)
                                    pci_unin_set_irq, pci_unin_map_irq,
                                    s,
                                    &s->pci_mmio,
-                                   get_system_io(),
+                                   &s->pci_io,
                                    PCI_DEVFN(11, 0), 4, TYPE_PCI_BUS);
 
     pci_create_simple(h->bus, PCI_DEVFN(11, 0), "uni-north-pci");
@@ -155,6 +155,8 @@ static void pci_unin_main_init(Object *obj)
 
     memory_region_init(&s->pci_mmio, OBJECT(s), "unin-pci-mmio",
                        0x100000000ULL);
+    memory_region_init_io(&s->pci_io, OBJECT(s), &unassigned_io_ops, obj,
+                          "unin-pci-isa-mmio", 0x00800000);
 
     memory_region_init_alias(&s->pci_hole, OBJECT(s),
                              "unin-pci-hole", &s->pci_mmio,
@@ -168,6 +170,7 @@ static void pci_unin_main_init(Object *obj)
     sysbus_init_mmio(sbd, &h->conf_mem);
     sysbus_init_mmio(sbd, &h->data_mem);
     sysbus_init_mmio(sbd, &s->pci_hole);
+    sysbus_init_mmio(sbd, &s->pci_io);
 }
 
 static void pci_u3_agp_realize(DeviceState *dev, Error **errp)
@@ -179,7 +182,7 @@ static void pci_u3_agp_realize(DeviceState *dev, Error **errp)
                                    pci_unin_set_irq, pci_unin_map_irq,
                                    s,
                                    &s->pci_mmio,
-                                   get_system_io(),
+                                   &s->pci_io,
                                    PCI_DEVFN(11, 0), 4, TYPE_PCI_BUS);
 
     pci_create_simple(h->bus, PCI_DEVFN(11, 0), "u3-agp");
@@ -200,6 +203,8 @@ static void pci_u3_agp_init(Object *obj)
 
     memory_region_init(&s->pci_mmio, OBJECT(s), "unin-pci-mmio",
                        0x100000000ULL);
+    memory_region_init_io(&s->pci_io, OBJECT(s), &unassigned_io_ops, obj,
+                          "unin-pci-isa-mmio", 0x00800000);
 
     memory_region_init_alias(&s->pci_hole, OBJECT(s),
                              "unin-pci-hole", &s->pci_mmio,
@@ -213,6 +218,7 @@ static void pci_u3_agp_init(Object *obj)
     sysbus_init_mmio(sbd, &h->conf_mem);
     sysbus_init_mmio(sbd, &h->data_mem);
     sysbus_init_mmio(sbd, &s->pci_hole);
+    sysbus_init_mmio(sbd, &s->pci_io);
 }
 
 static void pci_unin_agp_realize(DeviceState *dev, Error **errp)
@@ -224,7 +230,7 @@ static void pci_unin_agp_realize(DeviceState *dev, Error **errp)
                                    pci_unin_set_irq, pci_unin_map_irq,
                                    s,
                                    &s->pci_mmio,
-                                   get_system_io(),
+                                   &s->pci_io,
                                    PCI_DEVFN(11, 0), 4, TYPE_PCI_BUS);
 
     pci_create_simple(h->bus, PCI_DEVFN(11, 0), "uni-north-agp");
@@ -261,7 +267,7 @@ static void pci_unin_internal_realize(DeviceState *dev, Error **errp)
                                    pci_unin_set_irq, pci_unin_map_irq,
                                    s,
                                    &s->pci_mmio,
-                                   get_system_io(),
+                                   &s->pci_io,
                                    PCI_DEVFN(14, 0), 4, TYPE_PCI_BUS);
 
     pci_create_simple(h->bus, PCI_DEVFN(14, 0), "uni-north-internal-pci");
diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
index 5d121a6071..5cb9f9abd0 100644
--- a/hw/ppc/mac_newworld.c
+++ b/hw/ppc/mac_newworld.c
@@ -146,7 +146,6 @@ static void ppc_core99_init(MachineState *machine)
     CPUPPCState *env = NULL;
     char *filename;
     qemu_irq *pic, **openpic_irqs;
-    MemoryRegion *isa = g_new(MemoryRegion, 1);
     MemoryRegion *unin_memory = g_new(MemoryRegion, 1);
     int linux_boot, i, j, k;
     MemoryRegion *ram = g_new(MemoryRegion, 1), *bios = g_new(MemoryRegion, 1);
@@ -274,11 +273,6 @@ static void ppc_core99_init(MachineState *machine)
         }
     }
 
-    /* Register 8 MB of ISA IO space */
-    memory_region_init_alias(isa, NULL, "isa_mmio",
-                             get_system_io(), 0, 0x00800000);
-    memory_region_add_subregion(get_system_memory(), 0xf2000000, isa);
-
     /* UniN init: XXX should be a real device */
     memory_region_init_io(unin_memory, NULL, &unin_ops, token, "unin", 0x1000);
     memory_region_add_subregion(get_system_memory(), 0xf8000000, unin_memory);
@@ -356,6 +350,9 @@ static void ppc_core99_init(MachineState *machine)
         /* PCI hole */
         memory_region_add_subregion(get_system_memory(), 0x80000000ULL,
                                     sysbus_mmio_get_region(s, 2));
+        /* Register 8 MB of ISA IO space */
+        memory_region_add_subregion(get_system_memory(), 0xf2000000,
+                                    sysbus_mmio_get_region(s, 3));
         sysbus_mmio_map(s, 0, 0xf0800000);
         sysbus_mmio_map(s, 1, 0xf0c00000);
 
@@ -390,6 +387,9 @@ static void ppc_core99_init(MachineState *machine)
         /* PCI hole */
         memory_region_add_subregion(get_system_memory(), 0x80000000ULL,
                                     sysbus_mmio_get_region(s, 2));
+        /* Register 8 MB of ISA IO space */
+        memory_region_add_subregion(get_system_memory(), 0xf2000000,
+                                    sysbus_mmio_get_region(s, 3));
         sysbus_mmio_map(s, 0, 0xf2800000);
         sysbus_mmio_map(s, 1, 0xf2c00000);
 
diff --git a/include/hw/pci-host/uninorth.h b/include/hw/pci-host/uninorth.h
index 6b520e753c..c4771aa7fa 100644
--- a/include/hw/pci-host/uninorth.h
+++ b/include/hw/pci-host/uninorth.h
@@ -48,6 +48,7 @@ typedef struct UNINState {
     qemu_irq irqs[4];
     MemoryRegion pci_mmio;
     MemoryRegion pci_hole;
+    MemoryRegion pci_io;
 } UNINState;
 
 #endif /* UNINORTH_H */
