diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 756df3b..ff559c0 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -383,14 +383,15 @@
 static void piix4_pm_machine_ready(Notifier *n, void *opaque)
 {
     PIIX4PMState *s = container_of(n, PIIX4PMState, machine_ready);
+    MemoryRegion *io_as = pci_address_space_io(&s->dev);
     uint8_t *pci_conf;
 
     pci_conf = s->dev.config;
-    pci_conf[0x5f] = (isa_is_ioport_assigned(0x378) ? 0x80 : 0) | 0x10;
+    pci_conf[0x5f] = 0x10 |
+        (memory_region_find(io_as, 0x378, 1).mr ? 0x80 : 0);
     pci_conf[0x63] = 0x60;
-    pci_conf[0x67] = (isa_is_ioport_assigned(0x3f8) ? 0x08 : 0) |
-	(isa_is_ioport_assigned(0x2f8) ? 0x90 : 0);
-
+    pci_conf[0x67] = (memory_region_find(io_as, 0x3f8, 1).mr ? 0x08 : 0) |
+        (memory_region_find(io_as, 0x2f8, 1).mr ? 0x90 : 0);
 }
 
 static int piix4_pm_initfn(PCIDevice *dev)
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 667e882..461ab7c 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -477,22 +477,23 @@
 static void ich9_lpc_machine_ready(Notifier *n, void *opaque)
 {
     ICH9LPCState *s = container_of(n, ICH9LPCState, machine_ready);
+    MemoryRegion *io_as = pci_address_space_io(&s->d);
     uint8_t *pci_conf;
 
     pci_conf = s->d.config;
-    if (isa_is_ioport_assigned(0x3f8)) {
+    if (memory_region_find(io_as, 0x3f8, 1).mr) {
         /* com1 */
         pci_conf[0x82] |= 0x01;
     }
-    if (isa_is_ioport_assigned(0x2f8)) {
+    if (memory_region_find(io_as, 0x2f8, 1).mr) {
         /* com2 */
         pci_conf[0x82] |= 0x02;
     }
-    if (isa_is_ioport_assigned(0x378)) {
+    if (memory_region_find(io_as, 0x378, 1).mr) {
         /* lpt */
         pci_conf[0x82] |= 0x04;
     }
-    if (isa_is_ioport_assigned(0x3f0)) {
+    if (memory_region_find(io_as, 0x3f0, 1).mr) {
         /* floppy */
         pci_conf[0x82] |= 0x08;
     }