diff --git a/hw/acpi_piix4.c b/hw/acpi_piix4.c
index 519269a013..dbddde13ab 100644
--- a/hw/acpi_piix4.c
+++ b/hw/acpi_piix4.c
@@ -438,7 +438,7 @@ static int piix4_pm_initfn(PCIDevice *dev)
     pci_conf[0x3d] = 0x01; // interrupt pin 1
 
     /* APM */
-    apm_init(&s->apm, apm_ctrl_changed, s);
+    apm_init(dev, &s->apm, apm_ctrl_changed, s);
 
     register_ioport_write(ACPI_DBG_IO_ADDR, 4, 4, acpi_dbg_writel, s);
 
diff --git a/hw/apm.c b/hw/apm.c
index 2aead52a74..e988ad9939 100644
--- a/hw/apm.c
+++ b/hw/apm.c
@@ -22,6 +22,7 @@
 
 #include "apm.h"
 #include "hw.h"
+#include "pci.h"
 
 //#define DEBUG
 
@@ -35,7 +36,8 @@
 #define APM_CNT_IOPORT  0xb2
 #define APM_STS_IOPORT  0xb3
 
-static void apm_ioport_writeb(void *opaque, uint32_t addr, uint32_t val)
+static void apm_ioport_writeb(void *opaque, hwaddr addr, uint64_t val,
+                              unsigned size)
 {
     APMState *apm = opaque;
     addr &= 1;
@@ -51,7 +53,7 @@ static void apm_ioport_writeb(void *opaque, uint32_t addr, uint32_t val)
     }
 }
 
-static uint32_t apm_ioport_readb(void *opaque, uint32_t addr)
+static uint64_t apm_ioport_readb(void *opaque, hwaddr addr, unsigned size)
 {
     APMState *apm = opaque;
     uint32_t val;
@@ -78,12 +80,23 @@ const VMStateDescription vmstate_apm = {
     }
 };
 
-void apm_init(APMState *apm, apm_ctrl_changed_t callback, void *arg)
+static const MemoryRegionOps apm_ops = {
+    .read = apm_ioport_readb,
+    .write = apm_ioport_writeb,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+void apm_init(PCIDevice *dev, APMState *apm, apm_ctrl_changed_t callback,
+              void *arg)
 {
     apm->callback = callback;
     apm->arg = arg;
 
     /* ioport 0xb2, 0xb3 */
-    register_ioport_write(APM_CNT_IOPORT, 2, 1, apm_ioport_writeb, apm);
-    register_ioport_read(APM_CNT_IOPORT, 2, 1, apm_ioport_readb, apm);
+    memory_region_init_io(&apm->io, &apm_ops, apm, "apm-io", 2);
+    memory_region_add_subregion(pci_address_space_io(dev), APM_CNT_IOPORT,
+                                &apm->io);
 }
diff --git a/hw/apm.h b/hw/apm.h
index f7c741e327..5431b6d7c8 100644
--- a/hw/apm.h
+++ b/hw/apm.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include "qemu-common.h"
 #include "hw.h"
+#include "memory.h"
 
 typedef void (*apm_ctrl_changed_t)(uint32_t val, void *arg);
 
@@ -13,9 +14,11 @@ typedef struct APMState {
 
     apm_ctrl_changed_t callback;
     void *arg;
+    MemoryRegion io;
 } APMState;
 
-void apm_init(APMState *s, apm_ctrl_changed_t callback, void *arg);
+void apm_init(PCIDevice *dev, APMState *s, apm_ctrl_changed_t callback,
+              void *arg);
 
 extern const VMStateDescription vmstate_apm;
 
diff --git a/hw/lpc_ich9.c b/hw/lpc_ich9.c
index 2fc83a496f..7de5427a69 100644
--- a/hw/lpc_ich9.c
+++ b/hw/lpc_ich9.c
@@ -472,7 +472,7 @@ static int ich9_lpc_initfn(PCIDevice *d)
     lpc->isa_bus = isa_bus;
 
     ich9_cc_init(lpc);
-    apm_init(&lpc->apm, ich9_apm_ctrl_changed, lpc);
+    apm_init(d, &lpc->apm, ich9_apm_ctrl_changed, lpc);
     return 0;
 }
 
diff --git a/hw/vt82c686.c b/hw/vt82c686.c
index 5d7c00cf4b..7f11dbe782 100644
--- a/hw/vt82c686.c
+++ b/hw/vt82c686.c
@@ -427,7 +427,7 @@ static int vt82c686b_pm_initfn(PCIDevice *dev)
     register_ioport_write(s->smb_io_base, 0xf, 1, smb_ioport_writeb, &s->smb);
     register_ioport_read(s->smb_io_base, 0xf, 1, smb_ioport_readb, &s->smb);
 
-    apm_init(&s->apm, NULL, s);
+    apm_init(dev, &s->apm, NULL, s);
 
     acpi_pm_tmr_init(&s->ar, pm_tmr_timer);
     acpi_pm1_cnt_init(&s->ar);