diff --git a/hw/isa-bus.c b/hw/isa-bus.c
index e9c1712..d8e1880 100644
--- a/hw/isa-bus.c
+++ b/hw/isa-bus.c
@@ -16,6 +16,7 @@
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  */
+#include <glib.h>
 #include "hw.h"
 #include "monitor.h"
 #include "sysbus.h"
@@ -103,6 +104,44 @@ void isa_register_ioport(ISADevice *dev, MemoryRegion *io, uint16_t start)
     }
 }
 
+void isa_register_old_portio_list(ISADevice *dev, uint16_t start,
+                                  const MemoryRegionPortio *pio_start,
+                                  void *opaque, const char *name)
+{
+    MemoryRegion *io_space = isabus->address_space_io;
+    const MemoryRegionPortio *pio_iter;
+
+    /* START is how we should treat DEV, regardless of the actual
+       contents of the portio array.  This is how the old code
+       actually handled e.g. the FDC device.  */
+    if (dev) {
+        isa_init_ioport(dev, start);
+    }
+
+    for (; pio_start->size != 0; pio_start = pio_iter + 1) {
+        unsigned int off_low = UINT_MAX, off_high = 0;
+        MemoryRegionOps *ops;
+        MemoryRegion *region;
+
+        for (pio_iter = pio_start; pio_iter->size; ++pio_iter) {
+            if (pio_iter->offset < off_low) {
+                off_low = pio_iter->offset;
+            }
+            if (pio_iter->offset + pio_iter->len > off_high) {
+                off_high = pio_iter->offset + pio_iter->len;
+            }
+        }
+
+        ops = g_new(MemoryRegionOps, 1);
+        ops->old_portio = pio_start;
+
+        region = g_new(MemoryRegion, 1);
+        memory_region_init_io(region, ops, opaque, name, off_high - off_low);
+        memory_region_set_offset(region, start + off_low);
+        memory_region_add_subregion(io_space, start + off_low, region);
+    }
+}
+
 static int isa_qdev_init(DeviceState *qdev, DeviceInfo *base)
 {
     ISADevice *dev = DO_UPCAST(ISADevice, qdev, qdev);
diff --git a/hw/isa.h b/hw/isa.h
index c5c2618..117d8b0 100644
--- a/hw/isa.h
+++ b/hw/isa.h
@@ -28,7 +28,6 @@ ISABus *isa_bus_new(DeviceState *dev, MemoryRegion *address_space_io);
 void isa_bus_irqs(qemu_irq *irqs);
 qemu_irq isa_get_irq(int isairq);
 void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq);
-void isa_register_ioport(ISADevice *dev, MemoryRegion *io, uint16_t start);
 void isa_init_ioport(ISADevice *dev, uint16_t ioport);
 void isa_init_ioport_range(ISADevice *dev, uint16_t start, uint16_t length);
 void isa_qdev_register(ISADeviceInfo *info);
@@ -37,6 +36,38 @@ ISADevice *isa_create(const char *name);
 ISADevice *isa_try_create(const char *name);
 ISADevice *isa_create_simple(const char *name);
 
+/**
+ * isa_register_ioport: Install an I/O port region on the ISA bus.
+ *
+ * Register an I/O port region via memory_region_add_subregion
+ * inside the ISA I/O address space.
+ *
+ * @dev: the ISADevice against which these are registered; may be NULL.
+ * @io: the #MemoryRegion being registered.
+ * @start: the base I/O port.
+ */
+void isa_register_ioport(ISADevice *dev, MemoryRegion *io, uint16_t start);
+
+/**
+ * isa_register_old_portio_list: Initialize a set of ISA io ports
+ *
+ * Several ISA devices have many dis-joint I/O ports.  Worse, these I/O
+ * ports can be interleaved with I/O ports from other devices.  This
+ * function makes it easy to create multiple MemoryRegions for a single
+ * device and use the legacy portio routines.
+ *
+ * @dev: the ISADevice against which these are registered; may be NULL.
+ * @start: the base I/O port against which the portio->offset is applied.
+ * @old_portio: A concatenation of several #MemoryRegionOps old_portio
+ *   parameters.  The entire list should be terminated by a double
+ *   PORTIO_END_OF_LIST().
+ * @opaque: passed into the old_portio callbacks.
+ * @name: passed into memory_region_init_io.
+ */
+void isa_register_old_portio_list(ISADevice *dev, uint16_t start,
+                                  const MemoryRegionPortio *old_portio,
+                                  void *opaque, const char *name);
+
 extern target_phys_addr_t isa_mem_base;
 
 void isa_mmio_setup(MemoryRegion *mr, target_phys_addr_t size);
