pci: add pci_address_space_io()

Returns the I/O address space.  Useful for implementing
PCI-ISA bridge devices.
Signed-off-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAvi Kivity <avi@redhat.com>

hw/pci.c

@@ -2124,3 +2124,8 @@ MemoryRegion *pci_address_space(PCIDevice *dev)
 {
     return dev->bus->address_space_mem;
 }
+
+MemoryRegion *pci_address_space_io(PCIDevice *dev)
+{
+    return dev->bus->address_space_io;
+}

hw/pci.h

@@ -218,6 +218,7 @@ void pci_default_write_config(PCIDevice *d,
 void pci_device_save(PCIDevice *s, QEMUFile *f);
 int pci_device_load(PCIDevice *s, QEMUFile *f);
 MemoryRegion *pci_address_space(PCIDevice *dev);
+MemoryRegion *pci_address_space_io(PCIDevice *dev);
 
 typedef void (*pci_set_irq_fn)(void *opaque, int irq_num, int level);
 typedef int (*pci_map_irq_fn)(PCIDevice *pci_dev, int irq_num);