isa: Add isa_address_space_io()

This function permits to retrieve ISA IO address space.
It will be usefull when we need to pass IO address space as argument.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Acked-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

hw/isa-bus.c

@@ -264,4 +264,13 @@ MemoryRegion *isa_address_space(ISADevice *dev)
     return get_system_memory();
 }
 
+MemoryRegion *isa_address_space_io(ISADevice *dev)
+{
+    if (dev) {
+        return isa_bus_from_device(dev)->address_space_io;
+    }
+
+    return isabus->address_space_io;
+}
+
 type_init(isabus_register_types)

hw/isa.h

@@ -43,6 +43,7 @@ void isa_bus_irqs(ISABus *bus, qemu_irq *irqs);
 qemu_irq isa_get_irq(ISADevice *dev, int isairq);
 void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq);
 MemoryRegion *isa_address_space(ISADevice *dev);
+MemoryRegion *isa_address_space_io(ISADevice *dev);
 ISADevice *isa_create(ISABus *bus, const char *name);
 ISADevice *isa_try_create(ISABus *bus, const char *name);
 ISADevice *isa_create_simple(ISABus *bus, const char *name);