Some SuperI/O devices such as the VIA south bridges or the PC87312 controller
allow to enable or disable their SuperI/O functions. Add a convenience function
for implementing this in the VIA south bridges.

The naming of the functions is inspired by its memory_region_set_enabled()
pendant.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 docs/devel/migration.rst | 1 +
 include/exec/ioport.h    | 1 +
 system/ioport.c          | 9 +++++++++
 3 files changed, 11 insertions(+)

diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst
index 389fa24bde..466be609a2 100644
--- a/docs/devel/migration.rst
+++ b/docs/devel/migration.rst
@@ -465,6 +465,7 @@ Examples of such memory API functions are:
   - memory_region_set_address()
   - memory_region_set_alias_offset()
   - portio_list_set_address()
+  - portio_list_set_enabled()
 
 Iterative device migration
 --------------------------
diff --git a/include/exec/ioport.h b/include/exec/ioport.h
index 96858e5ac3..4397f12f93 100644
--- a/include/exec/ioport.h
+++ b/include/exec/ioport.h
@@ -71,6 +71,7 @@ void portio_list_add(PortioList *piolist,
                      struct MemoryRegion *address_space,
                      uint32_t addr);
 void portio_list_del(PortioList *piolist);
+void portio_list_set_enabled(PortioList *piolist, bool enabled);
 void portio_list_set_address(PortioList *piolist, uint32_t addr);
 
 #endif /* IOPORT_H */
diff --git a/system/ioport.c b/system/ioport.c
index 000e0ee1af..fd551d0375 100644
--- a/system/ioport.c
+++ b/system/ioport.c
@@ -324,6 +324,15 @@ void portio_list_del(PortioList *piolist)
     }
 }
 
+void portio_list_set_enabled(PortioList *piolist, bool enabled)
+{
+    unsigned i;
+
+    for (i = 0; i < piolist->nr; ++i) {
+        memory_region_set_enabled(piolist->regions[i], enabled);
+    }
+}
+
 void portio_list_set_address(PortioList *piolist, uint32_t addr)
 {
     MemoryRegionPortioList *mrpio;
-- 
2.43.0