memory: introduce memory_region_set_enabled()

This allows users to disable a memory region without removing
it from the hierarchy, simplifying the implementation of
memory routers.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/memory.h b/memory.h
index 53bf261792..c6997c4ee3 100644
--- a/memory.h
+++ b/memory.h
@@ -123,6 +123,7 @@ struct MemoryRegion {
     bool terminates;
     bool readable;
     bool readonly; /* For RAM regions */
+    bool enabled;
     MemoryRegion *alias;
     target_phys_addr_t alias_offset;
     unsigned priority;
@@ -501,6 +502,22 @@ void memory_region_add_subregion_overlap(MemoryRegion *mr,
 void memory_region_del_subregion(MemoryRegion *mr,
                                  MemoryRegion *subregion);
 
+
+/*
+ * memory_region_set_enabled: dynamically enable or disable a region
+ *
+ * Enables or disables a memory region.  A disabled memory region
+ * ignores all accesses to itself and its subregions.  It does not
+ * obscure sibling subregions with lower priority - it simply behaves as
+ * if it was removed from the hierarchy.
+ *
+ * Regions default to being enabled.
+ *
+ * @mr: the region to be updated
+ * @enabled: whether to enable or disable the region
+ */
+void memory_region_set_enabled(MemoryRegion *mr, bool enabled);
+
 /* Start a transaction; changes will be accumulated and made visible only
  * when the transaction ends.
  */