docs: document memory API interaction with migration
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/docs/migration.txt b/docs/migration.txt
index 4848c1e..f3ddd2f 100644
--- a/docs/migration.txt
+++ b/docs/migration.txt
@@ -219,6 +219,18 @@
Example: You can look at hpet.c, that uses the three function to
massage the state that is transferred.
+If you use memory API functions that update memory layout outside
+initialization (i.e., in response to a guest action), this is a strong
+indication that you need to call these functions in a post_load callback.
+Examples of such memory API functions are:
+
+ - memory_region_add_subregion()
+ - memory_region_del_subregion()
+ - memory_region_set_readonly()
+ - memory_region_set_enabled()
+ - memory_region_set_address()
+ - memory_region_set_alias_offset()
+
=== Subsections ===
The use of version_id allows to be able to migrate from older versions
