summary refs log tree commit diff stats
diff options
context:
space:
mode:
authorDavid Hildenbrand <david@redhat.com>2023-01-05 13:45:27 +0100
committerJuan Quintela <quintela@redhat.com>2023-02-06 19:22:56 +0100
commit59bcc049c17a50d8ac0353f164f597e7d904589d (patch)
treee22606a9fde283db4105f258baf7e610d415cc04
parent7cc8e9e0fadc734065d4d5c9cb0bd8997e743146 (diff)
downloadfocaccia-qemu-59bcc049c17a50d8ac0353f164f597e7d904589d.tar.gz
focaccia-qemu-59bcc049c17a50d8ac0353f164f597e7d904589d.zip
migration/ram: Rely on used_length for uffd_change_protection()
ram_mig_ram_block_resized() will abort migration (including background
snapshots) when resizing a RAMBlock. ram_block_populate_read() will only
populate RAM up to used_length, so at least for anonymous memory
protecting everything between used_length and max_length won't
actually be protected and is just a NOP.

So let's only protect everything up to used_length.

Note: it still makes sense to register uffd-wp for max_length, such
that RAM_UF_WRITEPROTECT is independent of a changing used_length.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
-rw-r--r--migration/ram.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/migration/ram.c b/migration/ram.c
index efaae07dd8..a6956c9e7d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1901,7 +1901,7 @@ int ram_write_tracking_start(void)
 
         /* Apply UFFD write protection to the block memory range */
         if (uffd_change_protection(rs->uffdio_fd, block->host,
-                block->max_length, true, false)) {
+                                   block->used_length, true, false)) {
             goto fail;
         }