From: David Hildenbrand <da...@redhat.com>
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 <pet...@redhat.com>
Reviewed-by: Juan Quintela <quint...@redhat.com>
Signed-off-by: David Hildenbrand <da...@redhat.com>
Signed-off-by: Juan Quintela <quint...@redhat.com>
---
migration/ram.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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;
}
--
2.39.1
