diff options
| -rw-r--r-- | migration/ram.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/migration/ram.c b/migration/ram.c index 644f52a..9c0bcfe 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -494,6 +494,7 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data, return 1; } +/* Called with rcu_read_lock() to protect migration_bitmap */ static inline ram_addr_t migration_bitmap_find_and_reset_dirty(MemoryRegion *mr, ram_addr_t start) @@ -502,26 +503,31 @@ ram_addr_t migration_bitmap_find_and_reset_dirty(MemoryRegion *mr, unsigned long nr = base + (start >> TARGET_PAGE_BITS); uint64_t mr_size = TARGET_PAGE_ALIGN(memory_region_size(mr)); unsigned long size = base + (mr_size >> TARGET_PAGE_BITS); + unsigned long *bitmap; unsigned long next; + bitmap = atomic_rcu_read(&migration_bitmap); if (ram_bulk_stage && nr > base) { next = nr + 1; } else { - next = find_next_bit(migration_bitmap, size, nr); + next = find_next_bit(bitmap, size, nr); } if (next < size) { - clear_bit(next, migration_bitmap); + clear_bit(next, bitmap); migration_dirty_pages--; } return (next - base) << TARGET_PAGE_BITS; } +/* Called with rcu_read_lock() to protect migration_bitmap */ static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length) { + unsigned long *bitmap; + bitmap = atomic_rcu_read(&migration_bitmap); migration_dirty_pages += - cpu_physical_memory_sync_dirty_bitmap(migration_bitmap, start, length); + cpu_physical_memory_sync_dirty_bitmap(bitmap, start, length); } @@ -1017,10 +1023,15 @@ void free_xbzrle_decoded_buf(void) static void migration_end(void) { - if (migration_bitmap) { + /* caller have hold iothread lock or is in a bh, so there is + * no writing race against this migration_bitmap + */ + unsigned long *bitmap = migration_bitmap; + atomic_rcu_set(&migration_bitmap, NULL); + if (bitmap) { memory_global_dirty_log_stop(); - g_free(migration_bitmap); - migration_bitmap = NULL; + synchronize_rcu(); + g_free(bitmap); } XBZRLE_cache_lock(); |