Commit 2ff64038 authored by Li Zhijian's avatar Li Zhijian Committed by Juan Quintela
Browse files

migration: protect migration_bitmap 



Signed-off-by: default avatarLi Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: default avatarWen Congyang <wency@cn.fujitsu.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent 59f39a47

migration/ram.c

+17 −6
Original line number Diff line number Diff line
@@ -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();