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migration: protect migration_bitmap

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Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Li Zhijian 2015-07-02 20:18:05 +08:00 committed by Juan Quintela
parent 59f39a4741
commit 2ff64038a5
1 changed files with 17 additions and 6 deletions
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23
migration/ram.c
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@ -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();