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| author | Haozhong Zhang <haozhong.zhang@intel.com> | 2017-06-28 16:37:04 +0800 |
|---|---|---|
| committer | Juan Quintela <quintela@redhat.com> | 2017-06-28 12:23:58 +0200 |
| commit | 084140bd4989095d39978269fd0f43e398a0015d (patch) | |
| tree | 4a18368c0195ba881a42018767d4385f4a30c76f /include/exec | |
| parent | c788ada8163127d20505e3ebf9b8735ba313d661 (diff) | |
| download | qemu-084140bd4989095d39978269fd0f43e398a0015d.tar.gz | |
exec: fix access to ram_list.dirty_memory when sync dirty bitmap
In cpu_physical_memory_sync_dirty_bitmap(rb, start, ...), the 2nd
argument 'start' is relative to the start of the ramblock 'rb'. When
it's used to access the dirty memory bitmap of ram_list (i.e.
ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION]->blocks[]), an offset to
the start of all RAM (i.e. rb->offset) should be added to it, which has
however been missed since c/s 6b6712efcc. For a ramblock of host memory
backend whose offset is not zero, cpu_physical_memory_sync_dirty_bitmap()
synchronizes the incorrect part of the dirty memory bitmap of ram_list
to the per ramblock dirty bitmap. As a result, a guest with host
memory backend may crash after migration.
Fix it by adding the offset of ramblock when accessing the dirty memory
bitmap of ram_list in cpu_physical_memory_sync_dirty_bitmap().
Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20170628083704.24997-1-haozhong.zhang@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Tested-by: Juan Quintela <quintela@redhat.com>
Tested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'include/exec')
| -rw-r--r-- | include/exec/ram_addr.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index 73d1bea8b6..c04f4f67f6 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -386,8 +386,9 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, int k; int nr = BITS_TO_LONGS(length >> TARGET_PAGE_BITS); unsigned long * const *src; - unsigned long idx = (page * BITS_PER_LONG) / DIRTY_MEMORY_BLOCK_SIZE; - unsigned long offset = BIT_WORD((page * BITS_PER_LONG) % + unsigned long word = BIT_WORD((start + rb->offset) >> TARGET_PAGE_BITS); + unsigned long idx = (word * BITS_PER_LONG) / DIRTY_MEMORY_BLOCK_SIZE; + unsigned long offset = BIT_WORD((word * BITS_PER_LONG) % DIRTY_MEMORY_BLOCK_SIZE); rcu_read_lock(); @@ -414,9 +415,11 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, rcu_read_unlock(); } else { + ram_addr_t offset = rb->offset; + for (addr = 0; addr < length; addr += TARGET_PAGE_SIZE) { if (cpu_physical_memory_test_and_clear_dirty( - start + addr, + start + addr + offset, TARGET_PAGE_SIZE, DIRTY_MEMORY_MIGRATION)) { *real_dirty_pages += 1; |