diff --git a/migration/ram.c b/migration/ram.c index 74c9306c78..d3d72b6f4f 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1585,25 +1585,30 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data, encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE, XBZRLE.encoded_buf, TARGET_PAGE_SIZE); + + /* + * Update the cache contents, so that it corresponds to the data + * sent, in all cases except where we skip the page. + */ + if (!last_stage && encoded_len != 0) { + memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE); + /* + * In the case where we couldn't compress, ensure that the caller + * sends the data from the cache, since the guest might have + * changed the RAM since we copied it. + */ + *current_data = prev_cached_page; + } + if (encoded_len == 0) { trace_save_xbzrle_page_skipping(); return 0; } else if (encoded_len == -1) { trace_save_xbzrle_page_overflow(); xbzrle_counters.overflow++; - /* update data in the cache */ - if (!last_stage) { - memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE); - *current_data = prev_cached_page; - } return -1; } - /* we need to update the data in the cache, in order to get the same data */ - if (!last_stage) { - memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE); - } - /* Send XBZRLE based compressed page */ bytes_xbzrle = save_page_header(rs, rs->f, block, offset | RAM_SAVE_FLAG_XBZRLE);