func: BlockAIOCB *dma_bdrv_write(BlockDriverState *bs,
  
                             QEMUSGList *sg, uint64_t sector,
  
                             void (*cb)(void *opaque, int ret), void *opaque)
  
  {
  
      return dma_bdrv_io(bs, sg, sector, bdrv_aio_writev, cb, opaque,
  
                         DMA_DIRECTION_TO_DEVICE);
  
  }
  