-/*
-extern int
-xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nents,
- enum dma_data_direction dir);
-
-extern void
-xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nents,
- enum dma_data_direction dir);
-*/