iopt_reserve_iova
rc = iopt_reserve_iova(iopt, 0, geometry->aperture_start - 1,
rc = iopt_reserve_iova(iopt, geometry->aperture_end + 1,
rc = iopt_reserve_iova(iopt, resv->start,
int iopt_reserve_iova(struct io_pagetable *iopt, unsigned long start,
rc = iopt_reserve_iova(&ioas->iopt, start, last, NULL);