get_pgsize
pgsize = get_pgsize(iova, len - unmapped_len, &pgcount);
size_t pgsize = get_pgsize(iova | paddr, len, &pgcount);
size_t pgsize = get_pgsize(iova, len - unmapped_len, &pgcount);
size_t pgsize = get_pgsize(iova + offset, size - offset, &pgcount);
size_t pgsize = get_pgsize(iova | paddr, len, &pgcount);