Bitfields for VDS flags:
Bit(s)	Description	)
 0	reserved (zero)
 1	data should be copied into buffer (ignored if 2 set)
 2	buffer should not be allocated if region noncontiguous or crosses
	  physical alignment boundary specified by 4-5
 3	don't attempt automatic remap
 4	region must not cross 64K physical alignment boundary
 5	region must not cross 128K physical alignment boundary
 6-15	reserved (zero)