[openib-general] Re: [kDAPL]questions about the LMR creation of different types of memory

[James Lentini]

ian> As your mentioned, ULPs in OpenIB (e.g. SDP or IPoIB) are 
ian> responsible for properly mapping and unmapping for DMA use. 
ian> AFAIK, SDP is implemented with the IB native verbs. What about 
ian> the kDAPL? In my opinion the kDAPL does not do the mapping and 
ian> unmapping work. So it is the responsibility of the kernel 
ian> applications using the kDAPL. Am I right?

Per the spec, it depends on the flag you pass dat_lmr_kcreate. If you 
register using the DAT_MEM_TYPE_PHYSICAL flag, the memory address 
should be physical addresses. If you register using DAT_MEM_TYPE_IA, 
the addresses should be a DMA (aka an I/O, aka a bus) address. 

Currently the code is assuming that physical addresses are valid DMA 
addresses and not performing a translation.