On Fri, Apr 10, 2015 at 01:17:23PM -0600, Jason Gunthorpe wrote: > On Fri, Apr 10, 2015 at 02:24:26PM -0400, Doug Ledford wrote: > > > IPoIB is more than just an ULP. It's a spec. And it's very IB > > specific. It will only work with OPA because OPA is imitating IB. > > To run it on another fabric, you would need more than just to make > > it work. If the new fabric doesn't have a broadcast group, or has > > multicast registration like IB does, you need the equivalent of > > IBTA, whatever that may be for this new fabric, buy in on the > > pre-defined multicast groups and you might need firmware support in > > the switches. > > It feels like the 'cap_ib_addressing' or whatever we call it captures > this very well. The IPoIB RFC is very much concerned with GID's and > MGID's and broadly requires the IBA addressing > scheme. cap_ib_addressing asserts the port uses that scheme. > > We wouldn't accept patches to IPoIB to add a new addressing scheme > without seeing proper diligence to the standards work. > > Looking away from the stadards, using cap_XX seems very sane: We are > building a well defined system of invarients, You can't call into the > sa functions if cap_sa is not set, you can't call into the mcast > functions if cap_mcast is not set, you can't form a AH from IB > GIDs/MGID/LID without cap_ib_addressing. Yep. > > I makes so much sense for the ULP to directly require the needed cap's > for the kernel APIs it intends to call, or not use the RDMA port at > all. Yes. So trying to sum up. Have we settled on the following "capabilities"? Helper function names aside. /* legacy to communicate to userspace */ RDMA_LINK_LAYER_IB = 0x0000000000000001, RDMA_LINK_LAYER_ETH = 0x0000000000000002, RDMA_LINK_LAYER_MASK = 0x000000000000000f, /* more bits? */ /* I'm hoping we don't need more bits here */ /* legacy to communicate to userspace */ RDMA_TRANSPORT_IB = 0x0000000000000010, RDMA_TRANSPORT_IWARP = 0x0000000000000020, RDMA_TRANSPORT_USNIC = 0x0000000000000040, RDMA_TRANSPORT_USNIC_UDP = 0x0000000000000080, RDMA_TRANSPORT_MASK = 0x00000000000000f0, /* more bits? */ /* I'm hoping we don't need more bits here */ /* New flags */ RDMA_MGMT_IB_MAD = 0x0000000000000100, /* ib_mad module support */ RDMA_MGMT_QP0 = 0x0000000000000200, /* ib_mad QP0 support */ RDMA_MGMT_IB_SA = 0x0000000000000400, /* ib_sa module support */ /* NOTE includes IB Mcast */ RDMA_MGMT_IB_CM = 0x0000000000000800, /* ib_cm module support */ RDMA_MGMT_OPA_MAD = 0x0000000000001000, /* ib_mad OPA MAD support */ RDMA_MGMT_MASK = 0x00000000000fff00, RDMA_ADDR_IB = 0x0000000000100000, /* Port does IB AH, PR, Pkey */ RDMA_ADDR_IBoE = 0x0000000000200000, /* Port does IBoE AH, PR, Pkey */ /* Do we need iWarp (TCP) here? */ RDMA_ADDR_IB_MASK = 0x000000000ff00000, RDMA_SEPARATE_READ_SGE = 0x0000000010000000, RDMA_QUIRKS_MASK = 0x000000fff0000000 > > > > We can see how this might work in future, lets say OPAv2 *requires* the > > > 32 bit LID, for that case cap_ib_address = 0 cap_opa_address = 1. If > > > we don't update IPoIB and it uses the tests from above then it > > > immediately, and correctly, stops running on those OPAv2 devices. > > > > > > Once patched to support cap_op_address then it will begin working > > > again. That seems very sane.. > > > > It is very sane from an implementation standpoint, but from the larger > > interoperability standpoint, you need that spec to be extended to the > > new fabric simultaneously. > > I liked the OPAv2 hypothetical because it doesn't actually touch the > IPoIB spec. IPoIB spec has little to say about LIDs or LRHs it works > entirely at the GID/MGID/GRH level. Agreed. Ira -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
