[ofw] Current recommended APIs for kernel and user

[Hefty, Sean]

I don't know if anyone responded to this, but in case not...

> We are working on a project that involves both kernel and user mode code
> communicating over Mellanox adapters (RoCE mode) on Windows Server 2012. We do
> need to interoperate with Linux. This is for a commercial datacenter product.
> 
> 
> 
> I see there are multiple APIs that can be used, and am wondering what the OFW
> team is currently recommending for new code?
> 
> 
> 
> It seems like the options include: NDv1, NDv2, IBAL, WinVerbs, libibverbs.
> Compatibility with preexisting Linux code is useful, but having maximum
> performance likely is more important. It seems like NDv1/NDv2 is officially
> supported by Microsoft in user mode, and there currently is no officially
> supported Microsoft kernel RDMA API.

ND is the official API defined by MS.  I believe that there's a kernel ND API in Server 2012, but someone from MS will need to confirm.

RoCE support comes directly from Mellanox, so you would need to ask them what APIs they will support.

In addition to the APIs you list, there is a userspace version of the Linux libibverbs available on windows as part of WinOFED.

- Sean