Re: [RFC PATCH 00/13] Ultra Ethernet driver introduction

Yunsheng Lin
2025-03-21T02:02:14Z

On 2025/3/21 4:12, Jason Gunthorpe wrote:
> On Thu, Mar 20, 2025 at 08:05:05PM +0000, Sean Hefty wrote:
>>>> As the existing rdma subsystem doesn't seems to support the above use
>>>> case yet
>>>
>>> Why would you say that? If EFA needs SRD and RDM objects in RDMA they
>>> can create them, it is not a big issue. To my knowledge they haven't asked for
>>> them.
>>
>> When looking at how to integrate UET support into verbs, there were
>> changes relevant to this discussion that I found needed.
>>
>> 1. Allow an RDMA device to indicate that it supports multiple transports, separated per port.
>> 2. Specify the QP type separate from the protocol.
>> 3. Define a reliable, unconnected QP type.
>>
>> Lin might be referring to 2 (assuming 3 is resolved).

Yes, that was mainly my concern too. If supporting different protocol need
to use the driver specific QP type and do most of the handling in the driver
in the existing rdma subsystem, then it does not seem reasonable from new
protocol perspective if multi vendors implementing the same new protocol
might have duplicated code in their drivers.

>
> That's at a verbs level though, at the kernel uAPI level we already have
> various ways to do all three..
>
> What you say makes sense to me for verbs.

I suppose the verbs is corresponding to what is defined in IB spec, and
verbs is not easily updated without updating the IB spec?

>
> Jason
>