[openib-general] Re: [PATCH] agent: Add IB ping server agent

[Michael S. Tsirkin]

Quoting r. Roland Dreier <roland at topspin.com>:
> Subject: Re: [PATCH] agent: Add IB ping server agent
> 
>     Michael> I mean, they will go to the SM LID.
> 
> Are you sure?  Where is this in the spec?  I really thought that get
> responses for SM class queries will be formed the same way as
> responses for any other class.  That is, the response will be sent to
> source LID of the query, etc.
> 
>  - R.
> 

I'm not necessarily talking about routing - it seems to me that these MADs
were designed for SM use, not for anything else.

For direct route SMPs we clearly have:
C14-5: Only a SM shall originate a directed route SMP.

For LID-routed SMPs its not that  clear, but still we have things like
Table 122 "SM MAD Sources and Destinations", which if I read it correctly
seem to say that responses shall go to the SM.

Generally, I see:

13.5.1.1 PROCESSING SUBNET MANAGEMENT PACKETS (SMPS)
The Subnet Management Interface (SMI) is associated with QP0. QP0 is
used exclusively for sending and receiving subnet management MADs.
Communications with the SMA in a channel adapter, switch, or router is
always through the SMI. If a channel adapter, switch, or router hosts a
SM, then communications between that SM and the SMA of each channel
adapter, switch, or router in the subnet is also through the SMI. Only
SMAs and SM communicate through this interface. No other entities may
do so.

One other issue I can see is mkey protection, although you always might
say the user must set the key protecion bits to allow get port info ...

-- 
MST - Michael S. Tsirkin