[openib-general] IPoIB interface for unauthorized partition

[Eitan Zahavi]

Hi Roland,

Roland Dreier wrote:
>     Eitan> I thought the intent of the IB spec when defining P_Key
>     Eitan> index usage (and not P_Key value) was that the P_Key values
>     Eitan> would never need to be known above the driver level.  To
>     Eitan> avoid exposing the P_Key values we could use P_Key index
>     Eitan> for creating the IPoIB interfaces.
> 
>     Eitan> Does it make sense to work on a patch that would setup
>     Eitan> IPoIB interfaces by the P_Key index (and not by P_Key
>     Eitan> value)?
> 
> I don't see how this is feasible.  The index that a particular P_Key
> lands at is completely undetermined -- if two nodes wanted to talk on
> partition 0x8001 say, how does one know which interface to use without
> knowing the index of that P_Key?
OK, I get it. Actually the way IPoIB defines the broadcast group MGID exposes P_Key anyway.

> 
>     Eitan> Also I think the expected behavior for IPoIB should be that
>     Eitan> IPoIB "child" interfaces should be "automatically"
>     Eitan> initialized by the code that brings up the interface
>     Eitan> (ifconfig scripts). All valid IPoIB partitions (valid =
>     Eitan> have corresponding broadcast groups) should be
>     Eitan> initialized. By doing so we provide a centralized control
>     Eitan> of the partitions and their IPoIB interfaces through the
>     Eitan> SM.
> 
> Not sure if this is so.  I may want a partition strictly for storage
> traffic something like that, so it doesn't make sense to create an
> IPoIB interface for that partition.
OpenSM provides this capability in the "partition policy":
Each partition is marked explicitly if to be used for IPoIB or not.
So through one file one could actually control the IPoIB interfaces
that will exist in the subnet.

My intent is to write some extension to ifup for IPoIB such that all sub
interfaces will be automatically started (based on pre-availability of IPoIB
broadcast MGID).

> 
>  - R.
>