[Users] /dev/.../umad permissions

[John Valdes]

On Wed, Feb 27, 2013 at 04:14:46PM -0800, Ira Weiny wrote:
> On Wed, 27 Feb 2013 17:30:55 -0600 John Valdes <valdes at anl.gov> wrote:
> > 
> > I'd like to have a non-root user be able to query
> > port stats [...]
> > making umad non-root readable would be the simplest approach, I'm
> > curious to know the security implications before actually making it
> > so.
> 
> The problem with this approach is that perfquery, ibqueryerrors must also write to the umad device to send the Get() MAD's.  This is true with most of the diags out there.

Oh right, of course; to read data from a network, you need to send out
a read request, which requires write access to the network (umad)
device.  OK, I guess I go with option 2 or 3.

> Another option would be to look into the performance manager within OpenSM.  With a lot of luck it will soon be able to query PortCountersExtended and be able to give accurate data counters!  :-D

Or option 4. ;)

It's too bad the extended port counters aren't exposed under /sys (eg,
in /sys/class/infiniband/mlx4_0/ports/1/counters), as those are
directly readable by anyone and don't require any network
communication to read.

John

----------------------------------------------------------------------
John Valdes                  Mathematics and Computer Science Division
valdes at anl.gov                             Argonne National Laboratory