On Thu, 28 Feb 2019 09:44:29 +0100, Jiri Pirko wrote:

quoted

Okay, so let me explain the way I see it, and you can explain your way
or tell me where you disagree.  Those devlink ports and netdevs are pf
ports and vf ports, which most refer to as "representor".  If one sends
packets to the netdev indicated in DEVLINK_ATTR_PORT_NETDEV_*
attributes they will _egress_ the switch from that port.  For physical
port that means going onto the Ethernet or IB wire.  For PCIe it means
getting DMAed over the PCIe link to host memory.

There is a netdev construct on the host which is in charge of that 
host memory.  Maybe we shall call that host netdev?

(I said I don't like "representor" for the reason that people don't
refer to the physical port as "representor" even though it has exactly
the semantics we are following.  This distinction between behaviour of
physical and PCI ports is what leads to confusion, I think.)

Let me bring out the moose :)

                   HOST A             ||          HOST B                  
                                      ||                                  
       PF A       | V | V | V | V     ||       PF B        | V | V | V               
                  |*F |*F |*F |*F ... ||                   |*F |*F |*F ...           
*port A0 |*port A1 | 0 | 1 | 2 | 3     ||*port B0 |*port B1 | 0 | 1 | 2            
                                      ||                                  
            PCI Express link          ||        PCI Express link          
       \      \      \  |   |   |          |       |      /   /   /         
        \      \      \ |   |   |          |       |     /   /   /          
     /\  \______\______\'___|___|__________|_______'____/___/___/__    /\
     ||  |+PF0s0|+PF0s1 |+VF0|+VF1| ...|   |+PF1s0|+PF1s1|+VF0|+VF1|   ||  
 i   ||  |------ ------ ----- ---- ----|--- ------ ------ ---- ----|   ||   i
d n H ||  |               <<==========                              |   || d n H
e s O ||  |                            ==========>>                 |   || e s O
v t S ||  |                    SR-IOV e-switch                      |   || v t S
l a T ||  |               <<==========                              |   || l a T
i n   ||  |                            ==========>>                 |   || i n
n c A ||  |               ________ _________ ________               |   || n c B
k e   ||  |              |+Phys 0 |+Phys 1  |+Phys 2 |              |   || k e
     ||  \---------------------------------------------------------/   ||
     \/                      |        |         |                      \/    
                             |        |         |                          
                                ||         ||                               
                         MAC 0  ||  MAC 1  || MAC 2                   
                                ||         ||                              

Things marked with + are devlink ports and have port (-repr-) netdevs
(including physical ports).
Things marked with * are host netdevs, don't have devlink ports.  

Okay, I got it. So you say that devlink ports should always be only
ports of eswitch.

PF host netdev should have "devlink port" instance, correct?
But it still "belongs" under the ASIC represented by the devlink
instance...

Yes, I think so.