On Wed, 27 Feb 2019 14:08:29 +0100, Jiri Pirko wrote:

Tue, Feb 26, 2019 at 07:24:34PM CET, jakub.kicinski@netronome.com wrote:

quoted

Devlink ports represent ports of a switch device (or SR-IOV
NIC which has an embedded switch). In case of SR-IOV when
PCIe PFs are exposed the PFs which are directly connected
to the local machine may also spawn PF netdev (much like
VFs have a port/"repr" and an actual VF netdev).

Allow devlink to expose such linking. There is currently no
way to find out which netdev corresponds to which PF.

Example:

$ devlink port
pci/0000:82:00.0/0: type eth netdev p4p1 flavour physical
pci/0000:82:00.0/10000: type eth netdev eth1 flavour pci_pf pf 0 peer_netdev enp130s0
pci/0000:82:00.0/10001: type eth netdev eth0 flavour pci_vf pf 0 vf 0
pci/0000:82:00.0/10002: type eth netdev eth2 flavour pci_vf pf 0 vf 1  

Peer as the other side of a "virtual cable". For PF, that is probably
sufficient. But I think what a "peer of devlink port" should be "a
devlink port".

Maybe I'm not clear on what devlink port is - to me its a port of the
ASIC.  The notion of devlink port connected to devlink port seems
to counter such definition :S  

I do not think that every netdev should have a devlink port associated.

Not sure about VF.

Consider a simple problem of setting up a VF mac address. In legacy, you
do it like this:
$ ip link set eth2 vf 1 mac 00:52:44:11:22:33
However, in new model, you so far cannot do that.

Why?

$ devlink port set pci/0000:82:00.0/10001 peer_eth_addr 00:52:44:11:22:33

It's more of a neighbour info situation than a local port situation.

What I was thinking about was some "dummy peer" which would be on the
host. Not sure if only as a "dummy peer devlink port" or even as some
sort of "dummy netdev".

One way or another, it would provide the user some info about which VF
representor is connected to which VF in VM (mac mapping).

Ack, but isn't the MAC setting is the only thing we're missing from
"switchdev SR-IOV"?  Would the "dummy netdev" be used for anything
else?  I would rather not introduce new netdev just to do that 
(that'd be a third for that port.)