Re: [PATCH/RFC net-next 1/2] devlink: expose port function commands to assign VFs to multiple netdevs

Simon Horman
2023-02-08T12:08:12Z

On Wed, Feb 08, 2023 at 12:40:45PM +0100, Jiri Pirko wrote:
> Mon, Feb 06, 2023 at 04:36:02PM CET, simon.horman@corigine.com wrote:
> >From: Fei Qin <fei.qin@corigine.com>
> >
> >Multiple physical ports of the same NIC may share the single
> >PCI address. In some cases, assigning VFs to different physical
> >ports can be demanded, especially under high-traffic scenario.
> >Load balancing can be realized in virtualised use¬cases through
> >distributing packets between different physical ports with LAGs
> >of VFs which are assigned to those physical ports.
> >
> >This patch adds new attribute "vf_count" to 'devlink port function'
> >API which only can be shown and configured under devlink ports
> >with flavor "DEVLINK_PORT_FLAVOUR_PHYSICAL".
>
> I have to be missing something. That is the meaning of "assigning VF"
> to a physical port? Why there should be any relationship between
> physical port and VF other than configured forwarding (using TC for
> example)?
>
> This seems very wrong. Preliminary NAK.

Of course if TC is involved, then we have flexibility.

What we are talking about here is primarily legacy mode.
And the behaviour described would, when enabled allow NFP based NICs
to behave more like most other multi-port NICs.

That is, we can envisage a VEB with some VFs and one physical port.
And anther with other VFs and another physical port.

This is as opposed to a single VEB with all VFs, as is currently
the case on NFP based NICs (but not most other multi-port NICs).