RE: [PATCH net-next 12/19] devlink: Introduce mdev port flavour

Parav Pandit
2019-11-08T15:45:13Z

> -----Original Message-----
> From: Jiri Pirko <jiri@resnulli.us>
> Sent: Friday, November 8, 2019 3:47 AM
> To: Parav Pandit <parav@mellanox.com>
> Cc: Jakub Kicinski <jakub.kicinski@netronome.com>;
> alex.williamson@redhat.com; davem@davemloft.net; kvm@vger.kernel.org;
> netdev@vger.kernel.org; Saeed Mahameed <saeedm@mellanox.com>;
> kwankhede@nvidia.com; leon@kernel.org; cohuck@redhat.com; Jiri Pirko
> <jiri@mellanox.com>; linux-rdma@vger.kernel.org
> Subject: Re: [PATCH net-next 12/19] devlink: Introduce mdev port flavour
>
> Fri, Nov 08, 2019 at 03:31:02AM CET, parav@mellanox.com wrote:
> >
> >
> >> -----Original Message-----
> >> From: Jakub Kicinski <jakub.kicinski@netronome.com>
> >> Sent: Thursday, November 7, 2019 8:20 PM
> >> To: Parav Pandit <parav@mellanox.com>
> >> Cc: alex.williamson@redhat.com; davem@davemloft.net;
> >> kvm@vger.kernel.org; netdev@vger.kernel.org; Saeed Mahameed
> >> <saeedm@mellanox.com>; kwankhede@nvidia.com; leon@kernel.org;
> >> cohuck@redhat.com; Jiri Pirko <jiri@mellanox.com>; linux-
> >> rdma@vger.kernel.org
> >> Subject: Re: [PATCH net-next 12/19] devlink: Introduce mdev port
> >> flavour
> >>
> >> On Fri, 8 Nov 2019 01:44:53 +0000, Parav Pandit wrote:
> >> > > I'm talking about netlink attributes. I'm not suggesting to
> >> > > sprintf it all into the phys_port_name.
> >> > >
> >> > I didn't follow your comment. For devlink port show command output
> >> > you said,
> >> >
> >> > "Surely those devices are anchored in on of the PF (or possibly
> >> > VFs) that should be exposed here from the start."
> >> > So I was trying to explain why we don't expose PF/VF detail in the
> >> > port attributes which contains
> >> > (a) flavour
> >> > (b) netdev representor (name derived from phys_port_name)
> >> > (c) mdev alias
> >> >
> >> > Can you please describe which netlink attribute I missed?
> >>
> >> Identification of the PCI device. The PCI devices are not linked to
> >> devlink ports, so the sysfs hierarchy (a) is irrelevant, (b) may not
> >> be visible in multi- host (or SmartNIC).
> >>
> >
> >It's the unique mdev device alias. It is not right to attach to the PCI device.
> >Mdev is bus in itself where devices are identified uniquely. So an alias
> suffice that identity.
>
> Wait a sec. For mdev, what you say is correct. But here we talk about
> devlink_port which is representing this mdev. And this devlink_port is very
> similar to VF devlink_port. It is bound to specific PF (in case of mdev it could
> be PF-VF).
>
But mdev port has unique phys_port_name in system, it incorrect to use PF/VF prefix.
What in hypothetical case, mdev is not on top of PCI...