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

Jiri Pirko
2019-11-08T16:31:44Z

Fri, Nov 08, 2019 at 04:45:06PM CET, parav@mellanox.com wrote:
>
>
>> -----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.

Why incorrect? It is always bound to pf/vf?

>What in hypothetical case, mdev is not on top of PCI...

Okay, let's go hypothetical. In that case, it is going to be on top of
something else, wouldn't it?