[systemd-devel] Better systemd naming for Azure/MANA nic

[Haiyang Zhang]

+ systemd-devel at lists.freedesktop.org<mailto:systemd-devel at lists.freedesktop.org>
+ dimitri.ledkov at surgut.co.uk<mailto:dimitri.ledkov at surgut.co.uk>

From: Haiyang Zhang
Sent: Tuesday, April 16, 2024 5:59 PM
To: dimitri.ledkov at canonical.com
Cc: Jack Aboutboul <jaboutboul at microsoft.com>; Sharath George John <sgeorgejohn at microsoft.com>; Luca Boccassi <Luca.Boccassi at microsoft.com>; Partha Sarangam <partha.sarangam at microsoft.com>; Paul Rosswurm <paulros at microsoft.com>
Subject: Better systemd naming for Azure/MANA nic
Importance: High

Hi Dimitri,

During the meeting a few months ago, you mentioned we cannot set "net.if_name=0" due to impact of other device naming... We have recently fixed the Physical slot number of MANA NICs, could you change the naming scheme as discussed last time?

Currently the domain number is part of the name (and Physical Slot + dev_port), e.g. enP30832s1, enP30832s1d1, enP30832s1d2... But domain number is long, and may not be the same on different VMs.

As discussed previously, we prefer a short name based on the VF "Physical Slot" + dev_port.
For VF the Physical Slot starts from 1, and increment by 1 for each additional VF device. (PF nic doesn't have the Physical Slot number, so you can continue to use "0" there).
The dev_port starts from 0, and increment by 1 for each additional dev_port (NIC).

Here is the logic we hope to have in the systemd: If a NIC's driver is "mana", use this naming scheme:
<prefix><Physical Slot>d<dev_port>

//During the meeting, we briefly talked about the prefix can be "enm" (enthernet, mana), so the names of two VF devices with 3 dev_ports (NICs) each, can be:

enm1  // omits the dev_port number if it's 0.
enm1d1
enm1d2

enm2
enm2d1
enm2d2



Here is the Physical Slot, dev_port info from a running VM:
root at lisa--500-e0-n1:/sys/class/net# lspci -v -s7870:00:00.0
7870:00:00.0 Ethernet controller: Microsoft Corporation Device 00ba
        Subsystem: Microsoft Corporation Device 00b9
        Physical Slot: 1
        Flags: bus master, fast devsel, latency 0, NUMA node 0
        Memory at fc2000000 (64-bit, prefetchable) [size=32M]
        Memory at fc4000000 (64-bit, prefetchable) [size=32K]
        Capabilities: [70] Express Endpoint, MSI 00
        Capabilities: [b0] MSI-X: Enable+ Count=1024 Masked-
        Capabilities: [100] Alternative Routing-ID Interpretation (ARI)
        Kernel driver in use: mana

root at lisa--500-e0-n1:/sys/class/net# grep "" en*/dev_port
enP30832s1/dev_port:0
enP30832s1d1/dev_port:1
enP30832s1d2/dev_port:2

Thanks,

  *   Haiyang

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