11/06/2021 07:14, Xia, Chenbo:

From: Thomas Monjalon <redacted>

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10/06/2021 12:33, Ferruh Yigit:

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On 5/27/2021 2:37 PM, Xueming Li wrote:

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SubFunction [1] is a portion of the PCI device, a SF netdev has its

own

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dedicated queues(txq, rxq). A SF shares PCI level resources with other
SFs and/or with its parent PCI function. Auxiliary bus is the
fundamental of SF.

This patch set introduces SubFunction support for mlx5 PMD driver
including class net, regex, vdpa and compress.

There is already an mdev patch, originated from long ago. Aren't

subfunctions

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presented as mdev device? If so can't we use mdev for it?

No unfortunately that's different.
mlx5 SF is based on top of auxiliary bus in the kernel/sysfs.

Just out of curiosity:

Does SF use mdev before aux bus is introduced in kernel. I see some history
of it but am not sure: [1] seems SF was base on mdev. [2] seems BlueField
software v2.5 is using mdev for SF. I saw it yesterday and try to figure
out the history. Since you are here, guess you know something 😊

[1] https://patchwork.ozlabs.org/project/netdev/cover/20191107160448.20962-1-parav@mellanox.com/
[2] https://docs.mellanox.com/display/BlueFieldSWv25011176/Mediated+Devices

Kernel maintainers rejected the use of mdev for this purpose
and suggested to use a real bus.
You can follow the discussion here:
https://lore.kernel.org/netdev/20191108205204.GB1277001@kroah.com/ (local)

Does Intel plan to use mdev for SF?

For the sake of follow-up discussion, this is the official mdev doc:
https://www.kernel.org/doc/Documentation/vfio-mediated-device.txt