From: Jakub Kicinski <kuba@kernel.org>
Sent: Tuesday, November 17, 2020 3:53 AM

On Thu, 12 Nov 2020 08:39:58 +0200 Parav Pandit wrote:

quoted

FAQs:
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1. Where does userspace vdpa tool reside which users can use?
Ans: vdpa tool can possibly reside in iproute2 [1] as it enables user
to create vdpa net devices.

2. Why not create and delete vdpa device using sysfs/configfs?
Ans:

quoted

3. Why not use ioctl() interface?

Obviously I'm gonna ask you - why can't you use devlink?

This was considered.
However it seems that extending devlink for vdpa specific stats, devices, config sounds overloading devlink beyond its defined scope.

quoted

Next steps:
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(a) Post this patchset and iproute2/vdpa inclusion, remaining two
drivers will be coverted to support vdpa tool instead of creating
unmanaged default device on driver load.
(b) More net specific parameters such as mac, mtu will be added.

How does MAC and MTU belong in this new VDPA thing?

MAC only make sense when user wants to run VF/SF Netdev and vdpa together with different mac address.
Otherwise existing devlink well defined API to have one MAC per function is fine.
Same for MTU, if queues of vdpa vs VF/SF Netdev queues wants have different MTU it make sense to add configure per vdpa device.