Query regarding netvsc PMD : VF removal

[Stephen Hemminger]

On Thu, 25 Jul 2024 11:41:59 -0700
Nandini Rangaswamy <nandini.rangaswamy at broadcom.com> wrote:

> Hi Stephen,
> I am using the DPDK 22.11.5 LTS. Should the DPDK code take care of
> unbinding synthetic interface from uio_hv_generic or should it be done by
> the app when it gets hotplug notification?
> Regards,
> Nandini

The synthetic device (netvsc) controlled by uio_hv_generic is never hot plugged.
Only the VF which is mlx device can be removed and added.
The management of the VF for traffic is handled completely internally to
the netvsc device (same as the Linux netdevice). What happens is the
host notifys the guest over vmbus when VF changes. For devices handled
by the DPDK (netvsc PMD), this notification causes it to add/remove use
of the VF.

The VF should not be used directly. The synthetic device (netvsc) routes
traffic over the VF and reads from it when it is present and up.