kernel: enable thunderbolt-net driver

[dezren39]

@dezren39 thunderbolt.ko is already built with recent versions of xcpng. But it sounds like you are regering to thunderbolt-net, which afair isnt built by default. But i think that is an entirely different issue, so please open a separate issue

Originally posted by @hoerup in #404 (comment)

I would like thunderbolt-net module to be loaded automatically when appropriate, so that the interface can be used as a virtual nic.

• relevant kernel docs:
  • https://www.kernel.org/doc/html/latest/admin-guide/thunderbolt.html#networking-over-thunderbolt-cable

Below are some use cases, I assume they would all be covered just by enabling the driver, but I'm elaborating just in case so you can understand my use case.

• I would like to be able to connect 3 2-port thunderbolt 4 motherboards together using thunderbolt ip, in order to create a fast backplane for pool operations.

  • I would hope that I could plug 3 cables in a triangle between the 3 servers while they are off and, upon powering up the servers, the appropriate configuration is done so that each server shows 2 virtual ethernet interfaces for configuration from within the xen orchestra.
  • Like so:

  •   _C_
     /   \
    A --- B
    

• I'd like to be able to bridge the 2 thunderbolt ports so that traffic from A can be forwarded by B to C, say if they were connected like so:

  • (other place) --- A --- B --- C, where --- equals one thunderbolt cable.

• I'd like to be able to bond the 2 thunderbolts so that traffic from A to B can target a single virtual interface (composed of 2 bonded virtual interfaces), like so:

  • A === B, where === equals 2 thunderbolt cables