Merge branch 'devlink-add-port-function-attribute-to-enable-disable-roce-and-migratable'

Merge branch 'devlink-add-port-function-attribute-to-enable-disable-roce-and-migratable'

Shay Drory says:

====================
devlink: Add port function attribute to enable/disable Roce and migratable

This series is a complete rewrite of the series "devlink: Add port
function attribute to enable/disable roce"
link:
https://lore.kernel.org/netdev/20221102163954.279266-1-danielj@nvidia.com/

Currently mlx5 PCI VF and SF are enabled by default for RoCE
functionality. And mlx5 PCI VF is disable by dafault for migratable
functionality.

Currently a user does not have the ability to disable RoCE for a PCI
VF/SF device before such device is enumerated by the driver.

User is also incapable to do such setting from smartnic scenario for a
VF from the smartnic.

Current 'enable_roce' device knob is limited to do setting only at
driverinit time. By this time device is already created and firmware has
already allocated necessary system memory for supporting RoCE.

Also, Currently a user does not have the ability to enable migratable
for a PCI VF.

The above are a hyper visor level control, to set the functionality of
devices passed through to guests.

This is achieved by extending existing 'port function' object to control
capabilities of a function. This enables users to control capability of
the device before enumeration.

Examples when user prefers to disable RoCE for a VF when using switchdev
mode:

$ devlink port show pci/0000:06:00.0/1
pci/0000:06:00.0/1: type eth netdev pf0vf0 flavour pcivf controller 0
pfnum 0 vfnum 0 external false splittable false
  function:
    hw_addr 00:00:00:00:00:00 roce enable

$ devlink port function set pci/0000:06:00.0/1 roce disable

$ devlink port show pci/0000:06:00.0/1
pci/0000:06:00.0/1: type eth netdev pf0vf0 flavour pcivf controller 0
pfnum 0 vfnum 0 external false splittable false
  function:
    hw_addr 00:00:00:00:00:00 roce disable

FAQs:
-----
1. What does roce enable/disable do?
Ans: It disables RoCE capability of the function before its enumerated,
so when driver reads the capability from the device firmware, it is
disabled.
At this point RDMA stack will not be able to create UD, QP1, RC, XRC
type of QPs. When RoCE is disabled, the GID table of all ports of the
device is disabled in the device and software stack.

2. How is the roce 'port function' option different from existing
devlink param?
Ans: RoCE attribute at the port function level disables the RoCE
capability at the specific function level; while enable_roce only does
at the software level.

3. Why is this option for disabling only RoCE and not the whole RDMA
device?
Ans: Because user still wants to use the RDMA device for non RoCE
commands in more memory efficient way.
====================

Link: https://lore.kernel.org/r/20221206185119.380138-1-shayd@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>