net/mlx5e: VF tunnel TX traffic offloading

net/mlx5e: VF tunnel TX traffic offloading

When tunnel endpoint is on VF, driver still assumes that endpoint is on
uplink and incorrectly configures encap rule offload according to that
assumption. As a result, traffic is sent directly to the uplink and rules
installed on representor of tunnel endpoint VF are ignored.

Implement following changes to allow offloading tx traffic with tunnel
endpoint on VF:

- For tunneling flows perform route lookup on route and out devices pair.
If out device is uplink and route device is VF of same physical port, then
modify packet reg_c_0 metadata register (source port) with the value of VF
vport. Use eswitch vhca_id->vport mapping introduced in one of previous
patches in the series to obtain vport from route netdevice.

- Recirculate encapsulated packets to VF vport in order to apply any flow
rules installed on VF representor that match on encapsulated traffic.

Only enable support for this functionality when all following conditions
are true:

- Hardware advertises capability to preserve reg_c_0 value on packet
recirculation.

- Vport metadata matching is enabled.

- Termination tables are to be used by the flow.

Example TC rules for VF tunnel traffic:

1. Rule that redirects packets from UL to VF rep that has the tunnel
endpoint IP address:

$ tc -s filter show dev enp8s0f0 ingress
filter protocol ip pref 4 flower chain 0
filter protocol ip pref 4 flower chain 0 handle 0x1
  dst_mac 16:c9:a0:2d:69:2c
  src_mac 0c:42:a1:58:ab:e4
  eth_type ipv4
  ip_flags nofrag
  in_hw in_hw_count 1
        action order 1: mirred (Egress Redirect to device enp8s0f0_0) stolen
        index 3 ref 1 bind 1 installed 377 sec used 0 sec
        Action statistics:
        Sent 114096 bytes 952 pkt (dropped 0, overlimits 0 requeues 0)
        Sent software 0 bytes 0 pkt
        Sent hardware 114096 bytes 952 pkt
        backlog 0b 0p requeues 0
        cookie 878fa48d8c423fc08c3b6ca599b50a97
        no_percpu
        used_hw_stats delayed

2. Rule that decapsulates the tunneled flow and redirects to destination VF
representor:

$ tc -s filter show dev vxlan_sys_4789 ingress
filter protocol ip pref 4 flower chain 0
filter protocol ip pref 4 flower chain 0 handle 0x1
  dst_mac ca:2e:a7:3f:f5:0f
  src_mac 0a:40:bd:30:89:99
  eth_type ipv4
  enc_dst_ip 7.7.7.5
  enc_src_ip 7.7.7.1
  enc_key_id 98
  enc_dst_port 4789
  enc_tos 0
  ip_flags nofrag
  in_hw in_hw_count 1
        action order 1: tunnel_key  unset pipe
         index 2 ref 1 bind 1 installed 434 sec used 434 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0
        used_hw_stats delayed

        action order 2: mirred (Egress Redirect to device enp8s0f0_1) stolen
        index 4 ref 1 bind 1 installed 434 sec used 0 sec
        Action statistics:
        Sent 129936 bytes 1082 pkt (dropped 0, overlimits 0 requeues 0)
        Sent software 0 bytes 0 pkt
        Sent hardware 129936 bytes 1082 pkt
        backlog 0b 0p requeues 0
        cookie ac17cf398c4c69e4a5b2f7aabd1b88ff
        no_percpu
        used_hw_stats delayed

Co-developed-by: Dmytro Linkin <dlinkin@nvidia.com>
Signed-off-by: Dmytro Linkin <dlinkin@nvidia.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>