net/mlx5e: TC, Offload rewrite and mirror on tunnel over ovs internal port

net/mlx5e: TC, Offload rewrite and mirror on tunnel over ovs internal port

To offload the encap rule when the tunnel IP is configured on an
openvswitch internal port, driver need to overwrite vport metadata in
reg_c0 to the value assigned to the internal port, then forward
packets to root table to be processed again by the rules matching on
the metadata for such internal port.

When such rule is combined with header rewrite and mirror, openvswitch
generates the rule like the following, because it resets mirror after
packets are modified.
    in_port(enp8s0f0npf0sf1),..,
        actions:enp8s0f0npf0sf2,set(tunnel(...)),set(ipv4(...)),vxlan_sys_4789,enp8s0f0npf0sf2

The split_count was introduced before to support rewrite and mirror.
Driver splits the rule into two different hardware rules in order to
offload it. But it's not enough to offload the above complicated rule
because of the limitations, in both driver and firmware.

To resolve this issue, the destination array is split again after the
destination indexed by split_count. An extra rule is added for the
leftover destinations (in the above example, it is enp8s0f0npf0sf2),
and is inserted to post_act table. And the extra destination is added
in the original rule to forward to post_act table, so the extra mirror
is done there.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20240808055927.2059700-4-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>