net/mlx5: add workaround for VLAN in virtual machine

net/mlx5: add workaround for VLAN in virtual machine

On some virtual setups (particularly on ESXi) when we have SR-IOV and
E-Switch enabled there is the problem to receive VLAN traffic on VF
interfaces. The NIC driver in ESXi hypervisor does not setup E-Switch
vport setting correctly and VLAN traffic targeted to VF is dropped.

The patch provides the temporary workaround - if the rule
containing the VLAN pattern is being installed for VF the VLAN
network interface over VF is created, like the command does:

  ip link add link vf.if name mlx5.wa.1.100 type vlan id 100

The PMD in DPDK maintains the database of created VLAN interfaces
for each existing VF and requested VLAN tags. When all of the RTE
Flows using the given VLAN tag are removed the created VLAN interface
with this VLAN tag is deleted.

The name of created VLAN interface follows the format:

  evmlx.d1.d2, where d1 is VF interface ifindex, d2 - VLAN ifindex

Implementation limitations:

- mask in rules is ignored, rule must specify VLAN tags exactly,
  no wildcards (which are implemented by the masks) are allowed

- virtual environment is detected via rte_hypervisor() call,
  and the type of hypervisor is checked. Currently we engage
  the workaround for ESXi and unrecognized hypervisors (which
  always happen on platforms other than x86 - it means workaround
  applied for the Flow over PCI VF). There are no confirmed data
  the other hypervisors (HyperV, Qemu) need this workaround,
  we are trying to reduce the list of configurations on those
  workaround should be applied.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>