RDMA (ibverb) Ethernet driver

This driver relies on Linux rdma-core (libibverb) userspace poll-mode driver to rx/tx Ethernet packets. Despite using the RDMA APIs, this is not about RDMA (no Infiniband, no RoCE, no iWARP), just pure traditional Ethernet packets.

Maturity level

Under development: it should work, but has not been thoroughly tested.

Supported Hardware

• Mellanox ConnectX-4
• Mellanox ConnectX-5

Features

• bifurcation: MAC based flow steering for transparent sharing of a single physical port between multiple virtual interfaces including Linux netdev
• multiqueue

Security considerations

When creating a rdma interface, it will receive all packets to the MAC address attributed to the interface plus a copy of all broadcast and multicast traffic. The MAC address is under the control of VPP: the user controlling VPP can divert all traffic of any MAC address to the VPP process, including the Linux netdev MAC address as long as it can create a rdma interface. The rights to create a rdma interface are controlled by the access rights of the /dev/infiniband/uverbs[0-9]+device nodes.

Quickstart

1. Make sure the ib_uverbs module is loaded:

   ~# modprobe ib_uverbs

2. In VPP, create a new rdma virtual interface tied to the Linux netdev of the physical port you want to use (enp94s0f0 in this example):

   vpp# create int rdma host-if enp94s0f0 name rdma-0

3. Use the interface as usual, eg.: ``` vpp# set int ip addr rdma-0 1.1.1.1/24 vpp# set int st rdma-0 up vpp# ping 1.1.1.100`

   ## Containers support
   It should work in containers as long as:
    - the `ib_uverbs` module is loaded
    - the device nodes `/dev/infiniband/uverbs[0-9]+` are usable from the
      container (but see [security considerations](#Security considerations))
   
   ## SR-IOV VFs support
   It should work on SR-IOV VFs the same way it does with PFs. Because of VFs
   security containment features, make sure the MAC address of the rdma VPP
   interface matches the MAC address assigned to the underlying VF.
   For example:

   host# echo 1 > /sys/class/infiniband/mlx5_0/device/sriov_numvfs host# ip l set dev enp94s0f0 vf 0 mac 92:5d:f5:df:b1:6f spoof on trust off host# ip l set dev enp94s0f2 up vpp# create int rdma host-if enp94s0f2 name rdma-0 vpp# set int mac address rdma-0 92:5d:f5:df:b1:6f

   If you plan to use L2 features such as switching, make sure the underlying
   VF is configured in trusted mode and spoof-checking is disabled (of course, be
   aware of the [security considerations](#Security considerations)):

   host# ip l set dev enp94s0f0 vf 0 spoof off trust on ```

Direct Verb mode

Direct Verb allows the driver to access the NIC HW RX/TX rings directly instead of having to go through libibverb and suffering associated overhead. It will be automatically selected if the adapter supports it.