net/mlx5: E-Switch, Support VLAN actions in the offloads mode
Many virtualization systems use a policy under which a vlan tag is pushed to packets sent by guests, and popped before the packet is forwarded to the VM. The current generation of the mlx5 HW doesn't fully support that on a per flow level. As such, we are addressing the above common use case with the SRIOV e-Switch abilities to push vlan into packets sent by VFs and pop vlan from packets forwarded to VFs. The HW can match on the correct vlan being present in packets forwarded to VFs (eSwitch steering is done before stripping the tag), so this part is offloaded as is. A common practice for vlans is to avoid both push vlan and pop vlan for inter-host VM/VM (east-west) communication because in this case, push on egress cancels out with pop on ingress. For supporting that, we use a global eswitch vlan pop policy, hence allowing guest A to communicate with both remote VM B and local VM C. This works since the HW pops the vlan only if it exists (e.g for C --> A packets but not for B --> A packets). On the slow path, when a VF vport has an offloaded flow which involves pushing vlans, wheres another flow is not currently offloaded, the packets from the 2nd flow seen by the VF representor on the host have vlan. The VF rep driver removes such vlan before calling into the host networking stack. Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com> Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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