Message-ID: <87wmz5t6t4.fsf@nvidia.com>
Date: Wed, 12 Jul 2023 19:47:05 +0300
From: Vlad Buslov <vladbu@...dia.com>
To: Wojciech Drewek <wojciech.drewek@...el.com>
CC: <intel-wired-lan@...ts.osuosl.org>, <netdev@...r.kernel.org>,
	<kuba@...nel.org>, <david.m.ertman@...el.com>,
	<michal.swiatkowski@...ux.intel.com>, <marcin.szycik@...ux.intel.com>,
	<pawel.chmielewski@...el.com>, <sridhar.samudrala@...el.com>,
	<pmenzel@...gen.mpg.de>, <simon.horman@...igine.com>,
	<dan.carpenter@...aro.org>
Subject: Re: [PATCH iwl-next v6 00/12] ice: switchdev bridge offload


On Wed 12 Jul 2023 at 13:03, Wojciech Drewek <wojciech.drewek@...el.com> wrote:
> Linux bridge provides ability to learn MAC addresses and vlans
> detected on bridge's ports. As a result of this, FDB (forward data base)
> entries are created and they can be offloaded to the HW. By adding
> VF's port representors to the bridge together with the uplink netdev,
> we can learn VF's and link partner's MAC addresses. This is achieved
> by slow/exception-path, where packets that do not match any filters
> (FDB entries in this case) are send to the bridge ports.
>
> Driver keeps track of the netdevs added to the bridge
> by listening for NETDEV_CHANGEUPPER event. We distinguish two types
> of bridge ports: uplink port and VF's representor port. Linux
> bridge always learns src MAC of the packet on rx path. With the
> current slow-path implementation, it means that we will learn
> VF's MAC on port repr (when the VF transmits the packet) and
> link partner's MAC on uplink (when we receive it on uplink from LAN).
>
> The driver is notified about learning of the MAC/VLAN by
> SWITCHDEV_FDB_{ADD|DEL}_TO_DEVICE events. This is followed by creation
> of the HW filter. The direction of the filter is based on port
> type (uplink or VF repr). In case of the uplink, rule forwards
> the packets to the LAN (matching on link partner's MAC). When the
> notification is received on VF repr then the rule forwards the
> packets to the associated VF (matching on VF's MAC).
>
> This approach would not work on its own however. This is because if
> one of the directions is offloaded, then the bridge would not be able
> to learn the other one. If the egress rule is added (learned on uplink)
> then the response from the VF will be sent directly to the LAN.
> The packet will not got through slow-path, it would not be seen on
> VF's port repr. Because of that, the bridge would not learn VF's MAC.
>
> This is solved by introducing guard rule. It prevents forward rule from
> working until the opposite direction is offloaded.
>
> Aging is not fully supported yet, aging time is static for now. The
> follow up submissions will introduce counters that will allow us to
> keep track if the rule is actually being used or not.
>
> A few fixes/changes are needed for this feature to work with ice driver.
> These are introduced in first 5 patches.
> ---
> v2: two patches were droped from the series:
>     - "ice: Remove exclusion code for RDMA+SRIOV" was sent as separate
>       patch: https://lore.kernel.org/netdev/20230516113055.7336-1-wojciech.drewek@intel.com/
>     - "ice: Ethtool fdb_cnt stats" was dropped because of the comments
>       suggesting that ethtool is not a good option for such statistic.
>       An alternative will be send as a separate patch.
> v3: small changes in patch 5, 7 and 8 including kdoc, style fixes.
> v4: split 1st patch in the series into 4 as Paul suggested
> v5: drop "ice: Accept LAG netdevs in bridge offloads" patch,
>     it will go with LAG patchset, I kept dev_hold and dev_put since the
>     discussion was not resolved
> v6: resolve Vlad's comments: delete FDB entries associated with
>     deleted vlan, add missing vlan_ops calls when clearing pvid
>
> Marcin Szycik (2):
>   ice: Add guard rule when creating FDB in switchdev
>   ice: Add VLAN FDB support in switchdev mode
>
> Michal Swiatkowski (2):
>   ice: implement bridge port vlan
>   ice: implement static version of ageing
>
> Pawel Chmielewski (1):
>   ice: add tracepoints for the switchdev bridge
>
> Wojciech Drewek (7):
>   ice: Skip adv rules removal upon switchdev release
>   ice: Prohibit rx mode change in switchdev mode
>   ice: Don't tx before switchdev is fully configured
>   ice: Disable vlan pruning for uplink VSI
>   ice: Unset src prune on uplink VSI
>   ice: Implement basic eswitch bridge setup
>   ice: Switchdev FDB events support
>
>  drivers/net/ethernet/intel/ice/Makefile       |    2 +-
>  drivers/net/ethernet/intel/ice/ice.h          |    5 +-
>  drivers/net/ethernet/intel/ice/ice_eswitch.c  |   46 +-
>  .../net/ethernet/intel/ice/ice_eswitch_br.c   | 1308 +++++++++++++++++
>  .../net/ethernet/intel/ice/ice_eswitch_br.h   |  120 ++
>  drivers/net/ethernet/intel/ice/ice_lib.c      |   25 +
>  drivers/net/ethernet/intel/ice/ice_lib.h      |    1 +
>  drivers/net/ethernet/intel/ice/ice_main.c     |    4 +-
>  drivers/net/ethernet/intel/ice/ice_repr.c     |    2 +-
>  drivers/net/ethernet/intel/ice/ice_repr.h     |    3 +-
>  drivers/net/ethernet/intel/ice/ice_switch.c   |  150 +-
>  drivers/net/ethernet/intel/ice/ice_switch.h   |    6 +-
>  drivers/net/ethernet/intel/ice/ice_trace.h    |   90 ++
>  drivers/net/ethernet/intel/ice/ice_type.h     |    1 +
>  .../ethernet/intel/ice/ice_vf_vsi_vlan_ops.c  |  186 +--
>  .../ethernet/intel/ice/ice_vf_vsi_vlan_ops.h  |    4 +
>  .../net/ethernet/intel/ice/ice_vsi_vlan_lib.c |   84 +-
>  .../net/ethernet/intel/ice/ice_vsi_vlan_lib.h |    8 +
>  .../net/ethernet/intel/ice/ice_vsi_vlan_ops.h |    1 +
>  19 files changed, 1860 insertions(+), 186 deletions(-)
>  create mode 100644 drivers/net/ethernet/intel/ice/ice_eswitch_br.c
>  create mode 100644 drivers/net/ethernet/intel/ice/ice_eswitch_br.h

Reviewed-by: Vlad Buslov <vladbu@...dia.com>

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