Re: [PATCH v3] netdev-dpdk: add control plane protection support

[Kevin Traynor <ktraynor@redhat.com>]

Fixing To: to add back in OVS ML.

+cc Ori, as mlx5 operation discussed below.

On 11/11/2022 18:15, Kevin Traynor wrote:
> Hi Robin,
> 
> On 21/10/2022 15:53, Robin Jarry wrote:
>> Some control protocols are used to maintain link status between
>> forwarding engines (e.g. LACP). When the system is not sized properly,
>> the PMD threads may not be able to process all incoming traffic from the
>> configured Rx queues. When a signaling packet of such protocols is
>> dropped, it can cause link flapping, worsening the situation.
>>
>> Use the RTE flow API to redirect these protocols into a dedicated Rx
>> queue. The assumption is made that the ratio between control protocol
>> traffic and user data traffic is very low and thus this dedicated Rx
>> queue will never get full. The RSS redirection table is re-programmed to
>> only use the other Rx queues. The RSS table size is stored in the
>> netdev_dpdk structure at port initialization to avoid requesting the
>> information again when changing the port configuration.
>>
>> The additional Rx queue will be assigned a PMD core like any other Rx
>> queue. Polling that extra queue may introduce increased latency and
>> a slight performance penalty at the benefit of preventing link flapping.
>>
>> This feature must be enabled per port on specific protocols via the
>> cp-protection option. This option takes a coma-separated list of
>> protocol names. It is only supported on ethernet ports.
>>
>> If the user has already configured multiple Rx queues on the port, an
>> additional one will be allocated for control plane packets. If the
>> hardware cannot satisfy the requested number of requested Rx queues, the
>> last Rx queue will be assigned for control plane. If only one Rx queue
>> is available, the cp-protection feature will be disabled. If the
>> hardware does not support the RTE flow matchers/actions, the feature
>> will be disabled.
>>
>> It cannot be enabled when other_config:hw-offload=true as it may
>> conflict with the offloaded RTE flows. Similarly, if hw-offload is
>> enabled while some ports already have cp-protection enabled, the RTE
>> flow offloading will be disabled on these ports.
>>
>> Example use:
>>
>>    ovs-vsctl add-bond br-phy bond0 phy0 phy1 -- \
>>      set interface phy0 type=dpdk options:dpdk-devargs=0000:ca:00.0 -- \
>>      set interface phy0 options:cp-protection=lacp -- \
>>      set interface phy1 type=dpdk options:dpdk-devargs=0000:ca:00.1 -- \
>>      set interface phy1 options:cp-protection=lacp
>>
>> As a starting point, only one protocol is supported: LACP. Other
>> protocols can be added in the future. NIC compatibility should be
>> checked.
>>
>> To validate that this works as intended, I used a traffic generator to
>> generate random traffic slightly above the machine capacity at line rate
>> on a two ports bond interface. OVS is configured to receive traffic on
>> two VLANs and pop/push them in a br-int bridge based on tags set on
>> patch ports.
>>
>>      +----------------------+
>>      |         DUT          |
>>      |+--------------------+|
>>      ||       br-int       || default flow, action=NORMAL
>>      ||                    ||
>>      || patch10    patch11 ||
>>      |+---|-----------|----+|
>>      |    |           |     |
>>      |+---|-----------|----+|
>>      || patch00    patch01 ||
>>      ||  tag:10    tag:20  ||
>>      ||                    ||
>>      ||       br-phy       || default flow, action=NORMAL
>>      ||                    ||
>>      ||       bond0        || balance-slb, lacp=passive, lacp-time=fast
>>      ||    phy0   phy1     ||
>>      |+------|-----|-------+|
>>      +-------|-----|--------+
>>              |     |
>>      +-------|-----|--------+
>>      |     port0  port1     | balance L3/L4, lacp=active, lacp-time=fast
>>      |         lag          | mode trunk VLANs 10, 20
>>      |                      |
>>      |        switch        |
>>      |                      |
>>      |  vlan 10    vlan 20  |  mode access
>>      |   port2      port3   |
>>      +-----|----------|-----+
>>            |          |
>>      +-----|----------|-----+
>>      |   port0      port1   |  Random traffic that is properly balanced
>>      |                      |  across the bond ports in both directions.
>>      |  traffic generator   |
>>      +----------------------+
>>
>> Without cp-protection, the bond0 links are randomly switching to
>> "defaulted" when one of the LACP packets sent by the switch is dropped
>> because the RX queues are full and the PMD threads did not process them
>> fast enough. When that happens, all traffic must go through a single
>> link which causes above line rate traffic to be dropped.
>>
>> When cp-protection is enabled, no LACP packet is dropped and the bond
>> links remain enabled at all times, maximizing the throughput.
>>
>> This feature may be considered as "QoS". However, it does not work by
>> limiting the rate of traffic explicitly. It only guarantees that some
>> protocols have a lower chance of being dropped because the PMD cores
>> cannot keep up with regular traffic.
>>
>> The choice of protocols is limited on purpose. This is not meant to be
>> configurable by users. Some limited configurability could be considered
>> in the future but it would expose to more potential issues if users are
>> accidentally redirecting all traffic in the control plane queue.
>>
> 
> Not a full review, but rather send now with issue I saw on CX-5 that we
> discussed as it'll impact testing.
> 
>> Cc: Christophe Fontaine <cfontain@redhat.com>
>> Cc: Kevin Traynor <ktraynor@redhat.com>
>> Signed-off-by: Robin Jarry <rjarry@redhat.com>
>> ---
>> v2 -> v3:
>>
>> * Added dry_run validation that rte_flows are all supported by the NIC
>>     before configuring anything.
>> * Added check to make cp-protection and hw-offload mutually exclusive.
>> * Removed the "match-all" RSS flow that dealt with redirecting all
>>     non-control-plane traffic to all but the control-plane Rx queue. Very
>>     few NICs actually support "match-all" flows without any mask. This was
>>     replaced by reconfiguring the RSS redirection table. The
>> * Made sure to unconfigure everything and remove the extra Rx queue in
>>     the case the hardware does not support one of the RTE flows.
>> * Updated vswitchd/vswitch.xml
>> * Added diagnostics info in netdev_dpdk_get_status
>> * Tested under load on the following NICs:
>>     - Intel E810 (2x 25G)
>>     - Mellanox ConnectX-5 (2x 25G)
>> * Basic functionality tested on the following NICs:
>>     - Intel 82599ES (2x 10G)
>>     - Intel X710 (4x 10G)
>>     - Mellanox ConnectX-4 (2x 25G)
>>
>>    Documentation/topics/dpdk/phy.rst |  55 ++++++
>>    lib/netdev-dpdk.c                 | 293 +++++++++++++++++++++++++++++-
>>    vswitchd/vswitch.xml              |  26 +++
>>    3 files changed, 373 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/topics/dpdk/phy.rst b/Documentation/topics/dpdk/phy.rst
>> index 937f4c40e5a8..86e69d79b104 100644
>> --- a/Documentation/topics/dpdk/phy.rst
>> +++ b/Documentation/topics/dpdk/phy.rst
>> @@ -131,6 +131,61 @@ possible with DPDK acceleration. It is possible to configure multiple Rx queues
>>    for ``dpdk`` ports, thus ensuring this is not a bottleneck for performance. For
>>    information on configuring PMD threads, refer to :doc:`pmd`.
>>    
>> +Control Plane Protection
>> +------------------------
>> +
>> +Some control protocols are used to maintain link status between forwarding
>> +engines. In SDN environments, these packets share the same physical network
>> +than the user data traffic.
>> +
>> +When the system is not sized properly, the PMD threads may not be able to
>> +process all incoming traffic from the configured Rx queues. When a signaling
>> +packet of such protocols is dropped, it can cause link flapping, worsening the
>> +situation.
>> +
>> +Some physical NICs can be programmed to put these protocols in a dedicated
>> +hardware Rx queue using the rte_flow__ API.
>> +
>> +__ https://doc.dpdk.org/guides-21.11/prog_guide/rte_flow.html#device-compatibility
>> +
>> +The currently supported control plane protocols are:
>> +
>> +``lacp``
>> +   `Link Aggregation Control Protocol`__. Ether type ``0x8809``.
>> +
>> +   __ https://www.ieee802.org/3/ad/public/mar99/seaman_1_0399.pdf
>> +
>> +.. warning::
>> +
>> +   This feature is not compatible with all NICs. Refer to vendor documentation
>> +   for more information.
>> +
>> +Control plane protection must be enabled on specific protocols per port. The
>> +``cp-protection`` option requires a coma separated list of protocol names::
>> +
>> +   $ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
>> +        options:dpdk-devargs=0000:01:00.0 options:cp-protection=lacp
>> +
>> +.. note::
>> +
>> +   If multiple Rx queues are already configured, regular RSS (Receive Side
>> +   Scaling) queue balancing is done on all but the extra control plane
>> +   protection queue.
>> +
>> +.. tip::
>> +
>> +   You can check if control plane protection is supported on a port with the
>> +   following command::
>> +
>> +      $ ovs-vsctl get interface dpdk-p0 status
>> +      {cp_protection_queue="2", driver_name=..., rss_queues="0-1"}
>> +
>> +   If the hardware does not support redirecting control plane traffic to
>> +   a dedicated queue, it will be explicit::
>> +
>> +      $ ovs-vsctl get interface dpdk-p0 status
>> +      {cp_protection_queue=unsupported, driver_name=..., rss_queues="0-1"}
>> +
>>    .. _dpdk-phy-flow-control:
>>    
>>    Flow Control
>> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>> index 0dd655507b50..94f04437a641 100644
>> --- a/lib/netdev-dpdk.c
>> +++ b/lib/netdev-dpdk.c
>> @@ -410,6 +410,11 @@ enum dpdk_hw_ol_features {
>>        NETDEV_TX_SCTP_CHECKSUM_OFFLOAD = 1 << 4,
>>    };
>>    
>> +enum dpdk_cp_prot_flags {
>> +    DPDK_CP_PROT_UNSUPPORTED = 1 << 0,
>> +    DPDK_CP_PROT_LACP = 1 << 1,
>> +};
>> +
>>    /*
>>     * In order to avoid confusion in variables names, following naming convention
>>     * should be used, if possible:
>> @@ -453,6 +458,7 @@ struct netdev_dpdk {
>>            };
>>            struct dpdk_tx_queue *tx_q;
>>            struct rte_eth_link link;
>> +        uint16_t reta_size;
>>        );
>>    
>>        PADDED_MEMBERS_CACHELINE_MARKER(CACHE_LINE_SIZE, cacheline1,
>> @@ -529,6 +535,13 @@ struct netdev_dpdk {
>>    
>>            /* VF configuration. */
>>            struct eth_addr requested_hwaddr;
>> +
>> +        /* Requested control plane protection flags,
>> +         * from the enum set 'dpdk_cp_prot_flags' */
>> +        uint64_t requested_cp_prot_flags;
>> +        uint64_t cp_prot_flags;
>> +        size_t cp_prot_flows_num;
>> +        struct rte_flow **cp_prot_flows;
>>        );
>>    
>>        PADDED_MEMBERS(CACHE_LINE_SIZE,
>> @@ -1192,6 +1205,7 @@ dpdk_eth_dev_init(struct netdev_dpdk *dev)
>>                          netdev_get_name(&dev->up));
>>            }
>>        }
>> +    dev->reta_size = info.reta_size;
>>    
>>        n_rxq = MIN(info.max_rx_queues, dev->up.n_rxq);
>>        n_txq = MIN(info.max_tx_queues, dev->up.n_txq);
>> @@ -1309,6 +1323,10 @@ common_construct(struct netdev *netdev, dpdk_port_t port_no,
>>        dev->requested_n_txq = NR_QUEUE;
>>        dev->requested_rxq_size = NIC_PORT_DEFAULT_RXQ_SIZE;
>>        dev->requested_txq_size = NIC_PORT_DEFAULT_TXQ_SIZE;
>> +    dev->requested_cp_prot_flags = 0;
>> +    dev->cp_prot_flags = 0;
>> +    dev->cp_prot_flows_num = 0;
>> +    dev->cp_prot_flows = NULL;
>>    
>>        /* Initialize the flow control to NULL */
>>        memset(&dev->fc_conf, 0, sizeof dev->fc_conf);
>> @@ -1904,6 +1922,9 @@ dpdk_set_rxq_config(struct netdev_dpdk *dev, const struct smap *args)
>>        int new_n_rxq;
>>    
>>        new_n_rxq = MAX(smap_get_int(args, "n_rxq", NR_QUEUE), 1);
>> +    if (dev->requested_cp_prot_flags) {
>> +        new_n_rxq += 1;
>> +    }
>>        if (new_n_rxq != dev->requested_n_rxq) {
>>            dev->requested_n_rxq = new_n_rxq;
>>            netdev_request_reconfigure(&dev->up);
>> @@ -1927,6 +1948,53 @@ dpdk_process_queue_size(struct netdev *netdev, const struct smap *args,
>>        }
>>    }
>>    
>> +static int
>> +dpdk_cp_prot_set_config(struct netdev *netdev, struct netdev_dpdk *dev,
>> +                        const struct smap *args, char **errp)
>> +{
>> +    const char *arg = smap_get_def(args, "cp-protection", "");
>> +    uint64_t flags = 0;
>> +    char buf[256];
>> +    char *token, *saveptr;
>> +
>> +    ovs_strzcpy(buf, arg, sizeof(buf));
>> +    buf[sizeof(buf) - 1] = '\0';
>> +
>> +    token = strtok_r(buf, ",", &saveptr);
>> +    while (token) {
>> +        if (strcmp(token, "lacp") == 0) {
>> +            flags |= DPDK_CP_PROT_LACP;
>> +        } else {
>> +            VLOG_WARN_BUF(
>> +                errp, "%s options:cp-protection unknown protocol '%s'",
>> +                netdev_get_name(netdev), token);
>> +            return -1;
>> +        }
>> +        token = strtok_r(NULL, ",", &saveptr);
>> +    }
>> +
>> +    if (flags && dev->type != DPDK_DEV_ETH) {
>> +        VLOG_WARN_BUF( errp,
>> +            "%s options:cp-protection is only supported on ethernet ports",
>> +            netdev_get_name(netdev));
>> +        return -1;
>> +    }
>> +
>> +    if (flags && netdev_is_flow_api_enabled()) {
>> +        VLOG_WARN_BUF(errp,
>> +            "%s options:cp-protection is incompatible with hw-offload",
>> +            netdev_get_name(netdev));
>> +        return -1;
>> +    }
>> +
>> +    if (flags != dev->requested_cp_prot_flags) {
>> +        dev->requested_cp_prot_flags = flags;
>> +        netdev_request_reconfigure(netdev);
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>>    static int
>>    netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args,
>>                           char **errp)
>> @@ -1946,6 +2014,11 @@ netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args,
>>        ovs_mutex_lock(&dpdk_mutex);
>>        ovs_mutex_lock(&dev->mutex);
>>    
>> +    if (dpdk_cp_prot_set_config(netdev, dev, args, errp) < 0) {
>> +        err = EINVAL;
>> +        goto out;
>> +    }
>> +
>>        dpdk_set_rxq_config(dev, args);
>>    
>>        dpdk_process_queue_size(netdev, args, "n_rxq_desc",
>> @@ -3639,8 +3712,10 @@ netdev_dpdk_get_status(const struct netdev *netdev, struct smap *args)
>>    {
>>        struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>>        struct rte_eth_dev_info dev_info;
>> +    uint64_t cp_prot_flags;
>>        uint32_t link_speed;
>>        uint32_t dev_flags;
>> +    int n_rxq;
>>    
>>        if (!rte_eth_dev_is_valid_port(dev->port_id)) {
>>            return ENODEV;
>> @@ -3651,6 +3726,8 @@ netdev_dpdk_get_status(const struct netdev *netdev, struct smap *args)
>>        rte_eth_dev_info_get(dev->port_id, &dev_info);
>>        link_speed = dev->link.link_speed;
>>        dev_flags = *dev_info.dev_flags;
>> +    cp_prot_flags = dev->cp_prot_flags;
>> +    n_rxq = netdev->n_rxq;
>>        ovs_mutex_unlock(&dev->mutex);
>>        const struct rte_bus *bus;
>>        const struct rte_pci_device *pci_dev;
>> @@ -3703,6 +3780,24 @@ netdev_dpdk_get_status(const struct netdev *netdev, struct smap *args)
>>                            ETH_ADDR_ARGS(dev->hwaddr));
>>        }
>>    
>> +    if (cp_prot_flags) {
>> +        if (cp_prot_flags & DPDK_CP_PROT_UNSUPPORTED) {
>> +            smap_add(args, "cp_protection_queue", "unsupported");
>> +            if (n_rxq > 1) {
>> +                smap_add_format(args, "rss_queues", "0-%d", n_rxq - 1);
>> +            } else {
>> +                smap_add(args, "rss_queues", "0");
>> +            }
>> +        } else {
>> +            smap_add_format(args, "cp_protection_queue", "%d", n_rxq - 1);
>> +            if (n_rxq > 2) {
>> +                smap_add_format(args, "rss_queues", "0-%d", n_rxq - 2);
>> +            } else {
>> +                smap_add(args, "rss_queues", "0");
>> +            }
>> +        }
>> +    }
>> +
>>        return 0;
>>    }
>>    
>> @@ -4933,6 +5028,179 @@ static const struct dpdk_qos_ops trtcm_policer_ops = {
>>        .qos_queue_dump_state_init = trtcm_policer_qos_queue_dump_state_init
>>    };
>>    
>> +static int
>> +dpdk_cp_prot_add_flow(struct netdev_dpdk *dev,
>> +                      const struct rte_flow_attr *attr,
>> +                      const struct rte_flow_item items[],
>> +                      const struct rte_flow_action actions[],
>> +                      const char *desc, bool dry_run)
>> +{
>> +    struct rte_flow_error error;
>> +    struct rte_flow *flow;
>> +    size_t num;
>> +
>> +    if (dry_run) {
>> +        int ret;
>> +        ret = rte_flow_validate(dev->port_id, attr, items, actions, &error);
>> +        if (rte_flow_validate(dev->port_id, attr, items, actions, &error)) {
> 
> 'if (ret)'
> 
>> +            VLOG_WARN("%s: cp-protection: device does not support %s flow: %s",
>> +                netdev_get_name(&dev->up), desc, error.message);
>> +        }
>> +        return ret;
>> +    }
>> +
>> +    flow = rte_flow_create(dev->port_id, attr, items, actions, &error);
>> +    if (flow == NULL) {
>> +        VLOG_WARN("%s: cp-protection: failed to add %s flow: %s",
>> +            netdev_get_name(&dev->up), desc, error.message);
>> +        return rte_errno;
>> +    }
>> +
>> +    num = dev->cp_prot_flows_num + 1;
>> +    dev->cp_prot_flows = xrealloc(dev->cp_prot_flows, sizeof(flow) * num);
>> +    dev->cp_prot_flows[dev->cp_prot_flows_num] = flow;
>> +    dev->cp_prot_flows_num = num;
>> +
>> +    return 0;
>> +}
>> +
>> +static int
>> +dpdk_cp_prot_add_traffic_flow(struct netdev_dpdk *dev,
>> +                              const struct rte_flow_item items[],
>> +                              const char *desc, bool dry_run)
>> +{
>> +    const struct rte_flow_attr attr = { .ingress = 1 };
>> +    const struct rte_flow_action actions[] = {
>> +        {
>> +            .type = RTE_FLOW_ACTION_TYPE_QUEUE,
>> +            .conf = &(const struct rte_flow_action_queue) {
>> +                .index = dev->up.n_rxq - 1,
>> +            },
>> +        },
>> +        { .type = RTE_FLOW_ACTION_TYPE_END },
>> +    };
>> +
>> +    if (!dry_run) {
>> +        VLOG_INFO("%s: cp-protection: redirecting %s traffic to queue %d",
>> +            netdev_get_name(&dev->up), desc, dev->up.n_rxq - 1);
>> +    }
>> +    return dpdk_cp_prot_add_flow(dev, &attr, items, actions, desc, dry_run);
>> +}
>> +
>> +static int
>> +dpdk_cp_prot_rss_configure(struct netdev_dpdk *dev, int rss_n_rxq)
>> +{
>> +    struct rte_eth_rss_reta_entry64 *reta_conf;
>> +    size_t reta_conf_size;
>> +    int err;
>> +
>> +    if (rss_n_rxq == 1) {
>> +        VLOG_INFO("%s: cp-protection: redirecting other traffic to queue 0",
>> +            netdev_get_name(&dev->up));
>> +    } else {
>> +        VLOG_INFO("%s: cp-protection: applying rss on queues 0-%d",
>> +            netdev_get_name(&dev->up), rss_n_rxq - 1);
>> +    }
>> +
>> +    reta_conf_size = (dev->reta_size / RTE_ETH_RETA_GROUP_SIZE)
>> +        * sizeof(struct rte_eth_rss_reta_entry64);
> 
> In dpdk_eth_dev_init, we get reta_size from driver,
> 
> mlx5_ethdev.c
> 
> 333├>        info->reta_size = priv->reta_idx_n ?
> 334│                 priv->reta_idx_n : config->ind_table_max_size;
> 
> (gdb) p priv->reta_idx_n
> $5 = 1
> (gdb) p config->ind_table_max_size
> $6 = 512
> 
> and store:
> dev->reta_size = info.reta_size;
> 
> Now we use it,
> dev->reta_size = 1 / RTE_ETH_RETA_GROUP_SIZE   (64)
> but it results in reta_conf_size = 0
> 
>> +    reta_conf = xmalloc(reta_conf_size);
> 
> xmalloc only allocates 1 byte (void *p = malloc(size ? size : 1);)
> 
>> +    memset(reta_conf, 0, reta_conf_size);
>> +
>> +    for (uint16_t i = 0; i < dev->reta_size; i++) {
>> +        uint16_t idx = i / RTE_ETH_RETA_GROUP_SIZE;
>> +        uint16_t shift = i % RTE_ETH_RETA_GROUP_SIZE;
>> +        reta_conf[idx].mask |= 1ULL << shift;
>> +        reta_conf[idx].reta[shift] = i % rss_n_rxq;
>> +    }
>> +    err = rte_eth_dev_rss_reta_update(dev->port_id, reta_conf, dev->reta_size);
>> +    if (err < 0) {
>> +        VLOG_DBG("%s: failed to configure RSS redirection table: err=%d",
>> +            netdev_get_name(&dev->up), err);
>> +    }
>> +
>> +    free(reta_conf);
>> +
>> +    return err;
>> +}
>> +
>> +static int
>> +dpdk_cp_prot_configure(struct netdev_dpdk *dev, bool dry_run)
>> +{
>> +    int err = 0;
>> +
>> +    if (dev->requested_cp_prot_flags & DPDK_CP_PROT_UNSUPPORTED) {
>> +        goto out;
>> +    }
>> +    if (dev->up.n_rxq < 2) {
>> +        err = ENOTSUP;
>> +        VLOG_DBG("%s: cp-protection: not enough available rx queues",
>> +            netdev_get_name(&dev->up));
>> +        goto out;
>> +    }
>> +
>> +    if (dev->requested_cp_prot_flags & DPDK_CP_PROT_LACP) {
>> +        err = dpdk_cp_prot_add_traffic_flow(
>> +            dev,
>> +            (const struct rte_flow_item []) {
>> +                {
>> +                    .type = RTE_FLOW_ITEM_TYPE_ETH,
>> +                    .spec = &(const struct rte_flow_item_eth){
>> +                        .type = htons(ETH_TYPE_LACP),
>> +                    },
>> +                    .mask = &(const struct rte_flow_item_eth){
>> +                        .type = htons(0xffff),
>> +                    },
>> +                },
>> +                { .type = RTE_FLOW_ITEM_TYPE_END },
>> +            },
>> +            "lacp",
>> +            dry_run
>> +        );
>> +        if (err) {
>> +            goto out;
>> +        }
>> +    }
>> +
>> +    if (!dry_run && dev->cp_prot_flows_num) {
>> +        /* reconfigure RSS reta in all but the cp protection queue */
>> +        err = dpdk_cp_prot_rss_configure(dev, dev->up.n_rxq - 1);
>> +    }
>> +
>> +out:
>> +    if (!dry_run) {
>> +        dev->cp_prot_flags = dev->requested_cp_prot_flags;
>> +    }
>> +    if (err) {
>> +        dev->requested_cp_prot_flags |= DPDK_CP_PROT_UNSUPPORTED;
>> +    }
>> +    return err;
>> +}
>> +
>> +static void
>> +dpdk_cp_prot_unconfigure(struct netdev_dpdk *dev)
>> +{
>> +    struct rte_flow_error error;
>> +
>> +    if (dev->cp_prot_flows_num == 0) {
>> +        return;
>> +    }
>> +
>> +    VLOG_DBG("%s: cp-protection: reset flows", netdev_get_name(&dev->up));
>> +
>> +    for (int i = 0; i < dev->cp_prot_flows_num; i++) {
>> +        if (rte_flow_destroy(dev->port_id, dev->cp_prot_flows[i], &error)) {
>> +            VLOG_DBG("%s: cp-protection: failed to destroy flow: %s",
>> +                netdev_get_name(&dev->up), error.message);
>> +        }
>> +    }
>> +    free(dev->cp_prot_flows);
>> +    dev->cp_prot_flows_num = 0;
>> +    dev->cp_prot_flows = NULL;
>> +
>> +    (void) dpdk_cp_prot_rss_configure(dev, dev->up.n_rxq);
>> +}
>> +
>>    static int
>>    netdev_dpdk_reconfigure(struct netdev *netdev)
>>    {
>> @@ -4943,6 +5211,7 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>>    
>>        if (netdev->n_txq == dev->requested_n_txq
>>            && netdev->n_rxq == dev->requested_n_rxq
>> +        && dev->cp_prot_flags == dev->requested_cp_prot_flags
>>            && dev->mtu == dev->requested_mtu
>>            && dev->lsc_interrupt_mode == dev->requested_lsc_interrupt_mode
>>            && dev->rxq_size == dev->requested_rxq_size
>> @@ -4987,6 +5256,8 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>>            }
>>        }
>>    
>> +    dpdk_cp_prot_unconfigure(dev);
>> +
>>        err = dpdk_eth_dev_init(dev);
>>        if (dev->hw_ol_features & NETDEV_TX_TSO_OFFLOAD) {
>>            netdev->ol_flags |= NETDEV_TX_OFFLOAD_TCP_TSO;
>> @@ -5014,6 +5285,20 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>>        if (!dev->tx_q) {
>>            err = ENOMEM;
>>        }
>> +    if (!err && dev->requested_cp_prot_flags) {
>> +        /* dry run first */
>> +        err = dpdk_cp_prot_configure(dev, true);
>> +        if (!err) {
>> +            /* if no error, apply configuration */
>> +            err = dpdk_cp_prot_configure(dev, false);
>> +        }
>> +        if (err) {
>> +            /* no hw support, remove the extra queue & recover gracefully */
>> +            err = 0;
>> +            dev->requested_n_rxq -= 1;
>> +            netdev_request_reconfigure(netdev);
>> +        }
>> +    }
>>    
>>        netdev_change_seq_changed(netdev);
>>    
>> @@ -5215,7 +5500,13 @@ netdev_dpdk_flow_api_supported(struct netdev *netdev)
>>        ovs_mutex_lock(&dev->mutex);
>>        if (dev->type == DPDK_DEV_ETH) {
>>            /* TODO: Check if we able to offload some minimal flow. */
>> -        ret = true;
>> +        if (dev->requested_cp_prot_flags || dev->cp_prot_flags) {
>> +            VLOG_WARN(
>> +                "%s: hw-offload is mutually exclusive with cp-protection",
>> +                netdev_get_name(netdev));
>> +        } else {
>> +            ret = true;
>> +        }
>>        }
>>        ovs_mutex_unlock(&dev->mutex);
>>    out:
>> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
>> index 36388e3c42d7..7e6ae3df7583 100644
>> --- a/vswitchd/vswitch.xml
>> +++ b/vswitchd/vswitch.xml
>> @@ -3430,6 +3430,32 @@ ovs-vsctl add-port br0 p0 -- set Interface p0 type=patch options:peer=p1 \
>>            <p>This option may only be used with dpdk VF representors.</p>
>>          </column>
>>    
>> +      <column name="options" key="cp-protection"
>> +              type='{"type": "string", "enum": ["set", ["lacp"]]}'>
>> +        <p>
>> +          Allocate an extra Rx queue for control plane packets of the specified
>> +          protocol(s).
>> +        </p>
>> +        <p>
>> +          If the user has already configured multiple
>> +          <code>options:n_rxq</code> on the port, an additional one will be
>> +          allocated for control plane packets. If the hardware cannot satisfy
>> +          the requested number of requested Rx queues, the last Rx queue will
>> +          be assigned for control plane. If only one Rx queue is available or
>> +          if the hardware does not support the RTE flow matchers/actions
>> +          required to redirect the selected protocols,
>> +          <code>cp-protection</code> will be disabled.
>> +        </p>
>> +        <p>
>> +          This feature is multually exclusive with
>> +          <code>other_options:hw-offload</code> as it may conflict with the
>> +          offloaded RTE flows.
>> +        </p>
>> +        <p>
>> +          Disabled by default.
>> +        </p>
>> +      </column>
>> +
>>          <column name="other_config" key="tx-steering"
>>                  type='{"type": "string",
>>                         "enum": ["set", ["thread", "hash"]]}'>
> 
>