On 11 Dec 2025, at 11:05, Eli Britstein wrote:

>> -----Original Message-----
>> From: dev <[email protected]> On Behalf Of Eelco Chaudron
>> Sent: Tuesday, 2 December 2025 16:05
>> To: [email protected]
>> Subject: [ovs-dev] [PATCH v2 16/41] dpif-offload: Move
>> hw_miss_packet_postprocess netdev API to dpif.
>>
>> This patch moves the hardware packet miss recovery API from the netdev-
>> offload to the dpif-offload provider. The API name has been changed from
>> hw_miss_packet_recover() to hw_miss_packet_postprocess() to reflect that it
>> may also be used for other tasks in the future, such as conntrack post-
>> processing.
> I think "recover" is still a better name than "postprocess".
> If a packet was partially processed in the HW and missed to SW, need to set 
> its state to be as if it was processed in SW from the beginning.
> In current netdev-offload-dpdk, the only scenario currently supported is with 
> tunnel decap.
> With CT we will have to recover more metadata of the packet, like recirc-id, 
> ct-state/mark/label.
> With dp-hash we will have to recover the hash value calculated by the HW.
> The term "postprocess" might imply some processing done after further SW 
> processing but it's the not.
> I also agree "recover" might not be the perfect term, but still better than 
> "postprocess".
> In the API definition comment, you also mention "recover":
> " * Recover and/or set the packet state ..."
> If you still stick with renaming, need to be consistent and also change 
> function names like netdev_offload_dpdk_hw_miss_packet_recover.
> WDYT?

Hi Eli,

Thanks for the feedback. I understand your concern about the naming. Here are 
some points on why I chose hw_miss_packet_postprocess() and my thoughts on 
alternatives:

- I used “postprocess” in the context of post-hardware processing, not general 
SW processing.
- In a later patch, this function will be used for flow lookup as part of 
partial HW offload, so it’s more general than just “recovering” a packet.
- This is a general callback for anything that needs HW post-processing, hence 
the name (not SW processing).
- The name already contains hw, so it conveys the hardware context.
- We could consider removing packet_miss from the name entirely to emphasize 
the generality, e.g., hw_post_processing().

WDYT? I’m happy to settle on a name that is both general enough for future use 
and clear about its purpose.

//Eelco

>>
>> Signed-off-by: Eelco Chaudron <[email protected]>
>> ---
>> lib/dpif-netdev.c             | 18 +++++++++++-------
>> lib/dpif-offload-dpdk.c       | 10 ++++++++++
>> lib/dpif-offload-provider.h   | 12 ++++++++++++
>> lib/dpif-offload.c            | 36 +++++++++++++++++++++++++++++++++++
>> lib/dpif-offload.h            |  2 ++
>> lib/netdev-offload-dpdk.c     |  3 +--
>> lib/netdev-offload-dpdk.h     |  2 ++
>> lib/netdev-offload-provider.h |  6 ------
>> lib/netdev-offload.c          | 33 +++-----------------------------
>> lib/netdev-offload.h          |  4 ++--
>> lib/netdev.c                  |  2 +-
>> 11 files changed, 80 insertions(+), 48 deletions(-)
>>
>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index 82df85823..5d32a47b3
>> 100644
>> --- a/lib/dpif-netdev.c
>> +++ b/lib/dpif-netdev.c
>> @@ -122,7 +122,7 @@ COVERAGE_DEFINE(datapath_drop_invalid_bond);
>> COVERAGE_DEFINE(datapath_drop_invalid_tnl_port);
>> COVERAGE_DEFINE(datapath_drop_rx_invalid_packet);
>> #ifdef ALLOW_EXPERIMENTAL_API /* Packet restoration API required. */ -
>> COVERAGE_DEFINE(datapath_drop_hw_miss_recover);
>> +COVERAGE_DEFINE(datapath_drop_hw_miss_postprocess);
>> #endif
>>
>> /* Protects against changes to 'dp_netdevs'. */ @@ -8423,14 +8423,18 @@
>> dp_netdev_hw_flow(const struct dp_netdev_pmd_thread *pmd,  #ifdef
>> ALLOW_EXPERIMENTAL_API /* Packet restoration API required. */
>>     /* Restore the packet if HW processing was terminated before completion.
>> */
>>     struct dp_netdev_rxq *rxq = pmd->ctx.last_rxq;
>> -    bool miss_api_supported;
>> +    bool postprocess_api_supported;
>> +
>> +    atomic_read_relaxed(&rxq->port->netdev-
>>> hw_info.postprocess_api_supported,
>> +                        &postprocess_api_supported);
>> +    if (postprocess_api_supported) {
>> +        int err = dpif_offload_netdev_hw_miss_packet_postprocess(
>> +            rxq->port->netdev, packet);
> Blank line

Already has a blank line.
>>
>> -    atomic_read_relaxed(&rxq->port->netdev->hw_info.miss_api_supported,
>> -                        &miss_api_supported);
>> -    if (miss_api_supported) {
>> -        int err = netdev_hw_miss_packet_recover(rxq->port->netdev, packet);
>>         if (err && err != EOPNOTSUPP) {
>> -            COVERAGE_INC(datapath_drop_hw_miss_recover);
>> +            if (err != ECANCELED) {
>> +                COVERAGE_INC(datapath_drop_hw_miss_postprocess);
>> +            }
>>             return -1;
>>         }
>>     }
>> diff --git a/lib/dpif-offload-dpdk.c b/lib/dpif-offload-dpdk.c index
>> 76a8946c9..c8ae1adb2 100644
>> --- a/lib/dpif-offload-dpdk.c
>> +++ b/lib/dpif-offload-dpdk.c
>> @@ -286,6 +286,14 @@ dpif_offload_dpdk_netdev_flow_flush(const struct
>> dpif_offload *offload
>>     return netdev_offload_dpdk_flow_flush(netdev);
>> }
>>
>> +static int
>> +dpif_offload_dpdk_netdev_hw_miss_packet_postprocess(
>> +    const struct dpif_offload *offload_ OVS_UNUSED, struct netdev *netdev,
>> +    struct dp_packet *packet)
>> +{
>> +    return netdev_offload_dpdk_hw_miss_packet_recover(netdev, packet);
>> +}
>> +
>> struct dpif_offload_class dpif_offload_dpdk_class = {
>>     .type = "dpdk",
>>     .supported_dpif_types = (const char *const[]) { @@ -300,6 +308,8 @@
>> struct dpif_offload_class dpif_offload_dpdk_class = {
>>     .port_del = dpif_offload_dpdk_port_del,
>>     .flow_get_n_offloaded = dpif_offload_dpdk_get_n_offloaded,
>>     .netdev_flow_flush = dpif_offload_dpdk_netdev_flow_flush,
>> +    .netdev_hw_miss_packet_postprocess = \
>> +        dpif_offload_dpdk_netdev_hw_miss_packet_postprocess,
>> };
>>
>> /* XXX: Temporary functions below, which will be removed once fully diff 
>> --git
>> a/lib/dpif-offload-provider.h b/lib/dpif-offload-provider.h index
>> 60d6c5321..78cf5d7fa 100644
>> --- a/lib/dpif-offload-provider.h
>> +++ b/lib/dpif-offload-provider.h
>> @@ -168,6 +168,18 @@ struct dpif_offload_class {
>>     /* Deletes all offloaded flows on this netdev.  Return 0 if successful,
>>      * otherwise returns a positive errno value. */
>>     int (*netdev_flow_flush)(const struct dpif_offload *, struct netdev *);
>> +
>> +    /* Recover and/or set the packet state (contents and metadata) for
>> +     * continued processing in software, and perform any additional
>> +     * post-processing required by the offload provider.
>> +     *
>> +     * Return 0 if successful and the packet requires further processing;
>> +     * otherwise, return a positive errno value and take ownership of the
>> +     * packet if errno != EOPNOTSUPP.  Return ECANCELED if the packet was
>> +     * fully consumed by the provider for non-error conditions. */
>> +    int (*netdev_hw_miss_packet_postprocess)(const struct dpif_offload *,
>> +                                             struct netdev *,
>> +                                             struct dp_packet *);
>> };
>>
>>
>> diff --git a/lib/dpif-offload.c b/lib/dpif-offload.c index 
>> 99cfe2aac..8ac0f8f96
>> 100644
>> --- a/lib/dpif-offload.c
>> +++ b/lib/dpif-offload.c
>> @@ -846,6 +846,42 @@ dpif_offload_netdev_flush_flows(struct netdev
>> *netdev)
>>     return EOPNOTSUPP;
>> }
>>
>> +int
>> +dpif_offload_netdev_hw_miss_packet_postprocess(struct netdev *netdev,
>> +                                               struct dp_packet
>> +*packet) {
>> +    const struct dpif_offload *offload;
>> +    bool postprocess_api_supported;
>> +    int rc;
>> +
>> +    atomic_read_relaxed(&netdev->hw_info.postprocess_api_supported,
>> +                        &postprocess_api_supported);
>> +    if (!postprocess_api_supported) {
>> +        return EOPNOTSUPP;
>> +    }
>> +
>> +    offload = ovsrcu_get(const struct dpif_offload *,
>> + &netdev->dpif_offload);
>> +
>> +    if (!offload || !offload->class->netdev_hw_miss_packet_postprocess) {
>> +        if (offload) {
>> +            /* Offload is configured and API unsupported by the port;
>> +             * avoid subsequent calls. */
>> +            atomic_store_relaxed(&netdev->hw_info.postprocess_api_supported,
>> +                                 false);
>> +        }
>> +        return EOPNOTSUPP;
>> +    }
>> +
>> +    rc = offload->class->netdev_hw_miss_packet_postprocess(offload, netdev,
>> +                                                           packet);
>> +    if (rc == EOPNOTSUPP) {
>> +        /* API unsupported by the port; avoid subsequent calls. */
>> +        atomic_store_relaxed(&netdev->hw_info.postprocess_api_supported,
>> +                             false);
>> +    }
>> +    return rc;
>> +}
>> +
>>
>>
>>
>> struct dpif_offload_port_mgr *
>> dpif_offload_port_mgr_init(void)
>> diff --git a/lib/dpif-offload.h b/lib/dpif-offload.h index 
>> fb7edf269..fe73b278d
>> 100644
>> --- a/lib/dpif-offload.h
>> +++ b/lib/dpif-offload.h
>> @@ -75,5 +75,7 @@ void dpif_offload_meter_del(const struct dpif *dpif,
>> ofproto_meter_id meter_id,
>>
>>
>>
>> /* Netdev specific function, which can be used in the fast path. */  int
>> dpif_offload_netdev_flush_flows(struct netdev *);
>> +int dpif_offload_netdev_hw_miss_packet_postprocess(struct netdev *,
>> +                                                   struct dp_packet *);
>>
>> #endif /* DPIF_OFFLOAD_H */
>> diff --git a/lib/netdev-offload-dpdk.c b/lib/netdev-offload-dpdk.c index
>> d1781d8e4..c3d5e83f5 100644
>> --- a/lib/netdev-offload-dpdk.c
>> +++ b/lib/netdev-offload-dpdk.c
>> @@ -2685,7 +2685,7 @@ get_vport_netdev(const char *dpif_type,
>>     return aux.vport;
>> }
>>
>> -static int
>> +int
>> netdev_offload_dpdk_hw_miss_packet_recover(struct netdev *netdev,
>>                                            struct dp_packet *packet)  { @@ 
>> -2803,5 +2803,4
>> @@ const struct netdev_flow_api netdev_offload_dpdk = {
>>     .init_flow_api = netdev_offload_dpdk_init_flow_api,
>>     .uninit_flow_api = netdev_offload_dpdk_uninit_flow_api,
>>     .flow_get = netdev_offload_dpdk_flow_get,
>> -    .hw_miss_packet_recover =
>> netdev_offload_dpdk_hw_miss_packet_recover,
>> };
>> diff --git a/lib/netdev-offload-dpdk.h b/lib/netdev-offload-dpdk.h index
>> d5061b40c..475822e1b 100644
>> --- a/lib/netdev-offload-dpdk.h
>> +++ b/lib/netdev-offload-dpdk.h
>> @@ -24,5 +24,7 @@ struct netdev;
>>  * associated dpif offload provider. */  int
>> netdev_offload_dpdk_flow_flush(struct netdev *);  uint64_t
>> netdev_offload_dpdk_flow_get_n_offloaded(struct netdev *);
>> +int netdev_offload_dpdk_hw_miss_packet_recover(struct netdev *,
>> +                                               struct dp_packet *);
>>
>> #endif /* NETDEV_OFFLOAD_DPDK_H */
>> diff --git a/lib/netdev-offload-provider.h b/lib/netdev-offload-provider.h 
>> index
>> 898df8333..f762af19a 100644
>> --- a/lib/netdev-offload-provider.h
>> +++ b/lib/netdev-offload-provider.h
>> @@ -80,12 +80,6 @@ struct netdev_flow_api {
>>     int (*flow_del)(struct netdev *, const ovs_u128 *ufid,
>>                     struct dpif_flow_stats *);
>>
>> -    /* Recover the packet state (contents and data) for continued processing
>> -     * in software.
>> -     * Return 0 if successful, otherwise returns a positive errno value and
>> -     * takes ownership of a packet if errno != EOPNOTSUPP. */
>> -    int (*hw_miss_packet_recover)(struct netdev *, struct dp_packet *);
>> -
>>     /* Initializies the netdev flow api.
>>      * Return 0 if successful, otherwise returns a positive errno value. */
>>     int (*init_flow_api)(struct netdev *); diff --git a/lib/netdev-offload.c
>> b/lib/netdev-offload.c index 0c4209290..be5787f4d 100644
>> --- a/lib/netdev-offload.c
>> +++ b/lib/netdev-offload.c
>> @@ -186,7 +186,8 @@ netdev_assign_flow_api(struct netdev *netdev)
>>     CMAP_FOR_EACH (rfa, cmap_node, &netdev_flow_apis) {
>>         if (!rfa->flow_api->init_flow_api(netdev)) {
>>             ovs_refcount_ref(&rfa->refcnt);
>> -            atomic_store_relaxed(&netdev->hw_info.miss_api_supported, true);
>> +            atomic_store_relaxed(&netdev->hw_info.postprocess_api_supported,
>> +                                 true);
>>             ovsrcu_set(&netdev->flow_api, rfa->flow_api);
>>             VLOG_INFO("%s: Assigned flow API '%s'.",
>>                       netdev_get_name(netdev), rfa->flow_api->type); @@ 
>> -195,7
>> +196,7 @@ netdev_assign_flow_api(struct netdev *netdev)
>>         VLOG_DBG("%s: flow API '%s' is not suitable.",
>>                  netdev_get_name(netdev), rfa->flow_api->type);
>>     }
>> -    atomic_store_relaxed(&netdev->hw_info.miss_api_supported, false);
>> +    atomic_store_relaxed(&netdev->hw_info.postprocess_api_supported,
>> + false);
>>     VLOG_INFO("%s: No suitable flow API found.", netdev_get_name(netdev));
>>
>>     return -1;
>> @@ -254,34 +255,6 @@ netdev_flow_put(struct netdev *netdev, struct match
>> *match,
>>            : EOPNOTSUPP;
>> }
>>
>> -int
>> -netdev_hw_miss_packet_recover(struct netdev *netdev,
>> -                              struct dp_packet *packet)
>> -{
>> -    const struct netdev_flow_api *flow_api;
>> -    bool miss_api_supported;
>> -    int rv;
>> -
>> -    atomic_read_relaxed(&netdev->hw_info.miss_api_supported,
>> -                        &miss_api_supported);
>> -    if (!miss_api_supported) {
>> -        return EOPNOTSUPP;
>> -    }
>> -
>> -    flow_api = ovsrcu_get(const struct netdev_flow_api *, 
>> &netdev->flow_api);
>> -    if (!flow_api || !flow_api->hw_miss_packet_recover) {
>> -        return EOPNOTSUPP;
>> -    }
>> -
>> -    rv = flow_api->hw_miss_packet_recover(netdev, packet);
>> -    if (rv == EOPNOTSUPP) {
>> -        /* API unsupported by the port; avoid subsequent calls. */
>> -        atomic_store_relaxed(&netdev->hw_info.miss_api_supported, false);
>> -    }
>> -
>> -    return rv;
>> -}
>> -
>> int
>> netdev_flow_get(struct netdev *netdev, struct match *match,
>>                 struct nlattr **actions, const ovs_u128 *ufid, diff --git 
>> a/lib/netdev-
>> offload.h b/lib/netdev-offload.h index 2b32179ec..6006396b9 100644
>> --- a/lib/netdev-offload.h
>> +++ b/lib/netdev-offload.h
>> @@ -47,7 +47,8 @@ struct ovs_action_push_tnl;
>> /* Offload-capable (HW) netdev information */  struct netdev_hw_info {
>>     bool oor;                         /* Out of Offload Resources ? */
>> -    atomic_bool miss_api_supported;   /* hw_miss_packet_recover()
>> supported.*/
>> +    /* Is hw_miss_packet_postprocess() supported.*/
>> +    atomic_bool postprocess_api_supported;
>>     int offload_count;                /* Offloaded flow count */
>>     int pending_count;                /* Pending (non-offloaded) flow count 
>> */
>>     OVSRCU_TYPE(void *) offload_data; /* Offload metadata. */ @@ -110,7
>> +111,6 @@ bool netdev_flow_dump_next(struct netdev_flow_dump *, struct
>> match *,  int netdev_flow_put(struct netdev *, struct match *, struct nlattr
>> *actions,
>>                     size_t actions_len, const ovs_u128 *,
>>                     struct offload_info *, struct dpif_flow_stats *); -int
>> netdev_hw_miss_packet_recover(struct netdev *, struct dp_packet *);  int
>> netdev_flow_get(struct netdev *, struct match *, struct nlattr **actions,
>>                     const ovs_u128 *, struct dpif_flow_stats *,
>>                     struct dpif_flow_attrs *, struct ofpbuf *wbuffer); diff 
>> --git
>> a/lib/netdev.c b/lib/netdev.c index 6a05e9a7e..13f3d707e 100644
>> --- a/lib/netdev.c
>> +++ b/lib/netdev.c
>> @@ -435,7 +435,7 @@ netdev_open(const char *name, const char *type,
>> struct netdev **netdevp)
>>                     seq_read(netdev->reconfigure_seq);
>>                 ovsrcu_set(&netdev->flow_api, NULL);
>>                 netdev->hw_info.oor = false;
>> -                atomic_init(&netdev->hw_info.miss_api_supported, false);
>> +                atomic_init(&netdev->hw_info.postprocess_api_supported,
>> + false);
>>                 netdev->node = shash_add(&netdev_shash, name, netdev);
>>
>>                 /* By default enable one tx and rx queue per netdev. */

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