OOPS, I forgot to add the RFC tag.
Just to clarify: this series is still an RFC.

Cheers,
Eelco


On 26 Sep 2025, at 13:41, Eelco Chaudron via dev wrote:

> This RFC patch series introduces a major architectural
> refactoring of Open vSwitch's hardware offload
> infrastructure. It replaces the tightly coupled
> `netdev-offload` implementation with a new, modular
> `dpif-offload-provider` framework.
>
> MOTIVATION
> -------------------------------------------------------------
> The existing `netdev-offload` API tightly couples datapath
> implementations (like `dpif-netdev`) with specific offload
> technologies (rte_flow). This design has several
> limitations:
>
> - Rigid Architecture: It creates complex dependencies,
>   making the code difficult to maintain and extend.
>
> - Limited Flexibility: Supporting multiple offload backends
>   simultaneously or adding new ones is cumbersome.
>
> - Inconsistent APIs: The logic for handling different
>   offload types is scattered, leading to an inconsistent
>   and hard-to-follow API surface.
>
> This refactoring aims to resolve these issues by creating a
> clean separation of concerns, improving modularity, and
> establishing a clear path for future hardware offload
> integrations.
>
> PROPOSED SOLUTION: THE `DPIF-OFFLOAD-PROVIDER` FRAMEWORK
> -------------------------------------------------------------
> This series introduces the `dpif-offload-provider`
> framework, which functions similarly to the existing
> `dpif-provider` pattern. It treats hardware offload as a
> distinct layer with multiple, dynamically selectable
> backends.
>
> Key features of the new framework include:
>
> 1. Modular Architecture: A clean separation between the
>    generic datapath interface and specific offload
>    provider implementations (e.g., `dpif-offload-tc`,
>    `dpif-offload-rte_flow`). `dpif` layers are now generic
>    clients of the offload API.
>
> 2. Provider-based System: Allows multiple offload backends
>    to coexist.
>
> 3. Unified and Asynchronous API: Establishes a consistent
>    API across all offload providers. For userspace
>    datapaths, the API is extended to support asynchronous
>    flow operations with callbacks, making `dpif-netdev` a
>    more efficient client.
>
> 4. Enhanced Configuration: Provides granular control over
>    offload provider selection through a global and per-port
>    priority system (`hw-offload-priority`), allowing
>    fine-tuned policies for different hardware.
>
> 5. Improved Testing: Includes a new test framework
>    specifically for validating RTE_Flow offloads, enhancing
>    long-term maintainability.
>
> PATCH SERIES ORGANIZATION
> -------------------------------------------------------------
> This large series is organized logically to facilitate
> review:
>
> 1. Framework Foundation: The initial patches establish the
>    core `dpif-offload-provider` framework, including the
>    necessary APIs for port management, flow mark
>    allocation, configuration, and a dummy provider for
>    testing.
>
> 2. Provider Implementation: These patches introduce the new
>    `dpif-offload-tc` and `dpif-offload-rte_flow` providers,
>    building out their specific implementations on top of
>    the new framework.
>
> 3. API Migration and Decoupling: The bulk of the series
>    systematically migrates functionality from the legacy
>    `netdev-offload` layer to the new providers. Key
>    commits here decouple `dpif-netdev` and, crucially,
>    `dpif-netlink` from their hardware offload
>    entanglements.
>
> 4. Cleanup: The final patches remove the now-redundant
>    global APIs and structures from `netdev-offload`,
>    completing the transition.
>
> BACKWARD COMPATIBILITY
> -------------------------------------------------------------
> This refactoring maintains full API compatibility from a
> user's perspective. All existing `ovs-vsctl` and
> `ovs-appctl` commands continue to function as before. The
> changes are primarily internal architectural improvements
> designed to make OVS more robust and extensible.
>
> REQUEST FOR COMMENTS
> -------------------------------------------------------------
> This is a significant architectural change that affects
> core OVS infrastructure. We welcome feedback on:
>
> - The overall architectural approach and the
>   `dpif-offload-provider` concept.
> - The API design, particularly the new asynchronous model
>   for `dpif-netdev`.
> - The migration strategy and any potential backward
>   compatibility concerns.
> - Performance implications of the new framework.
>
> -------------------------------------------------------------
>
> v2:
>  - Fixed some minor AI review comments (see individual patches)
>  - Fix some Coverity issues reported on this patch set.
>  - Fixed and investigated some rte_flow unit test.
>
>
> Eelco Chaudron (41):
>   dpif-offload-provider: Add dpif-offload-provider implementation.
>   dpif-offload: Add provider for tc offload.
>   dpif-offload: Add provider for rte_flow.
>   dpif-offload: Allow configuration of offload provider priority.
>   dpif-offload: Move hw-offload configuration to dpif-offload.
>   dpif-offload: Add offload provider set_config API.
>   dpif-offload: Add port registration and management APIs.
>   dpif-offload-tc: Add port management framework.
>   dpif-offload-rte_flow: Add port management framework.
>   dpif-offload: Validate mandatory port class callbacks on registration.
>   dpif-offload: Allow per-port offload provider priority config.
>   dpif-offload: Introduce provider debug information API.
>   dpif-offload: Call flow-flush netdev-offload APIs via dpif-offload.
>   dpif-offload: Call meter netdev-offload APIs via dpif-offload.
>   dpif-offload: Move the flow_get_n_flows() netdev-offload API to dpif.
>   dpif-offload: Move the hw_miss_packet_recover netdev API to dpif.
>   dpif-offload: Add flow dump APIs to dpif-offload.
>   dpif-offload: Move the tc flow dump netdev APIs to dpif-offload.
>   dpif-netlink: Remove netlink-offload integration.
>   dpif-netlink: Add API to get offloaded netdev from port_id.
>   dpif-offload: Add API to find offload implementation type.
>   dpif-offload: Add operate implementation to dpif-offload.
>   netdev-offload: Temporarily move thread-related APIs to dpif-netdev.
>   dpif-offload: Add port dump APIs to dpif-offload.
>   dpif-netdev: Remove indirect DPDK netdev offload API calls.
>   dpif: Add dpif_get_features() API.
>   dpif-offload: Add flow operations to dpif-offload-tc.
>   dpif-netlink: Remove entangled hardware offload.
>   dpif-offload-tc: Remove netdev-offload dependency.
>   netdev_dummy: Remove hardware offload override.
>   dpif-offload: Move the netdev_any_oor() API to dpif-offload.
>   netdev-offload: Remove the global netdev-offload API.
>   dpif-offload: Add flow mark allocation API.
>   dpif-offload: Add inline flow APIs for userspace datapaths.
>   dpif_netdev: Fix nullable memcpy in queue_netdev_flow_put().
>   dpif-offload: Move offload_stats_get() API to dpif-offload.
>   dpif-netdev: Add full name to the dp_netdev structure.
>   dpif-offload-rte: Abstract rte_flow implementation from dpif-netdev.
>   dpif-offload-dummy: Add flow add/del/get APIs.
>   tests: Fix NSH decap header test for real Ethernet devices.
>   tests: Add a simple rte_flow test framework.
>
>  Documentation/topics/testing.rst          |   19 +
>  include/openvswitch/json.h                |    1 +
>  include/openvswitch/netdev.h              |    1 +
>  lib/automake.mk                           |   12 +-
>  lib/dpctl.c                               |   50 +-
>  lib/dpdk.c                                |    2 -
>  lib/dpif-netdev-avx512.c                  |    3 +-
>  lib/dpif-netdev-private-flow.h            |    5 -
>  lib/dpif-netdev.c                         | 1090 +++----------
>  lib/dpif-netlink.c                        |  556 +------
>  lib/dpif-offload-dummy.c                  |  642 ++++++++
>  lib/dpif-offload-provider.h               |  399 +++++
>  lib/dpif-offload-rte_flow-private.h       |   34 +
>  lib/dpif-offload-rte_flow.c               | 1228 ++++++++++++++
>  lib/dpif-offload-tc.c                     |  873 ++++++++++
>  lib/dpif-offload.c                        | 1805 +++++++++++++++++++++
>  lib/dpif-offload.h                        |  214 +++
>  lib/dpif-provider.h                       |   65 +-
>  lib/dpif.c                                |  139 +-
>  lib/dpif.h                                |   14 +-
>  lib/dummy.h                               |    9 +
>  lib/json.c                                |    7 +
>  lib/netdev-dpdk.c                         |    9 +-
>  lib/netdev-dpdk.h                         |    2 +-
>  lib/netdev-dummy.c                        |  199 +--
>  lib/netdev-linux.c                        |    3 +-
>  lib/netdev-offload-dpdk.c                 |  178 +-
>  lib/netdev-offload-dpdk.h                 |   51 +
>  lib/netdev-offload-provider.h             |  148 --
>  lib/netdev-offload-tc.c                   |  261 +--
>  lib/netdev-offload-tc.h                   |   76 +
>  lib/netdev-offload.c                      |  838 +---------
>  lib/netdev-offload.h                      |  118 --
>  lib/netdev-provider.h                     |    9 +-
>  lib/netdev.c                              |   18 +-
>  lib/netdev.h                              |    1 +
>  ofproto/ofproto-dpif-upcall.c             |   47 +-
>  ofproto/ofproto-dpif.c                    |   89 +-
>  tests/.gitignore                          |    3 +
>  tests/automake.mk                         |   24 +
>  tests/dpif-netdev.at                      |   22 +-
>  tests/ofproto-dpif.at                     |  164 ++
>  tests/ofproto-macros.at                   |   17 +-
>  tests/system-dpdk.at                      |   35 +
>  tests/system-kmod-macros.at               |    5 +
>  tests/system-offloads-testsuite-macros.at |    5 +
>  tests/system-offloads-traffic.at          |   44 +
>  tests/system-rte-offloads-macros.at       |  230 +++
>  tests/system-rte-offloads-testsuite.at    |   28 +
>  tests/system-rte-offloads.at              |  111 ++
>  tests/system-traffic.at                   |    8 +-
>  tests/system-userspace-macros.at          |    5 +
>  vswitchd/bridge.c                         |    6 +-
>  vswitchd/vswitch.xml                      |   42 +
>  54 files changed, 6874 insertions(+), 3090 deletions(-)
>  create mode 100644 lib/dpif-offload-dummy.c
>  create mode 100644 lib/dpif-offload-provider.h
>  create mode 100644 lib/dpif-offload-rte_flow-private.h
>  create mode 100644 lib/dpif-offload-rte_flow.c
>  create mode 100644 lib/dpif-offload-tc.c
>  create mode 100644 lib/dpif-offload.c
>  create mode 100644 lib/dpif-offload.h
>  create mode 100644 lib/netdev-offload-dpdk.h
>  delete mode 100644 lib/netdev-offload-provider.h
>  create mode 100644 lib/netdev-offload-tc.h
>  create mode 100644 tests/system-rte-offloads-macros.at
>  create mode 100644 tests/system-rte-offloads-testsuite.at
>  create mode 100644 tests/system-rte-offloads.at
>
> -- 
> 2.50.1
>
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