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Thu, 12 Mar 2026 03:04:08 -0700 (PDT) From: Jiri Pirko To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, donald.hunter@gmail.com, corbet@lwn.net, skhan@linuxfoundation.org, saeedm@nvidia.com, leon@kernel.org, tariqt@nvidia.com, mbloch@nvidia.com, przemyslaw.kitszel@intel.com, mschmidt@redhat.com, andrew+netdev@lunn.ch, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, chuck.lever@oracle.com, matttbe@kernel.org, cjubran@nvidia.com, daniel.zahka@gmail.com, linux-doc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH net-next v4 00/13] devlink: introduce shared devlink instance for PFs on same chip Date: Thu, 12 Mar 2026 11:03:54 +0100 Message-ID: <20260312100407.551173-1-jiri@resnulli.us> X-Mailer: git-send-email 2.51.1 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jiri Pirko Multiple PFs on a network adapter often reside on the same physical chip, running a single firmware. Some resources and configurations are inherently shared among these PFs - PTP clocks, VF group rates, firmware parameters, and others. Today there is no good object in the devlink model to attach these chip-wide configuration knobs to. Drivers resort to workarounds like pinning shared state to PF0 or maintaining ad-hoc internal structures (e.g., ice_adapter) that are invisible to userspace. This problem was discussed extensively starting with Przemek Kitszel's "whole device devlink instance" RFC for the ice driver [1]. Several approaches for representing the parent instance were considered: using a partial PCI BDF as the dev_name (breaks when PFs have different BDFs in VMs), creating a per-driver bus, using auxiliary devices, or using faux devices. All of these required a backing struct device for the parent devlink instance, which does not naturally exist - there is no PCI device that represents the chip as a whole. This patchset takes a different approach: allow devlink instances to exist without any backing struct device. The instance is identified purely by its internal index, exposed over devlin netlink. This avoids fabricating fake devices and keeps the devlink handle semantics clean. The first ten patches prepare the devlink core for device-less instances by decoupling the handle from the parent device. The last three introduce the shared devlink infrastructure and its first user in the mlx5 driver. Example output showing the shared instance and nesting: pci/0000:08:00.0: index 0 nested_devlink: auxiliary/mlx5_core.eth.0 devlink_index/1: index 1 nested_devlink: pci/0000:08:00.0 pci/0000:08:00.1 auxiliary/mlx5_core.eth.0: index 2 pci/0000:08:00.1: index 3 nested_devlink: auxiliary/mlx5_core.eth.1 auxiliary/mlx5_core.eth.1: index 4 [1] https://lore.kernel.org/netdev/20250219164410.35665-1-przemyslaw.kitszel@intel.com/ --- Decoupled from "devlink and mlx5: Support cross-function rate scheduling" patchset to maintain 15-patches limit. See individual patches for changelog. Jiri Pirko (13): devlink: expose devlink instance index over netlink devlink: add helpers to get bus_name/dev_name devlink: avoid extra iterations when found devlink is not registered devlink: allow to use devlink index as a command handle devlink: support index-based lookup via bus_name/dev_name handle devlink: support index-based notification filtering devlink: introduce __devlink_alloc() with dev driver pointer devlink: add devlink_dev_driver_name() helper and use it in trace events devlink: add devl_warn() helper and use it in port warnings devlink: allow devlink instance allocation without a backing device devlink: introduce shared devlink instance for PFs on same chip documentation: networking: add shared devlink documentation net/mlx5: Add a shared devlink instance for PFs on same chip Documentation/netlink/specs/devlink.yaml | 58 +++ .../networking/devlink/devlink-shared.rst | 97 +++++ Documentation/networking/devlink/index.rst | 1 + .../net/ethernet/mellanox/mlx5/core/Makefile | 5 +- .../net/ethernet/mellanox/mlx5/core/main.c | 17 + .../ethernet/mellanox/mlx5/core/sh_devlink.c | 61 +++ .../ethernet/mellanox/mlx5/core/sh_devlink.h | 12 + include/linux/mlx5/driver.h | 1 + include/net/devlink.h | 10 + include/trace/events/devlink.h | 36 +- include/uapi/linux/devlink.h | 4 + net/devlink/Makefile | 2 +- net/devlink/core.c | 91 ++++- net/devlink/dev.c | 8 +- net/devlink/devl_internal.h | 34 +- net/devlink/netlink.c | 52 ++- net/devlink/netlink_gen.c | 355 +++++++++++------- net/devlink/port.c | 19 +- net/devlink/sh_dev.c | 161 ++++++++ 19 files changed, 815 insertions(+), 209 deletions(-) create mode 100644 Documentation/networking/devlink/devlink-shared.rst create mode 100644 drivers/net/ethernet/mellanox/mlx5/core/sh_devlink.c create mode 100644 drivers/net/ethernet/mellanox/mlx5/core/sh_devlink.h create mode 100644 net/devlink/sh_dev.c -- 2.51.1