From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87686CDB47E for ; Wed, 18 Oct 2023 08:20:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235048AbjJRIU1 (ORCPT ); Wed, 18 Oct 2023 04:20:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230031AbjJRIUX (ORCPT ); Wed, 18 Oct 2023 04:20:23 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79F4BB6 for ; Wed, 18 Oct 2023 01:20:21 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F510C433CC; Wed, 18 Oct 2023 08:20:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697617221; bh=kAQb1Dauqk/QmzH5qzVaRj1IjK5Gc50QF1fiNXcjCvg=; h=From:To:Cc:Subject:Date:From; b=NpVviRdtHRVoKEz8+v/XeRzsmtBxXo6p6FdYbxN1CAH3LiF6E7SLbpR5QjiICYSlJ VYrwkTxRrDlA//QFpH+j4HuUy3inTYg5TKbIVzoeZqXscZXbBlhVN4RRNj5AT8zI50 v4sNRLq7jS9besmy9bcpCnejfDVEq+UvGP2osZB1SC7T6GuS7Bt3lBPB/c+3vAwZ2d BSnt84RfYVZSMslz8CTIYga64p+IeGakRUTx38AnZ3TsrThi1huQrHkTSJI3W55n5m c7lZWP+3yzZkWwnypG2WFtgBf1iwfSigW955I16oA67UPvZ5yOgqmO4Llf51IXhDcM k4GuEa3oUkrwg== From: Saeed Mahameed To: Arnd Bergmann , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Leon Romanovsky , Jason Gunthorpe , Jiri Pirko , Saeed Mahameed Subject: [PATCH 0/5] mlx5 ConnectX diagnostic misc driver Date: Wed, 18 Oct 2023 01:19:36 -0700 Message-ID: <20231018081941.475277-1-saeed@kernel.org> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Saeed Mahameed Hello Greg and Arnd, The ConnectX HW family supported by the mlx5 drivers uses an architecture where a FW component executes "mailbox RPCs" issued by the driver to make changes to the device. This results in a complex debugging environment where the FW component has information and complex low level state that needs to be accessed to userspace for debugging purposes. Historically a userspace program was used that accessed the PCI register and config space directly through /sys/bus/pci/.../XXX and could operate these debugging interfaces in parallel with the running driver. This approach is incompatible with secure boot and kernel lockdown so this driver provides a secure and restricted interface to that. To solve this we add a misc driver "mlx5ctl" that would interface with mlx5_core ConnectX driver to access the underlaying device debug information. 1) The first patch in the series introduces the main driver file with the implementation of a new mlx5 auxiliary device driver to run on top mlx5_core device instances, on probe it creates a new misc device and in this patch we implement the open and release fops, On open the driver would allocate a special FW UID (user context ID) restricted to debug RPCs only, where all user debug RPCs will be executed under this UID, and on release the UID will be freed. 2) The second patch adds an info ioctl that will show the allocated UID and the available capability masks of the device and the current UID, and some other useful device information such as the underlying ConnectX device Example: $ mlx5ctl mlx5_core.ctl.0 mlx5dev: 0000:00:04.0 UCTX UID: 1 UCTX CAP: 0x3 DEV UCTX CAP: 0x3 USER CAP: 0x1d 3) Third patch adds RPC ioctl to execute debug RPCs under the special UID. In the mlx5 architecture the FW RPC commands are of the format of inbox and outbox buffers. The inbox buffer contains the command rpc layout as described in the ConnectX Programmers Reference Manual (PRM) document and as defined in linux/include/mlx5/mlx5_ifc.h. On success the user outbox buffer will be filled with the device's rpc response. For example to query device capabilities: a user fills out an inbox buffer with the inbox layout: struct mlx5_ifc_query_hca_cap_in_bits and expects an outbox buffer with the layout: struct mlx5_ifc_cmd_hca_cap_bits 4) The fourth patch adds the ability to register user memory into the ConntectX device and create a umem object that points to that memory. Command rpc outbox buffer is limited in size, which can be very annoying when trying to pull large traces out of the device. Many rpcs offer the ability to scatter output traces, contexts and logs directly into user space buffers in a single shot. The registered/pinned memory will be described by a device UMEM object which has a unique umem_id, this umem_id can be later used in the rpc inbox to tell the device where to populate the response output, e.g HW traces and other debug object queries. Example usecase, a ConnectX device coredump can be as large as 2MB. Using inline rpcs will take thousands of rpcs to get the full coredump which can consume multiple seconds. With UMEM, it can be done in a single rpc, using 2MB of umem user buffer. Other usecases with umem: - dynamic HW and FW trace monitoring - high frequency diagnostic counters sampling - batched objects and resource dumps See links below for information about user-space tools that use this interface: [1] https://github.com/saeedtx/mlx5ctl [2] https://github.com/Mellanox/mstflint see: d) mstregdump utility This utility dumps hardware registers from Mellanox hardware for later analysis by Mellanox. g) mstconfig This tool sets or queries non-volatile configurable options i) mstreg The mlxreg utility allows users to obtain information regarding supported access registers, such as their fields Saeed Mahameed (5): mlx5: Add aux dev for ctl interface misc: mlx5ctl: Add mlx5ctl misc driver misc: mlx5ctl: Add info ioctl misc: mlx5ctl: Add command rpc ioctl misc: mlx5ctl: Add umem reg/unreg ioctl .../userspace-api/ioctl/ioctl-number.rst | 1 + drivers/misc/Kconfig | 1 + drivers/misc/Makefile | 1 + drivers/misc/mlx5ctl/Kconfig | 14 + drivers/misc/mlx5ctl/Makefile | 5 + drivers/misc/mlx5ctl/main.c | 528 ++++++++++++++++++ drivers/misc/mlx5ctl/umem.c | 325 +++++++++++ drivers/misc/mlx5ctl/umem.h | 17 + drivers/net/ethernet/mellanox/mlx5/core/dev.c | 8 + include/uapi/misc/mlx5ctl.h | 51 ++ 10 files changed, 951 insertions(+) create mode 100644 drivers/misc/mlx5ctl/Kconfig create mode 100644 drivers/misc/mlx5ctl/Makefile create mode 100644 drivers/misc/mlx5ctl/main.c create mode 100644 drivers/misc/mlx5ctl/umem.c create mode 100644 drivers/misc/mlx5ctl/umem.h create mode 100644 include/uapi/misc/mlx5ctl.h -- 2.41.0