From patchwork Wed Dec 9 00:24:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 341116 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0743C19437 for ; Wed, 9 Dec 2020 00:28:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AFBBA239E5 for ; Wed, 9 Dec 2020 00:28:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731862AbgLIA2R (ORCPT ); Tue, 8 Dec 2020 19:28:17 -0500 Received: from mga09.intel.com ([134.134.136.24]:16959 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731930AbgLIAZ7 (ORCPT ); Tue, 8 Dec 2020 19:25:59 -0500 IronPort-SDR: Vbbf5Yyriz45L+TTe97gXCRqCa8l4alyyM3LT+6vagJYBn/POSMD+F7lNTiQu/X5n46HBNZVbW +fNorpOBFxZQ== X-IronPort-AV: E=McAfee;i="6000,8403,9829"; a="174142089" X-IronPort-AV: E=Sophos;i="5.78,404,1599548400"; d="scan'208";a="174142089" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Dec 2020 16:24:28 -0800 IronPort-SDR: vy0dthkPfL/gcxo52372VSggCr9CVKXZICPtYVNpoOJaYj/GUPeSKxYXAxc3lyPpo/6SgCyhm7 tHDJ9SRsvrsA== X-IronPort-AV: E=Sophos;i="5.78,404,1599548400"; d="scan'208";a="407838506" Received: from mlubyani-mobl2.amr.corp.intel.com (HELO bwidawsk-mobl5.local) ([10.252.137.9]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Dec 2020 16:24:27 -0800 From: Ben Widawsky To: linux-cxl@vger.kernel.org Cc: Ben Widawsky , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Ira Weiny , Dan Williams , Vishal Verma , "Kelley, Sean V" , Rafael Wysocki , Bjorn Helgaas , Jonathan Cameron , Jon Masters , Chris Browy , Randy Dunlap , Christoph Hellwig Subject: [RFC PATCH 09/14] cxl/mem: Add basic IOCTL interface Date: Tue, 8 Dec 2020 16:24:13 -0800 Message-Id: <20201209002418.1976362-10-ben.widawsky@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201209002418.1976362-1-ben.widawsky@intel.com> References: <20201209002418.1976362-1-ben.widawsky@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Add a straightforward IOCTL that provides a mechanism for userspace to query the supported memory device commands. Memory device commands are specified in 8.2.9 of the CXL 2.0 specification. They are submitted through a mailbox mechanism specified in 8.2.8.4. Signed-off-by: Ben Widawsky --- I did attempt to use the same struct for querying commands as well as sending commands (upcoming patch). The number of unused fields between the two made for a bad fit IMO. Signed-off-by: Ben Widawsky --- Documentation/cxl/memory-devices.rst | 9 +++ drivers/cxl/mem.c | 89 +++++++++++++++++++++++ include/uapi/linux/cxl_mem.h | 102 +++++++++++++++++++++++++++ 3 files changed, 200 insertions(+) create mode 100644 include/uapi/linux/cxl_mem.h diff --git a/Documentation/cxl/memory-devices.rst b/Documentation/cxl/memory-devices.rst index 5f723c25382b..ec54674b3822 100644 --- a/Documentation/cxl/memory-devices.rst +++ b/Documentation/cxl/memory-devices.rst @@ -32,6 +32,15 @@ CXL Memory Device .. kernel-doc:: drivers/cxl/mem.c :internal: +CXL IOCTL Interface +------------------- + +.. kernel-doc:: include/uapi/linux/cxl_mem.h + :doc: UAPI + +.. kernel-doc:: include/uapi/linux/cxl_mem.h + :internal: + External Interfaces =================== diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c index bb6ea58f6c7b..2c4aadcea0e4 100644 --- a/drivers/cxl/mem.c +++ b/drivers/cxl/mem.c @@ -7,6 +7,7 @@ #include #include #include +#include #include "acpi.h" #include "pci.h" #include "cxl.h" @@ -73,6 +74,49 @@ static DEFINE_IDR(cxl_mem_idr); /* protect cxl_mem_idr allocations */ static DEFINE_MUTEX(cxl_memdev_lock); +/* + * This table defines the supported mailboxes commands for the driver. The id is + * ordinal and thus gaps in this table aren't allowed. This table is made up of + * a UAPI structure. Non-negative values in the table will be validated against + * the user's input. For example, if size_in is 0, and the user passed in 1, it + * is an error. + */ +#define CXL_CMD(_id, _flags, sin, sout, _name, _enable, op) \ + { \ + { .id = CXL_MEM_COMMAND_ID_##_id, \ + .flags = CXL_MEM_COMMAND_FLAG_##_flags, \ + .size_in = sin, \ + .size_out = sout, \ + .name = _name }, \ + .enable = _enable, .opcode = op \ + } + +/** + * struct cxl_mem_command - Driver representation of a memory device command + * @info: Command information as it exists for the UAPI + * @opcode: The actual bits used for the mailbox protocol + * @enable: Whether the command is enabled. The driver may support a large set + * of commands that may not be enabled. The primary reason a command + * would not be enabled is for commands that are specified as optional + * and the hardware doesn't support the command. + * + * The cxl_mem_command is the driver's internal representation of commands that + * are supported by the driver. Some of these commands may not be supported by + * the hardware (!@enable). The driver will use @info to validate the fields + * passed in by the user then submit the @opcode to the hardware. + * + * See struct cxl_command_info. + */ +struct cxl_mem_command { + const struct cxl_command_info info; + const u16 opcode; + bool enable; +}; + +static struct cxl_mem_command mem_commands[] = { + CXL_CMD(INVALID, NONE, 0, 0, "Reserved", false, 0), +}; + static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm) { const int timeout = msecs_to_jiffies(2000); @@ -268,8 +312,53 @@ static int cxl_mem_open(struct inode *inode, struct file *file) return 0; } +static int cxl_mem_count_commands(void) +{ + int i, n = 0; + + for (i = 0; i < ARRAY_SIZE(mem_commands); i++) { + struct cxl_mem_command *c = &mem_commands[i]; + + if (c->enable) + n++; + } + + return n; +} + static long cxl_mem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { + if (cmd == CXL_MEM_QUERY_COMMANDS) { + struct cxl_mem_query_commands __user *q = (void __user *)arg; + u32 n_commands; + int i, j; + + if (get_user(n_commands, (u32 __user *)arg)) + return -EFAULT; + + if (n_commands == 0) + return put_user(cxl_mem_count_commands(), + (u32 __user *)arg); + + for (i = 0, j = 0; + i < ARRAY_SIZE(mem_commands) && j < n_commands; i++) { + struct cxl_mem_command *c = &mem_commands[i]; + const struct cxl_command_info *info = &c->info; + + if (!c->enable) + continue; + + if (copy_to_user(&q->commands[j], info, sizeof(*info))) + return -EFAULT; + + if (copy_to_user(&q->commands[j].name, info->name, + strlen(info->name))) + return -EFAULT; + + j++; + } + } + return -ENOTTY; } diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h new file mode 100644 index 000000000000..1d1e143f98ec --- /dev/null +++ b/include/uapi/linux/cxl_mem.h @@ -0,0 +1,102 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * CXL IOCTLs for Memory Devices + */ + +#ifndef _UAPI_CXL_MEM_H_ +#define _UAPI_CXL_MEM_H_ + +#if defined(__cplusplus) +extern "C" { +#endif + +/** + * DOC: UAPI + * + * CXL memory devices expose UAPI to have a standard user interface. + * Userspace can refer to these structure definitions and UAPI formats + * to communicate to driver + */ + +#define CXL_MEM_QUERY_COMMANDS _IOR('C', 1, struct cxl_mem_query_commands) + +#define CXL_MEM_COMMAND_NAME_LENGTH 32 + +/** + * struct cxl_command_info - Command information returned from a query. + * @id: ID number for the command. + * @flags: Flags that specify command behavior. + * + * - CXL_MEM_COMMAND_FLAG_TAINT: Using this command will taint the kernel. + * @size_in: Expected input size, or -1 if variable length. + * @size_out: Expected output size, or -1 if variable length. + * @name: Name describing the command. + * + * Represents a single command that is supported by both the driver and the + * hardware. The is returned as part of an array from the query ioctl. The + * following would be a command named "foobar" that takes a variable length + * input and returns 0 bytes of output. + * + * - @id = 10 + * - @name = foobar + * - @flags = 0 + * - @size_in = -1 + * - @size_out = 0 + * + * See struct cxl_mem_query_commands. + */ +struct cxl_command_info { + __u32 id; +#define CXL_MEM_COMMAND_ID_INVALID 0 + + __u32 flags; +#define CXL_MEM_COMMAND_FLAG_NONE 0 +#define CXL_MEM_COMMAND_FLAG_TAINT BIT(0) + + __s32 size_in; + __s32 size_out; + + char name[32]; +}; + +/** + * struct cxl_mem_query_commands - Query supported commands. + * @n_commands: In/out parameter. When @n_commands is > 0, the driver will + * return min(num_support_commands, n_commands). When @n_commands + * is 0, driver will return the number of total supported commands. + * @rsvd: Reserved for future use. + * @commands: Output array of supported commands. This array must be allocated + * by userspace to be at least min(num_support_commands, @n_commands) + * + * Allow userspace to query the available commands supported by both the driver, + * and the hardware. Commands that aren't supported by either the driver, or the + * hardware are not returned in the query. + * + * Examples: + * + * - { .n_commands = 0 } // Get number of supported commands + * - { .n_commands = 15, .commands = buf } // Return first 15 (or less) + * supported commands + * + * See struct cxl_command_info. + */ +struct cxl_mem_query_commands { + /* + * Input: Number of commands to return (space allocated by user) + * Output: Number of commands supported by the driver/hardware + * + * If n_commands is 0, kernel will only return number of commands and + * not try to populate commands[], thus allowing userspace to know how + * much space to allocate + */ + __u32 n_commands; + __u32 rsvd; + + struct cxl_command_info __user commands[]; /* out: supported commands */ +}; + +#if defined(__cplusplus) +} +#endif + +#endif