From patchwork Wed Jan 12 23:47:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12712070 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 73DC4C4321E for ; Wed, 12 Jan 2022 23:48:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235627AbiALXsH (ORCPT ); Wed, 12 Jan 2022 18:48:07 -0500 Received: from mga04.intel.com ([192.55.52.120]:13987 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235641AbiALXsF (ORCPT ); Wed, 12 Jan 2022 18:48:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642031285; x=1673567285; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=RN9M3F/1IKA4m4L9Hh4iWFeC1JI6OdIzY1su0XKvB4Q=; b=C5ZOMHev3aj3UXGkhffSpU1iNrAVyb5eesZOM4vm2HxoULfXUTNpYuaa 2rrJhFVKcj1dTd1NTcwzyukbaWCWjxuFifvmCLnNo0diVYgwdoL2hEHku US91GFfy3o+kwvL2v6Cv99ZX4H+5yx9h00jTua1rP8LouuGEeLcnuNqvY eqvzdSGJDFcZW+QHw0T13E4+TzJWe2jySEj026+xzmSv4FZibKwt1hvyR c2C1fjS8Yg1Jxq8NzM8Vz65PExt13odkmm971paJglkt4C8Syi9SROzmn r5cFLLkmeoqAviI3Q7QSdfWSi+CxB12sY3OpNBx7Ddbeppe50HJwk/Hrf A==; X-IronPort-AV: E=McAfee;i="6200,9189,10225"; a="242695326" X-IronPort-AV: E=Sophos;i="5.88,284,1635231600"; d="scan'208";a="242695326" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 15:48:04 -0800 X-IronPort-AV: E=Sophos;i="5.88,284,1635231600"; d="scan'208";a="670324176" Received: from jmaclean-mobl1.amr.corp.intel.com (HELO localhost.localdomain) ([10.252.136.131]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 15:48:04 -0800 From: Ben Widawsky To: linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev, linux-pci@vger.kernel.org Cc: patches@lists.linux.dev, Bjorn Helgaas , Ben Widawsky , Alison Schofield , Dan Williams , Ira Weiny , Jonathan Cameron , Vishal Verma Subject: [PATCH v2 03/15] cxl/region: Add region creation ABI Date: Wed, 12 Jan 2022 15:47:37 -0800 Message-Id: <20220112234749.1965960-4-ben.widawsky@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220112234749.1965960-1-ben.widawsky@intel.com> References: <20220112234749.1965960-1-ben.widawsky@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Regions are created as a child of the decoder that encompasses an address space with constraints. Regions have a number of attributes that must be configured before the region can be activated. The ABI is not meant to be secure, but is meant to avoid accidental races. As a result, a buggy process may create a region by name that was allocated by a different process. However, multiple processes which are trying not to race with each other shouldn't need special synchronization to do so. // Allocate a new region name region=$(cat /sys/bus/cxl/devices/decoder0.0/create_region) // Create a new region by name echo $region > /sys/bus/cxl/devices/decoder0.0/create_region // Region now exists in sysfs stat -t /sys/bus/cxl/devices/decoder0.0/$region // Delete the region, and name echo $region > /sys/bus/cxl/devices/decoder0.0/delete_region Signed-off-by: Ben Widawsky --- Documentation/ABI/testing/sysfs-bus-cxl | 23 ++ .../driver-api/cxl/memory-devices.rst | 11 + drivers/cxl/core/Makefile | 1 + drivers/cxl/core/core.h | 3 + drivers/cxl/core/port.c | 16 ++ drivers/cxl/core/region.c | 209 ++++++++++++++++++ drivers/cxl/cxl.h | 9 + drivers/cxl/region.h | 38 ++++ tools/testing/cxl/Kbuild | 1 + 9 files changed, 311 insertions(+) create mode 100644 drivers/cxl/core/region.c create mode 100644 drivers/cxl/region.h diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl index 498ae288e143..0fbdd8613654 100644 --- a/Documentation/ABI/testing/sysfs-bus-cxl +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -136,3 +136,26 @@ Description: memory (type-3). The 'target_type' attribute indicates the current setting which may dynamically change based on what memory regions are activated in this decode hierarchy. + +What: /sys/bus/cxl/devices/decoderX.Y/create_region +Date: November, 2021 +KernelVersion: v5.17 +Contact: linux-cxl@vger.kernel.org +Description: + Creates a new CXL region. Writing a value of the form + "regionX.Y:Z" will create a new uninitialized region that will + be mapped by the CXL decoderX.Y. Reading from this node will + return a newly allocated region name. In order to create a + region (writing) you must use a value returned from reading the + node. Regions must be subsequently configured and bound to a + region driver before they can be used. + +What: /sys/bus/cxl/devices/decoderX.Y/delete_region +Date: November, 2021 +KernelVersion: v5.17 +Contact: linux-cxl@vger.kernel.org +Description: + Deletes the named region. A region must be unbound from the + region driver before being deleted. The attributes expects a + region in the form "regionX.Y:Z". The region's name, allocated + by reading create_region, will also be released. diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst index e101ef02b547..dc756ed23a3a 100644 --- a/Documentation/driver-api/cxl/memory-devices.rst +++ b/Documentation/driver-api/cxl/memory-devices.rst @@ -71,6 +71,17 @@ CXL Core .. kernel-doc:: drivers/cxl/core/mbox.c :doc: cxl mbox +CXL Regions +----------- +.. kernel-doc:: drivers/cxl/region.h + :identifiers: + +.. kernel-doc:: drivers/cxl/core/region.c + :doc: cxl core region + +.. kernel-doc:: drivers/cxl/core/region.c + :identifiers: + External Interfaces =================== diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile index 6d37cd78b151..39ce8f2f2373 100644 --- a/drivers/cxl/core/Makefile +++ b/drivers/cxl/core/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_CXL_BUS) += cxl_core.o ccflags-y += -I$(srctree)/drivers/cxl cxl_core-y := port.o cxl_core-y += pmem.o +cxl_core-y += region.o cxl_core-y += regs.o cxl_core-y += memdev.o cxl_core-y += mbox.o diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h index 19d1f9d8ceba..1d4d1699b479 100644 --- a/drivers/cxl/core/core.h +++ b/drivers/cxl/core/core.h @@ -10,6 +10,9 @@ extern const struct device_type cxl_memdev_type; extern struct attribute_group cxl_base_attribute_group; +extern struct device_attribute dev_attr_create_region; +extern struct device_attribute dev_attr_delete_region; + struct cxl_send_command; struct cxl_mem_query_commands; int cxl_query_cmd(struct cxl_memdev *cxlmd, diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index ecab7cfa88f0..ef3840c50e3e 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -196,6 +196,8 @@ static struct attribute_group cxl_decoder_base_attribute_group = { }; static struct attribute *cxl_decoder_root_attrs[] = { + &dev_attr_create_region.attr, + &dev_attr_delete_region.attr, &dev_attr_cap_pmem.attr, &dev_attr_cap_ram.attr, &dev_attr_cap_type2.attr, @@ -236,11 +238,23 @@ static const struct attribute_group *cxl_decoder_endpoint_attribute_groups[] = { NULL, }; +static int delete_region(struct device *dev, void *arg) +{ + struct cxl_decoder *cxld = to_cxl_decoder(dev->parent); + + return cxl_delete_region(cxld, dev_name(dev)); +} + static void cxl_decoder_release(struct device *dev) { struct cxl_decoder *cxld = to_cxl_decoder(dev); struct cxl_port *port = to_cxl_port(dev->parent); + device_for_each_child(&cxld->dev, cxld, delete_region); + + dev_WARN_ONCE(dev, !ida_is_empty(&cxld->region_ida), + "Lost track of a region"); + ida_free(&port->decoder_ida, cxld->id); kfree(cxld); } @@ -1021,6 +1035,8 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, cxld->target_type = CXL_DECODER_EXPANDER; cxld->platform_res = (struct resource)DEFINE_RES_MEM(0, 0); + ida_init(&cxld->region_ida); + return cxld; err: kfree(cxld); diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c new file mode 100644 index 000000000000..e3a82f3c118e --- /dev/null +++ b/drivers/cxl/core/region.c @@ -0,0 +1,209 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2021 Intel Corporation. All rights reserved. */ +#include +#include +#include +#include +#include +#include +#include +#include "core.h" + +/** + * DOC: cxl core region + * + * Regions are managed through the Linux device model. Each region instance is a + * unique struct device. CXL core provides functionality to create, destroy, and + * configure regions. This is all implemented here. Binding a region + * (programming the hardware) is handled by a separate region driver. + */ + +static void cxl_region_release(struct device *dev); + +static const struct device_type cxl_region_type = { + .name = "cxl_region", + .release = cxl_region_release, +}; + +static ssize_t create_region_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct cxl_port *port = to_cxl_port(dev->parent); + struct cxl_decoder *cxld = to_cxl_decoder(dev); + int rc; + + if (dev_WARN_ONCE(dev, !is_root_decoder(dev), + "Invalid decoder selected for region.")) { + return -ENODEV; + } + + rc = ida_alloc(&cxld->region_ida, GFP_KERNEL); + if (rc < 0) { + dev_err(&cxld->dev, "Couldn't get a new id\n"); + return rc; + } + + return sysfs_emit(buf, "region%d.%d:%d\n", port->id, cxld->id, rc); +} + +static ssize_t create_region_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct cxl_port *port = to_cxl_port(dev->parent); + struct cxl_decoder *cxld = to_cxl_decoder(dev); + int decoder_id, port_id, region_id; + struct cxl_region *region; + ssize_t rc; + + if (sscanf(buf, "region%d.%d:%d", &port_id, &decoder_id, ®ion_id) != 3) + return -EINVAL; + + if (decoder_id != cxld->id) + return -EINVAL; + + if (port_id != port->id) + return -EINVAL; + + region = cxl_alloc_region(cxld, region_id); + if (IS_ERR(region)) + return PTR_ERR(region); + + rc = cxl_add_region(cxld, region); + if (rc) { + kfree(region); + return rc; + } + + return len; +} +DEVICE_ATTR_RW(create_region); + +static ssize_t delete_region_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct cxl_decoder *cxld = to_cxl_decoder(dev); + int rc; + + rc = cxl_delete_region(cxld, buf); + if (rc) + return rc; + + return len; +} +DEVICE_ATTR_WO(delete_region); + +struct cxl_region *to_cxl_region(struct device *dev) +{ + if (dev_WARN_ONCE(dev, dev->type != &cxl_region_type, + "not a cxl_region device\n")) + return NULL; + + return container_of(dev, struct cxl_region, dev); +} +EXPORT_SYMBOL_GPL(to_cxl_region); + +static void cxl_region_release(struct device *dev) +{ + struct cxl_decoder *cxld = to_cxl_decoder(dev->parent); + struct cxl_region *region = to_cxl_region(dev); + + ida_free(&cxld->region_ida, region->id); + kfree(region); +} + +struct cxl_region *cxl_alloc_region(struct cxl_decoder *cxld, int id) +{ + struct cxl_region *region; + + region = kzalloc(sizeof(*region), GFP_KERNEL); + if (!region) + return ERR_PTR(-ENOMEM); + + region->id = id; + + return region; +} + +/** + * cxl_add_region - Adds a region to a decoder + * @cxld: Parent decoder. + * @region: Region to be added to the decoder. + * + * This is the second step of region initialization. Regions exist within an + * address space which is mapped by a @cxld. That @cxld must be a root decoder, + * and it enforces constraints upon the region as it is configured. + * + * Return: 0 if the region was added to the @cxld, else returns negative error + * code. The region will be named "regionX.Y.Z" where X is the port, Y is the + * decoder id, and Z is the region number. + */ +int cxl_add_region(struct cxl_decoder *cxld, struct cxl_region *region) +{ + struct cxl_port *port = to_cxl_port(cxld->dev.parent); + struct device *dev = ®ion->dev; + int rc; + + device_initialize(dev); + dev->parent = &cxld->dev; + device_set_pm_not_required(dev); + dev->bus = &cxl_bus_type; + dev->type = &cxl_region_type; + rc = dev_set_name(dev, "region%d.%d:%d", port->id, cxld->id, + region->id); + if (rc) + goto err; + + rc = device_add(dev); + if (rc) + goto err; + + dev_dbg(dev, "Added %s to %s\n", dev_name(dev), dev_name(&cxld->dev)); + + return 0; + +err: + put_device(dev); + return rc; +} + +static struct cxl_region *cxl_find_region_by_name(struct cxl_decoder *cxld, + const char *name) +{ + struct device *region_dev; + + region_dev = device_find_child_by_name(&cxld->dev, name); + if (!region_dev) + return ERR_PTR(-ENOENT); + + return to_cxl_region(region_dev); +} + +/** + * cxl_delete_region - Deletes a region + * @cxld: Parent decoder + * @region_name: Named region, ie. regionX.Y:Z + */ +int cxl_delete_region(struct cxl_decoder *cxld, const char *region_name) +{ + struct cxl_region *region; + + device_lock(&cxld->dev); + + region = cxl_find_region_by_name(cxld, region_name); + if (IS_ERR(region)) { + device_unlock(&cxld->dev); + return PTR_ERR(region); + } + + dev_dbg(&cxld->dev, "Requested removal of %s from %s\n", + dev_name(®ion->dev), dev_name(&cxld->dev)); + + device_unregister(®ion->dev); + device_unlock(&cxld->dev); + + put_device(®ion->dev); + + return 0; +} diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 6eeb82711443..79c5781b6173 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -202,6 +202,7 @@ enum cxl_decoder_type { * @interleave_granularity: data stride per dport * @target_type: accelerator vs expander (type2 vs type3) selector * @flags: memory type capabilities and locking + * @region_ida: allocator for region ids. * @nr_targets: number of elements in @target * @target: active ordered target list in current decoder configuration */ @@ -216,6 +217,7 @@ struct cxl_decoder { int interleave_granularity; enum cxl_decoder_type target_type; unsigned long flags; + struct ida region_ida; const int nr_targets; struct cxl_dport *target[]; }; @@ -315,6 +317,13 @@ struct cxl_ep { struct list_head list; }; +bool is_cxl_region(struct device *dev); +struct cxl_region *to_cxl_region(struct device *dev); +struct cxl_region *cxl_alloc_region(struct cxl_decoder *cxld, + int interleave_ways); +int cxl_add_region(struct cxl_decoder *cxld, struct cxl_region *region); +int cxl_delete_region(struct cxl_decoder *cxld, const char *region); + static inline bool is_cxl_root(struct cxl_port *port) { return port->uport == port->dev.parent; diff --git a/drivers/cxl/region.h b/drivers/cxl/region.h new file mode 100644 index 000000000000..3e6e5fb35822 --- /dev/null +++ b/drivers/cxl/region.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright(c) 2021 Intel Corporation. */ +#ifndef __CXL_REGION_H__ +#define __CXL_REGION_H__ + +#include + +#include "cxl.h" + +/** + * struct cxl_region - CXL region + * @dev: This region's device. + * @id: This regions id. Id is globally unique across all regions. + * @list: Node in decoder's region list. + * @res: Resource this region carves out of the platform decode range. + * @config: HDM decoder program config + * @config.size: Size of the region determined from LSA or userspace. + * @config.uuid: The UUID for this region. + * @config.eniw: Number of interleave ways this region is configured for. + * @config.ig: Interleave granularity of region + * @config.targets: The memory devices comprising the region. + */ +struct cxl_region { + struct device dev; + int id; + struct list_head list; + struct resource *res; + + struct { + u64 size; + uuid_t uuid; + int eniw; + int ig; + struct cxl_memdev *targets[CXL_DECODER_MAX_INTERLEAVE]; + } config; +}; + +#endif diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild index 8b20e34090f7..73735f561c89 100644 --- a/tools/testing/cxl/Kbuild +++ b/tools/testing/cxl/Kbuild @@ -43,6 +43,7 @@ cxl_core-y += $(CXL_CORE_SRC)/memdev.o cxl_core-y += $(CXL_CORE_SRC)/mbox.o cxl_core-y += $(CXL_CORE_SRC)/pci.o cxl_core-y += $(CXL_CORE_SRC)/hdm.o +cxl_core-y += $(CXL_CORE_SRC)/region.o cxl_core-y += config_check.o obj-m += test/