From patchwork Fri Oct 22 18:36:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12578459 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 326AAC43217 for ; Fri, 22 Oct 2021 18:37:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11FC46054F for ; Fri, 22 Oct 2021 18:37:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233930AbhJVSji (ORCPT ); Fri, 22 Oct 2021 14:39:38 -0400 Received: from mga02.intel.com ([134.134.136.20]:5584 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233713AbhJVSjg (ORCPT ); Fri, 22 Oct 2021 14:39:36 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10145"; a="216528960" X-IronPort-AV: E=Sophos;i="5.87,173,1631602800"; d="scan'208";a="216528960" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2021 11:37:18 -0700 X-IronPort-AV: E=Sophos;i="5.87,173,1631602800"; d="scan'208";a="445854688" Received: from aagregor-mobl3.amr.corp.intel.com (HELO bad-guy.kumite) ([10.252.134.35]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2021 11:37:18 -0700 From: Ben Widawsky To: linux-cxl@vger.kernel.org, Chet Douglas Cc: Ben Widawsky , Alison Schofield , Dan Williams , Ira Weiny , Jonathan Cameron , Vishal Verma Subject: [RFC PATCH v2 18/28] cxl/region: Add region creation ABI Date: Fri, 22 Oct 2021 11:36:59 -0700 Message-Id: <20211022183709.1199701-19-ben.widawsky@intel.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211022183709.1199701-1-ben.widawsky@intel.com> References: <20211022183709.1199701-1-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 After creating a region, it will show up in sysfs /sys/bus/cxl/devices/ ├── decoder0.0 -> ../../../devices/platform/ACPI0017:00/root0/decoder0.0 ├── decoder1.0 -> ../../../devices/platform/ACPI0017:00/root0/port1/decoder1.0 ├── decoder2.0 -> ../../../devices/platform/ACPI0017:00/root0/port1/port2/decoder2.0 ├── mem0 -> ../../../devices/pci0000:34/0000:34:00.0/0000:35:00.0/mem0 ├── pmem0 -> ../../../devices/pci0000:34/0000:34:00.0/0000:35:00.0/mem0/pmem0 ├── port1 -> ../../../devices/platform/ACPI0017:00/root0/port1 ├── port2 -> ../../../devices/platform/ACPI0017:00/root0/port1/port2 └── root0 -> ../../../devices/platform/ACPI0017:00/root0 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/bus.c | 84 +++++++++++ drivers/cxl/core/region.c | 139 ++++++++++++++++++ drivers/cxl/cxl.h | 9 ++ drivers/cxl/region.h | 37 +++++ tools/testing/cxl/Kbuild | 1 + 8 files changed, 305 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 0b6a2e6e8fbb..5c48d2ed108f 100644 --- a/Documentation/ABI/testing/sysfs-bus-cxl +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -127,3 +127,26 @@ 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: June, 2021 +KernelVersion: v5.16 +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: June, 2021 +KernelVersion: v5.16 +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 d04d07ae7118..0ed00906acdd 100644 --- a/Documentation/driver-api/cxl/memory-devices.rst +++ b/Documentation/driver-api/cxl/memory-devices.rst @@ -65,6 +65,17 @@ 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 9d33d2d5bf09..6a3b3ecd7a25 100644 --- a/drivers/cxl/core/Makefile +++ b/drivers/cxl/core/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_CXL_BUS) += cxl_core.o ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl cxl_core-y := bus.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/bus.c b/drivers/cxl/core/bus.c index 4b4e6033b774..7a51a290ed25 100644 --- a/drivers/cxl/core/bus.c +++ b/drivers/cxl/core/bus.c @@ -157,6 +157,74 @@ static ssize_t target_list_show(struct device *dev, } static DEVICE_ATTR_RO(target_list); +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_decoder *cxld = to_cxl_decoder(dev); + int decoder, port, region_id; + struct cxl_region *region; + ssize_t rc; + + if (sscanf(buf, "region%d.%d:%d", &decoder, &port, ®ion_id) != 3) + return -EINVAL; + + if (decoder != cxld->id) + return -EINVAL; + + if (cxld->id != port) + 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; +} +static 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; +} +static DEVICE_ATTR_WO(delete_region); + static struct attribute *cxl_decoder_base_attrs[] = { &dev_attr_start.attr, &dev_attr_size.attr, @@ -170,6 +238,8 @@ 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, @@ -210,11 +280,23 @@ 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); } @@ -750,6 +832,8 @@ struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, else dev->type = &cxl_decoder_root_type; + 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..588f0ca65bb2 --- /dev/null +++ b/drivers/cxl/core/region.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2021 Intel Corporation. All rights reserved. */ +#include +#include +#include +#include +#include +#include +#include + +/** + * 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, +}; + +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 5823c267a4de..bcef2cb4e55b 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -220,6 +220,7 @@ 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 */ @@ -231,6 +232,7 @@ 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[]; }; @@ -305,6 +307,13 @@ struct cxl_dport { struct list_head root_port_link; }; +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); + struct cxl_port *to_cxl_port(struct device *dev); struct cxl_port *devm_cxl_add_port(struct device *uport, resource_size_t component_reg_phys, diff --git a/drivers/cxl/region.h b/drivers/cxl/region.h new file mode 100644 index 000000000000..d032df438832 --- /dev/null +++ b/drivers/cxl/region.h @@ -0,0 +1,37 @@ +/* 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: Address space consumed by this region. + * @size: Size of the region determined from LSA or userspace. + * @uuid: The UUID for this region. + * @eniw: Number of interleave ways this region is configured for. + * @ig: Interleave granularity of region + * @targets: The memory devices comprising the region. + */ +struct cxl_region { + struct device dev; + int id; + struct list_head list; + + struct { + struct resource *res; + u64 size; + uuid_t uuid; + int eniw; + int ig; + struct cxl_memdev *targets[CXL_DECODER_MAX_INTERLEAVE]; + }; +}; + +#endif diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild index 46db4dd345a0..3e5a1c4dce14 100644 --- a/tools/testing/cxl/Kbuild +++ b/tools/testing/cxl/Kbuild @@ -32,6 +32,7 @@ cxl_core-y += $(CXL_CORE_SRC)/regs.o 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)/region.o cxl_core-y += config_check.o cxl_core-y += mock_pmem.o