From patchwork Fri Jul 15 00:00:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 12918543 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 456116035 for ; Fri, 15 Jul 2022 00:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657843243; x=1689379243; h=subject:from:to:cc:date:message-id:mime-version: content-transfer-encoding; bh=/igNN+MI/KQRdqq25+CgroKlBSV1jxojTVQDW5IfuHk=; b=g+o6WMeZuqMfgOE3lJAAKEaln+IRz9XpKalZahfDGkyPIf7+dg6eLu89 MnXPMIdvOkR+7xXRpLiLg4e7qtJatTduaGIeFFRirVeOEhL7Sk7wFTPHa EeoMYp/ZITSn2sM2KNILW5OtFtwunrhKG2XP4WIsiBLKZw6vpx0gmxAsX XTl4+ShKvi3KqFzYd3tvuwm5qlK3mXVq8MFv9Qg2kZpuAZHrOj8CgPox5 zXXtA04qxWPRHUpJLHgNeyweqgMlZar1DIbwMH4R7KlZsN8J7edlsi/7/ tcgmvgSuJW9nNdMSwfCj/kzfV+6G4HhJh6NWBLvbd9j+i9H9F/UFArmF9 A==; X-IronPort-AV: E=McAfee;i="6400,9594,10408"; a="347338748" X-IronPort-AV: E=Sophos;i="5.92,272,1650956400"; d="scan'208";a="347338748" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2022 17:00:42 -0700 X-IronPort-AV: E=Sophos;i="5.92,272,1650956400"; d="scan'208";a="923289979" Received: from jlcone-mobl1.amr.corp.intel.com (HELO dwillia2-xfh.jf.intel.com) ([10.209.2.90]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2022 17:00:41 -0700 Subject: [PATCH v2 00/28] CXL PMEM Region Provisioning From: Dan Williams To: linux-cxl@vger.kernel.org Cc: David Hildenbrand , Tony Luck , Jason Gunthorpe , Ben Widawsky , Jonathan Cameron , Christoph Hellwig , Greg Kroah-Hartman , Matthew Wilcox , Andrew Morton , nvdimm@lists.linux.dev, linux-pci@vger.kernel.org Date: Thu, 14 Jul 2022 17:00:41 -0700 Message-ID: <165784324066.1758207.15025479284039479071.stgit@dwillia2-xfh.jf.intel.com> User-Agent: StGit/0.18-3-g996c Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Changes since v1 [1]: - Move 19 patches that have received a Reviewed-by to the 'pending' branch in cxl.git (Thanks Alison, Adam, and Jonathan!) - Improve the changelog and add more Cc's to "cxl/acpi: Track CXL resources in iomem_resource" and highlight the new export of insert_resource_expand_to_fit() - Switch all occurrences of the pattern "rc = -ECODE; if (condition) goto err;" to "if (condition) { rc = -ECODE; goto err; }" (Jonathan) - Re-organize all the cxl_{root,switch,endpoint}_decoder() patches to move the decoder-type-specific setup into the decoder-type-specific allocation routines (Jonathan) - Add kdoc to clarify the behavior of add_cxl_resources() (Jonathan) - Add IORES_DESC_CXL for kernel components like EDAC to determine when they might be dealing with a CXL address range (Tony) - Drop usage of dev_set_drvdata() for passing @cxl_res (Jonathan) - Drop @remove_action argument to __cxl_dpa_release(), make it behave like any other devm_ helper (Jonathan) - Clarify 'skip' vs 'skipped' in DPA handling helpers (Jonathan) - Clarify why port teardown no proceeds under the lock with the conversion from list to xarray (Jonathan) - Revert rename of cxl_find_dport_by_dev() (Jonathan) - Fold down_read() / up_write() mismatch fix to the patch that introduced the problem (Jonathan) - Fix description of interleave_ways and interleave_granularity in the sysfs ABI document - Clarify tangential cleanups in "resource: Introduce alloc_free_mem_region()" (Jonathan) - Clarify rationale for the region creation / naming ABI (Jonathan) - Add SET_CXL_REGION_ATTR() to supplement CXL_REGION_ATTR() the former is used to optionally added region attributes to an attribute list (position independent) and the latter is used to retrieve a pointer to the attribute in code. (Jonathan) - For writes to region attributes allow the same value to be written multiple times without error (Jonathan) - Clarify the actions performed by cxl_port_attach_region() (Jonathan) - Commit message spelling fixes (Alison and Jonathan) - Rename cxl_dpa_resource() => cxl_dpa_resource_start() (Jonathan) - Reword error message in cxl_parse_cfmws() (Adam) - Keep @expected_len signed in cxl_acpi_cfmws_verify() (Jonathan) - Miscellaneous formatting and doc fixes (Jonathan) - Rename port->dpa_end port->hdm_end (Jonathan) - Rename unregister_region() => unregister_nvdimm_region() (Jonathan) [1]: https://lore.kernel.org/linux-cxl/165603869943.551046.3498980330327696732.stgit@dwillia2-xfh Reported-by: Peter Maydell Signed-off-by: Jonathan Cameron --- Until the CXL 2.0 definition arrived there was little reason for OS drivers to care about CXL memory expanders. Similar to DDR they just implemented a physical address range that was described to the OS by platform firmware (EFI Memory Map + ACPI SRAT/SLIT/HMAT etc). The CXL 2.0 definition adds support for PMEM, hotplug, switch topologies, and device-interleaving which exceeds the limits of what can be reasonably abstracted by EFI + ACPI mechanisms. As a result, Linux needs a native capability to provision new CXL regions. The term "region" is the same term that originated in the LIBNVDIMM implementation to describe a host physical / system physical address range. For PMEM a region is a persistent memory range that can be further sub-divided into namespaces. For CXL there are three classifications of regions: - PMEM: set up by CXL native tooling and persisted in CXL region labels - RAM: set up dynamically by CXL native tooling after hotplug events, or leftover capacity not mapped by platform firmware. Any persistent configuration would come from set up scripts / configuration files in userspace. - System RAM: set up by platform firmware and described by EFI + ACPI metadata, these regions are static. For now, these patches implement just PMEM regions without region label support. Note though that the infrastructure routines like cxl_region_attach() and cxl_region_setup_targets() are building blocks for region-label support, provisioning RAM regions, and enumerating System RAM regions. The general flow for provisioning a CXL region is to: - Find a device or set of devices with available device-physical-address (DPA) capacity - Find a platform CXL window that has free capacity to map a new region and that is able to target the devices in the previous step. - Allocate DPA according to the CXL specification rules of sequential enabling of decoders by id and when a device hosts multiple decoders make sure that lower-id decoders map lower HPA and higher-id decoders map higher HPA. - Assign endpoint decoders to a region and validate that the switching topology supports the requested configuration. Recall that interleaving is governed by modulo or xormap math that constrains which device can support which positions in a given region interleave. - Program all the decoders an all endpoints and participating switches to bring the new address range online. Once the range is online then existing drivers like LIBNVDIMM or device-dax can manage the memory range as if the ACPI BIOS had conveyed its parameters at boot. This patch kit is the result of significant amounts of path finding work [2] and long discussions with Ben. Thank you Ben for all that work! Where the patches in this kit go in a different design direction than the RFC, the authorship is changed and a Co-developed-by is added mainly so I get blamed for the bad decisions and not Ben. The major updates from that last posting are: - all CXL resources are reflected in full in iomem_resource - host-physical-address (HPA) range allocation moves to a devm_request_free_mem_region() derivative - locking moves to two global rwsems, one for DPA / endpoint decoders and one for HPA / regions. - the existing port scanning path is augmented to cache more topology information rather than recreate it at region creation time [2]: https://lore.kernel.org/r/20220413183720.2444089-1-ben.widawsky@intel.com --- Ben Widawsky (4): cxl/hdm: Add sysfs attributes for interleave ways + granularity cxl/region: Add region creation support cxl/region: Add a 'uuid' attribute cxl/region: Add interleave geometry attributes Dan Williams (24): Documentation/cxl: Use a double line break between entries cxl/core: Define a 'struct cxl_switch_decoder' cxl/acpi: Track CXL resources in iomem_resource cxl/core: Define a 'struct cxl_root_decoder' cxl/core: Define a 'struct cxl_endpoint_decoder' cxl/hdm: Enumerate allocated DPA cxl/hdm: Add 'mode' attribute to decoder objects cxl/hdm: Track next decoder to allocate cxl/hdm: Add support for allocating DPA to an endpoint decoder cxl/port: Record dport in endpoint references cxl/port: Record parent dport when adding ports cxl/port: Move 'cxl_ep' references to an xarray per port cxl/port: Move dport tracking to an xarray cxl/mem: Enumerate port targets before adding endpoints resource: Introduce alloc_free_mem_region() cxl/region: Allocate HPA capacity to regions cxl/region: Enable the assignment of endpoint decoders to regions cxl/acpi: Add a host-bridge index lookup mechanism cxl/region: Attach endpoint decoders cxl/region: Program target lists cxl/hdm: Commit decoder state to hardware cxl/region: Add region driver boiler plate cxl/pmem: Fix offline_nvdimm_bus() to offline by bridge cxl/region: Introduce cxl_pmem_region objects Documentation/ABI/testing/sysfs-bus-cxl | 213 +++ Documentation/driver-api/cxl/memory-devices.rst | 11 drivers/cxl/Kconfig | 8 drivers/cxl/acpi.c | 185 ++ drivers/cxl/core/Makefile | 1 drivers/cxl/core/core.h | 49 + drivers/cxl/core/hdm.c | 623 +++++++- drivers/cxl/core/pmem.c | 4 drivers/cxl/core/port.c | 669 ++++++-- drivers/cxl/core/region.c | 1830 +++++++++++++++++++++++ drivers/cxl/cxl.h | 263 +++ drivers/cxl/cxlmem.h | 18 drivers/cxl/mem.c | 32 drivers/cxl/pmem.c | 259 +++ drivers/nvdimm/region_devs.c | 28 include/linux/ioport.h | 3 include/linux/libnvdimm.h | 5 kernel/resource.c | 185 ++ mm/Kconfig | 5 tools/testing/cxl/Kbuild | 1 tools/testing/cxl/test/cxl.c | 75 + 21 files changed, 4156 insertions(+), 311 deletions(-) create mode 100644 drivers/cxl/core/region.c base-commit: b060edfd8cdd52bc8648392500bf152a8dd6d4c5