Re: [PATCH v6 0/8] cxl: support CXL memory RAS features

[Dave Jiang <dave.jiang@intel.com>]

On 5/21/25 5:47 AM, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> Support for CXL memory EDAC features: patrol scrub, ECS, soft-PPR and
> memory sparing.
> 
> Detailed history of the complete EDAC series with CXL EDAC patches
> up to V20 [1] and this CXL specific series had separated from V20 of
> the above series.
> 
> The series is based on [2] v6.15-rc4 (based on comment from Dave
> in the thread [4]).
> 
> Also applied(no conflicts) and tested on cxl.git [3] branch: next
> 
> 1. https://lore.kernel.org/linux-cxl/20250212143654.1893-1-shiju.jose@huawei.com/
> 2. https://github.com/torvalds/linux.git
> 3. https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git
> 4. https://lore.kernel.org/all/d83a83d1-37e7-4192-913f-243098f679e3@intel.com/
> 
> Userspace code for CXL memory repair features [5] and
> sample boot-script for CXL memory repair [6].
> 
> [5]: https://lore.kernel.org/lkml/20250207143028.1865-1-shiju.jose@huawei.com/
> [6]: https://lore.kernel.org/lkml/20250207143028.1865-5-shiju.jose@huawei.com/

Applied to cxl/next

> 
> Changes
> =======
> v5 -> v6:
> 1. Fixed feedback from Randy Dunlap on CXL EDAC documentation.
> 
> 2. Feedback from Alison:
>   - Replace #ifdef using IS_ENABLED() in the series
>   - Fix for the kfree() oops in devm_cxl_memdev_edac_release()
>     while unloading cxl-test module. 
>   - Added separate helper functions for scrub set attributes for
>     dev scrub and region scrub.
>   - renaming to scrub_cycle and scrub_region_id.
>       
> 3. Feedback from Dave:
>   - Fix for the kfree() oops in devm_cxl_memdev_edac_release()
>     while unloading cxl-test module.
>   - Add cxl_test inclusion of edac.o
>   - Check return from cxl_feature_info() with IS_ERR in the series. 
>  
> 4. Rebased to linux.git [2] v6.15-rc4 (based on comment from Dave
> in the thread [4]).
>    
> v4 -> v5:
> 1. Fixed a compilation warning introduced by v3->v4, reported by Dave Jiang on v4. 
>    drivers/cxl/core/edac.c: In function ‘cxl_mem_perform_sparing’:
>    drivers/cxl/core/edac.c:1335:29: warning: the comparison will always evaluate as ‘true’ for the address of ‘validity_flags’ will never be NULL [-Waddress]
>  1335 |                         if (!rec->media_hdr.validity_flags)
>       |                             ^
>    In file included from ./drivers/cxl/cxlmem.h:10,
>                  from drivers/cxl/core/edac.c:21:
>    ./include/cxl/event.h:35:12: note: ‘validity_flags’ declared here
>    35 |         u8 validity_flags[2];
>       |            ^~~~~~~~~~~~~~
> 2. Updated patches for tags given.
> 
> v3 -> v4:
> 1. Feedback from Dave Jiang on v3,
> 1.1. Changes for comments in EDAC scrub documentation for CXL use cases.
>      https://lore.kernel.org/all/2df68c68-f1a8-4327-abc9-d265326c133d@intel.com/
> 1.2. Changes for comments in CXL memory sparing control feature.
>      https://lore.kernel.org/all/4ee3323c-fb27-4fbe-b032-78fd54bc21a0@intel.com/
>       
> v2 -> v3:
> 1. Feedback from Dan Williams on v2,
>    https://lore.kernel.org/linux-mm/20250320180450.539-1-shiju.jose@huawei.com/
>   - Modified get_support_feature_info() in fwctl series generic to use in
>     cxl/fxctl and cxl/edac and replace cxl_get_feature_entry() in the CXL edac
>     series.
>   - Add usecase note for CXL ECS in Documentation/edac/scrub.rst.
>   - Add info message when device scrub rate set by a region overwritten with a
>     local device scrub rate or another region's scrub rate.
>   - Replace 'ps' with patrol_scrub in the patrol scrub feature.
>   - Replaced usage of intermediate objects struct cxl_memdev_ps_params and
>     enum cxl_scrub_param etc for patrol scrub and did same for ECS.
>   - Rename CXL_MEMDEV_PS_* macros.
>   - Rename scrub_cycle_hrs-> scrub_cycle_hours
>   - Add if (!cxl_dev_name)
> 	return -ENOMEM;  to devm_cxl_memdev_edac_register()
>   - Add  devm_cxl_region_edac_register(cxlr) for CXL_PARTMODE_PMEM case.
>   - Add separate configurations for CXL scrub, ECS and memory repair
>     CXL_EDAC_SCRUB, CXL_EDAC_ECS and CXL_EDAC_MEM_REPAIR.
>   - Add 
>        if (!capable(CAP_SYS_RAWIO))
>              return -EPERM; for set attributes callbacks for CXL scrub, ECS and
>     memory repair.  	       
>   - In patch "cxl/mbox: Add support for PERFORM_MAINTENANCE mailbox command"
>     * cxl_do_maintenance() -> cxl_perform_maintenance() and moved to cxl/core/edac.c 
>     * kmalloc() -> kvzalloc()
>   - In patch, "cxl: Support for finding memory operation attributes from the current boot"  
>     * Moved code from drivers/cxl/core/ras.c to drivers/cxl/core/edac.c
>     * Add few logics to releasing the cache to give safety with respect to error storms and burning
>     * unlimited memory. 
>     * Add estimated memory overhead expense of this feature documented in the Kconfig.
>     * Unified various names such as attr, param, attrbs throughout the patches.
>     * Moved > struct xarray rec_gen_media and struct xarray rec_dram; out of struct cxl_memdev
>       to CXL edac object, but there is required a pointer to this object in struct cxl_memdev
>       because the error records are reported and thus stored in the cxl_memdev context not
>       in the CXL EDAC context.
>       
> 2. Feedback from Borislav on v2,
>   - In include/linux/edac.h 
>     Replace EDAC_PPR -> EDAC_REPAIR_PPR
>             EDAC_CACHELINE_SPARING -> EDAC_REPAIR_CACHELINE_SPARING etc.
> 
> v1 -> v2:
> 1. Feedback from Dan Williams on v1,
>    https://lore.kernel.org/linux-mm/20250307091137.00006a0a@huawei.com/T/
>   - Fixed lock issues in region scrubbing, added local cxl_acquire()
>     and cxl_unlock.
>   - Replaced CXL examples using cat and echo from EDAC .rst docs
>     with short description and ref to ABI docs. Also corrections
>     in existing descriptions as suggested by Dan.
>   - Add policy description for the scrub control feature.
>     However this may require inputs from CXL experts.
>   - Replaced CONFIG_CXL_RAS_FEATURES with CONFIG_CXL_EDAC_MEM_FEATURES.
>   - Few changes to depends part of CONFIG_CXL_EDAC_MEM_FEATURES.
>   - Rename drivers/cxl/core/memfeatures.c as drivers/cxl/core/edac.c
>   - snprintf() -> kasprintf() in few places.
> 
> 2. Feedback from Alison on v1,
>   - In cxl_get_feature_entry()(patch 1), return NULL on failures and
>     reintroduced checks in cxl_get_feature_entry().
>   - Changed logic in for loop in region based scrubbing code.
>   - Replace cxl_are_decoders_committed() to cxl_is_memdev_memory_online()
>     and add as a local function to drivers/cxl/core/edac.c
>   - Changed few multiline comments to single line comments.
>   - Removed unnecessary comments from the code.
>   - Reduced line length of few macros in ECS and memory repair code.
>   - In new files, changed "GPL-2.0-or-later" -> "GPL-2.0-only".
>   - Ran clang-format for new files and updated.                                                                                                                                          
> 3. Changes for feedbacks from Jonathan on v1.
>   - Changed few multiline comments to single line comments.
> 
> Shiju Jose (8):
>   EDAC: Update documentation for the CXL memory patrol scrub control
>     feature
>   cxl: Update prototype of function get_support_feature_info()
>   cxl/edac: Add CXL memory device patrol scrub control feature
>   cxl/edac: Add CXL memory device ECS control feature
>   cxl/edac: Add support for PERFORM_MAINTENANCE command
>   cxl/edac: Support for finding memory operation attributes from the
>     current boot
>   cxl/edac: Add CXL memory device memory sparing control feature
>   cxl/edac: Add CXL memory device soft PPR control feature
> 
>  Documentation/edac/memory_repair.rst |   31 +
>  Documentation/edac/scrub.rst         |   76 +
>  drivers/cxl/Kconfig                  |   71 +
>  drivers/cxl/core/Makefile            |    1 +
>  drivers/cxl/core/core.h              |    2 +
>  drivers/cxl/core/edac.c              | 2103 ++++++++++++++++++++++++++
>  drivers/cxl/core/features.c          |   17 +-
>  drivers/cxl/core/mbox.c              |   11 +-
>  drivers/cxl/core/memdev.c            |    1 +
>  drivers/cxl/core/region.c            |   10 +
>  drivers/cxl/cxl.h                    |   10 +
>  drivers/cxl/cxlmem.h                 |   30 +
>  drivers/cxl/mem.c                    |    4 +
>  drivers/edac/mem_repair.c            |    9 +
>  include/linux/edac.h                 |    7 +
>  tools/testing/cxl/Kbuild             |    1 +
>  16 files changed, 2372 insertions(+), 12 deletions(-)
>  create mode 100644 drivers/cxl/core/edac.c
>