[ndctl PATCH v8 0/7] Add error injection support

Ben Cheatham
2026-02-06T21:50:25Z

v8 Changes:
- Split inject-error command into 'inject-protocol-error', 'inject-media-poison' (Vishal, Alison)
- Rename 'cxl-clear-error' command to 'cxl-clear-media-poison' (Alison)
- Documentation rework to reflect new commands
- Cleaned up a few error prints
- Updated help messages
- Change "clear" param of poison_action() to "inj" and reverse usage accordingly
- Change cxl_memdev_has_poison_injection() to cxl_memdev_has_poison_support()
- Used in poison_action() (cxl/inject-error.c) to report missing functionality
more accurately
- Print usage when '-a' option is missing for media-poison commands
- Remove checking if '-a' option is empty in poison_action() (no longer needed)
- Allow clearing poison when 'inject_poison' file is missing in debugfs (and vice versa)
- Updated cover letter and commit messages

v7 Changes:
- Use PATH_MAX instead of strlen(ctx->cxl_debugfs) for debugfs paths (Dave)
- Add goto for error paths to memdev poison functions in patch 3/7 (Dave)
- Add Dave's Reviewed-by tags

v6 Changes:
- Rebase to pending branch (Alison)
- Drop const for ctx->debugfs (Alison)
- Rename get_debugfs_dir() to get_cxl_debugfs_dir() and return cxl directory in debugfs
(i.e. "/sys/kernel/debug" -> "/sys/kernel/debug/cxl")
- Rename ctx->debugfs to ctx->cxl_debugfs
- Fix missing free of einj path (Alison)
- Add protocol errors in order to perrors list (Alison)
- Use hex constants instead of BIT() for protocol errors (Alison)
- Add symbols to LIBCXL_11 instead of LIBCXL_10 (Alison)
- Update commit message to reflect util_cxl_dport_filter() behavior (Alison)
- Remove EINJ_TYPES_BUF_SIZE #ifdef (Alison)
- Fix type mismatch of addr in poison_action() (Alison)
- Fix inject_action() to catch missing 'type' option (Alison)
- Remove '-N' option and show the information behind that option by default when
CXL debugfs is present (Alison)
- Add 'protocol_injectable' attribute for dports (Alison)
- Update inject-error man page with port injection example (Alison)
- Add warning to inject-error man page (Alison)

v5 Changes:
- Use setmntent()/getmntent() instead of open-coding getting the
debugfs path (Dave)
- Use correct return code for sysfs_read_attr() (Dave)

This series adds support for injecting CXL protocol (CXL.cache/mem)
errors[1] into CXL RCH Downstream ports and VH root ports[2] and
poison into CXL memory devices through the CXL debugfs. Protocol errors
are injected using a new 'inject-protocol-error' command. Device poison
can be injected and cleared using the 'inject-media-poison' and
'clear-media-poison' commands, respectively. All three commands require
access to the CXL driver's debugfs.

The documentation for the new commands show both usage and the possible
device/error types, as well as how to retrieve them using cxl-list. cxl-list
has been updated to include the possible error types for protocol error
injection (under the "bus" object) and which CXL dports and memory devices
support injection.

[1]: ACPI v6.5 spec, section 18.6.4
[2]: ACPI v6.5 spec, table 18.31

Ben Cheatham (7):
libcxl: Add debugfs path to CXL context
libcxl: Add CXL protocol errors
libcxl: Add poison injection support
cxl: Add inject-protocol-error command
cxl: Add poison injection/clear commands
cxl/list: Add injectable errors in output
Documentation: Add docs for protocol and poison injection commands

Documentation/cxl/cxl-clear-media-poison.txt | 85 +++++
Documentation/cxl/cxl-inject-media-poison.txt | 85 +++++
.../cxl/cxl-inject-protocol-error.txt | 105 ++++++
Documentation/cxl/meson.build | 3 +
cxl/builtin.h | 3 +
cxl/cxl.c | 3 +
cxl/filter.c | 26 ++
cxl/filter.h | 2 +
cxl/inject-error.c | 312 +++++++++++++++++
cxl/json.c | 38 ++
cxl/lib/libcxl.c | 329 ++++++++++++++++++
cxl/lib/libcxl.sym | 10 +
cxl/lib/private.h | 14 +
cxl/libcxl.h | 18 +
cxl/meson.build | 1 +
15 files changed, 1034 insertions(+)
create mode 100644 Documentation/cxl/cxl-clear-media-poison.txt
create mode 100644 Documentation/cxl/cxl-inject-media-poison.txt
create mode 100644 Documentation/cxl/cxl-inject-protocol-error.txt
create mode 100644 cxl/inject-error.c

base-commit: 39085f76b6a9d3ac349c3c5dab1cb820c86a293d
--
2.52.0