[ndctl PATCH v6 0/7] Add error injection support

Ben Cheatham
2026-01-09T16:07:32Z

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)

v4 Changes:
- Variable renames for clarity (Dave)
- Use errno instead of rc for access() calls (Dave)
- Check returns for snprintf() (Dave)
- Add util_cxl_dport_filter() (Dave)
- Replace printf() calls with log_info() (Dave)
- Write correct value to debugfs during protocol error injection
(BIT(error) vs. error)

v3 Changes:
- Rebase on v83 release
- Fix whitespace errors (Alison)

v2 Changes:
- Make the --clear option of 'inject-error' its own command (Alison)
- Debugfs is now found using the /proc/mount entry instead of
providing the path using a --debugfs option
- Man page added for 'clear-error'
- Reword commit descriptions for clarity

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. Errors are
injected using a new 'inject-error' command. Device poison can be
cleared using the 'clear-error' command. The 'inject-error' and
'clear-error' commands require access to the CXL driver's debugfs.

The documentation for the new cxl-inject-error command shows 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-error command
cxl: Add clear-error command
cxl/list: Add injectable errors in output
Documentation: Add docs for inject/clear-error commands

Documentation/cxl/cxl-clear-error.txt | 69 ++++++
Documentation/cxl/cxl-inject-error.txt | 161 ++++++++++++
Documentation/cxl/meson.build | 2 +
cxl/builtin.h | 2 +
cxl/cxl.c | 2 +
cxl/filter.c | 26 ++
cxl/filter.h | 2 +
cxl/inject-error.c | 248 +++++++++++++++++++
cxl/json.c | 38 +++
cxl/lib/libcxl.c | 330 +++++++++++++++++++++++++
cxl/lib/libcxl.sym | 10 +
cxl/lib/private.h | 14 ++
cxl/libcxl.h | 18 ++
cxl/meson.build | 1 +
14 files changed, 923 insertions(+)
create mode 100644 Documentation/cxl/cxl-clear-error.txt
create mode 100644 Documentation/cxl/cxl-inject-error.txt
create mode 100644 cxl/inject-error.c

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2.52.0