The CXL subsystem in QEMU currently has no trace coverage: hw/cxl/
does not have its own trace-events file, and there are no trace_*()
calls across hw/cxl/ or hw/mem/cxl_type3.c. Debugging mailbox
commands, HDM decoder programming, CDAT ingestion, event log
activity, and CFMWS address decoding currently relies on temporary
printf instrumentation or qemu_log_mask output. Trace events offer a
more structured mechanism for observing these paths during
development.

This series introduces trace-events infrastructure for the CXL
subsystem and adds 12 trace points covering the paths listed above.
The events all use the cxl_ prefix so a single -trace 'cxl_*'
captures everything. The two cxl_hdm_decoder_* events live in the
existing hw/mem/trace-events alongside the file they trace
(hw/mem/cxl_type3.c); the cxl_ prefix preserves the unified
filtering UX.

Each patch is independent and corresponds to a self-contained debug
scenario:

  1/3 trace infrastructure + mailbox dispatch
      - cxl_mailbox_command, cxl_mailbox_invalid_payload,
        cxl_mailbox_handler_return

  2/3 HDM decoder commit + CDAT load
      - cxl_hdm_decoder_write, cxl_hdm_decoder_commit,
        cxl_cdat_init, cxl_cdat_loaded

  3/3 event log + CFMWS HPA -> device decoding
      - cxl_event_insert, cxl_event_overflow, cxl_event_clear
      - cxl_cfmws_lookup, cxl_cfmws_target_resolved

Junjie Cao (3):
  hw/cxl: add trace-events for mailbox dispatch
  hw/cxl: trace HDM decoder commit and CDAT load
  hw/cxl: trace event log activity and CFMWS address decoding

 hw/cxl/cxl-cdat.c          |  3 +++
 hw/cxl/cxl-events.c        |  8 +++++++-
 hw/cxl/cxl-host.c          |  4 ++++
 hw/cxl/cxl-mailbox-utils.c |  5 +++++
 hw/cxl/trace-events        | 21 +++++++++++++++++++++
 hw/cxl/trace.h             |  4 ++++
 hw/mem/cxl_type3.c         | 17 ++++++++++++++++-
 hw/mem/trace-events        |  4 ++++
 meson.build                |  1 +
 9 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 hw/cxl/trace-events
 create mode 100644 hw/cxl/trace.h


base-commit: 5611a9268dae7b7ff99d478ed134052a9fc7e9f7
--
2.43.0