[v7,0/4] hw/cxl: Poison get, inject, clear

Message

Jonathan Cameron May 22, 2023, 2:50 p.m. UTC

Whilst the discussion on naming of the 24 bit bswap is perhaps ongoing, this
version makes the assumption that we'll keep it as originally proposed.
I'm rushing it out a little because I want to send the events series on
top of it so that I can get feedback on the updated docs.

v7:
- Dropped assert in 24 bit bswap
- Added regex to the loads-stores.rst doc
- Reformated the QMP as suggested by Markus
- Used define in place of bare 64.

Precursors now all upstream which make this email easier to write :)

The kernel support for Poison handling is now upstream.

This code has been very useful for testing and helped identify various
corner cases.

Updated cover letter.

The series supports:
1) Injection of variable length poison regions via QMP (to fake real
   memory corruption and ensure we deal with odd overflow corner cases
   such as clearing the middle of a large region making the list overflow
   as we go from one long entry to two smaller entries.
2) Read of poison list via the CXL mailbox.
3) Injection via the poison injection mailbox command (limited to 64 byte
   entries - spec constraint)
4) Clearing of poison injected via either method.

The implementation is meant to be a valid combination of impdef choices
based on what the spec allowed. There are a number of places where it could
be made more sophisticated that we might consider in future:
* Fusing adjacent poison entries if the types match.
* Separate injection list and main poison list, to test out limits on
  injected poison list being smaller than the main list.
* Poison list overflow event (needs event log support in general)
* Connecting up to the poison list error record generation (rather complex
  and not needed for currently kernel handling testing).
* Triggering the synchronous and asynchronous errors that occur on reads
  and writes of the memory when the host receives poison.

As the kernel code is currently fairly simple, it is likely that the above
does not yet matter but who knows what will turn up in future!


Ira Weiny (1):
  bswap: Add the ability to store to an unaligned 24 bit field

Jonathan Cameron (3):
  hw/cxl: QMP based poison injection support
  hw/cxl: Add poison injection via the mailbox.
  hw/cxl: Add clear poison mailbox command support.

 docs/devel/loads-stores.rst |   2 +
 qapi/cxl.json               |  21 ++++
 include/hw/cxl/cxl.h        |   1 +
 include/hw/cxl/cxl_device.h |  21 ++++
 include/qemu/bswap.h        |  25 +++++
 hw/cxl/cxl-mailbox-utils.c  | 214 ++++++++++++++++++++++++++++++++++++
 hw/mem/cxl_type3.c          |  93 ++++++++++++++++
 hw/mem/cxl_type3_stubs.c    |   6 +
 8 files changed, 383 insertions(+)