[PATCH v2 0/3] firmware: coreboot: Support for System Management Interrupt (SMI) handling in coreboot payload (MM payload concept)

[Michal Gorlas <michal.gorlas@9elements.com>]

Hi,

This patchset adds support for MM payload when Linux is used as
coreboot's payload. The main idea is to delegate higher-level SMM
functions to the payload, limiting the coreboot's System Management
Mode (SMM) related responsibilities to the minimum of basic SMM setup [1]. This is
done by loading a blob with SMI handler to the shared buffer, from
which it is copied to SMRAM [2].

The MM payload is still in a Proof of Concept stage, and we are still
working on getting the patches needed for coreboot upstreamed, but I would
appreciate any feedback that you may have.

Thanks,
Michal

[1]: https://github.com/9elements/LinuxBootSMM/wiki/Proposed-design#current-design-approach---mm-payload
[2]: https://github.com/9elements/LinuxBootSMM/wiki/Proof-of-Concept-(PoC)

Changes in v2:
- merged mm_info into mm_loader
- removed mm_loader_exit in favour of allocating memory with devm_*()
- added forgotten "\n\t" in trigger_smi()
- added gitignore in mm_handler/
- added COREBOOT_PAYLOAD_MM dependency on x86
- error handling for mm_info struct
- error handling for shared_buffer
- removed whitespace changes in coreboot_table.h
- removed INFO level prints 

---
Michal Gorlas (3):
      firmware: coreboot: support for parsing SMM related  informations from coreboot tables
      firmware: coreboot: loader for Linux-owned SMI handler
      firmware: coreboot: Linux-owned SMI handler to be loaded by coreboot

 drivers/firmware/google/Kconfig                  |  12 +
 drivers/firmware/google/Makefile                 |  11 +
 drivers/firmware/google/coreboot_table.h         |  11 +
 drivers/firmware/google/mm_blob.S                |  20 +
 drivers/firmware/google/mm_handler/.gitignore    |   4 +
 drivers/firmware/google/mm_handler/Makefile      |  51 +++
 drivers/firmware/google/mm_handler/handler.lds.S |  46 ++
 drivers/firmware/google/mm_handler/mm_handler.S  | 510 +++++++++++++++++++++++
 drivers/firmware/google/mm_handler/mm_handler.h  |  21 +
 drivers/firmware/google/mm_handler/mm_header.S   |  19 +
 drivers/firmware/google/mm_loader.c              | 215 ++++++++++
 drivers/firmware/google/mm_payload.h             |  58 +++
 12 files changed, 978 insertions(+)
---
base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
change-id: 20250613-coreboot-payload-mm-6642bb42284a

Best regards,
-- 
Michal Gorlas <michal.gorlas@9elements.com>