[PATCH v3 0/9] Add RISC-V Worlds ISA support to OpenSBI

[Yu-Chien Peter Lin]

This patch series adds support for the RISC-V Worlds ISA extensions in
OpenSBI, introducing a WID-based hart protection backend to enforce
hardware isolation boundaries across domains.

Trust Model and Boot-time Roles
-------------------------------

The implementation adheres to the two-phase M-mode trust model:

- RoT M-mode phase: An earlier boot stage (e.g., ROM or SPL) may program
  mwid and mlwidlist, locking mwid prior to handing off execution to
  OpenSBI.

- Regular M-mode phase (OpenSBI): OpenSBI treats the non-ISA platform
  constraints (pmwid, pmwidlist, pmlwidlist) and CSR states (mwid,
  mlwidlist) as immutable input policies from the hardware/RoT. It locks
  mwid if still unlocked, preventing subsequent M-mode software from
  altering its own WID, and programs per-domain mlwid and mwiddeleg based
  on device tree configuration.

Device Tree Bindings
--------------------

Per-hart properties defined in Linux kernel DT bindings v3 [1]:
- riscv,pmwid: M-mode World ID
- riscv,pmwidlist: M-mode permitted WID bitmap
- riscv,pmlwidlist: S/U-mode permitted WID bitmap

Per-domain properties (see docs/domain_support.md):
- wid: World ID assigned to this domain for S/U-mode
- widdeleg: WID delegation bitmap for this domain

Changes since v2
----------------
- Make 'wid' property mandatory for all domains (including root) when
  Smlwid is implemented; reject misconfigured domains at boot.
- Remove M-mode WID fallback logic (mwid/pmwid) for S-mode domain WID.
- Validate domain wid and widdeleg against pmlwidlist and mlwidlist masks.
- Introduce a new patch to propagate error from sbi_hart_protection_reconfigure()
  in sbi_domain_context.
- Adapt to upstream domain state framework API rename (sbi_domain_data ->
  sbi_domain_state).
- Update documentation and boot log output accordingly.

[1] https://patchwork.kernel.org/project/linux-riscv/cover/20260812122131.1534906-1-peter.lin@sifive.com/

Yu-Chien Peter Lin (9):
  lib: sbi_hart: detect RISC-V Worlds ISA extensions
  lib: utils: fdt_helper: parse RISC-V Worlds per-hart WID properties
  lib: fdt_domain: parse domain WID properties
  lib: sbi_hart: lock mwid CSR for RoT immutability
  lib: sbi_domain_context: propagate error from
    sbi_hart_protection_reconfigure
  lib: sbi_hart_worlds: Implement WID hart protection backend
  include: sbi_types: add PRIx64 format macro
  lib: sbi: display World ID configuration at boot
  docs: document WID DT properties

 docs/domain_support.md             |  36 +++++
 include/sbi/riscv_encoding.h       |  12 ++
 include/sbi/sbi_domain.h           |   6 +
 include/sbi/sbi_hart.h             |  15 +++
 include/sbi/sbi_hart_worlds.h      |  24 ++++
 include/sbi/sbi_types.h            |   2 +
 include/sbi_utils/fdt/fdt_helper.h |   2 +
 lib/sbi/objects.mk                 |   1 +
 lib/sbi/sbi_domain.c               |  20 +++
 lib/sbi/sbi_domain_context.c       |   5 +-
 lib/sbi/sbi_hart.c                 |  38 ++++++
 lib/sbi/sbi_hart_worlds.c          | 210 +++++++++++++++++++++++++++++
 lib/sbi/sbi_init.c                 |  13 ++
 lib/utils/fdt/fdt_domain.c         |  84 ++++++++++++
 lib/utils/fdt/fdt_helper.c         |  90 +++++++++++++
 platform/generic/platform.c        |  13 +-
 16 files changed, 569 insertions(+), 2 deletions(-)
 create mode 100644 include/sbi/sbi_hart_worlds.h
 create mode 100644 lib/sbi/sbi_hart_worlds.c

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2.43.7