ci: add LMS sim feature combinations to test matrix

Cover sig-lms across the same swap/validate/multiimage/ram-load/
direct-xip/downgrade-prevention/hw-rollback-protection axes the
sig-ecdsa-psa mbedtls-v4 rows do, minus encryption — LMS+enc isn't
wired anywhere yet (see plan-lms.md). sig-lms auto-routes to the
mbedtls 4.x PSA build path via add_mbedtls_v4_psa_lms() in
build.rs, so no separate mbedtls-v4 feature is needed on these
rows.

Also extend sim_run.sh's --test-threads=1 guard to match lms and
mbedtls-v4. PSA's global state is only thread-safe with
MBEDTLS_THREADING_C, which our v4 configs don't enable; LMS
verification sits on psa_hash_* and inherits the constraint
regardless of feature label, and the simulator's external-RNG
stub uses libc rand() which is not thread-safe either.

Assisted-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: David Brown <david.brown@linaro.org>

Author: d3zd3z

.github/workflows/sim.yaml

@@ -68,6 +68,15 @@ jobs:
         # BOOT_ENC_KEY_SIZE. PSA_KEY_TYPE_AES covers all AES key
         # sizes so no config delta.
         - "sig-ecdsa-psa enc-aes256-ec256 mbedtls-v4,sig-ecdsa-psa enc-aes256-ec256 swap-offset validate-primary-slot max-align-16 mbedtls-v4"
+        # LMS post-quantum signatures. sig-lms auto-routes to the
+        # mbedtls 4.x PSA build path (see add_mbedtls_v4_psa_lms in
+        # build.rs) — no separate mbedtls-v4 feature needed. No
+        # encryption combos: LMS+enc isn't wired anywhere yet.
+        - "sig-lms,sig-lms swap-move,sig-lms swap-offset"
+        - "sig-lms validate-primary-slot,sig-lms overwrite-only,sig-lms multiimage"
+        - "sig-lms bootstrap max-align-16,sig-lms max-align-32"
+        - "sig-lms ram-load,sig-lms direct-xip"
+        - "sig-lms overwrite-only downgrade-prevention,sig-lms hw-rollback-protection multiimage"
         - "ram-load enc-aes256-kw multiimage"
         - "ram-load enc-aes256-kw sig-ecdsa-mbedtls multiimage"
     runs-on: ubuntu-latest

ci/sim_run.sh

@@ -44,10 +44,15 @@ if [[ ! -z $MULTI_FEATURES ]]; then
   IFS=','
   read -ra multi_features <<< "$MULTI_FEATURES"
 
-  # psa crypto tests require single thread mode
+  # PSA crypto's global state is only thread-safe when
+  # MBEDTLS_THREADING_C is enabled, which our v4 configs don't set.
+  # sig-lms inherits this constraint — mbedtls's LMS verifier sits on
+  # top of psa_hash_* — and the simulator's external-RNG stub uses
+  # libc rand() which is not thread-safe either. Force single-thread
+  # mode for any feature combination that touches the v4 PSA path.
   TEST_ARGS=''
   for features in "${multi_features[@]}"; do
-    if [[ $features =~ "psa" ]]; then
+    if [[ $features =~ "psa" || $features =~ "lms" || $features =~ "mbedtls-v4" ]]; then
         TEST_ARGS='--test-threads=1'
         break
     fi