diff --git a/aws-proofs/README.md b/aws-proofs/README.md
index 2daced4c..486555b5 100644
--- a/aws-proofs/README.md
+++ b/aws-proofs/README.md
@@ -18,6 +18,7 @@ automatically spins up and terminates the corresponding AWS instance.
 - `L4V_FEATURES`: Optional kernel features to test. Either `MCS` or empty.
 - `L4V_PLAT`:    Platform variant to test (optional). Either a platform name or
                  unset.
+- `NUM_DOMAINS`: Optional override for the `KenrelNumDomains` config setting.
 - `session`:     which session to run (e.g. `CRefine` or `ASpec`, or `ASpec
                  CRefine`, i.e. a space-separated string). Runs all sessions if
                  unset.
diff --git a/aws-proofs/action.yml b/aws-proofs/action.yml
index 5fce2212..a5864cca 100644
--- a/aws-proofs/action.yml
+++ b/aws-proofs/action.yml
@@ -17,6 +17,9 @@ inputs:
   L4V_PLAT:
     description: 'Platform variant to test (optional). Either a platform name or unset.'
     required: false
+  NUM_DOMAINS:
+    description: 'Optional override for KernelNumDomains config setting.'
+    required: false
   session:
     description: 'Which proof session to run (space-separated string)'
     required: false
diff --git a/aws-proofs/steps.sh b/aws-proofs/steps.sh
index 3e4e0f7a..e6b42ef1 100755
--- a/aws-proofs/steps.sh
+++ b/aws-proofs/steps.sh
@@ -67,6 +67,7 @@ ssh -o SendEnv=INPUT_CI_BRANCH \
     -o SendEnv=INPUT_L4V_ARCH \
     -o SendEnv=INPUT_L4V_FEATURES \
     -o SendEnv=INPUT_L4V_PLAT \
+    -o SendEnv=INPUT_NUM_DOMAINS \
     -o SendEnv=INPUT_MANIFEST \
     -o SendEnv=INPUT_ISA_BRANCH \
     -o SendEnv=INPUT_SESSION \
diff --git a/aws-proofs/vm-steps.sh b/aws-proofs/vm-steps.sh
index 1a17ff97..efe3f0a1 100755
--- a/aws-proofs/vm-steps.sh
+++ b/aws-proofs/vm-steps.sh
@@ -58,7 +58,11 @@ isabelle/bin/isabelle components -a
 export L4V_ARCH=${INPUT_L4V_ARCH}
 export L4V_FEATURES=${INPUT_L4V_FEATURES}
 export L4V_PLAT=${INPUT_L4V_PLAT}
-L4V_ARCH_FEATURES="${L4V_ARCH}${L4V_FEATURES:+-${L4V_FEATURES}}${L4V_PLAT:+-${L4V_PLAT}}"
+
+FEATURES_STR=${L4V_FEATURES:+-${L4V_FEATURES}}
+PLAT_STR=${L4V_PLAT:+-${L4V_PLAT}}
+NUM_DOMAINS_STR=${INPUT_NUM_DOMAINS:+-${INPUT_NUM_DOMAINS}}
+L4V_ARCH_FEATURES="${L4V_ARCH}${FEATURES_STR}${PLAT_STR}${NUM_DOMAINS_STR}"
 
 CACHE_NAME=${INPUT_CACHE_NAME}
 if [ -z "${CACHE_NAME}" ]