diff --git a/build_opts/ARM_X86 b/build_opts/ARM_X86
new file mode 100644
index 0000000000..9f622c6211
--- /dev/null
+++ b/build_opts/ARM_X86
@@ -0,0 +1,6 @@
+BUILD_ISA=y
+USE_ARM_ISA=y
+USE_X86_ISA=y
+RUBY=y
+PROTOCOL="MESI_Two_Level"
+RUBY_PROTOCOL_MESI_Two_Level=y
diff --git a/configs/learning_gem5/part3/test_caches.py b/configs/learning_gem5/part3/test_caches.py
index c987551377..32df2ba236 100644
--- a/configs/learning_gem5/part3/test_caches.py
+++ b/configs/learning_gem5/part3/test_caches.py
@@ -47,7 +47,7 @@ from m5.util import fatal
 
 class TestCacheSystem(RubySystem):
     def __init__(self):
-        if buildEnv["PROTOCOL"] != "MSI":
+        if not "RUBY_PROTOCOL_MSI" in buildEnv:
             fatal("This system assumes MSI from learning gem5!")
 
         super().__init__()
diff --git a/ext/testlib/configuration.py b/ext/testlib/configuration.py
index 92a9df85f0..ed0f6550d4 100644
--- a/ext/testlib/configuration.py
+++ b/ext/testlib/configuration.py
@@ -255,6 +255,9 @@ def define_constants(constants):
     constants.all_compiled_tag = "ALL"
     constants.null_all_ruby = "NULL_All_Ruby"
 
+    # Need this build in order to run the fs/linux/arm testlib tests.
+    constants.arm_x86_tag = "ARM_X86"
+
     constants.variant_tag_type = "variant"
     constants.opt_tag = "opt"
     constants.debug_tag = "debug"
diff --git a/tests/gem5/fs/linux/arm/test.py b/tests/gem5/fs/linux/arm/test.py
index 6cceea0e37..067ab6e055 100644
--- a/tests/gem5/fs/linux/arm/test.py
+++ b/tests/gem5/fs/linux/arm/test.py
@@ -169,7 +169,7 @@ for name in arm_fs_long_tests:
         verifiers=verifier_list(name),  # TODO: Add basic stat verifiers
         config=joinpath(filepath, "run.py"),
         config_args=args,
-        valid_isas=(constants.all_compiled_tag,),
+        valid_isas=(constants.arm_x86_tag,),
         length=constants.long_tag,
         fixtures=(arm_fs_binaries,),
         uses_kvm=name in arm_fs_kvm_tests,
diff --git a/tests/gem5/learning_gem5/part3_test.py b/tests/gem5/learning_gem5/part3_test.py
index 668f57dc25..48863ad97f 100644
--- a/tests/gem5/learning_gem5/part3_test.py
+++ b/tests/gem5/learning_gem5/part3_test.py
@@ -38,7 +38,6 @@ gem5_verify_config(
     verifiers=(verifier.MatchStdoutNoPerf(joinpath(ref_path, "threads")),),
     config=joinpath(config_path, "simple_ruby.py"),
     config_args=[],
-    protocol="MSI",
     # Currently only x86 has the threads test
     valid_isas=(constants.all_compiled_tag,),
     # dynamically linked
@@ -51,7 +50,6 @@ gem5_verify_config(
     verifiers=(verifier.MatchStdout(joinpath(ref_path, "test")),),
     config=joinpath(config_path, "ruby_test.py"),
     config_args=[],
-    protocol="MSI",
     # Currently only x86 has the threads test
     valid_isas=(constants.all_compiled_tag,),
     length=constants.long_tag,