diff --git a/pycheribuild/projects/cross/libcxx.py b/pycheribuild/projects/cross/libcxx.py
index 935197eb3..1515d4a80 100644
--- a/pycheribuild/projects/cross/libcxx.py
+++ b/pycheribuild/projects/cross/libcxx.py
@@ -401,6 +401,11 @@ def setup(self):
 
             if external_cxxabi is not None:
                 self.add_cmake_options(LIBCXX_CXX_ABI=external_cxxabi)
+                if not self.compiling_for_host():
+                    self.add_cmake_options(
+                        LIBCXX_CXX_ABI_INCLUDE_PATHS=self.sdk_sysroot / "usr/include/c++/v1/",
+                        LIBCXX_CXX_ABI_LIBRARY_PATH=self.sdk_sysroot / "usr" / self.target_info.default_libdir,
+                    )
                 # LIBCXX_ENABLE_ABI_LINKER_SCRIPT is needed if we use libcxxrt/system libc++abi in the tests
                 self.add_cmake_options(LIBCXX_ENABLE_STATIC_ABI_LIBRARY=False, LIBCXX_ENABLE_ABI_LINKER_SCRIPT=True)
             else:
@@ -428,15 +433,28 @@ def setup(self):
             self.add_cmake_options(UNIX=1)
             self.COMMON_FLAGS.append("-D_GNU_SOURCE=1")  # strtoll_l is guarded by __GNU_VISIBLE
 
-        if self.test_localhost_via_ssh:
+        test_executor = None
+        if not self.compiling_for_host():
+            if self._have_compile_only_executor():
+                # The compile_only executor does not exist for upstream (yet)
+                test_executor = self.commandline_to_str([self.source_dir / "../libcxx/utils/compile_only.py"])
+        elif self.test_localhost_via_ssh:
             ssh_host = self.config.get_user_name() + "@" + platform.node()
-            self.add_cmake_options(LIBCXX_EXECUTOR=self.commandline_to_str(
-                [self.source_dir / "../libcxx/utils/ssh.py", "--host", ssh_host]))
-
+            test_executor = self.commandline_to_str([self.source_dir / "../libcxx/utils/ssh.py", "--host", ssh_host])
+        if test_executor:
+            self.set_cmake_flag_for_each_runtime(EXECUTOR=test_executor)
         # The cheribuild default RPATH settings break the linker script (but should also be unnecessary without it).
         self.add_cmake_options(CMAKE_INSTALL_RPATH_USE_LINK_PATH=False, CMAKE_BUILD_RPATH_USE_ORIGIN=False,
                                CMAKE_INSTALL_RPATH="", _replace=True)
 
+    def _have_compile_only_executor(self):
+        # The compile_only executor does not exist upstream (yet).
+        return self.llvm_project is BuildCheriLLVM
+
+    def set_cmake_flag_for_each_runtime(self, **kwargs):
+        flags = {f"{x.upper()}_{k}": v for x in self.get_enabled_runtimes() for k, v in kwargs.items()}
+        self.add_cmake_options(**flags)
+
     @classmethod
     def setup_config_options(cls, **kwargs):
         super().setup_config_options(**kwargs)
@@ -445,18 +463,38 @@ def setup_config_options(cls, **kwargs):
                                                               "it works correctly)")
 
     def run_tests(self):
-        if self.compiling_for_host() or self.target_info.is_baremetal():
-            # Without setting LC_ALL lit attempts to encode some things as ASCII and fails.
-            # This only happens on FreeBSD, but we might as well set it everywhere
+        # Without setting LC_ALL lit attempts to encode some things as ASCII and fails.
+        # This only happens on FreeBSD, but we might as well set it everywhere
+        if self.compiling_for_host() or self._have_compile_only_executor():
             with self.set_env(LC_ALL="en_US.UTF-8", FILECHECK_DUMP_INPUT_ON_FAILURE=1):
                 self.run_cmd("cmake", "--build", self.build_dir, "--target", "check-runtimes")
-                return
-        elif self.can_run_binaries_on_remote_morello_board():
-            executor = [self.source_dir / "utils/ssh.py", "--host", self.config.remote_morello_board]
-            # The Morello board has 4 CPUs, so run 4 tests in parallel.
-            self.run_cmd([sys.executable, self.build_dir / "bin/llvm-lit", "-j4", "-vv",
-                          f"--xunit-xml-output={self.build_dir / 'test-results.xml'}",
-                          "-Dexecutor=" + self.commandline_to_str(executor), "test"], cwd=self.build_dir)
+
+        if self.target_info.is_cheribsd() and not self.compiling_for_host():
+            if self.can_run_binaries_on_remote_morello_board():
+                executor = [self.source_dir / "utils/ssh.py", "--host", self.config.remote_morello_board]
+                # The Morello board has 4 CPUs, so run 4 tests in parallel.
+                self.run_cmd(
+                    [
+                        sys.executable,
+                        self.build_dir / "bin/llvm-lit",
+                        "-j4",
+                        "-vv",
+                        f"--xunit-xml-output={self.build_dir / 'test-results.xml'}",
+                        "-Dexecutor=" + self.commandline_to_str(executor),
+                        "--param",
+                        "executor=" + self.commandline_to_str(executor),
+                        *[f"runtimes/{d}" for d in self.get_enabled_runtimes()],
+                    ],
+                    cwd=self.build_dir,
+                )
+            if "libunwind" in self.get_enabled_runtimes():
+                self.target_info.run_cheribsd_test_script(
+                    "run_libunwind_tests.py",
+                    "--lit-debug-output",
+                    "--ssh-executor-script",
+                    self.source_dir / "../libcxx/utils/ssh.py",
+                    mount_sysroot=True,
+                )
 
 
 class BuildLlvmLibs(_BuildLlvmRuntimes):
@@ -476,18 +514,6 @@ class BuildLibunwind(_BuildLlvmRuntimes):
     default_build_type = BuildType.DEBUG
     _enabled_runtimes: "typing.ClassVar[tuple[str, ...]]" = ("libunwind",)
 
-    def run_tests(self) -> None:
-        if self.target_info.is_cheribsd() and not self.compiling_for_host():
-            self.target_info.run_cheribsd_test_script(
-                "run_libunwind_tests.py",
-                "--lit-debug-output",
-                "--ssh-executor-script",
-                self.source_dir / "../libcxx/utils/ssh.py",
-                mount_sysroot=True,
-            )
-        else:
-            super().run_tests()
-
 
 class BuildUpstreamLlvmLibs(_BuildLlvmRuntimes):
     target = "upstream-llvm-libs"