diff --git a/.github/workflows/libcxx-build-and-test.yaml b/.github/workflows/libcxx-build-and-test.yaml
index 8c011425abfcf..0f4c6f53d6e8d 100644
--- a/.github/workflows/libcxx-build-and-test.yaml
+++ b/.github/workflows/libcxx-build-and-test.yaml
@@ -137,7 +137,7 @@ jobs:
           'generic-hardening-mode-fast',
           'generic-hardening-mode-fast-with-abi-breaks',
           'generic-merged',
-          'generic-modules-lsv',
+          'generic-modules-cxx17-lsv',
           'generic-no-exceptions',
           'generic-no-experimental',
           'generic-no-filesystem',
diff --git a/libcxx/cmake/caches/Generic-modules-cxx17-lsv.cmake b/libcxx/cmake/caches/Generic-modules-cxx17-lsv.cmake
new file mode 100644
index 0000000000000..c73e2a142092b
--- /dev/null
+++ b/libcxx/cmake/caches/Generic-modules-cxx17-lsv.cmake
@@ -0,0 +1,2 @@
+set(LIBCXX_TEST_PARAMS "enable_modules=clang-lsv;std=c++17" CACHE STRING "")
+set(LIBCXXABI_TEST_PARAMS "${LIBCXX_TEST_PARAMS}" CACHE STRING "")
diff --git a/libcxx/cmake/caches/Generic-modules-lsv.cmake b/libcxx/cmake/caches/Generic-modules-lsv.cmake
deleted file mode 100644
index 395fccc217650..0000000000000
--- a/libcxx/cmake/caches/Generic-modules-lsv.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-set(LIBCXX_TEST_PARAMS "enable_modules=clang-lsv" CACHE STRING "")
-set(LIBCXXABI_TEST_PARAMS "${LIBCXX_TEST_PARAMS}" CACHE STRING "")
diff --git a/libcxx/test/libcxx/atomics/atomics.syn/incompatible_with_stdatomic.verify.cpp b/libcxx/test/libcxx/atomics/atomics.syn/incompatible_with_stdatomic.verify.cpp
index ca092d9c60275..a788ea32dddc8 100644
--- a/libcxx/test/libcxx/atomics/atomics.syn/incompatible_with_stdatomic.verify.cpp
+++ b/libcxx/test/libcxx/atomics/atomics.syn/incompatible_with_stdatomic.verify.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: no-threads
 // REQUIRES: c++03 || c++11 || c++14 || c++17 || c++20
 
+// No diagnostic gets emitted when we build with modules.
+// XFAIL: clang-modules-build
+
 // This test ensures that we issue a reasonable diagnostic when including <atomic> after
 // <stdatomic.h> has been included. Before C++23, this otherwise leads to obscure errors
 // because <atomic> may try to redefine things defined by <stdatomic.h>.
diff --git a/libcxx/utils/ci/run-buildbot b/libcxx/utils/ci/run-buildbot
index 947932f3802a1..29eebd1f92189 100755
--- a/libcxx/utils/ci/run-buildbot
+++ b/libcxx/utils/ci/run-buildbot
@@ -454,9 +454,9 @@ generic-modules)
     check-runtimes
     check-abi-list
 ;;
-generic-modules-lsv)
+generic-modules-cxx17-lsv)
     clean
-    generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-modules-lsv.cmake"
+    generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-modules-cxx17-lsv.cmake"
     check-runtimes
     check-abi-list
 ;;
diff --git a/libcxx/utils/libcxx/test/params.py b/libcxx/utils/libcxx/test/params.py
index 93dc3a8be3f08..58ace0ba96e35 100644
--- a/libcxx/utils/libcxx/test/params.py
+++ b/libcxx/utils/libcxx/test/params.py
@@ -210,7 +210,8 @@ def getSuitableClangTidy(cfg):
         choices=["none", "clang", "clang-lsv"],
         type=str,
         help="Whether to build the test suite with modules enabled. "
-             "Select `clang` for Clang modules, and 'clang-lsv' for Clang modules with Local Submodule Visibility.",
+             "Select `clang` for Clang modules, and 'clang-lsv' for Clang modules with Local Submodule Visibility. "
+             "Note that in recent versions of Clang, using Clang modules with -std=c++20 and later implies LSV.",
         default="none",
         actions=lambda modules: filter(None, [
             AddFeature("clang-modules-build")           if modules in ("clang", "clang-lsv") else None,