diff --git a/libcxx/cmake/caches/Generic-msan.cmake b/libcxx/cmake/caches/Generic-msan.cmake
index 9e50255fe4ff6..a8fbd285a9adf 100644
--- a/libcxx/cmake/caches/Generic-msan.cmake
+++ b/libcxx/cmake/caches/Generic-msan.cmake
@@ -1,2 +1,4 @@
 set(LLVM_USE_SANITIZER "MemoryWithOrigins" CACHE STRING "")
+set(LIBCXX_TEST_PARAMS "long_tests=False" CACHE STRING "") # MSAN is really slow and tests can sometimes timeout otherwise
+set(LIBCXXABI_TEST_PARAMS "${LIBCXX_TEST_PARAMS}" CACHE STRING "")
 set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # MSAN is compiled against the system unwinder, which leads to false positives
diff --git a/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/get_info.local_time.pass.cpp b/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/get_info.local_time.pass.cpp
index ec3e490c0ed79..d424b41673b14 100644
--- a/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/get_info.local_time.pass.cpp
+++ b/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/get_info.local_time.pass.cpp
@@ -8,11 +8,10 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-filesystem, no-localization, no-tzdb
+// REQUIRES: long_tests
 
 // XFAIL: libcpp-has-no-experimental-tzdb
 // XFAIL: availability-tzdb-missing
-// Times out under HWASan
-// UNSUPPORTED: hwasan
 
 // <chrono>
 
diff --git a/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/sys_info.zdump.pass.cpp b/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/sys_info.zdump.pass.cpp
index 50b7bdb568d43..207f8e4df4541 100644
--- a/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/sys_info.zdump.pass.cpp
+++ b/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/sys_info.zdump.pass.cpp
@@ -8,6 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-filesystem, no-localization, no-tzdb, has-no-zdump
+// REQUIRES: long_tests
 
 // XFAIL: libcpp-has-no-experimental-tzdb
 // XFAIL: availability-tzdb-missing