diff --git a/inc/usersim/ex.h b/inc/usersim/ex.h
index d5a7f7d..4ba1e38 100644
--- a/inc/usersim/ex.h
+++ b/inc/usersim/ex.h
@@ -36,8 +36,12 @@ typedef struct _EX_SPIN_LOCK
 {
     SRWLOCK lock;
 } EX_SPIN_LOCK;
+
 typedef cxplat_rundown_reference_t EX_RUNDOWN_REF;
 
+// Initial usersim version of this API will not be cache aware and will use the same type as EX_RUNDOWN_REF.
+typedef cxplat_rundown_reference_t EX_RUNDOWN_REF_CACHE_AWARE;
+
 //
 // Pool Allocation routines (in pool.c)
 //
@@ -104,6 +108,26 @@ USERSIM_API
 void
 ExReleaseRundownProtection(_Inout_ EX_RUNDOWN_REF* rundown_ref);
 
+USERSIM_API
+EX_RUNDOWN_REF_CACHE_AWARE*
+ExAllocateCacheAwareRundownProtection(
+    _In_ __drv_strictTypeMatch(__drv_typeExpr) POOL_TYPE PoolType, unsigned long PoolTag);
+
+USERSIM_API
+BOOLEAN ExAcquireRundownProtectionCacheAware(
+  _Inout_ EX_RUNDOWN_REF_CACHE_AWARE* RunRefCacheAware
+);
+
+USERSIM_API
+void ExReleaseRundownProtectionCacheAware(
+  _Inout_ EX_RUNDOWN_REF_CACHE_AWARE* RunRefCacheAware
+);
+
+USERSIM_API
+void ExFreeCacheAwareRundownProtection(
+  _Inout_ EX_RUNDOWN_REF_CACHE_AWARE* RunRefCacheAware
+);
+
 USERSIM_API
 _Acquires_exclusive_lock_(push_lock->lock) void ExAcquirePushLockExclusiveEx(
     _Inout_ _Requires_lock_not_held_(*_Curr_) _Acquires_lock_(*_Curr_) EX_PUSH_LOCK* push_lock,
diff --git a/src/ex.cpp b/src/ex.cpp
index 4622536..1c24abe 100644
--- a/src/ex.cpp
+++ b/src/ex.cpp
@@ -45,6 +45,37 @@ ExReleaseRundownProtection(_Inout_ EX_RUNDOWN_REF* rundown_reference)
     cxplat_release_rundown_protection(rundown_reference);
 }
 
+EX_RUNDOWN_REF_CACHE_AWARE*
+ExAllocateCacheAwareRundownProtection(
+    _In_ __drv_strictTypeMatch(__drv_typeExpr) POOL_TYPE PoolType, unsigned long PoolTag)
+{
+    EX_RUNDOWN_REF_CACHE_AWARE* rundown_reference =
+        (EX_RUNDOWN_REF_CACHE_AWARE*)ExAllocatePoolWithTag(PoolType, sizeof(EX_RUNDOWN_REF_CACHE_AWARE), PoolTag);
+
+    if (rundown_reference != nullptr) {
+        cxplat_initialize_rundown_protection(rundown_reference);
+    }
+    return rundown_reference;
+}
+
+BOOLEAN
+ExAcquireRundownProtectionCacheAware(_Inout_ EX_RUNDOWN_REF_CACHE_AWARE* RunRefCacheAware)
+{
+    return (BOOLEAN)cxplat_acquire_rundown_protection(RunRefCacheAware);
+}
+
+void
+ExReleaseRundownProtectionCacheAware(_Inout_ EX_RUNDOWN_REF_CACHE_AWARE* RunRefCacheAware)
+{
+    cxplat_release_rundown_protection(RunRefCacheAware);
+}
+
+void
+ExFreeCacheAwareRundownProtection(_Inout_ EX_RUNDOWN_REF_CACHE_AWARE* RunRefCacheAware)
+{
+    ExFreePool(RunRefCacheAware);
+}
+
 _Acquires_exclusive_lock_(push_lock->lock) void ExAcquirePushLockExclusiveEx(
     _Inout_ _Requires_lock_not_held_(*_Curr_) _Acquires_lock_(*_Curr_) EX_PUSH_LOCK* push_lock,
     _In_ unsigned long flags)
diff --git a/tests/ex_test.cpp b/tests/ex_test.cpp
index f969e9d..fc767db 100644
--- a/tests/ex_test.cpp
+++ b/tests/ex_test.cpp
@@ -7,6 +7,9 @@
 #include <catch2/catch.hpp>
 #endif
 #include "usersim/ex.h"
+#include "cxplat_winuser.h"
+
+#include <thread>
 
 TEST_CASE("ExAllocatePool", "[ex]")
 {
@@ -116,4 +119,112 @@ TEST_CASE("ExRaiseDatatypeMisalignment", "[ex]")
         int64_t code = _atoi64(ex);
         REQUIRE(code == STATUS_DATATYPE_MISALIGNMENT);
     }
+}
+
+TEST_CASE("EX_RUNDOWN_REF", "[ex]")
+{
+    EX_RUNDOWN_REF ref;
+    std::atomic<bool> thread_completed = false;
+    ExInitializeRundownProtection(&ref);
+
+    // Acquire before rundown is initiated.
+    // Acquire the first rundown protection reference.
+    REQUIRE(ExAcquireRundownProtection(&ref));
+
+    // Acquire the second rundown protection reference.
+    REQUIRE(ExAcquireRundownProtection(&ref));
+
+    // Wait for the rundown protection to be released.
+    std::thread thread([&]() {
+        // Wait for the rundown protection to be released.
+        ExWaitForRundownProtectionRelease(&ref);
+        thread_completed = true;
+    });
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    // Thread should be waiting for the rundown protection to be released.
+    REQUIRE(!thread_completed);
+
+    // Acquire after rundown is initiated.
+    // Future acquire of the rundown protection should fail.
+    REQUIRE(!ExAcquireRundownProtection(&ref));
+
+    // Release the second rundown protection reference.
+    ExReleaseRundownProtection(&ref);
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    // Thread should be waiting for the rundown protection to be released.
+    REQUIRE(!thread_completed);
+
+    // Release the first rundown protection reference.
+    ExReleaseRundownProtection(&ref);
+
+    // Thread should have completed.
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    thread.join();
+
+    // Thread should be waiting for the rundown protection to be released.
+    REQUIRE(thread_completed);
+
+    // Acquire after rundown is completed.
+
+    // Future acquire of the rundown protection should fail.
+    REQUIRE(!ExAcquireRundownProtection(&ref));
+}
+
+TEST_CASE("EX_RUNDOWN_REF_CACHE_AWARE", "[ex]")
+{
+    EX_RUNDOWN_REF_CACHE_AWARE* ref = ExAllocateCacheAwareRundownProtection(NonPagedPoolNx, 'tset');
+    std::atomic<bool> thread_completed = false;
+    REQUIRE(ref != nullptr);
+
+    // Acquire before rundown is initiated.
+    // Acquire the first rundown protection reference.
+    REQUIRE(ExAcquireRundownProtectionCacheAware(ref));
+
+    // Acquire the second rundown protection reference.
+    REQUIRE(ExAcquireRundownProtectionCacheAware(ref));
+
+    // Wait for the rundown protection to be released.
+    std::thread thread([&]() {
+        // Wait for the rundown protection to be released.
+        ExWaitForRundownProtectionRelease(ref);
+        thread_completed = true;
+    });
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    // Thread should be waiting for the rundown protection to be released.
+    REQUIRE(!thread_completed);
+
+    // Acquire after rundown is initiated.
+    // Future acquire of the rundown protection should fail.
+    REQUIRE(!ExAcquireRundownProtectionCacheAware(ref));
+
+    // Release the second rundown protection reference.
+    ExReleaseRundownProtectionCacheAware(ref);
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    // Thread should be waiting for the rundown protection to be released.
+    REQUIRE(!thread_completed);
+
+    // Release the first rundown protection reference.
+    ExReleaseRundownProtectionCacheAware(ref);
+
+    // Thread should have completed.
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    thread.join();
+    REQUIRE(thread_completed);
+
+    // Acquire after rundown is completed.
+
+    // Future acquire of the rundown protection should fail.
+    REQUIRE(!ExAcquireRundownProtectionCacheAware(ref));
+
+    ExFreeCacheAwareRundownProtection(ref);
 }
\ No newline at end of file