diff --git a/include/hip/hcc_detail/hip_runtime_api.h b/include/hip/hcc_detail/hip_runtime_api.h
index 34ed2ed5ce..6fb7c0256e 100644
--- a/include/hip/hcc_detail/hip_runtime_api.h
+++ b/include/hip/hcc_detail/hip_runtime_api.h
@@ -111,17 +111,21 @@ enum hipLimit_t
 
 //! Flags that can be used with hipHostMalloc
 #define hipHostMallocDefault        0x0
-#define hipHostMallocPortable       0x1
-#define hipHostMallocMapped         0x2
+#define hipHostMallocPortable       0x1  ///< Memory is considered allocated by all contexts.
+#define hipHostMallocMapped         0x2  ///< Map the allocation into the address space for the current device.  The device pointer can be obtained with #hipHostGetDevicePointer.
 #define hipHostMallocWriteCombined  0x4
+#define hipHostMallocCoherent       0x40000000 ///< Allocate coherent memory. Overrides HIP_COHERENT_HOST_ALLOC for specific allocation.
+#define hipHostMallocNonCoherent    0x80000000 ///< Allocate non-coherent memory. Overrides HIP_COHERENT_HOST_ALLOC for specific allocation.
+
 
 //! Flags that can be used with hipHostRegister
 #define hipHostRegisterDefault      0x0  ///< Memory is Mapped and Portable
-#define hipHostRegisterPortable     0x1  ///< Memory is considered registered by all contexts.  HIP only supports one context so this is always assumed true.
+#define hipHostRegisterPortable     0x1  ///< Memory is considered registered by all contexts.
 #define hipHostRegisterMapped       0x2  ///< Map the allocation into the address space for the current device.  The device pointer can be obtained with #hipHostGetDevicePointer.
 #define hipHostRegisterIoMemory     0x4  ///< Not supported.
 
 
+
 #define hipDeviceScheduleAuto       0x0  ///< Automatically select between Spin and Yield
 #define hipDeviceScheduleSpin       0x1  ///< Dedicate a CPU core to spin-wait.  Provides lowest latency, but burns a CPU core and may consume more power.
 #define hipDeviceScheduleYield      0x2  ///< Yield the CPU to the operating system when waiting.  May increase latency, but lowers power and is friendlier to other threads in the system.
diff --git a/include/hip/nvcc_detail/hip_runtime_api.h b/include/hip/nvcc_detail/hip_runtime_api.h
index 01a93f7ba4..cbc7ed9f9c 100644
--- a/include/hip/nvcc_detail/hip_runtime_api.h
+++ b/include/hip/nvcc_detail/hip_runtime_api.h
@@ -65,6 +65,8 @@ hipMemcpyHostToHost
 #define hipHostMallocPortable      cudaHostAllocPortable
 #define hipHostMallocMapped        cudaHostAllocMapped
 #define hipHostMallocWriteCombined cudaHostAllocWriteCombined
+#define hipHostMallocCoherent      0x0 
+#define hipHostMallocNonCoherent   0x0
 
 #define hipHostRegisterPortable cudaHostRegisterPortable
 #define hipHostRegisterMapped   cudaHostRegisterMapped
diff --git a/src/hip_hcc.cpp b/src/hip_hcc.cpp
index e77c4186e8..4588f67c2d 100644
--- a/src/hip_hcc.cpp
+++ b/src/hip_hcc.cpp
@@ -74,7 +74,7 @@ int HIP_PROFILE_API= 0;
 std::string HIP_DB_START_API;
 std::string HIP_DB_STOP_API;
 int HIP_DB= 0;
-int HIP_VISIBLE_DEVICES = 0; /* Contains a comma-separated sequence of GPU identifiers */
+int HIP_VISIBLE_DEVICES = 0; 
 int HIP_NUM_KERNELS_INFLIGHT = 128;
 int HIP_WAIT_MODE = 0;
 
diff --git a/src/hip_memory.cpp b/src/hip_memory.cpp
index a3d761752e..3ab7713afa 100644
--- a/src/hip_memory.cpp
+++ b/src/hip_memory.cpp
@@ -267,17 +267,36 @@ hipError_t hipHostMalloc(void** ptr, size_t sizeBytes, unsigned int flags)
             trueFlags = hipHostMallocMapped | hipHostMallocPortable;
         }
 
-        const unsigned supportedFlags = hipHostMallocPortable | hipHostMallocMapped | hipHostMallocWriteCombined;
 
-        if (flags & ~supportedFlags) {
+        const unsigned supportedFlags = hipHostMallocPortable 
+                                      | hipHostMallocMapped 
+                                      | hipHostMallocWriteCombined 
+                                      | hipHostMallocCoherent 
+                                      | hipHostMallocNonCoherent;
+
+
+        const unsigned coherencyFlags = hipHostMallocCoherent | hipHostMallocNonCoherent;
+
+        if ((flags & ~supportedFlags) ||
+            ((flags & coherencyFlags) == coherencyFlags)) {
+            *ptr = nullptr;
+             // can't specify unsupported flags, can't specify both Coherent + NonCoherent
             hip_status = hipErrorInvalidValue;
-        }
-        else {
+        } else {
             auto device = ctx->getWriteableDevice();
-            unsigned amFlags = HIP_COHERENT_HOST_ALLOC ? amHostCoherent : amHostPinned;
+            
+            unsigned amFlags = 0;
+            if (flags & hipHostMallocCoherent) {
+                amFlags = amHostCoherent;
+            } else if (flags & hipHostMallocNonCoherent) {
+                amFlags = amHostPinned;
+            } else {
+                // depends on env variables:
+                amFlags = HIP_COHERENT_HOST_ALLOC ? amHostCoherent : amHostPinned;
+            }
 
 
-            *ptr = hip_internal::allocAndSharePtr(HIP_COHERENT_HOST_ALLOC ? "finegrained_host":"pinned_host",
+            *ptr = hip_internal::allocAndSharePtr((amFlags & amHostCoherent) ? "finegrained_host":"pinned_host",
                                                   sizeBytes, ctx, (trueFlags & hipHostMallocPortable) /*shareWithAll*/, amFlags, flags);
 
             if(sizeBytes  && (*ptr == NULL)){
diff --git a/tests/src/runtimeApi/memory/hipHostMalloc.cpp b/tests/src/runtimeApi/memory/hipHostMalloc.cpp
index d6b3b05a1d..31596b5ea5 100644
--- a/tests/src/runtimeApi/memory/hipHostMalloc.cpp
+++ b/tests/src/runtimeApi/memory/hipHostMalloc.cpp
@@ -31,14 +31,19 @@
 #define LEN 1024*1024
 #define SIZE LEN*sizeof(float)
 
-__global__ void Add(hipLaunchParm lp, float *Ad, float *Bd, float *Cd){
+__global__ void Add(float *Ad, float *Bd, float *Cd){
     int tx = hipThreadIdx_x + hipBlockIdx_x * hipBlockDim_x;
     Cd[tx] = Ad[tx] + Bd[tx];
 }
 
+
+__global__ void Set(int *Ad, int val){
+    int tx = hipThreadIdx_x + hipBlockIdx_x * hipBlockDim_x;
+    Ad[tx] = val;
+}
+
 int main(){
-    float *A, *B, *C;
-    float *Ad, *Bd, *Cd;
+
 
     hipDeviceProp_t prop;
     int device;
@@ -49,26 +54,72 @@ int main(){
         failed("Does support HostPinned Memory");
     }
 
-    HIPCHECK(hipHostMalloc((void**)&A, SIZE, hipHostMallocWriteCombined | hipHostMallocMapped));
-    HIPCHECK(hipHostMalloc((void**)&B, SIZE, hipHostMallocDefault));
-    HIPCHECK(hipHostMalloc((void**)&C, SIZE, hipHostMallocMapped));
 
-    HIPCHECK(hipHostGetDevicePointer((void**)&Ad, A, 0));
-    HIPCHECK(hipHostGetDevicePointer((void**)&Cd, C, 0));
+    {
+        float *A, *B, *C;
+        float *Ad, *Bd, *Cd;
+        HIPCHECK(hipHostMalloc((void**)&A, SIZE, hipHostMallocWriteCombined | hipHostMallocMapped));
+        HIPCHECK(hipHostMalloc((void**)&B, SIZE, hipHostMallocDefault));
+        HIPCHECK(hipHostMalloc((void**)&C, SIZE, hipHostMallocMapped));
+
+        HIPCHECK(hipHostGetDevicePointer((void**)&Ad, A, 0));
+        HIPCHECK(hipHostGetDevicePointer((void**)&Cd, C, 0));
+
+        for(int i=0;i<LEN;i++){
+            A[i] = 1.0f;
+            B[i] = 2.0f;
+        }
+
+        HIPCHECK(hipMalloc((void**)&Bd, SIZE));
+        HIPCHECK(hipMemcpy(Bd, B, SIZE, hipMemcpyHostToDevice));
+
+        dim3 dimGrid(LEN/512,1,1);
+        dim3 dimBlock(512,1,1);
 
-    for(int i=0;i<LEN;i++){
-        A[i] = 1.0f;
-        B[i] = 2.0f;
+        hipLaunchKernelGGL(Add, dimGrid, dimBlock, 0, 0, Ad, Bd, Cd);
+
+        HIPCHECK(hipDeviceSynchronize());
+
+        HIPCHECK(hipHostFree(A));
+        HIPCHECK(hipHostFree(B));
+        HIPCHECK(hipHostFree(C));
     }
 
-    HIPCHECK(hipMalloc((void**)&Bd, SIZE));
-    HIPCHECK(hipMemcpy(Bd, B, SIZE, hipMemcpyHostToDevice));
+    {
+        int *A, *B;
+        int numElements = 1024*16;
+        size_t sizeBytes = numElements * sizeof (int);
+#ifdef __HIP_PLATFORM_HCC__
+        HIPCHECK_API(hipHostMalloc((void**)&A, sizeBytes, hipHostMallocCoherent|hipHostMallocNonCoherent), hipErrorInvalidValue);
+
+        assert (A == 0);
+#endif
+
+        HIPCHECK(hipHostMalloc((void**)&A, sizeBytes, hipHostMallocCoherent));
+        hipStream_t s;
+        hipEvent_t e;
 
-    dim3 dimGrid(LEN/512,1,1);
-    dim3 dimBlock(512,1,1);
+        // Init:
+        HIPCHECK(hipStreamCreate(&s));
+        HIPCHECK(hipEventCreateWithFlags(&e, 0));
+        dim3 dimBlock(64,1,1);
+        dim3 dimGrid(numElements/dimBlock.x,1,1);
 
-    hipLaunchKernel(HIP_KERNEL_NAME(Add), dimGrid, dimBlock, 0, 0, Ad, Bd, Cd);
+        // Init array to know state:
+        hipLaunchKernelGGL(Set, dimGrid, dimBlock, 0, 0x0, A, -42);
+        HIPCHECK(hipDeviceSynchronize());
 
+        hipLaunchKernelGGL(Set, dimGrid, dimBlock, 0, s, A, 13);
+        HIPCHECK(hipEventRecord(e, s));
+
+        // Host waits for event :
+        HIPCHECK(hipEventSynchronize(e));
+
+        // check result?
+
+        HIPCHECK(hipHostMalloc((void**)&B, sizeBytes, hipHostMallocNonCoherent));
+    }
+        
     passed();
 
 }
diff --git a/util/vim/hip.vim b/util/vim/hip.vim
index b73066a786..f28761ad0b 100644
--- a/util/vim/hip.vim
+++ b/util/vim/hip.vim
@@ -185,6 +185,8 @@ syn keyword hipFlags hipHostMallocDefault
 syn keyword hipFlags hipHostMallocPortable
 syn keyword hipFlags hipHostMallocMapped
 syn keyword hipFlags hipHostMallocWriteCombined
+syn keyword hipFlags hipHostMallocCoherent
+syn keyword hipFlags hipHostMallocNonCoherent
 
 syn keyword hipFlags hipHostRegisterDefault
 syn keyword hipFlags hipHostRegisterPortable