Refine cmake based on comments

cmake/Modules/FindoneMKL.cmake

@@ -1,26 +1,54 @@
+set(ONEMKL_FOUND FALSE)
+
 set(ONEMKL_LIBRARIES)
 
+set(ONEMKL_DEFAULT_DIR "/opt/intel/oneapi/mkl/latest")
 if(DEFINED ENV{MKLROOT})
-  SET(INTEL_MKL_DIR $ENV{MKLROOT})
-else()
-  SET(INTEL_MKL_DIR "/opt/intel/oneapi/mkl/latest")
+  set(ONEMKL_ROOT $ENV{MKLROOT})
+elseif(EXISTS "${ONEMKL_DEFAULT_DIR}")
+  set(ONEMKL_ROOT "${ONEMKL_DEFAULT_DIR}")
+endif()
+
+if(NOT ONEMKL_ROOT)
+  message(WARNING "Cannot find oneMKL in ENV{MKLROOT} or default path, please setup oneMKL before building!!")
+  return()
+endif()
+
+find_file(
+  ONEMKL_INCLUDE_DIR
+  NAMES include
+  HINTS ${ONEMKL_ROOT}
+  NO_DEFAULT_PATH
+)
+
+find_file(
+  ONEMKL_LIB_DIR
+  NAMES lib
+  HINTS ${ONEMKL_ROOT}
+  NO_DEFAULT_PATH
+)
+
+if((NOT ONEMKL_INCLUDE_DIR) OR (NOT ONEMKL_LIB_DIR))
+  message(WARNING "oneMKL sdk is incomplete!!")
+  return()
 endif()
 
 set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH}
-    "${INTEL_MKL_DIR}/include")
+    "${ONEMKL_INCLUDE_DIR}")
 set(CMAKE_LIBRARY_PATH ${CMAKE_LIBRARY_PATH}
-    "${INTEL_MKL_DIR}/lib")
+    "${ONEMKL_LIB_DIR}")
 
 set(MKL_LIB_NAMES "mkl_intel_lp64" "mkl_gnu_thread" "mkl_core" "mkl_sycl_dft")
 
 foreach(LIB_NAME IN LISTS MKL_LIB_NAMES)
   find_library(
     ${LIB_NAME}_library
     NAMES ${LIB_NAME}
-    HINTS ${INTEL_MKL_DIR}/lib
+    HINTS ${ONEMKL_LIB_DIR}
     NO_CMAKE_PATH
     NO_CMAKE_ENVIRONMENT_PATH
   )
   list(APPEND ONEMKL_LIBRARIES ${${LIB_NAME}_library})
 endforeach()
 
+set(ONEMKL_FOUND TRUE)

src/CMakeLists.txt

@@ -64,5 +64,8 @@ if(CLANG_FORMAT)
 endif()
 
 find_package(oneMKL)
+if(NOT ONEMKL_FOUND)
+  message(FATAL_ERROR "Can NOT find ONEMKL cmake helpers module!")
+endif()
 
 target_link_libraries(torch_xpu_ops INTERFACE ${ONEMKL_LIBRARIES})