[SYCL][CUDA] Implement COPY_HOST_PTR (#1863)

When a PI Mem object is created with the PI_MEM_FLAGS_HOST_PTR_COPY,
the CUDA backend now does not use the input pointer for Map/Unmap,
but allocates internal memory for it.

Fixes #1462

Signed-off-by: Ruyman Reyes <[email protected]>

Author: Ruyk

sycl/plugins/cuda/pi_cuda.cpp

@@ -1513,6 +1513,9 @@ pi_result cuda_piMemBufferCreate(pi_context context, pi_mem_flags flags,
       allocMode = _pi_mem::alloc_mode::use_host_ptr;
     } else {
       retErr = PI_CHECK_ERROR(cuMemAlloc(&ptr, size));
+      if (flags & PI_MEM_FLAGS_HOST_PTR_COPY) {
+        allocMode = _pi_mem::alloc_mode::copy_in;
+      }
     }
 
     if (retErr == PI_SUCCESS) {
@@ -1572,6 +1575,7 @@ pi_result cuda_piMemRelease(pi_mem memObj) {
       ScopedContext active(uniqueMemObj->get_context());
 
       switch (uniqueMemObj->allocMode_) {
+      case _pi_mem::alloc_mode::copy_in:
       case _pi_mem::alloc_mode::classic:
         ret = PI_CHECK_ERROR(cuMemFree(uniqueMemObj->ptr_));
         break;

sycl/plugins/cuda/pi_cuda.hpp

@@ -192,7 +192,13 @@ struct _pi_mem {
   void *mapPtr_;
   cl_map_flags mapFlags_;
   std::atomic_uint32_t refCount_;
-  enum class alloc_mode { classic, use_host_ptr } allocMode_;
+  /** alloc_mode
+   * classic: Just a normal buffer allocated on the device via cuda malloc
+   * use_host_ptr: Use an address on the host for the device
+   * copy_in: The data for the device comes from the host but the host pointer
+      is not available later for re-use
+  */
+  enum class alloc_mode { classic, use_host_ptr, copy_in } allocMode_;
 
   _pi_mem(pi_context ctxt, pi_mem parent, alloc_mode mode, CUdeviceptr ptr, void *host_ptr,
           size_t size)
@@ -240,7 +246,7 @@ struct _pi_mem {
     assert(mapPtr_ == nullptr);
     mapOffset_ = offset;
     mapFlags_ = flags;
-    if (hostPtr_) {
+    if (hostPtr_ && (allocMode_ != alloc_mode::copy_in)) {
       mapPtr_ = static_cast<char *>(hostPtr_) + offset;
     } else {
       // TODO: Allocate only what is needed based on the offset