Add OrtExternalResourceImporter API for D3D12 shared resource import

include/onnxruntime/core/session/onnxruntime_c_api.h

@@ -330,6 +330,9 @@ ORT_RUNTIME_CLASS(EpDevice);
 ORT_RUNTIME_CLASS(KeyValuePairs);
 ORT_RUNTIME_CLASS(SyncStream);  // Opaque class to create an onnxruntime::Stream.
 ORT_RUNTIME_CLASS(ExternalInitializerInfo);
+ORT_RUNTIME_CLASS(ExternalResourceImporter);  // Capability object for external resource import
+ORT_RUNTIME_CLASS(ExternalMemoryHandle);      // EP-imported view of shared external allocation
+ORT_RUNTIME_CLASS(ExternalSemaphoreHandle);   // EP-imported view of shared external semaphore
 
 #ifdef _MSC_VER
 typedef _Return_type_success_(return == 0) OrtStatus* OrtStatusPtr;
@@ -955,6 +958,87 @@ typedef void (*RunAsyncCallbackFn)(void* user_data, OrtValue** outputs, size_t n
  *
  * \nosubgrouping
  */
+
+/** \addtogroup Global
+ * @{
+ */
+
+/** \brief External memory handle type for importing GPU resources.
+ *
+ * \since Version 1.24.
+ */
+typedef enum OrtExternalMemoryHandleType {
+  ORT_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE = 0, /**< Shared HANDLE from ID3D12Device::CreateSharedHandle(resource) */
+  ORT_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP = 1,     /**< Shared HANDLE from ID3D12Device::CreateSharedHandle(heap) */
+} OrtExternalMemoryHandleType;
+
+/** \brief Access mode for imported external memory.
+ *
+ * \since Version 1.24.
+ */
+typedef enum OrtExternalMemoryAccessMode {
+  ORT_EXTERNAL_MEMORY_ACCESS_READ_WRITE = 0, /**< Memory can be read and written */
+  ORT_EXTERNAL_MEMORY_ACCESS_READ_ONLY = 1,  /**< Memory is read-only */
+  ORT_EXTERNAL_MEMORY_ACCESS_WRITE_ONLY = 2, /**< Memory is write-only */
+} OrtExternalMemoryAccessMode;
+
+/** \brief Descriptor for importing external memory.
+ *
+ * \note The version field must be set to ORT_EXTERNAL_MEMORY_DESCRIPTOR_VERSION.
+ *       This ensures forward compatibility as fields may be added in future versions.
+ *
+ * \since Version 1.24.
+ */
+#define ORT_EXTERNAL_MEMORY_DESCRIPTOR_VERSION 1
+typedef struct OrtExternalMemoryDescriptor {
+  uint32_t version;                        /**< Must be ORT_EXTERNAL_MEMORY_DESCRIPTOR_VERSION */
+  OrtExternalMemoryHandleType handle_type; /**< Type of the external memory handle */
+  void* native_handle;                     /**< Platform-specific handle (e.g., Windows HANDLE) */
+  size_t size_bytes;                       /**< Total size in bytes of the external allocation */
+  size_t offset_bytes;                     /**< Offset in bytes into the allocation (default 0) */
+  OrtExternalMemoryAccessMode access_mode; /**< Access mode for the imported memory */
+} OrtExternalMemoryDescriptor;
+
+/** \brief External semaphore type for GPU synchronization.
+ *
+ * \since Version 1.24.
+ */
+typedef enum OrtExternalSemaphoreType {
+  ORT_EXTERNAL_SEMAPHORE_D3D12_FENCE = 0, /**< Shared HANDLE from ID3D12Device::CreateSharedHandle(fence) */
+} OrtExternalSemaphoreType;
+
+/** \brief Descriptor for importing external semaphores.
+ *
+ * \note The version field must be set to ORT_EXTERNAL_SEMAPHORE_DESCRIPTOR_VERSION.
+ *       This ensures forward compatibility as fields may be added in future versions.
+ *
+ * \since Version 1.24.
+ */
+#define ORT_EXTERNAL_SEMAPHORE_DESCRIPTOR_VERSION 1
+typedef struct OrtExternalSemaphoreDescriptor {
+  uint32_t version;              /**< Must be ORT_EXTERNAL_SEMAPHORE_DESCRIPTOR_VERSION */
+  OrtExternalSemaphoreType type; /**< Type of the external semaphore */
+  void* native_handle;           /**< Platform-specific handle (e.g., Windows HANDLE) */
+} OrtExternalSemaphoreDescriptor;
+
+/** \brief Descriptor for creating a tensor from imported external memory.
+ *
+ * \note The version field must be set to ORT_EXTERNAL_TENSOR_DESCRIPTOR_VERSION.
+ *       This ensures forward compatibility as fields may be added in future versions.
+ *
+ * \since Version 1.24.
+ */
+#define ORT_EXTERNAL_TENSOR_DESCRIPTOR_VERSION 1
+typedef struct OrtExternalTensorDescriptor {
+  uint32_t version;                       /**< Must be ORT_EXTERNAL_TENSOR_DESCRIPTOR_VERSION */
+  ONNXTensorElementDataType element_type; /**< Data type of tensor elements */
+  const int64_t* shape;                   /**< Array of dimension sizes */
+  size_t rank;                            /**< Number of dimensions */
+  size_t offset_bytes;                    /**< Optional offset within imported memory (default 0) */
+} OrtExternalTensorDescriptor;
+
+/// @}
+
 /*
  * Public enum for compiled model compatibility across EPs.
  */
@@ -6608,6 +6692,203 @@ struct OrtApi {
    * \since Version 1.24
    */
   ORT_API2_STATUS(KernelInfo_GetConfigEntries, _In_ const OrtKernelInfo* info, _Outptr_ OrtKeyValuePairs** out);
+
+  /// \name External Resource Import
+  /// @{
+
+  /** \brief Create an external resource importer for a specific EP device.
+   *
+   * The external resource importer is a capability object that provides methods for importing
+   * external GPU memory and semaphores for zero-copy import with an execution provider.
+   *
+   * \param[in] ep_device The OrtEpDevice instance to create the importer for.
+   * \param[out] out_importer Output parameter set to the created OrtExternalResourceImporter instance.
+   *                          Returns nullptr if the EP does not support external resource import.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(CreateExternalResourceImporterForDevice,
+                  _In_ const OrtEpDevice* ep_device,
+                  _Outptr_result_maybenull_ OrtExternalResourceImporter** out_importer);
+
+  /** \brief Release an OrtExternalResourceImporter instance.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance to release. May be nullptr.
+   *
+   * \since Version 1.24.
+   */
+  ORT_CLASS_RELEASE(ExternalResourceImporter);
+
+  /** \brief Check if the external resource importer can import a specific memory handle type.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] handle_type The type of external memory handle to check.
+   * \param[out] out_supported Set to true if the handle type is supported.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_CanImportMemory,
+                  _In_ const OrtExternalResourceImporter* importer,
+                  _In_ OrtExternalMemoryHandleType handle_type,
+                  _Out_ bool* out_supported);
+
+  /** \brief Import external memory into the execution provider.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] desc Descriptor containing the external memory handle and properties.
+   * \param[out] out_handle Output parameter set to the created OrtExternalMemoryHandle.
+   *                        The caller owns the returned handle and must call ReleaseExternalMemoryHandle to free it.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_ImportMemory,
+                  _In_ OrtExternalResourceImporter* importer,
+                  _In_ const OrtExternalMemoryDescriptor* desc,
+                  _Outptr_ OrtExternalMemoryHandle** out_handle);
+
+  /** \brief Release an OrtExternalMemoryHandle instance.
+   *
+   * \param[in] handle The OrtExternalMemoryHandle instance to release. May be nullptr.
+   *
+   * \since Version 1.24.
+   */
+  ORT_CLASS_RELEASE(ExternalMemoryHandle);
+
+  /** \brief Create a tensor backed by imported external memory.
+   *
+   * The created tensor is a view over the imported memory and does not copy data.
+   * The OrtExternalMemoryHandle must remain valid for the lifetime of the tensor.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] mem_handle The imported external memory handle.
+   * \param[in] tensor_desc Descriptor specifying tensor element type, shape, and optional offset.
+   * \param[in] tensor_location Optional OrtMemoryInfo for the tensor location. May be nullptr.
+   * \param[out] out_tensor Output parameter set to the created OrtValue containing the tensor.
+   *                        The caller owns the returned tensor and must call ReleaseValue to free it.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_CreateTensorFromMemory,
+                  _In_ OrtExternalResourceImporter* importer,
+                  _In_ const OrtExternalMemoryHandle* mem_handle,
+                  _In_ const OrtExternalTensorDescriptor* tensor_desc,
+                  _In_opt_ const OrtMemoryInfo* tensor_location,
+                  _Outptr_ OrtValue** out_tensor);
+
+  /** \brief Check if the external resource importer can import a specific semaphore type.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] type The type of external semaphore to check.
+   * \param[out] out_supported Set to true if the semaphore type is supported.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_CanImportSemaphore,
+                  _In_ const OrtExternalResourceImporter* importer,
+                  _In_ OrtExternalSemaphoreType type,
+                  _Out_ bool* out_supported);
+
+  /** \brief Import an external semaphore into the execution provider.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] desc Descriptor containing the external semaphore handle and type.
+   * \param[out] out_handle Output parameter set to the created OrtExternalSemaphoreHandle.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_ImportSemaphore,
+                  _In_ OrtExternalResourceImporter* importer,
+                  _In_ const OrtExternalSemaphoreDescriptor* desc,
+                  _Outptr_ OrtExternalSemaphoreHandle** out_handle);
+
+  /** \brief Release an OrtExternalSemaphoreHandle instance.
+   *
+   * \param[in] handle The OrtExternalSemaphoreHandle instance to release. May be nullptr.
+   *
+   * \since Version 1.24.
+   */
+  ORT_CLASS_RELEASE(ExternalSemaphoreHandle);
+
+  /** \brief Wait on an external semaphore on the EP's stream.
+   *
+   * Inserts a wait operation into the EP's stream that blocks until the semaphore
+   * reaches the specified value. This is used to synchronize with external GPU work
+   * (e.g., D3D12 timeline fence).
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] semaphore_handle The imported external semaphore.
+   * \param[in] stream The OrtSyncStream to wait on.
+   * \param[in] value The fence/semaphore value to wait for.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_WaitSemaphore,
+                  _In_ OrtExternalResourceImporter* importer,
+                  _In_ OrtExternalSemaphoreHandle* semaphore_handle,
+                  _In_ OrtSyncStream* stream,
+                  _In_ uint64_t value);
+
+  /** \brief Signal an external semaphore from the EP's stream.
+   *
+   * Inserts a signal operation into the EP's stream that sets the semaphore
+   * to the specified value when reached. This is used to notify external GPU work
+   * (e.g., D3D12 timeline fence) that ORT inference is complete.
+   *
+   * \param[in] importer The OrtExternalResourceImporter instance.
+   * \param[in] semaphore_handle The imported external semaphore.
+   * \param[in] stream The OrtSyncStream to signal from.
+   * \param[in] value The fence/semaphore value to signal.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24.
+   */
+  ORT_API2_STATUS(ExternalResourceImporter_SignalSemaphore,
+                  _In_ OrtExternalResourceImporter* importer,
+                  _In_ OrtExternalSemaphoreHandle* semaphore_handle,
+                  _In_ OrtSyncStream* stream,
+                  _In_ uint64_t value);
+
+  /** \brief Get the EP device assigned to each session output.
+   *
+   * Returns the OrtEpDevice assigned to each output of the session after graph partitioning.
+   * This allows validation that outputs are placed on the expected device for external resource sharing.
+   *
+   * The EP device for each output is determined by which execution provider claims that output
+   * during graph partitioning. This information is useful for:
+   * - Validating that outputs will be placed on the expected device for external resource sharing
+   * - Deciding whether to use external memory handles for outputs
+   *
+   * \param[in] session The OrtSession instance to query.
+   * \param[out] outputs_ep_devices An array to be filled with the EP device for each output.
+   *                                The array must be allocated by the caller with space for
+   *                                OrtEpDevice* values for each output.
+   *                                The order is the same as returned by SessionGetOutputName.
+   * \param[in] num_outputs The number of outputs in the session. Must match SessionGetOutputCount.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.24
+   */
+  ORT_API2_STATUS(SessionGetEpDeviceForOutputs, _In_ const OrtSession* session,
+                  _Out_writes_(num_outputs) const OrtEpDevice** outputs_ep_devices,
+                  _In_ size_t num_outputs);
+
+  /// @}
 };
 
 /*

include/onnxruntime/core/session/onnxruntime_cxx_api.h

@@ -1607,6 +1607,7 @@ struct ConstSessionImpl : Base<T> {
   std::vector<ConstMemoryInfo> GetMemoryInfoForInputs() const;   ///< Wrapper for OrtApi::SessionGetMemoryInfoForInputs
   std::vector<ConstMemoryInfo> GetMemoryInfoForOutputs() const;  ///< Wrapper for OrtApi::SessionGetMemoryInfoForOutputs
   std::vector<ConstEpDevice> GetEpDeviceForInputs() const;       ///< Wrapper for OrtApi::SessionGetEpDeviceForInputs
+  std::vector<ConstEpDevice> GetEpDeviceForOutputs() const;      ///< Wrapper for OrtApi::SessionGetEpDeviceForOutputs
 
   /** \brief Returns a copy of input name at the specified index.
    *

include/onnxruntime/core/session/onnxruntime_cxx_inline.h

@@ -1660,6 +1660,19 @@ inline std::vector<ConstEpDevice> ConstSessionImpl<T>::GetEpDeviceForInputs() co
   return input_devices;
 }
 
+template <typename T>
+inline std::vector<ConstEpDevice> ConstSessionImpl<T>::GetEpDeviceForOutputs() const {
+  auto num_outputs = GetOutputCount();
+  std::vector<ConstEpDevice> output_devices;
+  if (num_outputs > 0) {
+    output_devices.resize(num_outputs);
+    ThrowOnError(GetApi().SessionGetEpDeviceForOutputs(this->p_,
+                                                       reinterpret_cast<const OrtEpDevice**>(output_devices.data()),
+                                                       num_outputs));
+  }
+  return output_devices;
+}
+
 template <typename T>
 inline uint64_t ConstSessionImpl<T>::GetProfilingStartTimeNs() const {
   uint64_t out;