[XPU][NIXL] Add GPUDirect RDMA support for XPU (#35270)

Signed-off-by: zhenwei-intel <zhenwei.liu@intel.com>
Co-authored-by: Kunshang Ji <kunshang.ji@intel.com>

vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py

@@ -135,7 +135,10 @@ _NIXL_SUPPORTED_DEVICE = {
         "cpu",
     ),
     "tpu": ("cpu",),
-    "xpu": ("cpu",),
+    "xpu": (
+        "cpu",
+        "xpu",
+    ),
     "cpu": ("cpu",),
 }
 # support for oot platform by providing mapping in current_platform
@@ -945,7 +948,7 @@ class NixlConnectorWorker:
         # type based on kv_buffer_device
         nixl_memory_type = current_platform.get_nixl_memory_type()
         if nixl_memory_type is None:
-            if self.kv_buffer_device == "cuda":
+            if self.kv_buffer_device in ["cuda", "xpu"]:
                 nixl_memory_type = "VRAM"
             elif self.kv_buffer_device == "cpu":
                 nixl_memory_type = "DRAM"