[XPU] Support block fp8 moe by fallback to TritonExpert on XPU (#36458)

Signed-off-by: Kunshang Ji <kunshang.ji@intel.com>

vllm/model_executor/layers/fused_moe/fused_moe.py

@@ -1940,7 +1940,7 @@ class TritonExperts(mk.FusedMoEExpertsModular):
 
     @staticmethod
     def _supports_current_device() -> bool:
-        return current_platform.is_cuda_alike()
+        return current_platform.is_cuda_alike() or current_platform.is_xpu()
 
     @staticmethod
     def _supports_no_act_and_mul() -> bool:
@@ -1959,8 +1959,10 @@ class TritonExperts(mk.FusedMoEExpertsModular):
         else:
             is_rocm_on_gfx9 = False
 
-        device_supports_fp8 = is_rocm_on_gfx9 or (
-            p.is_cuda() and p.has_device_capability((8, 9))
+        device_supports_fp8 = (
+            is_rocm_on_gfx9
+            or (p.is_cuda() and p.has_device_capability((8, 9)))
+            or p.is_xpu()
         )
 
         if not device_supports_fp8:

vllm/model_executor/layers/fused_moe/oracle/fp8.py

@@ -94,6 +94,11 @@ def _get_priority_backends(
         else:
             _move_to_front(_AVAILABLE_BACKENDS, Fp8MoeBackend.TRITON)
 
+    if current_platform.is_xpu():
+        # XPU platform supports TritonExperts and XPUExpertsFp8,
+        # move XPU backend to the front.
+        _move_to_front(_AVAILABLE_BACKENDS, Fp8MoeBackend.XPU)
+
     return _AVAILABLE_BACKENDS