[Intel GPU] DeepSeek V4 6/N: use sgl-kernel implemetation of flash_mla_with_kvcache on XPU (#27914)

Signed-off-by: P V R K Jyothendra Varma <polisetty.v.r.k.jyothendra.varma@intel.com>
Co-authored-by: Ma Mingfei <mingfei.ma@intel.com>

python/sglang/srt/layers/attention/deepseek_v4_backend.py

@@ -50,7 +50,7 @@ from sglang.srt.mem_cache.deepseek_v4_memory_pool import DeepSeekV4TokenToKVPool
 from sglang.srt.model_executor.forward_batch_info import ForwardBatch, ForwardMode
 from sglang.srt.runtime_context import get_parallel
 from sglang.srt.speculative.eagle_utils import per_step_draft_out_cache_loc
-from sglang.srt.utils import ceil_align
+from sglang.srt.utils import ceil_align, is_xpu
 from sglang.srt.utils.common import is_sm120_supported
 
 if TYPE_CHECKING:
@@ -60,6 +60,7 @@ if TYPE_CHECKING:
     from sglang.srt.model_executor.model_runner import ModelRunner
 
 _is_sm120 = is_sm120_supported()
+_is_xpu = is_xpu()
 
 logger = logging.getLogger(__name__)
 
@@ -111,7 +112,7 @@ def _pad_last_dim(x: T, multiples_of: int = PAGE_INDEX_ALIGNED_SIZE) -> T:
 
 
 def _create_flashmla_metadata():
-    if _is_sm120:
+    if _is_sm120 or _is_xpu:
         return None
     import sgl_kernel.flash_mla as flash_mla
 
@@ -1433,9 +1434,12 @@ class DeepseekV4AttnBackend(
                     extra_topk_length=extra_topk_lengths,
                 )[0]
             else:
-                import sgl_kernel.flash_mla as flash_mla
+                if _is_xpu:
+                    from sgl_kernel import flash_mla_with_kvcache
+                else:
+                    from sgl_kernel.flash_mla import flash_mla_with_kvcache
 
-                o = flash_mla.flash_mla_with_kvcache(
+                o = flash_mla_with_kvcache(
                     q=q,
                     k_cache=swa_k_cache,
                     head_dim_v=self.head_dim_v,