XPU: Enable GLM5.1 (GlmMoeDsaForCausalLM) DSA Attention (#24959)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Ma Mingfei <mingfei.ma@intel.com>

python/sglang/kernels/ops/attention/dsa/index_buf_accessor.py

@@ -9,9 +9,10 @@ from sglang.srt.layers.attention.dsa.utils import (
     INDEXER_K_CACHE_PRESHUFFLE_TILE,
     aiter_can_use_preshuffle_paged_mqa,
 )
-from sglang.srt.utils import get_bool_env_var, is_hip
+from sglang.srt.utils import get_bool_env_var, is_hip, is_xpu
 
 _is_hip = is_hip()
+_is_xpu = is_xpu()
 _is_fp8_fnuz = is_fp8_fnuz()
 _use_aiter = get_bool_env_var("SGLANG_USE_AITER") and _is_hip
 # aiter cp_gather kernel with preshuffle=True is only valid when the indexer
@@ -311,6 +312,11 @@ def _set_k_and_s_triton(
             assert page_size % 16 == 0, (
                 f"HIP preshuffle requires page_size to be a multiple of 16, got {page_size}"
             )
+    elif _is_xpu:
+        assert page_size in (
+            64,
+            128,
+        ), f"XPU DSA requires page_size 64 or 128, got {page_size}"
     else:
         assert page_size == 64