Support speculative decoding in the trtllm_mha attention backend (#9331)

Co-authored-by: ispobock <ispobaoke@gmail.com>

python/sglang/srt/speculative/eagle_worker.py

@@ -266,6 +266,22 @@ class EAGLEWorker(TpModelWorker):
                 self.topk,
                 self.speculative_num_steps,
             )
+        elif self.server_args.attention_backend == "trtllm_mha":
+            from sglang.srt.layers.attention.trtllm_mha_backend import (
+                TRTLLMHAAttnBackend,
+                TRTLLMHAAttnMultiStepDraftBackend,
+            )
+
+            self.draft_attn_backend = TRTLLMHAAttnMultiStepDraftBackend(
+                self.draft_model_runner,
+                self.topk,
+                self.speculative_num_steps,
+            )
+            self.draft_extend_attn_backend = TRTLLMHAAttnBackend(
+                self.draft_model_runner,
+                skip_prefill=False,
+            )
+            self.has_prefill_wrapper_verify = True
         elif self.server_args.attention_backend == "trtllm_mla":
             if not global_server_args_dict["use_mla_backend"]:
                 raise ValueError(