[v0.18.0][Bugfix] fix ds3.2 dcp mtp (#7681)

### What this PR does / why we need it?
Fixed the issue where the DCP overlaps the MTP scenario in the ds3.2
scenario.

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?

cherry-pick from: https://github.com/vllm-project/vllm-ascend/pull/7617

Signed-off-by: weiguihua2 <weiguihua2@huawei.com>

vllm_ascend/attention/attention_v1.py

@@ -168,6 +168,7 @@ class AscendMetadata:
     # should simplified these parameters once attention schema in vLLM-Ascend
     # is unified.
     seq_lens: torch.Tensor = None
+    seq_lens_cpu: torch.Tensor = None
     seq_lens_list: list[int] = None  # type: ignore
     actual_seq_lengths_q: list[int] = None  # type: ignore
 
@@ -307,6 +308,7 @@ class AscendAttentionMetadataBuilder(AttentionMetadataBuilder[AscendMetadata]):
             block_tables=block_table,
             query_start_loc=query_start_loc,
             seq_lens=seq_lens,
+            seq_lens_cpu=seq_lens,
             seq_lens_list=seq_lens.tolist(),
             max_query_len=common_attn_metadata.max_query_len,
             actual_seq_lengths_q=query_start_loc_cpu[1:].tolist(),

vllm_ascend/attention/context_parallel/attention_cp.py

@@ -232,6 +232,7 @@ class AscendAttentionCPMetadataBuilder(AscendAttentionMetadataBuilder):
             block_tables=block_table,
             query_start_loc=query_start_loc,
             seq_lens=seq_lens,
+            seq_lens_cpu=seq_lens,
             seq_lens_list=seq_lens.tolist(),
             max_query_len=common_attn_metadata.max_query_len,
             actual_seq_lengths_q=query_start_loc_cpu[1:].tolist(),

vllm_ascend/attention/context_parallel/sfa_cp.py

@@ -257,8 +257,8 @@ class AscendSFACPImpl(AscendSFAImpl):
         return self._align_to_graph_bucket_tokens(attn_output, attn_metadata)
 
     def _align_to_graph_bucket_tokens(self, attn_output: torch.Tensor | None, attn_metadata: M) -> torch.Tensor | None:
-        if attn_output is None:
-            return None
+        if attn_output is None or self.pcp_size == 1:
+            return attn_output
         # In graph/piecewise mode, output buffer uses graph bucket token size
         # (forward_context.num_tokens), while PCP path may compute only valid
         # tokens. Align to the larger one to avoid later write-back mismatch.

vllm_ascend/attention/mla_v1.py

@@ -174,6 +174,7 @@ class AscendMLAMetadata:
     slot_mapping: torch.Tensor
     query_start_loc: torch.Tensor
     seq_lens: torch.Tensor
+    seq_lens_cpu: torch.Tensor
     block_tables: torch.Tensor
 
     # New for MLA (compared to FlashAttention)
@@ -457,6 +458,7 @@ class AscendMLAMetadataBuilder(MLACommonMetadataBuilder[AscendMLAMetadata]):
             query_start_loc=query_start_loc,
             block_tables=self.block_table,
             seq_lens=self.seq_lens,
+            seq_lens_cpu=self.seq_lens,
         )
 
     def build_chunked_metadata(

vllm_ascend/attention/sfa_v1.py

@@ -130,6 +130,7 @@ class AscendSFAMetadata:
     num_actual_tokens: int  # Number of tokens excluding padding.
     slot_mapping: torch.Tensor
     seq_lens: torch.Tensor
+    seq_lens_cpu: torch.Tensor
     cum_query_lens: torch.Tensor
     block_table: torch.Tensor
     sin: torch.Tensor
@@ -233,6 +234,7 @@ class AscendSFAMetadataBuilder(MLACommonMetadataBuilder[AscendSFAMetadata]):
 
         cum_query_lens = common_attn_metadata.query_start_loc[1 : num_reqs + 1]
         seq_lens = common_attn_metadata.seq_lens[:num_reqs]
+        seq_lens_cpu = common_attn_metadata.seq_lens_cpu[:num_reqs]
 
         cos, sin = get_cos_and_sin_mla(input_positions, True)
 
@@ -320,6 +322,7 @@ class AscendSFAMetadataBuilder(MLACommonMetadataBuilder[AscendSFAMetadata]):
             num_actual_tokens=num_actual_tokens,
             cum_query_lens=cum_query_lens,
             seq_lens=seq_lens,
+            seq_lens_cpu=seq_lens_cpu,
             slot_mapping=slot_mapping,
             head_dim=self.model_config.get_head_size(),
             attn_mask=self.attn_mask_builder.get_attention_mask(self.model_config),

vllm_ascend/spec_decode/eagle_proposer.py

@@ -600,7 +600,7 @@ class SpecDecodeBaseProposer(EagleProposer):
                     - 1
                 )
                 num_accept_tokens = query_lens_d.to(self.device) - num_reject_tokens
-                ori_seq_len = attn_metadata_i.seq_lens[:batch_size].clone()
+                ori_seq_len = attn_metadata_i.seq_lens_cpu[:batch_size].clone()
                 mtp_slot_mapping = self.runner.pcp_manager.mtp_slot_pad
 
                 # slot_mapping index base offset:
@@ -1247,7 +1247,8 @@ class SpecDecodeBaseProposer(EagleProposer):
 
         if self.pcp_size * self.dcp_size > 1:
             if self.vllm_config.model_config.use_mla:
-                attn_metadata.decode.cp_seq_len = cp_seq_len
+                if getattr(attn_metadata, "decode", None):
+                    attn_metadata.decode.cp_seq_len = cp_seq_len
             else:
                 attn_metadata.decode_meta.num_computed_tokens_of_pcp_dcp = num_computed_tokens_of_pcp_dcp