[V0 Deprecation] Deprecate virtual engine (#37195)

Signed-off-by: yewentao256 <zhyanwentao@126.com>

vllm/model_executor/models/plamo2.py

@@ -262,7 +262,7 @@ class Plamo2MambaMixer(MambaBase, PluggableLayer):
             assert isinstance(attn_metadata, dict)
             attn_metadata = attn_metadata[self.prefix]
             assert isinstance(attn_metadata, Mamba2AttentionMetadata)
-            self_kv_cache = self.kv_cache[forward_context.virtual_engine]
+            self_kv_cache = self.kv_cache[0]
             # conv_state = (..., dim, width-1) yet contiguous along 'dim'
             conv_state = self_kv_cache[0].transpose(-1, -2)
             ssm_state = self_kv_cache[1]

vllm/model_executor/models/qwen3_next.py

@@ -842,7 +842,6 @@ class Qwen3NextGatedDeltaNet(nn.Module, MambaBase):
                 a=a,
                 core_attn_out=core_attn_out,
                 attn_metadata=attn_metadata,
-                virtual_engine=forward_context.virtual_engine,
             )
 
         has_initial_state = attn_metadata.has_initial_state
@@ -853,7 +852,7 @@ class Qwen3NextGatedDeltaNet(nn.Module, MambaBase):
         non_spec_token_indx = attn_metadata.non_spec_token_indx
         spec_state_indices_tensor = attn_metadata.spec_state_indices_tensor  # noqa: E501
         non_spec_state_indices_tensor = attn_metadata.non_spec_state_indices_tensor  # noqa: E501
-        self_kv_cache = self.kv_cache[forward_context.virtual_engine]
+        self_kv_cache = self.kv_cache[0]
         conv_state = self_kv_cache[0].transpose(-1, -2)
         ssm_state = self_kv_cache[1]
         num_actual_tokens = attn_metadata.num_actual_tokens
@@ -1036,13 +1035,12 @@ class Qwen3NextGatedDeltaNet(nn.Module, MambaBase):
         a: torch.Tensor,
         core_attn_out: torch.Tensor,
         attn_metadata: GDNAttentionMetadata,
-        virtual_engine: int,
     ):
         """
         Core attention computation with a packed non-spec decode fast path.
         """
         non_spec_state_indices_tensor = attn_metadata.non_spec_state_indices_tensor  # noqa: E501
-        self_kv_cache = self.kv_cache[virtual_engine]
+        self_kv_cache = self.kv_cache[0]
         conv_state = self_kv_cache[0].transpose(-1, -2)
         ssm_state = self_kv_cache[1]
         num_actual_tokens = attn_metadata.num_actual_tokens

vllm/v1/worker/utils.py

@@ -510,7 +510,7 @@ def bind_kv_cache(
 
     # Bind kv_caches to forward context
     for layer_name, kv_cache in kv_caches.items():
-        # NOTE: Use list because of v0 PP virtual engine.
+        # NOTE: Keep list wrapper for layers that index kv_cache by engine slot.
         forward_context[layer_name].kv_cache = [kv_cache]