[Bugfix] Fix getting device for MoE LoRA (#29475)

Signed-off-by: Jee Jee Li <pandaleefree@gmail.com>

vllm/lora/layers/fused_moe.py

@@ -30,6 +30,8 @@ from vllm.model_executor.layers.fused_moe.fused_moe_modular_method import (
     FusedMoEModularMethod,
 )
 
+from .utils import _get_lora_device
+
 
 class FusedMoEWithLoRA(BaseLayerWithLoRA):
     def __init__(self, base_layer: FusedMoE) -> None:
@@ -41,7 +43,7 @@ class FusedMoEWithLoRA(BaseLayerWithLoRA):
         )
         self.tp_size = get_tensor_model_parallel_world_size()
         self.tp_rank = get_tensor_model_parallel_rank()
-        self.device = base_layer.w2_weight.device
+        self.device = _get_lora_device(base_layer)
         self._w13_slices = 2
         self._inject_lora_into_fused_moe()
 

vllm/lora/layers/utils.py

@@ -33,6 +33,15 @@ def _get_lora_device(base_layer: nn.Module) -> torch.device:
     # HQQ marlin
     elif hasattr(base_layer, "W_q"):
         return base_layer.W_q.device
+    # MoE layer
+    elif hasattr(base_layer, "w2_weight"):
+        return base_layer.w2_weight.device
+    # MoE Compressed Tensor
+    elif hasattr(base_layer, "w2_weight_packed"):
+        return base_layer.w2_weight_packed.device
+    # MoE GPTQ/AWQ/GGUF
+    elif hasattr(base_layer, "w2_qweight"):
+        return base_layer.w2_qweight.device
     else:
         raise ValueError(f"Unsupported base layer: {base_layer}")