[Bugfix] Fix a couple PPLX+CUTLASS MoE bugs (#20825)

Signed-off-by: ElizaWszola <ewszola@redhat.com>

Author: ElizaWszola

vllm/model_executor/layers/fused_moe/pplx_prepare_finalize.py

@@ -204,7 +204,7 @@ def prepare(
             out_expert_x_scale=expert_x_scale,
             dp_x=a1q,
             dp_x_scale=a1q_scale,
-            indices=topk_ids,
+            indices=topk_ids.view(dtype=torch.uint32),
             bound_m=bound_m,
         )
 
@@ -249,7 +249,7 @@ def finalize(
             topk_weights = torch.ones_like(topk_weights)
 
         self.a2a.combine(out_tokens=output,
-                         indices=topk_ids,
+                         indices=topk_ids.view(dtype=torch.uint32),
                          weights=topk_weights,
                          expert_y=fused_expert_output,
                          bound_m=bound_m)

vllm/model_executor/layers/quantization/compressed_tensors/compressed_tensors_moe.py

@@ -737,10 +737,8 @@ def __init__(
                 "For FP8 Fused MoE layer, we require either per tensor or "
                 "channelwise, dynamic per token quantization.")
 
-        from vllm.model_executor.layers.fused_moe.cutlass_moe import (
-            cutlass_moe_fp8)
         self.topk_indices_dtype = None
-        self.fused_experts = cutlass_moe_fp8  # type: ignore
+        self.fused_experts = None  # type: ignore
         self.disable_expert_map = False
 
     def create_weights(self, layer: torch.nn.Module, num_experts: int,
@@ -936,21 +934,40 @@ def apply(
         per_act_token = a1_scale.numel() != 1 if a1_scale is not None else (
             a2_scale.numel() != 1 if a2_scale is not None else False)
 
-        return self.fused_experts(
-            x,
-            layer.w13_weight,
-            layer.w2_weight,
-            topk_weights,
-            topk_ids,
-            per_act_token=per_act_token,
-            activation=activation,
-            global_num_experts=global_num_experts,
-            expert_map=None if self.disable_expert_map else expert_map,
-            w1_scale=layer.w13_weight_scale,
-            w2_scale=layer.w2_weight_scale,
-            a1_scale=a1_scale,
-            a2_scale=a2_scale,
-        )
+        if self.fused_experts is None:
+            # If no modular kernel is provided, use cutlass_moe_fp8
+            from vllm.model_executor.layers.fused_moe.cutlass_moe import (
+                cutlass_moe_fp8)
+            return cutlass_moe_fp8(
+                x,
+                layer.w13_weight,
+                layer.w2_weight,
+                topk_weights,
+                topk_ids,
+                per_act_token=per_act_token,
+                activation=activation,
+                global_num_experts=global_num_experts,
+                expert_map=None if self.disable_expert_map else expert_map,
+                w1_scale=layer.w13_weight_scale,
+                w2_scale=layer.w2_weight_scale,
+                a1_scale=a1_scale,
+                a2_scale=a2_scale,
+            )
+        else:
+            return self.fused_experts(
+                x,
+                layer.w13_weight,
+                layer.w2_weight,
+                topk_weights,
+                topk_ids,
+                activation=activation,
+                global_num_experts=global_num_experts,
+                expert_map=None if self.disable_expert_map else expert_map,
+                w1_scale=layer.w13_weight_scale,
+                w2_scale=layer.w2_weight_scale,
+                a1_scale=layer.w13_input_scale,
+                a2_scale=layer.w2_input_scale,
+            )
 
 
 class CompressedTensorsW8A8Int8MoEMethod(CompressedTensorsMoEMethod):