[V1][TPU] Pad the block_table.shape[1] so the ragged paged attention can handle correctly (#14597)

Author: vanbasten23

vllm/v1/worker/tpu_model_runner.py

@@ -23,7 +23,8 @@
 from vllm.sampling_params import SamplingType
 from vllm.sequence import IntermediateTensors
 from vllm.utils import LayerBlockType, cdiv, is_pin_memory_available
-from vllm.v1.attention.backends.pallas import (PallasAttentionBackend,
+from vllm.v1.attention.backends.pallas import (NUM_KV_PAGES_PER_BLOCK,
+                                               PallasAttentionBackend,
                                                PallasMetadata)
 from vllm.v1.core.encoder_cache_manager import compute_encoder_budget
 from vllm.v1.kv_cache_interface import (FullAttentionSpec, KVCacheConfig,
@@ -138,8 +139,10 @@ def __init__(
                                             device="cpu")
         self.slot_mapping_np = self.slot_mapping_cpu.numpy()
 
+        padded_max_num_blocks_per_req = _get_padded_number(
+            self.max_num_blocks_per_req, NUM_KV_PAGES_PER_BLOCK)
         self.block_table_cpu = torch.zeros(
-            (self.max_num_tokens, self.max_num_blocks_per_req),
+            (self.max_num_tokens, padded_max_num_blocks_per_req),
             dtype=self.input_batch.block_table.get_cpu_tensor().dtype,
             device="cpu")