diff --git a/vllm/attention/backends/rocm_flash_attn.py b/vllm/attention/backends/rocm_flash_attn.py
index 5a26ccafb46d7..660f26c71c381 100644
--- a/vllm/attention/backends/rocm_flash_attn.py
+++ b/vllm/attention/backends/rocm_flash_attn.py
@@ -621,11 +621,25 @@ def forward(
 
         if prefill_meta := attn_metadata.prefill_metadata:
             output = torch.empty_like(query)
-            (query_seq_start_loc, query_max_seq_len, key_seq_start_loc,
-             key_max_seq_len, seq_lens,
-             causal_mask) = _get_seq_len_block_table_args(
-                 prefill_meta, attn_type)
 
+            # Prompt run.
+            # normal attention and DECODER
+            if attn_type == AttentionType.DECODER and (
+                    kv_cache.numel() == 0 or prefill_meta.block_tables is None
+                    or prefill_meta.block_tables.numel() == 0):
+                (query_seq_start_loc, query_max_seq_len, key_seq_start_loc,
+                 key_max_seq_len, seq_lens,
+                 causal_mask) = (prefill_meta.seq_start_loc,
+                                 prefill_meta.max_prefill_seq_len,
+                                 prefill_meta.seq_start_loc,
+                                 prefill_meta.max_prefill_seq_len,
+                                 attn_metadata.seq_lens, True)
+            # prefix-enabled attention and ENCODER/ENCODER_DECODER
+            else:
+                (query_seq_start_loc, query_max_seq_len, key_seq_start_loc,
+                 key_max_seq_len, seq_lens,
+                 causal_mask) = _get_seq_len_block_table_args(
+                     prefill_meta, attn_type)
             # Prompt run.
             if kv_cache.numel() == 0 or prefill_meta.block_tables.numel() == 0:
                 # triton attention