[ROCm] Add Aiter PagedAttention with Sliding Window support

[sammysun0711]

Purpose

This PR aim to add Aiter PagedAttention (PA) with sliding window support, which can fix google/gemma-3-27b-it bfloat16 model accuracy issue with Aiter PA.

google/gemma-3-27b-it trained with additional parameter "sliding_window": 1024.

• Triton unified attention (default) unified_attention passed sliding windows as input:

  vllm/vllm/v1/attention/backends/triton_attn.py

  Lines 346 to 366 in 30700b1

  	unified_attention(
  	q=query[:num_actual_tokens],
  	k=key_cache,
  	v=value_cache,
  	out=output[:num_actual_tokens],
  	cu_seqlens_q=cu_seqlens_q,
  	max_seqlen_q=max_seqlen_q,
  	seqused_k=seqused_k,
  	max_seqlen_k=max_seqlen_k,
  	softmax_scale=self.scale,
  	causal=True,
  	alibi_slopes=self.alibi_slopes,
  	window_size=self.sliding_window,
  	block_table=block_table,
  	softcap=self.logits_soft_cap,
  	q_descale=None, # Not supported
  	k_descale=layer._k_scale.expand(descale_shape),
  	v_descale=layer._v_scale.expand(descale_shape),
  	sinks=self.sinks,
  	output_scale=output_scale,
  	)

• Aiter PA torch.ops.aiter.paged_attention_v1 does not pass sliding_windows as input:

  vllm/vllm/v1/attention/backends/rocm_aiter_fa.py

  Lines 810 to 828 in 30700b1

  	torch.ops.aiter.paged_attention_v1(
  	output[:num_decode_tokens],
  	workspace_buffer,
  	query[:num_decode_tokens],
  	key_cache,
  	value_cache,
  	self.scale,
  	attn_metadata.block_table[:num_decodes],
  	attn_metadata.query_start_loc[:num_decodes],
  	attn_metadata.seq_lens[:num_decodes],
  	attn_metadata.max_seq_len,
  	self.alibi_slopes,
  	self.kv_cache_dtype,
  	"NHD",
  	self.logits_soft_cap,
  	layer._k_scale,
  	layer._v_scale,
  	None,
  	_PARTITION_SIZE_ROCM,

If input prompt token is large than 1024, missing handling sliding_windows cause the gemma3 accuracy degradation with Aiter PA.

To fixed gemma3 accuracy issue, following 3 PR required:

• This PR aim to pass sliding_windows parameter to torch.ops.aiter.paged_attention_v1
• [Fix] Add sliding window feature for paged_attention_v1 ROCm/aiter#1362 need to be merged in Aiter main branch, and vllm upgrade dockerfile to latest Aiter main branch.
• [ROCm][Qwen3-32B] Fix AITER MHA accuracy issue cause by #25763 #28670 need to be merge to fix Aiter MHA issue.

Open as draft PR for now since it depends on other 2 PRs.

Test Plan

lm_eval test with gsm8k dataset

Test Result

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• The test plan, such as providing test command.
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[sammysun0711]

Sorry, need to close due to rebase issue, continue in new PR: #29065.