---
id: pr-vllm-21342
repo: vllm-project/vllm
pr: 21342
title: '[V1] port xformers backend to v1'
author: TheEpicDolphin
date: '2025-08-05'
url: https://github.com/vllm-project/vllm/pull/21342
source_category: upstream-code
architectures:
- sm100
tags: []
techniques: []
hardware_features: []
kernel_types: []
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: 469b3ffaaadb6ab15ddbebc47ac11a0c6fddfda2
inclusion_reason: defer
changed_paths:
- tests/v1/attention/utils.py
- vllm/engine/arg_utils.py
- vllm/platforms/cuda.py
- vllm/platforms/interface.py
- vllm/v1/attention/backends/tree_attn.py
- vllm/v1/attention/backends/xformers.py
artifact_dir: evidence/pull-bundles/vllm/gh-21342
head_ref_oid: 1a78486932e13ac722060e1198a1685ae093e94a
---
# [V1] port xformers backend to v1

- Repository: `vllm-project/vllm`
- PR: [21342](https://github.com/vllm-project/vllm/pull/21342)
- Decision: `defer`
- Reason: defer

## Changed Paths

- `tests/v1/attention/utils.py`
- `vllm/engine/arg_utils.py`
- `vllm/platforms/cuda.py`
- `vllm/platforms/interface.py`
- `vllm/v1/attention/backends/tree_attn.py`
- `vllm/v1/attention/backends/xformers.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-21342`
