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Fix APLIC MSI retriggering for deasserted level interrupts - #11966

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zijunteng238-dot wants to merge 6 commits into
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@zijunteng238-dot

@zijunteng238-dot zijunteng238-dot commented Nov 1, 2026 •

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拉取/合并请求描述:(PR description)

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为什么提交这份PR (why to submit this PR)

在 QEMU 8.2.2 上运行 bsp/qemu-virt64-riscv,采用 RV64、SMP 4 核及 AIA(APLIC/IMSIC)配置时,带有 rt_thread_mdelay(1000) 延时的计数打印程序仅输出 RISC-V test: 0,随后无法继续打印。

经排查,APLIC 驱动在处理电平中断的 EOI 时会无条件写入 setipnum_le。旧版 QEMU 在设备已经撤销中断后,仍可能因该写入产生新的 MSI,形成持续的虚假中断,阻碍系统定时器处理,导致延时线程无法正常恢复执行。

QEMU 上游已通过相关提交修复这一模拟问题。本 PR 在 RT-Thread 的 APLIC 驱动中增加兼容处理,使上述旧版 QEMU 环境也能正常运行。

你的解决方案是什么 (what is your solution)

修改 libcpu/risc-v/common/pic/pic-riscv-aplic.c 中的 aplic_msi_irq_eoi():对于高、低电平中断,先读取 in_clrip 中对应的有效输入状态(rectified input,已考虑中断极性),仅在设备仍保持中断有效时写入 setipnum_le。这样既保留了电平中断的重触发能力,也避免了设备撤销中断后,旧版 QEMU 继续产生虚假 MSI。

同时,将 bsp/qemu-virt64-riscv/applications/main.c 中原先仅打印一次 Hello RISC-V 的程序改为计数循环,依次输出 RISC-V test: 0 至 RISC-V test: 9,每次打印后调用 rt_thread_mdelay(1000)。该程序用于复现问题,并观察修复后的延时与线程恢复行为;完成十次打印和延时后退出 main()。

此外,补充问题记录,说明复现步骤、定位过程、兼容处理方式及验证结果。

请提供验证的bsp和config (provide the config and bsp)

  • BSP:bsp/qemu-virt64-riscv
  • .config:使用该 BSP 的现有配置,本次修复未修改 .config。关键选项如下:

CONFIG_ARCH_RISCV64=y
CONFIG_RT_USING_RISCV_NEW_COMMON=y
CONFIG_RT_USING_SMP=y
CONFIG_RT_CPUS_NR=4
CONFIG_RT_TICK_PER_SECOND=100

CONFIG_RT_USING_SMART is not set

AIA 由 qemu.py 的启动参数控制,RV64 下默认启用。测试时通过添加 -no-aia 切换到传统中断路径,进行对照验证。

验证环境:

  • QEMU 8.2.2
  • OpenSBI v1.3
  • riscv64-unknown-elf-gcc 13.2.0

在 BSP 目录执行 scons -j8,编译和链接通过。修复后,以下三种运行配置均能完整输出 RISC-V test: 0 至 RISC-V test: 9:

运行配置 验证结果
AIA,4 核,关闭网络、NVMe、virtio-console 和 PCI serial 完整输出计数
关闭 AIA,4 核,关闭上述设备 完整输出计数
AIA,4 核,开启默认设备组合 完整输出计数

第三项测试使用独立临时磁盘,并将宿主机监听端口调整为自动分配,以避免资源占用;虚拟机中的默认设备组合保持开启。

本次验证覆盖上述 QEMU 8.2.2 环境,尚未覆盖真实 APLIC 硬件、低电平外设及其他 QEMU 版本。
]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

  • 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
  • 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality:

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

  • 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
  • 代码风格正确,包括缩进空格,命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
  • 没有垃圾代码,代码尽量精简,不包含#if 0代码,不包含已经被注释了的代码 All redundant code is removed and cleaned up
  • 所有变更均有原因及合理的,并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
  • 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
  • 代码是高质量的 Code in this PR is of high quality
  • 已经使用clang-format 源码格式化工具确保格式符合RT-Thread代码规范 This PR has been formatted with clang-format and complies with RT-Thread code specification
  • 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

@CLAassistant

CLAassistant commented Nov 1, 2026 •

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CLA assistant check
All committers have signed the CLA.

@github-actions

github-actions Bot commented Nov 1, 2026

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👋 感谢您对 RT-Thread 的贡献!Thank you for your contribution to RT-Thread!

为确保代码符合 RT-Thread 的编码规范,请在你的仓库中执行以下步骤运行代码格式化工作流(如果格式化CI运行失败)。
To ensure your code complies with RT-Thread's coding style, please run the code formatting workflow by following the steps below (If the formatting of CI fails to run).


🛠 操作步骤 | Steps

  1. 前往 Actions 页面 | Go to the Actions page
    点击进入工作流 → | Click to open workflow →

  2. 点击 Run workflow | Click Run workflow

  • Use workflow from 保持默认分支(通常为 master)
    Keep the default branch (usually master) in Use workflow from
  • 在 branch 输入框填写 PR 分支 rt-thread-learning
    Enter PR branch rt-thread-learning in the branch field
  • 设置需排除的文件/目录(目录请以"/"结尾)
    Set files/directories to exclude (directories should end with "/")
  1. 等待工作流完成 | Wait for the workflow to complete
    格式化后的代码将作为独立提交推送至你的分支。
    The formatting changes will be pushed to your branch as a separate commit.

完成后,提交将自动更新至 rt-thread-learning 分支,关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the rt-thread-learning branch automatically, and the related Pull Request will be updated.

如有问题欢迎联系我们,再次感谢您的贡献!💐
If you have any questions, feel free to reach out. Thanks again for your contribution!

@github-actions github-actions Bot added BSP Doc This PR/issue related with documents Arch: RISC-V BSP related with risc-v libcpu labels Nov 1, 2026
@github-actions

github-actions Bot commented Nov 1, 2026

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📌 Code Review Assignment

🏷️ Tag: documentation

Reviewers: @CXSforHPU @GorrayLi @lianux-mm

Changed Files (Click to expand)
  • documentation/1.introduction/rt-thread-source-guide-zh.md
  • documentation/2.quick-start/riscv-qemu-aia-delay-issue.md
  • documentation/2.quick-start/riscv-qemu-learning-guide.md

🏷️ Tag: libcpu_riscv

Reviewers: @Yaochenger

Changed Files (Click to expand)
  • libcpu/risc-v/common/pic/pic-riscv-aplic.c

📊 Current Review Status (Last Updated: 2026-11-01 20:40 CST)


📝 Review Instructions

  1. 维护者可以通过单击此处来刷新审查状态: 🔄 刷新状态
    Maintainers can refresh the review status by clicking here: 🔄 Refresh Status

  2. 确认审核通过后评论 LGTM/lgtm
    Comment LGTM/lgtm after confirming approval

  3. PR合并前需至少一位维护者确认
    PR must be confirmed by at least one maintainer before merging

ℹ️ 刷新CI状态操作需要具备仓库写入权限。
ℹ️ Refresh CI status operation requires repository Write permission.

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