On 5/5/26 1:01 PM, Alex Bennée wrote:
> This provides basic instructions for building QEMU.
>
> Signed-off-by: Alex Bennée <[email protected]>
> ---
> .agents/skills/qemu-build/SKILL.md | 50 ++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
> create mode 100644 .agents/skills/qemu-build/SKILL.md
>
> diff --git a/.agents/skills/qemu-build/SKILL.md
> b/.agents/skills/qemu-build/SKILL.md
> new file mode 100644
> index 00000000000..a78678ff632
> --- /dev/null
> +++ b/.agents/skills/qemu-build/SKILL.md
> @@ -0,0 +1,50 @@
> +---
> +name: qemu-build
> +description: Provides step-by-step instructions on configuring and building
> QEMU. You MUST trigger this skill whenever the user asks to build QEMU or
> debug build failures. It includes critical details on build directory reuse
> and spawning sub-agents.
> +license: GPL-2.0-or-later
> +---
> +
> +# Instructions
> +
> +## Examining and Re-using Build Directories
> +Before creating a new build directory, check if an existing one can be
> re-used. QEMU uses out-of-tree builds, typically in `build` or `builds/`
> sub-directories.
> +
> +1. **Check existing configs**: You can examine how an existing build
> directory was configured by checking its `config.log`. Run `head -n 2
> builds/<dir>/config.log`. The second line typically contains the full
> `../configure` command line used.
> +2. **Re-use and Reconfigure**: You have latitude to re-use existing
> directories when appropriate (e.g., `builds/debug` which is a general-purpose
> debug directory for whatever is currently going on). If an existing directory
> has the right flags (like debug/sanitizers) but the wrong target list, you
> can reconfigure it to keep the same config but change the `--target-list`:
> + ```bash
> + cd builds/debug
> + # Check the old config.log, then re-run configure with the new target-list
> + ../../configure <old-flags> --target-list=<new-targets>
> + ```
> +
> +## Launching Builds
> +**Crucial**: You MUST NEVER run builds directly in the main agent context.
> You MUST ALWAYS launch them by spawning a sub-agent using the
> `eca__spawn_agent` tool.
"ECA heritage" showing with the eca__spawn_agent mention. Ending the
sentence after "sub-agent" is likely enough for the model to do the right
thing based on its available tools?
> +Always use the `qemu-helper-agent` for these tasks.
> +Pass the specific build commands, along with the required working directory,
> in the `task` argument. Give the subagent explicit instructions on what to
> verify and what to report back to you.
> +For example: `task: "Navigate to builds/debug and run ninja. If it fails,
> report the exact compiler errors."`
> +
> +## Configuring a New Build
> +If no suitable build directory exists, create a new one.
> +
> +1. **Create build directory**: `mkdir -p builds/test-target; cd
> builds/test-target`
> +2. **Basic Configure**: `../../configure --target-list=[list of targets]`
> + - Common targets: `x86_64-softmmu`, `aarch64-softmmu`, `riscv64-softmmu`,
> `x86_64-linux-user`.
> +3. **Common Options**:
> + - `--enable-debug-info`: Include symbols.
> + - `--enable-debug`: Enable assertions.
> +4. **Sanitizers**:
> + - `--enable-asan`: Address Sanitizer.
> + - `--enable-tsan`: Thread Sanitizer.
> + - `--enable-ubsan`: Undefined Behavior Sanitizer.
> +
> +## Building
> +**Important**: Always re-run the build after making changes to the source
> code.
> +
> +## Reporting Results
> +**Crucial**: After completing the build task, provide a concise summary of
> the results to the calling agent.
> +1. **Summary**: State whether the build passed or failed.
> +2. **Failure Excerpts**: If the build fails, include relevant excerpts from
> the logs (e.g., compiler errors).
> +3. **Full Paths**: Always provide the **absolute file paths** to the full
> logs for further inspection.
> +
> +## Debugging and Environment
> +- **Verbose**: `V=1` for detailed output.
