Qemu Build

QEMU Build

Use this operational skill when the task asks to inspect, configure, build, reconfigure, or diagnose a QEMU build.

Flow relationship

• For non-trivial work, qemu-flow-plan owns the plan and artifact root.
• qemu-build owns only build-directory decisions and build evidence.
• Store copied logs, command transcripts, and diagnosis reports under build/agent//.

Hard policy boundary

Do not produce source code intended for QEMU upstream submission. Do not add DCO or review trailers.

Build directory rule

Default to build/ in the QEMU source tree. Reuse it when suitable.

Before creating or reconfiguring anything, inspect:

• build/config.log for the configure command;
• build/build.ninja for configured state;
• build/pyvenv/bin/meson for Meson commands;
• build/meson-logs/meson-log.txt for configure failures;
• build/meson-info/intro-buildoptions.json for options.

Create another directory only when needed to preserve a different configuration, such as sanitizer vs non-sanitizer.

Configure

From the QEMU source root:

mkdir -p build
cd build
../configure --target-list=

Common targets:

• x86_64-softmmu
• aarch64-softmmu
• riscv64-softmmu
• loongarch64-softmmu
• x86_64-linux-user
• aarch64-linux-user

Useful options:

• --enable-debug
• --enable-debug-info
• --enable-trace-backends=log
• --enable-asan
• --enable-tsan
• --enable-ubsan

Use ../configure --help for the checked-out QEMU version.

Reconfigure safely

Reconstruct the old command from build/config.log, then change only the needed option.

Preserve:

• target list unless the task changes it;
• debug/sanitizer/trace options;
• dependency/accelerator options;
• build directory evidence until diagnosis is complete.

Do not delete build/ to make an error disappear.

Build

From the source root:

ninja -C build

Prefer narrow targets when possible:

ninja -C build qemu-system-riscv64
ninja -C build tests/qtest/

Use verbose mode only for diagnosis:

ninja -C build -v 

Failure classification

• Configure: missing dependency, unsupported option, Python/Meson issue, compiler mismatch.
• Compile: API/type/include/feature guard mismatch.
• Link: missing object in Meson, missing dependency, target-specific source not linked.
• Generated source: QAPI, trace-events, decodetree, or Meson generator input.
• Toolchain/host: sanitizer or compiler incompatibility.

For generated-source failures, fix the generator input, not generated files in build/.

Report

Write/report:

• PASS/FAIL/INCONCLUSIVE;
• source root and build dir;
• exact command;
• target list and key options;
• decisive failure excerpt;
• full log paths under build/ and copied notes under build/agent//;
• what the build proves.

Upstream references

• QEMU code provenance and AI policy: docs/devel/code-provenance.rst.
• QEMU RFC qemu-build skill.
• Testing overview: docs/devel/testing/main.rst.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: processmission
• Source: processmission/oh-my-qemu
• License: MIT
• Homepage: https://processmission.github.io/oh-my-qemu/

Install and usage instructions live in the source repository linked above.