Experimental QEMU8 build system

This is a build of QEMU8 from scratch on Linux, using AOSP-specific compiler toolchain and sysroot (based on an old glibc-2.17 to ensure the generated binaries run on a vast number of distributions).

Prerequisite:

Ensure podman is installed with sudo apt-get install podman

Reproducing a build in AOSP

This secion is about rebuilding QEMU with AOSP toolchain (with the repo tool). Information about how to iterate on this build can be found in the next section.

If you have an AOSP checkout, run:

$ANDROID_BUILD_TOP/device/google/cuttlefish_vmm/qemu/scripts/rebuild_in_container.sh

This will create a clean source checkout of QEMU and all relevant dependencies, and starts a build isolated in a podman container.

If you don't have an AOSP checkout, run:

mkdir cuttlefish_vmm
cd cuttlefish_vmm
repo init --manifest-url https://android.googlesource.com/device/google/cuttlefish_vmm \
  --manifest-name=qemu/manifest.xml
repo sync -j 12
qemu/scripts/rebuild_in_container.sh --from_existing_sources

--from_existing_sources also makes possible to reuse an existing QEMU source checkout to iterate faster.

The result is a portable QEMU archive that can be found in /tmp/qemu-build-output/qemu-portable.tar.gz

Development process

QEMU assembles many source trees that use git submodules. Hence it is more convenient to iterate on a checkout based on git submodules for development, and to capture the state in a repo manifest before submitting the changes to AOSP.

git clone sso://experimental-qemu-build-internal.googlesource.com/qemu-build qemu
cd qemu
git submodule update --init --depth 1 --recursive --jobs 4

You can build without isolation with:

qemu/scripts/rebuild.sh --build-dir ~/qemu-build.out

You can also build in a container with:

qemu/scripts/rebuild_in_container.sh --from_existing_sources

After sucessfull build the ASOP binaries can be updated with:

tar -xvf /tmp/qemu-build-output/qemu-portable.tar.gz \
  -C $ANDROID_BUILD_TOP/device/google/cuttlefish_vmm/qemu/x86_64-linux-gnu

This makes possible to upvert a dependency such as qemu and regenerate the repo manifest from the submodule tree.

python3 qemu/scripts/genrepo.py . --repo_manifest qemu/manifest.xml

Check your code before submit

The following script run pytype and pyformat.

scripts/check.sh

Regenerate Cargo crates list

Cargo crates are checked-in as part of the source tree and enumerated by qemu/third_party/.cargo/config.toml. This file hase be regenerated when qemu/third_party/rust/crate changes with the following command line:

ls qemu/third_party/rust/crates | awk '
  BEGIN {print "[patch.crates-io]"}
  {print $1 " = { path = \"rust/crates/" $1 "\" }"}' > qemu/third_party/.cargo/config.toml