Linux-loader

Short-description

• Parsing and loading vmlinux (raw ELF image) and bzImage images
• Linux command line parsing and generation
• Definitions and helpers for the Linux boot protocol

How to build

cd linux-loader
cargo build

Tests

Our Continuous Integration (CI) pipeline is implemented on top of Buildkite. For the complete list of tests, check our CI pipeline.

Each individual test runs in a container. To reproduce a test locally, you can use the dev-container on both x86 and arm64.

docker run -it \
           --security-opt seccomp=unconfined \
           --volume $(pwd):/linux-loader \
           rustvmm/dev:v2
cd linux-loader/
cargo test

Test Profiles

The integration tests support two test profiles:

• devel: this is the recommended profile for running the integration tests on a local development machine.
• ci (default option): this is the profile used when running the integration tests as part of the the Continuous Integration (CI).

The test profiles are applicable to tests that run using pytest. Currently only the coverage test follows this model as all the other integration tests are run using the Buildkite pipeline.

The difference between is declaring tests as passed or failed:

• with the devel profile the coverage test passes if the current coverage is equal or higher than the upstream coverage value. In case the current coverage is higher, the coverage file is updated to the new coverage value.
• with the ci profile the coverage test passes only if the current coverage is equal to the upstream coverage value.

Further details about the coverage test can be found in the Adaptive Coverage section.

Adaptive Coverage

The line coverage is saved in tests/coverage. To update the coverage before submitting a PR, run the coverage test:

docker run -it \
           --security-opt seccomp=unconfined \
           --volume $(pwd):/linux-loader \
           rustvmm/dev:v2
cd linux-loader/
pytest --profile=devel tests/test_coverage.py

If the PR coverage is higher than the upstream coverage, the coverage file needs to be manually added to the commit before submitting the PR:

git add tests/coverage

Failing to do so will generate a fail on the CI pipeline when publishing the PR.

NOTE: The coverage file is only updated in the devel test profile. In the ci profile the coverage test will fail if the current coverage is higher than the coverage reported in tests/coverage.

bzImage test

As we don't want to distribute an entire kernel bzImage, the load_bzImage test is ignored by default. In order to test the bzImage support, one needs to locally build a bzImage, copy it to the src/loader directory and run cargo test:

# Assuming your linux-loader and linux-stable are both under $LINUX_LOADER
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git $LINUX_LOADER/linux-stable
$ cd linux-stable
$ make bzImage 
$ cp linux-stable/arch/x86/boot/bzImage $LINUX_LOADER/linux-loader/src/loader/
$ cd $LINUX_LOADER/linux-loader
$ docker run -it \
           --security-opt seccomp=unconfined \
           --volume $(pwd):/linux-loader \
           rustvmm/dev:v2
$ cd linux-loader/
$ cargo test