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# kvm-ioctls

The kvm-ioctls crate provides safe wrappers over the
[KVM API](https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt), a set
of ioctls used for creating and configuring Virtual Machines (VMs) on Linux.
The ioctls are accessible through four structures:
- `Kvm` - wrappers over system ioctls
- `VmFd` - wrappers over VM ioctls
- `VcpuFd` - wrappers over vCPU ioctls
- `DeviceFd` - wrappers over device ioctls

For further details check the
[KVM API](https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt) as well
as the code documentation.

## Supported Platforms

The kvm-ioctls can be used on x86_64 and aarch64. Right now the aarch64 support
is considered experimental. For a production ready version, please check the
progress in the corresponding
[GitHub issue](https://github.com/rust-vmm/kvm-ioctls/issues/8).

## Running the tests

Our Continuous Integration (CI) pipeline is implemented on top of
[Buildkite](https://buildkite.com/).
For the complete list of tests, check our
[CI pipeline](https://buildkite.com/rust-vmm/kvm-ioctls-ci).

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

```bash
docker run --device=/dev/kvm \
           -it \
           --security-opt seccomp=unconfined \
           --volume $(pwd)/kvm-ioctls:/kvm-ioctls \
           fandree/rust-vmm-dev
cd kvm-ioctls/
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](tests/test_coverage.py) follows this model as all the other
integration tests are run using the
[Buildkite pipeline](https://buildkite.com/rust-vmm/kvm-ioctls-ci).

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](#adaptive-coverage) section.

### Adaptive Coverage

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

```bash
docker run --device=/dev/kvm \
           -it \
           --security-opt seccomp=unconfined \
           --volume $(pwd)/kvm-ioctls:/kvm-ioctls \
           fandree/rust-vmm-dev
cd kvm-ioctls/
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:

```bash
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](tests/coverage).