2b1b3644da
I plan to add some wrapper errors around vhost errors. These end up nesting other errors all the way to std::error::Error, which has no Eq trait. The implementations were only used for comparisions in tests. While there is a assert_matches!() in nightly [1] it seems unlikely that further testing lib additions are getting standarized soon (or ever). One could use assert!(matches!()), but that would worsen the error messages for test failures. Hence, during review [2] we agreed on introducing the assert_matches crate. It got no dependencies and allows us to keep the good error messages while not needing to depend on nightly. Signed-off-by: Erik Schilling <erik.schilling@linaro.org> [1] https://doc.rust-lang.org/std/assert_matches/macro.assert_matches.html [2] https://github.com/rust-vmm/vhost-device/pull/388#discussion_r1257831748 |
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| Cargo.toml | ||
| CODEOWNERS | ||
| coverage_config_x86_64.json | ||
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| README.md | ||
vhost-device
Design
This repository hosts various 'vhost-user' device backends in their own crates. See their individual README.md files for specific information about those crates.
Here is the list of device backends that we support:
Testing and Code Coverage
Like the wider rust-vmm project we expect new features to come with comprehensive code coverage. However as a multi-binary repository there are cases where avoiding a drop in coverage can be hard and an exception to the approach is allowable. These are:
- adding a new binary target (aim at least 60% overall coverage)
- expanding the main function (a small drop is acceptable)
However any new feature added to an existing binary should not cause a drop in coverage. The general aim should be to always improve coverage.
Separation of Concerns
The binaries built by this repository can be run with any VMM which can act as a vhost-user frontend. Typically they have been tested with QEMU although the rust-vmm project does provide a vhost-user frontend crate for rust based VMMs.
While it's possible to implement all parts of the backend inside the vhost-device workspace consideration should be given to separating the VirtQueue handling and response logic to a crate in vm-virtio devices. This way a monolithic rust-vmm VMM implementation can reuse the core logic to service the virtio requests directly in the application.
Build dependency
The GPIO crate needs a local installation of libgpiod library to be available. If your distro ships libgpiod >= v2.0, then you should be fine.
Otherwise, you will need to build libgpiod yourself:
git clone --depth 1 --branch v2.0.x https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/
cd libgpiod
./autogen.sh --prefix="$PWD/install/"
make install
In order to inform tools about the build location, you can now set:
export PKG_CONFIG_PATH="<PATH-TO-LIBGPIOD>/install/lib/pkgconfig/"
To prevent setting this in every terminal session, you can also configure cargo to set it automatically.
Xen support
Supporting Xen requires special handling while mapping the guest memory. The
vm-memory crate implements xen memory mapping support via a separate feature
xen, and this crate uses the same feature name to enable Xen support.
It was decided by the rust-vmm maintainers to keep the interface simple and
build the crate for either standard Unix memory mapping or Xen, and not both.