EriX Virtio Block Driver (drv-virtio-block)

drv-virtio-block is the raw block provider for the seeded QEMU virtio-blk device. It receives a validated BAR-derived DEVICE_FRAME from deviced, drives one polled virtqueue, and exposes synchronous block I/O to blockd through lib-block.

EriX is a clean-room, capability-based microkernel operating system written entirely in Rust.

Technical requirements are tracked in the EriX requirements, conventions, and project documentation.

See:

• docs for design documents, specifications, and development plans.
• Related architecture repositories for kernel, services, libraries, drivers, and integration tooling.

Purpose of This Repository

This repository implements the EriX virtio block driver service. Its purpose in EriX is to mediate virtio block hardware or protocol behavior under explicit deviced / procd ownership.

Functionally, it implements the driver startup, runtime, and validation contracts for virtio block. The repository keeps the implementation, interface contracts, tests, and documentation for that behavior in one reviewable ownership boundary.

The maintained responsibilities are:

• implement the virtio block driver logic behind explicit driver authority
• bind only to startup-assigned device, interrupt, and transport capabilities
• serve bounded driver operations without creating public service authority
• keep driver validation and failure behavior documented for integration tests

Clean-Room Policy

EriX follows a strict clean-room philosophy:

• No external source code may be copied.
• No external Rust crates are allowed.
• No code generation tools that embed third-party code.
• All code must be authored within the project.

Violations will result in rejection of the contribution.

License

All EriX repositories are licensed under the ISC License.

Development Model

EriX development is modular, deterministic, reproducible, authority-explicit, security-first, and self-hosting oriented.

This repository follows the project roadmap and the validation rules documented in its own roadmap.

Validation

• cargo fmt --all -- --check
• strict clippy with warnings as errors
• standalone crate CI through ../integration/scripts/setup-component-ci-overrides.sh so internal git dependencies resolve from the matching branch head without cross-repo path deps
• local unit tests for virtqueue layout, request framing, and read-only flag propagation
• full VM integration through the storage scenarios
• Cargo.toml keeps lib-block on branch = "main"; local branch-head validation relies on the generated integration CARGO_HOME overrides instead of a cross-repo path dependency

Governance Principles

drv-virtio-block governance is scoped to the virtio block driver role and its assigned hardware/provider authority.

The scoped governance rules are:

• It must be started and supervised through deviced and procd, not as an independently discovered public service.
• It uses only the device, interrupt, transport, and provider capabilities explicitly transferred at startup.
• It keeps hardware-specific behavior inside the driver while leaving device-matching policy to deviced.
• It rejects malformed device state and unexpected authority instead of broadening access.

Authority Boundaries

• drv-virtio-block does not receive named, filesystem-provider, or peer-driver authority.
• New hardware access requires explicit manifest, startup, and integration-test coverage.

Contact

Development occurs in EriX organization and discussions happen in issues and design documents.

No decisions are considered valid without documented rationale.

Maintainers can be reached via email: admin@erikinkinen.fi.