Greg Kurtzer's Ginux is now a userspace kernel

Gmux is a configurable userspace kernel designed to provide isolated Linux compatibility instances. It operates as a regular Linux process, establishing an explicit, versioned contract between managed workloads and the host kernel. This represents a significant pivot from its initial incarnation as an independent Rust kernel that booted directly through UEFI.

• The Pivot: The original bootable Rust kernel, developed with an AI coding agent, proved the concept of running a Linux userspace. However, the project recognized the impossibility of fully reimplementing the vast Linux ecosystem. The valuable lesson was the boundary exposed: Linux maintains a broad userspace ABI, but Ginux deliberately creates a smaller, explicit contract.
• Current Architecture: Ginux supervises native x86-64 programs, intercepting managed syscalls. It then decides whether to emulate the syscall from its own state, mediate it through a narrow host operation, or deny it entirely. This allows for precise control over what an instance can do.
• Key Features: Its implementation includes a security-focused x86-64 interpreter, strict instance configuration, a digest-pinned OCI root, and virtualized resources like /proc, /sys, cgroups, and network backends. It provides a baseline Rocky Linux 10 systemd environment with explicit compatibility claims, not full Linux ABI.
• Agent Containment: A primary research goal is to use Ginux as a containment boundary for AI agents and other automated software. By exposing only the necessary operations and virtual resources, it aims to create a reviewable and auditable boundary for untrusted code.
• Comparison: Ginux differentiates itself from tools like seccomp, User-Mode Linux, gVisor, and Gramine by focusing on a specific, versioned kernel contract that serves as a reviewable boundary for each instance.
• Development Method: The project employs Human-Directed Agentic Engineering (HDAE), where human architects define the intent, constraints, and tests, while AI agents assist in implementation, diagnosis, and testing.
• Limitations: Ginux is research software, lacks independent security certification, and does not provide full Linux compatibility. It is not ready for production workloads, with unknown contract operations defaulting to denial.

Ultimately, Ginux offers a novel, contract-based approach to Linux userspace isolation, particularly promising for sandboxing AI agents, by deliberately constraining the traditional Linux ABI rather than fully reimplementing it. While still in its research phase, its methodology presents an interesting alternative in the landscape of system virtualization and containment.