smolvm-core 0.0.10

Rust-accelerated network operations for SmolVM

smolvm-core

smolvm-core is the small native helper package for SmolVM. It handles low-level system work such as fast network setup, while the main smolvm package keeps the public Python API.

Most users should install smolvm, not smolvm-core directly:

pip install smolvm

That install pulls in the matching smolvm-core wheel automatically on supported platforms.

Install smolvm-core directly only if you are developing the native extension or testing package releases.

When the native extension is used

SmolVM uses smolvm-core for fast host networking — creating TAP devices, adding routes, writing sysctls — when it's available. When it isn't, SmolVM falls back to running ip, nft, and sysctl as subprocesses. Both paths produce the same result; the native path is just much faster.

Scenario	Path used	What happens
Linux + smolvm-core wheel installed	Native (netlink)	Direct kernel calls — microseconds per operation.
Linux + wheel missing or broken	Subprocess	Forks ip/nft/sysctl for each operation. Fully functional but significantly slower; VM creation takes longer.
macOS	Path never reached	macOS uses the QEMU backend with user-mode networking (SLIRP), so the host-networking code that would call smolvm-core isn't exercised.

On Linux, if SmolVM falls back to subprocess, it logs a warning at startup:

WARNING smolvm.host._accel: smolvm-core native extension is unavailable;
falling back to subprocess (ip/nft/sysctl) for network operations,
which is significantly slower. Reinstall smolvm to pick up the native wheel.

The fix is to reinstall smolvm so pip picks up the matching wheel for your platform.