Radiance

Experimental KVM based VMM for aarch64 platform.

Note

Currently only systems with GICv2/m like Raspberry Pi 4/5 are supported since this is the only aarch64 hardware I have for development.

Defining characteristics:

• no external dependencies
• statically compiled (no libc or musl)
• no memory allocations after the VM start
• minimal memory overhead over requested VM memory size
• support for Block,Net,Pmem,Uart,Rtc devices
• support for PCI (currently only for Block)
• optimized MMIO device path which makes MMIO devices as fast as PCI ones
• snapshot creation/restoration

Build:

zig build -Doptimize=ReleaseFast

Usage:

Usage:
        --config-path

Example:

Start VM from config

radiance --config-path config.toml

Pause/Snapshot/Resume

echo "pause" | sudo socat - UNIX-CONNECT:./test.socket
echo "snapshot snap.rad" | sudo socat - UNIX-CONNECT:./test.socket
echo "resume" | sudo socat - UNIX-CONNECT:./test.socket

Restore VM from snapshot

radiance --snapshot-path ./snap.rad

Example config file:

[machine]
vcpus = 2
memory_mb = 128
cmdline = "reboot=k panic=1"

[api]
socket_path = "./test.socket"

[uart]
enabled = true

[kernel]
path = "path_to_kernel"

[[drives]]
path = "path_to_rootfs"
read_only = true
rootfs = true
pci = true

[[networks]]
dev_name = "tap0"
mac = [AA, BB, CC, DD, EE, FF]

[[pmems]]
path = "some_file"

Rootfs:

Note

Generated ssh keys will be owned by root user. To use them with ssh change ownership with chown.

Ubuntu:

sudo bash mk_ubuntu.sh 300

This will produce ubuntu.ext4 rootfs file and ssh keys ubuntu.id_rsa and ubuntu.id_rsa.pub.

Alpine:

sudo bash mk_alpine.sh 100

This will produce alpine.ext4 rootfs file and ssh keys alpine.id_rsa and alpine.id_rsa.pub.

Linux kernel:

To compile small kernel for VM use resources/kernel_config.

make -Image -j

The resulting kernel image will be at arch/arm64/boot/Image.

Kcov:

zig test src/main.zig -lc --test-cmd kcov --test-cmd "--exclude-pattern=/nix" --test-cmd kcov-output --test-cmd-bin