zig-vmm

Virtual Machine Monitor for Linux KVM written in Zig.

This software is in early development. This repository is an experimental implementation and is not intended for production use.

Acknowledgment

gokvm provides me with a clear implementation example and many useful insights. Thank you so much!

Features

• virtio-console
• virtio-net
• virtio-blk

How to run

This page is provided with Ubuntu 22.10 running on zig-vmm.

Build Ubuntu RootFS

Run create_ubuntu_rootfs.sh to build ubuntu 22.10 rootFS.

$ ./create_ubuntu_rootfs.sh

RootFS disk image(ubuntu2210-base.img), initramfs(initrd.img-5.19.0-1018-kvm) and kernel(vmlinuz-5.19.0-1018-kvm) are created.

Build zig-vmm

Build zig-vmm with the latest zig(master/HEAD).

$ zig version
0.11.0-dev.1930+a097779b6
$ zig build

If zig-vmm is successfully built, zig-out/bin/zig-vmm exists.

Run zig-vmm

Run zig-vmm with sudo.

$ sudo ./zig-out/bin/zig-vmm --initramfs initrd.img-5.19.0-1018-kvm --vmlinuz vmlinuz-5.19.0-1018-kvm --disk_img ubuntu2210-base.img

INFO  [2023-03-13 05:01:29 9025]: KVM_GET_API_VERSION=12
INFO  [2023-03-13 05:01:29 9025]: KVM_CAP_USER_MEMORY is available
INFO  [2023-03-13 05:01:29 9025]: opened ./ubuntu2210-base.img(size=10737418240 sector_num=20971520)
INFO  [2023-03-13 05:01:29 9025]: waiting console client connection...

It waits for the console client connection. In an another terminal, run console client.

$ sudo ./zig-out/bin/zig-vmm --console_client

INFO  [2023-03-13 05:02:36 9104]: starting console
INFO  [2023-03-13 05:02:36 9104]: configured terminal to raw mode
INFO  [2023-03-13 05:02:36 9104]: connected to zig-vmm!
virtio_blk virtio2: 1/0/0 default/read/poll queues
virtio_blk virtio2: [vda] 20971520 512-byte logical blocks (10.7 GB/10.0 GiB)
Loading iSCSI transport class v2.0-870.
iscsi: registered transport (tcp)

...

[  OK  ] Started LSB: automatic crash report generation.
[  OK  ] Finished Terminate Plymouth Boot Screen.
[  OK  ] Started Serial Getty on hvc0.
[  OK  ] Created slice Slice /system/getty.
[  OK  ] Reached target Login Prompts.

Ubuntu 22.10 ubuntu hvc0

ubuntu login:

You can login with user ubuntu and password you configured. If you want to exit the console, type Ctrl+a then x.

Network

zig-vmm creates tap device for virtio-net. The tap device is assigned IPv4 address 192.168.200.1/24. The disk image is configured to assign 192.168.200.2/24 to the virtio-net NIC.

If you want to connect to the internet from zig-vmm's guest, please configure IPMasquerade.

sudo iptables -t nat -A POSTROUTING -s 192.168.200.0/24 -o [outgoing interface] -j MASQUERADE