VirtioFS

VirtioFS is a filesystem that allows mounting host path inside a VM with minimal performance overhead.

Host Setup

In order to use VirtioFS NixOS needs virtiofsd package:

virtualisation.libvirtd.qemu.vhostUserPackages = [ pkgs.virtiofsd ];

VM Setup

VirtioFS directories can be mounted directly in NixOS via the standard fileSystems option.

Assuming you setup a VirtioFS called VMShare in your VM manager, like libvirt, you can mount it by adding the following inside your VM.

   fileSystems."/mnt/VMShare" = {
     device = "VMShare";
     fsType = "virtiofs";
     options = [
       "nofail"
       "x-systemd.automount"
     ];
   };