anchor.diff:            -drive file=$NIX_DISK_IMAGE,if=virtio,boot=on \
             -kernel ${config.system.build.system}/kernel \
             -initrd ${config.system.build.system}/initrd \
  -          -redir tcp:8080::80 \
  -          -redir tcp:8022::22 \
  +          $QEMU_OPTS \
             -append "$(cat ${config.system.build.system}/kernel-params) init=${config.system.build.bootStage2} systemConfig=${config.system.build.system}"
       '';
   
  
positive.code: 
  let
  
    options = {
  
      virtualisation.diskImage =
        pkgs.lib.mkOption {
          default = "./${config.networking.hostName}.qcow2";
          description =
            ''
              Path to the disk image containing the root filesystem.
  
negative.code:     ''
        ensureDir $out/bin
        ln -s ${config.system.build.system} $out/system
        ln -s ${pkgs.writeScript "run-nixos-vm" startVM} $out/bin/run-${vmName}-vm
      '';
  
    # sendfile() is currently broken over CIFS, so fix it here for all
  