anchor.diff:            '';
         };
   
  +    virtualisation.xen.package = mkOption {
  +      type = types.package;
  +      default = pkgs.xen;
  +      defaultText = "pkgs.xen";
  +      example = literalExample "pkgs.xen-light";
  +      description = ''
  +        The package used for Xen binary.
  +      '';
  +    };
  +
  +    virtualisation.xen.qemu = mkOption {
  +      type = types.path;
  +      default = "${pkgs.xen}/lib/xen/bin/qemu-system-i386";
  +      defaultText = "''${pkgs.xen}/lib/xen/bin/qemu-system-i386";
  +      example = literalExample "''${pkgs.qemu_xen-light}/bin/qemu-system-i386";
  +      description = ''
  +        The qemu binary to use for Dom-0 backend.
  +      '';
  +    };
  +
  +    virtualisation.xen.qemu-package = mkOption {
  +      type = types.package;
  +      default = pkgs.xen;
  +      defaultText = "pkgs.xen";
  +      example = literalExample "pkgs.qemu_xen-light";
  +      description = ''
  +        The package with qemu binaries for xendomains.
  +      '';
  +    };
  +
       virtualisation.xen.bootParams =
         mkOption {
           default = "";
  
positive.code: 
      system.extraSystemBuilderCmds =
        ''
          ln -s ${pkgs.xen}/boot/xen.gz $out/xen.gz
          echo "${toString cfg.bootParams}" > $out/xen-params
        '';
  
  
negative.code:       before = [ "dhcpd.service" ];
        restartIfChanged = false;
        serviceConfig.RemainAfterExit = "yes";
        path = [ cfg.package cfg.qemu-package ];
        environment.XENDOM_CONFIG = "${cfg.package}/etc/sysconfig/xendomains";
        preStart = "mkdir -p /var/lock/subsys -m 755";
        serviceConfig.ExecStart = "${cfg.package}/etc/init.d/xendomains start";
        serviceConfig.ExecStop = "${cfg.package}/etc/init.d/xendomains stop";
      };
  
    };
  