anchor.diff:        '';
       };
   
  +    qemuOvmfPackage = mkOption {
  +      type = types.package;
  +      default = pkgs.OVMF;
  +      defaultText = literalExpression "pkgs.OVMF";
  +      example = literalExpression "pkgs.OVMFFull";
  +      description = ''
  +        OVMF package to use.
  +      '';
  +    };
  +
       extraOptions = mkOption {
         type = types.listOf types.str;
         default = [ ];
  
positive.code:       {
          assertion = config.security.polkit.enable;
          message = "The libvirtd module currently requires Polkit to be enabled ('security.polkit.enable = true').";
        }
      ];
  
  
negative.code:         done
  
          ${optionalString cfg.qemuOvmf ''
            ln -s --force ${cfg.qemuOvmfPackage.fd}/FV/${ovmfFilePrefix}_CODE.fd /run/${dirName}/nix-ovmf/
            ln -s --force ${cfg.qemuOvmfPackage.fd}/FV/${ovmfFilePrefix}_VARS.fd /run/${dirName}/nix-ovmf/
          ''}
        '';
  
  