# File lib/vagrant-libvirt/config.rb, line 488
      def redirfilter(options = {})
        raise 'Option allow must be specified.' if options[:allow].nil?

        @redirfilters = [] if @redirfilters == UNSET_VALUE

        @redirfilters.push(class: options[:class] || -1,
                           vendor: options[:vendor] || -1,
                           product: options[:product] || -1,
                           version: options[:version] || -1,
                           allow: options[:allow])
      end