def get_cpus_by_arch(cls, arch):
        """
        Get all CPUs info by arch

        Args:
            arch(str): CPU architecture

        Returns:
            lxml.etree.element: CPUs by arch XML

        Raises:
            :exc:`~LagoException`: If no such ARCH is found
        """

        with open('/usr/share/libvirt/cpu_map.xml', 'r') as cpu_map:
            cpu_xml = ET.parse(cpu_map)
        try:
            return cpu_xml.xpath('/cpus/arch[@name="{0}"]'.format(arch))[0]
        except IndexError:
            raise LagoException('No such arch: {0}'.format(arch))