def METHOD_NAME(dev_type):
    """
    Check the locked memory for the vm with multiple vDPA interfaces.
    1. The locked memory will be 1G + current memory * ${num of vDPA interface};
    2. Hot unplug the vDPA interface or Memory device will not decrease
        the locked memory;
    3. When hotplug a vDPA interface, the locked memory will not increase
        if there is enough locked memory(>=1G + current memory * ${num of vDPA interface});
    4. No error or fail in the qemu log.
    """
    test.log.info("TEST_STEP1: Start the vm with a vDPA interface.")
    vm.start()
    vm.wait_for_serial_login(timeout=240).close()
    qemu_log = "/var/log/libvirt/qemu/%s.log" % vm.name
    process.run("echo > {}".format(qemu_log), shell=True)
    new_vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
    expr_memlock = libvirt_memory.normalize_mem_size(
        new_vmxml.get_current_mem(),
        new_vmxml.get_current_mem_unit()) + 1073741824
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after VM startup!")
    test.log.info("TEST_STEP2: Hotplug memory device.")
    mem_dict1 = eval(params.get('mem_dict1', '{}'))
    mem_dev = libvirt_vmxml.create_vm_device_by_type("memory", mem_dict1)
    virsh.attach_device(vm_name, mem_dev.xml, **virsh_args)
    new_vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
    expr_memlock = libvirt_memory.normalize_mem_size(
        new_vmxml.get_current_mem(),
        new_vmxml.get_current_mem_unit()) + 1073741824
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after attaching a memory "
                  "device!")
    test.log.info("TEST_STEP3: Add one more vDPA interface.")
    iface2 = interface_base.create_iface(dev_type, eval(params.get('iface_dict2', "{'source': {'dev':'/dev/vhost-vdpa-1'}}")))
    virsh.attach_device(vm_name, iface2.xml, **virsh_args)
    new_vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
    expr_memlock = libvirt_memory.normalize_mem_size(
        new_vmxml.get_current_mem(),
        new_vmxml.get_current_mem_unit()) * 2 + 1073741824
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after attaching the 2nd "
                  "interface device!")
    test.log.info("TEST_STEP4: Hotplut one more memory device.")
    mem_dict2 = eval(params.get('mem_dict2', '{}'))
    mem_dev2 = libvirt_vmxml.create_vm_device_by_type("memory", mem_dict2)
    virsh.attach_device(vm_name, mem_dev2.xml, **virsh_args)
    new_vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
    expr_memlock = libvirt_memory.normalize_mem_size(
        new_vmxml.get_current_mem(),
        new_vmxml.get_current_mem_unit()) * 2 + 1073741824
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after attaching the 2nd "
                  "interface device!")
    test.log.info("TEST_STEP5: Detach a memory device and vDPA interface.")
    memxml = vm_xml.VMXML.new_from_dumpxml(vm_name).get_devices('memory')[-1]
    virsh.detach_device(vm_name, memxml.xml, debug=True)
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after detaching a memory device!")
    iface = vm_xml.VMXML.new_from_dumpxml(vm_name).get_devices('interface')[-1]
    virsh.detach_device(vm_name, iface.xml,
                        wait_for_event=True,
                        **virsh_args)
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after detaching a vDPA interface!")
    test.log.info("TEST_STEP6: Hotplug a vDPA interface.")
    virsh.attach_device(vm_name, iface.xml, **virsh_args)
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after re-attaching a vDPA interface!")
    test.log.info("TEST_STEP7: Hotplug one more vDPA interface.")
    iface3 = interface_base.create_iface(dev_type, eval(params.get('iface_dict3', "{'source': {'dev':'/dev/vhost-vdpa-2'}}")))
    virsh.attach_device(vm_name, iface3.xml, **virsh_args)
    new_vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
    expr_memlock = libvirt_memory.normalize_mem_size(
        new_vmxml.get_current_mem(),
        new_vmxml.get_current_mem_unit()) * 3 + 1073741824
    if not libvirt_memory.comp_memlock(expr_memlock):
        test.fail("Unalbe to get correct MEMLOCK after attaching the 3rd "
                  "interface device!")
    test.log.info("TEST_STEP8: Check qemu log.")
    libvirt.check_logfile("fail|error", qemu_log, str_in_log=False)