diff --git a/virttest/utils_libvirt/libvirt_memory.py b/virttest/utils_libvirt/libvirt_memory.py
index 322b045d32..a82a503def 100644
--- a/virttest/utils_libvirt/libvirt_memory.py
+++ b/virttest/utils_libvirt/libvirt_memory.py
@@ -6,11 +6,30 @@
 
 import logging
 
+from avocado.core import exceptions
 from avocado.utils import process
 
 LOG = logging.getLogger('avocado.' + __name__)
 
 
+def comp_memlock(exp_memlock):
+    """
+    Compare the locked mem with the given value.
+
+    :param exp_memlock: The expected locked mem value
+    :raise: TestError if the actual locked mem is invalid
+    :return: True on success
+    """
+    LOG.debug("Check if the memlock is %s.", exp_memlock)
+    tmp_act_memlock = get_qemu_process_memlock_hard_limit()
+    LOG.debug("Actual memlock is {}.".format(tmp_act_memlock))
+    try:
+        act_memlock = int(tmp_act_memlock)
+    except ValueError as e:
+        raise exceptions.TestError(e)
+    return exp_memlock == act_memlock
+
+
 def get_qemu_process_memlock_hard_limit():
     """
     Get qemu process memlock hard limit
@@ -18,3 +37,20 @@ def get_qemu_process_memlock_hard_limit():
     """
     cmd = "prlimit -p `pidof qemu-kvm` -l |awk '/MEMLOCK/ {print $7}'"
     return process.run(cmd, shell=True).stdout_text.strip()
+
+
+def normalize_mem_size(mem_size, mem_unit):
+    """
+    Normalize the mem size and convert it to bytes.
+
+    :param mem_size: The mem size
+    :param mem_unit: The mem size unit
+    :return: Byte format size
+    """
+    try:
+        mem_size = float(mem_size)
+        mem_unit_idx = ['B', 'K', 'M', 'G', 'T'].index(mem_unit[0].upper())
+    except ValueError as e:
+        raise exceptions.TestError(e)
+
+    return int(mem_size * 1024 ** mem_unit_idx)