diff --git a/qemu/tests/cfg/rng_maxbytes_period.cfg b/qemu/tests/cfg/rng_maxbytes_period.cfg
index e6f104fe0e..5344b13bf5 100644
--- a/qemu/tests/cfg/rng_maxbytes_period.cfg
+++ b/qemu/tests/cfg/rng_maxbytes_period.cfg
@@ -35,13 +35,13 @@
             variants:
                 - maxbytes_0:
                     no aarch64
+                    not_preprocess = yes
                     max-bytes_virtio-rng = 0
-                    read_rng_timeout = 10
-                    read_rng_cmd  = "dd if=/dev/hwrng of=/dev/null bs=1 count=1"
+                    expected_error_info = "'max-bytes' parameter must be positive, and less than 2^63"
                 - maxbytes_negative:
                     not_preprocess = yes
                     max-bytes_virtio-rng = -1
-                    expected_error_info = "'max-bytes' parameter must be non-negative, and less than 2^63"
+                    expected_error_info = "'max-bytes' parameter must be positive, and less than 2^63"
                 - period_0:
                     not_preprocess = yes
                     period_virtio-rng = 0
diff --git a/qemu/tests/rng_maxbytes_period.py b/qemu/tests/rng_maxbytes_period.py
index 910cd9dc0c..273bf1b740 100644
--- a/qemu/tests/rng_maxbytes_period.py
+++ b/qemu/tests/rng_maxbytes_period.py
@@ -5,8 +5,6 @@
 from virttest import virt_vm
 from virttest import utils_misc
 
-from aexpect.exceptions import ShellTimeoutError
-
 
 @error_context.context_aware
 def run(test, params, env):
@@ -37,17 +35,16 @@ def _is_rngd_running():
     if not max_bytes and not period:
         test.error("Please specify the expected max-bytes and/or period.")
     if not max_bytes or not period:
-        if max_bytes != '0':
-            error_info = params["expected_error_info"]
-            try:
-                env_process.process(test, params, env,
-                                    env_process.preprocess_image,
-                                    env_process.preprocess_vm)
-            except virt_vm.VMCreateError as e:
-                if error_info not in e.output:
-                    test.fail("Expected error info '%s' is not reported, "
-                              "output: %s" % (error_info, e.output))
-            return
+        error_info = params["expected_error_info"]
+        try:
+            env_process.process(test, params, env,
+                                env_process.preprocess_image,
+                                env_process.preprocess_vm)
+        except virt_vm.VMCreateError as e:
+            if error_info not in e.output:
+                test.fail("Expected error info '%s' is not reported, "
+                          "output: %s" % (error_info, e.output))
+        return
 
     vm = env.get_vm(params["main_vm"])
     vm.verify_alive()
@@ -66,23 +63,15 @@ def _is_rngd_running():
             if status:
                 test.error(output)
 
-    if max_bytes == '0':
-        try:
-            s, o = session.cmd_status_output(read_rng_cmd, timeout=read_rng_timeout)
-        except ShellTimeoutError:
-            pass
-        else:
-            test.fail("Unexpected dd result, status: %s, output: %s" % (s, o))
-    else:
-        s, o = session.cmd_status_output(read_rng_cmd, timeout=read_rng_timeout)
-        if s:
-            test.error(o)
-        test.log.info(o)
-        data_rate = re.search(r'\s(\d+\.\d+) kB/s', o, re.M)
-        expected_data_rate = float(params["expected_data_rate"])
-        if float(data_rate.group(1)) > expected_data_rate * 1.1:
-            test.error("Read data rate is not as expected. "
-                       "data rate: %s kB/s, max-bytes: %s, period: %s" %
-                       (data_rate.group(1), max_bytes, period))
+    s, o = session.cmd_status_output(read_rng_cmd, timeout=read_rng_timeout)
+    if s:
+        test.error(o)
+    test.log.info(o)
+    data_rate = re.search(r'\s(\d+\.\d+) kB/s', o, re.M)
+    expected_data_rate = float(params["expected_data_rate"])
+    if float(data_rate.group(1)) > expected_data_rate * 1.1:
+        test.error("Read data rate is not as expected. "
+                   "data rate: %s kB/s, max-bytes: %s, period: %s" %
+                   (data_rate.group(1), max_bytes, period))
 
     session.close()