qemu.tests: Add case for nvdimm backed by host emulated device

Signed-off-by: NYumei Huang <yuhuang@redhat.com>

qemu/tests/cfg/nvdimm.cfg

@@ -4,6 +4,7 @@
     maxmem_mem = 32G
     kill_vm_on_error = yes
     login_timeout = 240
+    only x86_64
     no Windows
     no RHEL.6 RHEL.5 RHEL.4 RHEL.3
     no RHEL.7.2 RHEL.7.1 RHEL.7.0
@@ -27,3 +28,11 @@
 
     variants:
         - nvdimm_basic:
+        - nvdimm_emulate:
+            # Please update host kernel line first, such as add "memmap=1G!5G":
+            # 1G is the size, 5G is the start address of host memory
+            start_vm = "no"
+            nv_backend = "/dev/pmem0"
+            mem-path = ${nv_backend}
+            del pre_command
+            del post_command

qemu/tests/nvdimm.py

+import os
 import logging
 
 from autotest.client.shared import error
+from avocado.utils import process
+
+from virttest import env_process
 
 
 class NvdimmTest(object):
@@ -101,6 +105,18 @@ def run(test, params, env):
     :param params: Dictionary with the test parameters
     :param env: Dictionary with test environment.
     """
+    if params["start_vm"] == "no":
+        error.context("Check nvdimm backend in host", logging.info)
+        try:
+            process.system("grep 'memmap=' /proc/cmdline")
+        except process.CmdError:
+            raise error.TestError("Please add kernel param 'memmap' before start test.")
+        if not os.path.exists(params["nv_backend"]):
+            raise error.TestError("Check nv_backend in host failed!")
+        params["start_vm"] = "yes"
+        vm_name = params['main_vm']
+        env_process.preprocess_vm(test, params, env, vm_name)
+
     nvdimm_test = NvdimmTest(params, env)
     vm = env.get_vm(params["main_vm"])
     vm.verify_alive()