tp-qemu: Add new test case "slof_device_tree" for SLOF feature (ppc only)

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1324342

qemu/tests/cfg/slof_device_tree.cfg

+- slof_device_tree: install setup image_copy unattended_install.cdrom
+    virt_test_type = qemu
+    type = slof_device_tree
+    restart_vm = yes
+    kill_vm_on_error = yes
+    login_timeout = 240
+    only ppc64 ppc64le
+    only Linux
+    uuid = random
+    no scsi-cd

qemu/tests/slof_device_tree.py

+import logging
+
+from avocado.utils import process
+from avocado.core import exceptions
+
+from virttest import utils_misc
+from virttest.qemu_devices import qcontainer
+from virttest import error_context
+
+
+@error_context.context_aware
+def run(test, params, env):
+    """
+    slof_device_tree test:
+    steps:
+    1. Boot up a guest.
+    2. Check the guest device tree information
+    3. Compare the value with expected result.
+    :param test: Kvm test object
+    :param params: Dictionary with the test parameters
+    :param env: Dictionary with test environment.
+    """
+
+    def get_info(vm_session, guest_info):
+        """
+        Check the corresponding information from vm.
+
+        :param vm_session: session to checked vm.
+        :return: corresponding prompt
+        """
+        (status, output) = vm_session.cmd_status_output(
+            "echo `cat /proc/device-tree/%s`" % guest_info)
+        if status != 0:
+            raise exceptions.TestFail("Failed to get %s" % guest_info)
+        return output.strip()
+
+    def check_nonexist_aliases(vm_session, devices):
+        """
+        Check a nonexist device aliases.
+
+        :param vm_session: session to checked vm.
+        :return: corresponding prompt
+        """
+
+        status = vm_session.cmd_status(
+            "test -f /proc/device-tree/aliases/cdrom")
+        error_context.context(
+            "Checking whether aliases file is indeed nonexisting", logging.info)
+        if status == 0:
+            raise exceptions.TestFail(
+                "Nonexist cdrom aliases check failed.")
+
+    vm = env.get_vm(params["main_vm"])
+    vm.verify_alive()
+    timeout = int(params.get("login_timeout", 600))
+
+    session = vm.wait_for_login(timeout=timeout)
+
+    try:
+        guest_system_id = get_info(session, "system-id")
+        if guest_system_id != vm.get_uuid():
+            raise exceptions.TestFail("Guest system id does not match to uuid")
+
+        guest_uuid = get_info(session, "vm,uuid")
+        if guest_uuid != vm.get_uuid():
+            raise exceptions.TestFail(
+                "Guest uuid does not match to expected id.")
+
+        host_system_id = process.system_output(
+            "echo `cat /proc/device-tree/system-id`", shell=True).strip()
+        host_system_id_in_guest = get_info(session, "host-serial")
+        if host_system_id != host_system_id_in_guest:
+            raise exceptions.TestFail(
+                "Host system id does not match to value in guest.")
+
+        guest_partition_name = get_info(session, "ibm,partition-name")
+        if guest_partition_name != params.get("main_vm"):
+            raise exceptions.TestFail("Guest partition name is wrong.")
+
+        qemu_binary = utils_misc.get_qemu_binary(params)
+        devices = qcontainer.DevContainer(qemu_binary, vm, strict_mode="no")
+        check_nonexist_aliases(session, devices)
+
+    finally:
+        session.close()