virsh_detach_device_alias: enhancement for pci

Currently the cases are skipped in most time because below error:

error: Failed to attach device from pci.xml
error: internal error: Non-endpoint PCI devices cannot be assigned to guests

This is because the incorrect pci device is used to attach to the vm.
This fix is an enhancement to increase possiblities of finding the suitable pci device.

Signed-off-by: Dan Zheng <[email protected]>

libvirt/tests/src/virsh_cmd/domain/virsh_detach_device_alias.py

@@ -1,6 +1,7 @@
+import logging as log
 import os
+import platform
 import uuid
-import logging as log
 
 from virttest import data_dir
 from virttest import virsh
@@ -22,6 +23,34 @@
 logging = log.getLogger('avocado.' + __name__)
 
 
+def get_suitable_pci_device(test):
+    """
+    Get a suitable pci device ID for attaching to the vm
+    The host PCI devices will vary on different hardwares, so it is hard
+    to always get an usable pci device to do this.
+
+    :param test: test object
+    :return: str, the pci devce full id or None
+    """
+    pci_ids = utils_sys.get_host_bridge_id()
+    if not pci_ids:
+        test.error("Not Found any pci devices")
+
+    if platform.machine() != "aarch64":
+        good_pci = utils_misc.get_full_pci_id(pci_ids[-1]).split("\n")[0]
+        return good_pci
+    else:
+        suitable_pci_ids = [id for id in pci_ids if id != "0000:00"]
+        for pci_id in suitable_pci_ids:
+            full_ids = utils_misc.get_full_pci_id(pci_id)
+            good_pci = "%s:00.0" % pci_id
+            if full_ids.count(good_pci):
+                test.log.debug("PCI ID '%s' is chosen", good_pci)
+                return good_pci
+    test.log.warning("No suitable PCI ID is chosen")
+    return None
+
+
 def run(test, params, env):
     """
     Test detach-device-alias command with
@@ -159,12 +188,7 @@ def start_usbredirserver():
                                                dev_type='controller',
                                                dev_dict=controller_dict,
                                                index=int(params.get("index")))
-
-                pci_ids = utils_sys.get_host_bridge_id()
-                if not pci_ids:
-                    test.error("Not Found any pci devices")
-                pci_id = utils_misc.get_full_pci_id(pci_ids[-1])
-
+                pci_id = get_suitable_pci_device(test)
                 if not vm.is_alive():
                     vm.start()
                 vm.wait_for_login()