Add a param to force use serial session in case of failure

Currently, we do have a logic in wait_for_login to
return serial session incase of failure if provided
by the user through function param, this patch extends
that functionality by adding a param which can be used
to set, So serial session is returned in case of failure,
as most of the testcases using wait_for_login with default
params and we do not need to modify the testcases,
this can be useful during certain env issues if we want to
force use serial logins for the same test.

Signed-off-by: Satheesh Rajendran <[email protected]>

shared/cfg/base.cfg

@@ -165,6 +165,10 @@ q35, arm64-pci, arm64-mmio:
 serials = "serial0"
 serial_type = "isa-serial"
 
+# Enable this to "yes" if you want to force wait_for_login
+# to give serial session incase of failure
+force_use_serial_login = "no"
+
 # Emulated machine type, run following command to see supported machine type.
 # qemu-kvm -M ?
 # machine_type = pc

virttest/virt_vm.py

@@ -1187,6 +1187,8 @@ def print_guest_network_info():
                     session.close()
 
         error = None
+        if not serial:
+            serial = self.params.get("force_use_serial_login", "no") == "yes"
         logging.debug("Attempting to log into '%s' (timeout %ds)",
                       self.name, timeout)
         start_time = time.time()