python/qemu/machine: Allow to use other serial consoles than default

Currently the QEMU Python module limits the QEMUMachine class to
use the first serial console.

Some machines/guest might use another console than the first one as
the 'boot console'. For example the Raspberry Pi uses the second
(AUX) console.

To be able to use the Nth console as default, we simply need to
connect all the N - 1 consoles to the null chardev.

Add an index argument, so we can use a specific serial console as
default.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-Id: <20200120235159.18510-5-f4bug@amsat.org>
[PMD: zero-initialize _console_index in __init__()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/python/qemu/machine.py b/python/qemu/machine.py
index 734efd8..183d8f3 100644
--- a/python/qemu/machine.py
+++ b/python/qemu/machine.py
@@ -112,6 +112,7 @@ class QEMUMachine(object):
         self._sock_dir = sock_dir
         self._launched = False
         self._machine = None
+        self._console_index = 0
         self._console_set = False
         self._console_device_type = None
         self._console_address = None
@@ -241,6 +242,8 @@ class QEMUMachine(object):
                          'chardev=mon,mode=control'])
         if self._machine is not None:
             args.extend(['-machine', self._machine])
+        for i in range(self._console_index):
+            args.extend(['-serial', 'null'])
         if self._console_set:
             self._console_address = os.path.join(self._sock_dir,
                                                  self._name + "-console.sock")
@@ -527,7 +530,7 @@ class QEMUMachine(object):
         """
         self._machine = machine_type
 
-    def set_console(self, device_type=None):
+    def set_console(self, device_type=None, console_index=0):
         """
         Sets the device type for a console device
 
@@ -548,9 +551,14 @@ class QEMUMachine(object):
                             chardev:console" command line argument will
                             be used instead, resorting to the machine's
                             default device type.
+        @param console_index: the index of the console device to use.
+                              If not zero, the command line will create
+                              'index - 1' consoles and connect them to
+                              the 'null' backing character device.
         """
         self._console_set = True
         self._console_device_type = device_type
+        self._console_index = console_index
 
     @property
     def console_socket(self):