@@ -229,6 +229,17 @@ Debugging a test case
The following options to the ``check`` script can be useful when debugging
a failing test:
+* ``-gdb`` wraps every QEMU invocation in a ``gdbserver``, which waits for a
+ connection from a gdb client. The options given to ``gdbserver`` (e.g. the
+ address on which to listen for connections) are taken from the ``$GDB_OPTIONS``
+ environment variable. By default (if ``$GDB_OPTIONS`` is empty), it listens on
+ ``localhost:12345``.
+ It is possible to connect to it for example with
+ ``gdb -iex "target remote $addr"``, where ``$addr`` is the address
+ ``gdbserver`` listens on.
+ If the ``-gdb`` option is not used, ``$GDB_OPTIONS`` is ignored,
+ regardless on whether it is set or not.
+
* ``-d`` (debug) just increases the logging verbosity, showing
for example the QMP commands and answers.