scripts/qemu-trace-stap: Convert documentation to rST

The qemu-trace-stap documentation is currently in
scripts/qemu-trace-stap.texi in Texinfo format, which we
present to the user as:
 * a qemu-trace-stap manpage
 * but not (unusually for QEMU) part of the HTML docs

Convert the documentation to rST format that lives in
the docs/ subdirectory, and present it to the user as:
 * a qemu-trace-stap manpage
 * part of the interop/ Sphinx manual

There are minor formatting changes to suit Sphinx, but no
content changes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200124162606.8787-8-peter.maydell@linaro.org

docs/interop/conf.py

@@ -22,5 +22,7 @@ man_pages = [
     ('qemu-img', 'qemu-img', u'QEMU disk image utility',
      ['Fabrice Bellard'], 1),
     ('qemu-nbd', 'qemu-nbd', u'QEMU Disk Network Block Device Server',
-     ['Anthony Liguori <anthony@codemonkey.ws>'], 8)
+     ['Anthony Liguori <anthony@codemonkey.ws>'], 8),
+    ('qemu-trace-stap', 'qemu-trace-stap', u'QEMU SystemTap trace tool',
+     [], 1)
 ]

docs/interop/index.rst

@@ -20,5 +20,6 @@ Contents:
    qemu-ga
    qemu-img
    qemu-nbd
+   qemu-trace-stap
    vhost-user
    vhost-user-gpu

docs/interop/qemu-trace-stap.rst

@@ -0,0 +1,124 @@
+QEMU SystemTap trace tool
+=========================
+
+Synopsis
+--------
+
+**qemu-trace-stap** [*GLOBAL-OPTIONS*] *COMMAND* [*COMMAND-OPTIONS*] *ARGS*...
+
+Description
+-----------
+
+The ``qemu-trace-stap`` program facilitates tracing of the execution
+of QEMU emulators using SystemTap.
+
+It is required to have the SystemTap runtime environment installed to use
+this program, since it is a wrapper around execution of the ``stap``
+program.
+
+Options
+-------
+
+.. program:: qemu-trace-stap
+
+The following global options may be used regardless of which command
+is executed:
+
+.. option:: --verbose, -v
+
+  Display verbose information about command execution.
+
+The following commands are valid:
+
+.. option:: list BINARY PATTERN...
+
+  List all the probe names provided by *BINARY* that match
+  *PATTERN*.
+
+  If *BINARY* is not an absolute path, it will be located by searching
+  the directories listed in the ``$PATH`` environment variable.
+
+  *PATTERN* is a plain string that is used to filter the results of
+  this command. It may optionally contain a ``*`` wildcard to facilitate
+  matching multiple probes without listing each one explicitly. Multiple
+  *PATTERN* arguments may be given, causing listing of probes that match
+  any of the listed names. If no *PATTERN* is given, the all possible
+  probes will be listed.
+
+  For example, to list all probes available in the ``qemu-system-x86_64``
+  binary:
+
+  ::
+
+    $ qemu-trace-stap list qemu-system-x86_64
+
+  To filter the list to only cover probes related to QEMU's cryptographic
+  subsystem, in a binary outside ``$PATH``
+
+  ::
+
+    $ qemu-trace-stap list /opt/qemu/4.0.0/bin/qemu-system-x86_64 'qcrypto*'
+
+.. option:: run OPTIONS BINARY PATTERN...
+
+  Run a trace session, printing formatted output any time a process that is
+  executing *BINARY* triggers a probe matching *PATTERN*.
+
+  If *BINARY* is not an absolute path, it will be located by searching
+  the directories listed in the ``$PATH`` environment variable.
+
+  *PATTERN* is a plain string that matches a probe name shown by the
+  *LIST* command. It may optionally contain a ``*`` wildcard to
+  facilitate matching multiple probes without listing each one explicitly.
+  Multiple *PATTERN* arguments may be given, causing all matching probes
+  to be monitored. At least one *PATTERN* is required, since stap is not
+  capable of tracing all known QEMU probes concurrently without overflowing
+  its trace buffer.
+
+  Invocation of this command does not need to be synchronized with
+  invocation of the QEMU process(es). It will match probes on all
+  existing running processes and all future launched processes,
+  unless told to only monitor a specific process.
+
+  Valid command specific options are:
+
+  .. program:: qemu-trace-stap-run
+
+  .. option:: --pid=PID, -p PID
+
+    Restrict the tracing session so that it only triggers for the process
+    identified by *PID*.
+
+  For example, to monitor all processes executing ``qemu-system-x86_64``
+  as found on ``$PATH``, displaying all I/O related probes:
+
+  ::
+
+    $ qemu-trace-stap run qemu-system-x86_64 'qio*'
+
+  To monitor only the QEMU process with PID 1732
+
+  ::
+
+    $ qemu-trace-stap run --pid=1732 qemu-system-x86_64 'qio*'
+
+  To monitor QEMU processes running an alternative binary outside of
+  ``$PATH``, displaying verbose information about setup of the
+  tracing environment:
+
+  ::
+
+    $ qemu-trace-stap -v run /opt/qemu/4.0.0/qemu-system-x86_64 'qio*'
+
+See also
+--------
+
+:manpage:`qemu(1)`, :manpage:`stap(1)`
+
+..
+  Copyright (C) 2019 Red Hat, Inc.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.