[PATCH v4 00/13] new plugin argument passing scheme

[Mahmoud Mandour <ma.mandourr@gmail.com>]

Hello,

This series removes passing arguments to plugins through "arg=" since
it's redundant and reduces readability especially when the argument
itself is composed of a name and a value.

Also, passing arguments through "arg=" still works but is marked as
deprecated and will produce a deprecation warning.

Right now, the code for parsing the argument before passing it to the
plugin is unfortunately not so clean but that's mainly because "arg=" is
still supported.

At first, considering boolean parameters, those were not special to
plugins and QEMU did not complain about passing them in the form
"arg=bool_arg" even though that's considered a short-form boolean, which
is deprecated. As "arg" is removed, a deprecation warning is issued.

This is mitigated by making plugins aware of boolean arguments and
parses them through a newly exposed API, namely the `qapi_bool_parse`
function through a plugin API function. Now plugins expect boolean
parameters to be passed in the form that other parts of QEMU expect,
i.e. "bool_arg=[on|true|yes|off|false|no]".

Since we're still supporting "arg=arg_name", there are some assumptions
that I made that I think are suitable:

    1. "arg=arg_name" will be passed to the plugin as "arg_name=on".
    2. "arg=on" and "arg" will not be assumed to be the old way of
        passing args. Instead, it will assume that the argument name is
        "arg" and it's a boolean parameter. (will be passed to plugin
        as "arg=on")

The docs are updated accordingly and a deprecation notice is put in the
deprecated.rst file.

Based-on: <20210722065428.134608-1-ma.mandourr@gmail.com>

However, the dependency is so light and it should only be in the patch

    docs/tcg-plugins: new passing parameters scheme for cache docs

where it depends on

    docs/devel/tcg-plugins: added cores arg to cache plugin

in the aforementioned series (conflict lies in the argument "cores=N" only.)

Patches that still need review:
    plugins/api: added a boolean parsing plugin api
    docs/deprecated: deprecate passing plugin args through `arg=`
    plugins/hwprofile: adapt to the new plugin arguments scheme

v3 -> v4:
    1. added Reviewed-by and Tested-By tags to commit messages of the
    already-reviewed patches.

v2 -> v3:
    1. Protected calling `qapi_bool_parse` by ensuring name & value are
    not NULL.
    2. Updated the docs for the hotpages plugin to include its arguments
    3. Typo in tests/plugins/mem (hadrr -> haddr)
    4. Reword the deprecation entry in deprecated.rst

Mahmoud Mandour (13):
  plugins: allow plugin arguments to be passed directly
  plugins/api: added a boolean parsing plugin api
  plugins/hotpages: introduce sortby arg and parsed bool args correctly
  plugins/hotblocks: Added correct boolean argument parsing
  plugins/lockstep: make socket path not positional & parse bool arg
  plugins/hwprofile: adapt to the new plugin arguments scheme
  plugins/howvec: adapting to the new argument passing scheme
  docs/tcg-plugins: new passing parameters scheme for cache docs
  tests/plugins/bb: adapt to the new arg passing scheme
  tests/plugins/insn: made arg inline not positional and parse it as
    bool
  tests/plugins/mem: introduce "track" arg and make args not positional
  tests/plugins/syscalls: adhere to new arg-passing scheme
  docs/deprecated: deprecate passing plugin args through `arg=`

 contrib/plugins/hotblocks.c | 14 ++++++++--
 contrib/plugins/hotpages.c  | 30 ++++++++++++++-------
 contrib/plugins/howvec.c    | 27 +++++++++++++------
 contrib/plugins/hwprofile.c | 39 ++++++++++++++++++---------
 contrib/plugins/lockstep.c  | 31 +++++++++++++++-------
 docs/devel/tcg-plugins.rst  | 53 ++++++++++++++++++++++++-------------
 docs/system/deprecated.rst  |  7 +++++
 include/qemu/qemu-plugin.h  | 13 +++++++++
 linux-user/main.c           |  2 +-
 plugins/api.c               |  5 ++++
 plugins/loader.c            | 24 ++++++++++++++---
 qemu-options.hx             |  9 +++----
 tests/plugin/bb.c           | 15 ++++++++---
 tests/plugin/insn.c         | 14 ++++++++--
 tests/plugin/mem.c          | 47 +++++++++++++++++++-------------
 tests/plugin/syscall.c      | 23 +++++++++++-----
 16 files changed, 252 insertions(+), 101 deletions(-)

-- 
2.25.1