Re: [Qemu-devel] [RFC PATCH 1/6] utils/python_api: add scripting interface for Qemu with python lib

[Daniel P . Berrangé]

On Wed, Aug 07, 2019 at 12:44:40PM +0530, Balamuruhan S wrote:
> Adds scripting interface with python library to call functions in
> python modules from Qemu that can be used to feed input externally
> and without recompiling Qemu that can be used for early development,
> testing and can be extended to abstract some of Qemu code out to a
> python script to ease maintenance.

I admit the use case is interesting, but this is opening a can of
worms...

Historically the project has held the view that we do not wish
to have an mechanism to support loading out of tree code into the
QEMU process. Much previously talk was around dlopen'd C plugins,
but dynanically loaded Python plugins are doing the same thing
at a conceptual level.

We didn't wish to expose internals of QEMU in a plugin API to
avoid having any kind of API promise across releases.

There was also the question of licensing with plugins opening
the door for people to extend QEMU with non-free/closed source
functionality.

While this series only uses the plugin for one fairly obscure
device, once a python plugin feature is intergrated in QEMU
there will inevitably be requests to use it in further areas
of QEMU.

IOW, acceptance of this patch is a significant question for
the project, and a broader discussion point, than just this
PPC feature patch series.

> Signed-off-by: Balamuruhan S <address@hidden>
> ---
>  configure                   |  10 +++++
>  include/sysemu/python_api.h |  30 +++++++++++++
>  util/Makefile.objs          |   1 +
>  util/python_api.c           | 100 
> ++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 141 insertions(+)
>  create mode 100644 include/sysemu/python_api.h
>  create mode 100644 util/python_api.c

Regards,
Daniel
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