[PATCH 00/10] RFC: Move SPICE to a load module

[Christophe de Dinechin]

There has been a bit of discussion regarding the possibility to move
SPICE code to a module in order to reduce the attack surface and
memory usage when SPICE is not used.

This WIP series proposes one way to do it that is relatively cheap in
terms of code changes, relative to other ideas I tested, and seems to
be working on simple test cases, unlike a couple of more
"sophisiticated" ideas I tried where I ran into rather nasty SPICE
initialization order issues.

Furthermore, the approach presented here requires relatively few code
changes in order to apply to other components as well. It relies on a
couple of macros added to the module.h file, MODIFACE and MODIMPLE.

MODIFACE declare the interface for a module function. A module
function is transformed into a pointer when you build with modules,
and that pointer is used instead of the original function.

MODIMPL implements a MODIFACE, and patches the pointer at load time to
call the function in the shared library.

Thanks to some suggestions from Gerd, I also moved QXL to a module,
although at the moment it does not load correctly.

There are a few known hacks in the present state, including:

- Adding various non-UI files into spice-app.so, which required a
  couple of ../pwd/foo.o references in the makefile. Not very nice,
  but I did not want to spend too much time fixing the makefiles.

- qmp_query_spice had to be dealt with "manually" because its
  interface is generated.

With these changes, the following shared libraries are no longer
needed in the main binary:

        libspice-server.so.1 => /lib64/libspice-server.so.1 (HEX)
        libopus.so.0 => /lib64/libopus.so.0 (HEX)
        liblz4.so.1 => /lib64/liblz4.so.1 (HEX)
        libgstapp-1.0.so.0 => /lib64/libgstapp-1.0.so.0 (HEX)
        libgstvideo-1.0.so.0 => /lib64/libgstvideo-1.0.so.0 (HEX)
        libgstbase-1.0.so.0 => /lib64/libgstbase-1.0.so.0 (HEX)
        libgstreamer-1.0.so.0 => /lib64/libgstreamer-1.0.so.0 (HEX)
        libssl.so.1.1 => /lib64/libssl.so.1.1 (HEX)
        liborc-0.4.so.0 => /lib64/liborc-0.4.so.0 (HEX)

I will keep pushing updates on branch "modular-spice"
on https://github.com/c3d/qemu.git

Christophe de Dinechin (10):
  modules: Provide macros making it easier to identify module exports
  minikconf: Pass variables for modules
  spice: Make spice a module configuration
  spice: Move all the spice-related code in spice-app.so
  build: Avoid build failure when building drivers as modules
  trivial: Remove extra trailing whitespace
  qxl - FIXME: Build as module
  build: Add SPICE_CFLAGS and SPICE_LIBS to relevant files
  spice: Put spice functions in a separate load module
  REMOVE: Instrumentation to show the module functions being replaced

 Makefile                 |  1 +
 Makefile.objs            |  2 ++
 Makefile.target          |  7 +++++++
 audio/Makefile.objs      |  2 +-
 chardev/Makefile.objs    |  2 +-
 configure                |  6 +++---
 hw/Makefile.objs         |  1 +
 hw/display/Makefile.objs |  4 +++-
 hw/display/qxl.c         |  2 +-
 hw/i386/Makefile.objs    |  1 +
 include/qemu/module.h    | 28 ++++++++++++++++++++++++++++
 include/ui/qemu-spice.h  | 24 +++++++++++++++---------
 monitor/Makefile.objs    |  3 +++
 monitor/hmp-cmds.c       |  6 ++++++
 scripts/minikconf.py     |  4 ++--
 softmmu/Makefile.objs    |  2 +-
 softmmu/vl.c             |  1 +
 stubs/Makefile.objs      |  2 +-
 ui/Makefile.objs         | 12 ++++++------
 ui/spice-core.c          | 31 +++++++++++++++++++++----------
 ui/spice-display.c       |  2 +-
 util/module.c            | 13 +++++++++++--
 22 files changed, 117 insertions(+), 39 deletions(-)

-- 
2.26.2