Re: [PATCH 60/60] contrib/qemu-vnc: add standalone VNC server over D-Bus

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Hi

On Tue, Mar 24, 2026 at 7:24 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Tue, Mar 17, 2026 at 12:51:14PM +0400, Marc-André Lureau wrote:
> > Add a standalone VNC server binary that connects to a running QEMU
> > instance via the D-Bus display interface (org.qemu.Display1, via the bus
> > or directly p2p). This allows serving a VNC display without compiling
> > VNC support directly into the QEMU system emulator, and enables running
> > the VNC server as a separate process with independent lifecycle and
> > privilege domain.
>
> IIUC, this new binary is linking to all the existnig ui/vnc.c
> code, so there's no actual new impl of the RFB protocol, just
> a new glue layer for launching the existing impl with comms
> over DBus instead of from direct callback functions ?
>
> > Built only when both VNC and D-Bus display support are enabled.
> > If we wanted to have qemu -vnc disabled, and qemu-vnc built, we would
> > need to split CONFIG_VNC. This is left as a future exercise.
> >
> > I left out for now:
> >  - sasl & tls authz
>
> IMHO these are must have features, as the default VNC protocol
> security is a very bad joke.

Ok that should be doable. One thing that bothers me a bit is mapping
the -object options (authz) to a more regular CLI. Perhaps I'll just
add -object args and wire it with the other options..

>
> >  - some runtime functionalities (better done by restarting)
> >  - a few legacy options
> >  - Windows support
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  MAINTAINERS                    |   5 +
> >  docs/conf.py                   |   3 +
> >  docs/interop/dbus-display.rst  |   2 +
> >  docs/interop/dbus-vnc.rst      |  26 ++
> >  docs/interop/index.rst         |   1 +
> >  docs/meson.build               |   1 +
> >  docs/tools/index.rst           |   1 +
> >  docs/tools/qemu-vnc.rst        | 199 +++++++++++
> >  meson.build                    |  17 +
> >  contrib/qemu-vnc/qemu-vnc.h    |  46 +++
> >  contrib/qemu-vnc/trace.h       |   4 +
> >  contrib/qemu-vnc/audio.c       | 307 +++++++++++++++++
> >  contrib/qemu-vnc/chardev.c     | 127 +++++++
> >  contrib/qemu-vnc/clipboard.c   | 378 +++++++++++++++++++++
> >  contrib/qemu-vnc/console.c     | 168 ++++++++++
> >  contrib/qemu-vnc/dbus.c        | 439 ++++++++++++++++++++++++
> >  contrib/qemu-vnc/display.c     | 456 +++++++++++++++++++++++++
> >  contrib/qemu-vnc/input.c       | 239 ++++++++++++++
> >  contrib/qemu-vnc/qemu-vnc.c    | 450 +++++++++++++++++++++++++
> >  contrib/qemu-vnc/stubs.c       |  66 ++++
> >  contrib/qemu-vnc/utils.c       |  59 ++++
>
> IMHO we should not really be adding more things to the contrib
> directory, and rather wish most of the existing stuff was
> not there. When I see "contrib" directories in projects, the
> message is generally "unmaintained, abandoned junk".
>
> If this is a serious maintained feature we expect people to use,
> it should be formally under the ui/ directory, possibly a
> 'ui/dbus-vnc' subdir ?

It is intended to be maintained. (although I hope we can deprecate it
in favour of qemu-rdp in the long term). I'll follow the "Cleaning up
contrib/ and tools/" thread and see where it could land.
.

>
> >  tests/qtest/dbus-vnc-test.c    | 733 +++++++++++++++++++++++++++++++++++++++++
> >  contrib/qemu-vnc/meson.build   |  26 ++
> >  contrib/qemu-vnc/qemu-vnc1.xml | 174 ++++++++++
> >  contrib/qemu-vnc/trace-events  |  20 ++
> >  meson_options.txt              |   2 +
> >  scripts/meson-buildoptions.sh  |   3 +
> >  tests/dbus-daemon.sh           |  14 +-
> >  tests/qtest/meson.build        |   8 +
> >  29 files changed, 3971 insertions(+), 3 deletions(-)
> >
>
> > diff --git a/meson_options.txt b/meson_options.txt
> > index 31d5916cfce..ef938e74793 100644
> > --- a/meson_options.txt
> > +++ b/meson_options.txt
> > @@ -119,6 +119,8 @@ option('vfio_user_server', type: 'feature', value: 'disabled',
> >         description: 'vfio-user server support')
> >  option('dbus_display', type: 'feature', value: 'auto',
> >         description: '-display dbus support')
> > +option('qemu_vnc', type: 'feature', value: 'auto',
> > +       description: 'standalone VNC server over D-Bus')
>
> Every option is about QEMU, so 'qemu_' on a name feels redundant,
> and QEMU alrady has a VNC server too.
>
> I suggest 'dbus_vnc' is possibly a better name
>

Well, I just named the option after the binary's name. I think that's easier.

>
> >  option('tpm', type : 'feature', value : 'auto',
> >         description: 'TPM support')
> >  option('valgrind', type : 'feature', value: 'auto',
>
> With regards,
> Daniel
> --
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>