QEMU currently crashes when there is a [vnc] section in the config
file that does not have an "id = ..." line:
$ echo "[vnc]" > /tmp/qemu.conf
$ ./qemu-system-x86_64 -readconfig /tmp/qemu.conf
qemu-system-x86_64: ../../devel/qemu/ui/vnc.c:4347: vnc_init_func:
Assertion `id' failed.
Aborted (core dumped)
The required "id" is only set up automatically while parsing the command
line, but not when reading the options from the config file.
Thus let's move code that automatically adds the id (if it does not
exist yet) to the init function that needs the id for the first time,
replacing the assert() statement there.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2836
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250821145130.845104-1-thuth@redhat.com>
qio_channel_socket_connect_sync() returns 0 on success, and -1 on
failure, with errp set. Some callers check the return value, and some
check whether errp was set.
For consistency, always check the return value, and always check it's
negative.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250723133257.1497640-3-armbru@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
parse_keyboard_layout() passes a possibly null @filename to
trace_keymap_parse(). Trace backend log then formats it with %s,
which crashes on some systems.
Fix by moving the null check before the trace_keymap_parse().
While there, improve the error messages a bit.
Fixes: d3b787fa7d (keymaps: add tracing)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250723131504.1482657-1-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
When a VNC client sends a "set pixel format" message, the
'client_endian' field will get initialized, however, it is
valid to omit this message if the client wants to use the
server's native pixel format. In the latter scenario nothing
is initializing the 'client_endian' field, so it remains set
to 0, matching neither G_LITTLE_ENDIAN nor G_BIG_ENDIAN. This
then results in pixel format conversion routines taking the
wrong code paths.
This problem existed before the 'client_be' flag was changed
into the 'client_endian' value, but the lack of initialization
meant it semantically defaulted to little endian, so only big
endian systems would potentially be exposed to incorrect pixel
translation.
The 'virt-viewer' / 'remote-viewer' apps always send a "set
pixel format" message so aren't exposed to any problems, but
the classical 'vncviewer' app will show the problem easily.
Fixes: 7ed96710e8
Reported-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Allow user to set a preferred scale (defaulting to 1) of the virtual
display. Along with zoom-to-fix=false, this would be helpful for users
running QEMU on hi-dpi host desktop to achieve pixel to pixel display --
e.g., if the scale factor of a user's host desktop is set to 200%, then
they can set a 0.5 scale for the virtual display to avoid magnification
that might cause blurriness.
Signed-off-by: Weifeng Liu <weifeng.liu.z@gmail.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20250601045245.36778-3-weifeng.liu.z@gmail.com>
The worker thread copies data in VncState to avoid race, but some
data are too big to copy. Such data are held with pointers to avoid
the overhead to copy, but it requires tedious memory management and
makes them vulnerable to race.
Introduce the VncWorker type to contain all data shared without copying.
It allows allocating and freeing all shared data at once and shows that
the race with the worker thread needs to be taken care of when
accessing them.
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20250603-zlib-v3-2-20b857bd8d05@rsg.ci.i.u-tokyo.ac.jp>
vnc_worker_thread_loop() copies z_stream stored in its local VncState to
the persistent VncState, and the copied one is freed with deflateEnd()
later. However, deflateEnd() refuses to operate with a copied z_stream
and returns Z_STREAM_ERROR, leaking the allocated memory.
Avoid copying the zlib state to fix the memory leak.
Fixes: bd023f953e ("vnc: threaded VNC server")
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20250603-zlib-v3-1-20b857bd8d05@rsg.ci.i.u-tokyo.ac.jp>
If a virtual machine is paused for an extended period time, for example,
due to an incoming migration, there are also no changes on the screen.
VNC in such case increases the display update interval by
VNC_REFRESH_INTERVAL_INC (50 ms). The update interval can then grow up
to VNC_REFRESH_INTERVAL_MAX (3000 ms).
When the machine resumes, it can then take up to 3 seconds for the first
display update. Furthermore, the update interval is then halved with
each display update with changes on the screen. If there are moving
elements on the screen, such as a video, this can be perceived as
freezing and stuttering for few seconds before the movement is smooth
again.
This patch resolves this issue, by adding a listener to VM state changes
and changing the update interval when the VM state changes to RUNNING.
The update_displaychangelistener() function updates the internal timer,
and the display is refreshed immediately if the timer is expired.
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Link: https://lore.kernel.org/r/20250521151616.3951178-1-jmarcin@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
In fixed-scale mode (zoom-to-fit=false), we expect that scale should not
change, meaning that if window size is larger than guest surface,
padding is supposed to be added to preserve the scale. However, in
OpenGL mode (gl=on), guest surface is always painted to the whole canvas
without any padding. This change tries to fix this bug by adding
appropriate padding when drawing surfaces.
Signed-off-by: Weifeng Liu <weifeng.liu.z@gmail.com>
Message-ID: <20250511073337.876650-9-weifeng.liu.z@gmail.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
The ui width and height sent to guest is supposed to be in buffer
coordinate. Hence conversion is required.
If scaling (global window scale and zooming scale) is not respected in
non-free-scale mode, window size could keep changing because of the
existence of the iteration of the following steps:
1. In resize event or configure event, a size larger (or smaller) than
the currently used one might be calculated due to not considering
scaling.
2. On reception of the display size change event in guest, the guest
might decide to do a mode setting and use the larger (or smaller)
mode.
3. When the new guest scan-out command arrives, QEMU would request the
window size to change to fit the new buffer size. This will trigger a
resize event or a configure event, making us go back to step 1.
Signed-off-by: Weifeng Liu <weifeng.liu.z@gmail.com>
Message-ID: <20250511073337.876650-8-weifeng.liu.z@gmail.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
