qemu/ui
Phil Dennis-Jordan f5ab12caba ui & main loop: Redesign of system-specific main thread event handling
macOS's Cocoa event handling must be done on the initial (main) thread
of the process. Furthermore, if library or application code uses
libdispatch, the main dispatch queue must be handling events on the main
thread as well.

So far, this has affected Qemu in both the Cocoa and SDL UIs, although
in different ways: the Cocoa UI replaces the default qemu_main function
with one that spins Qemu's internal main event loop off onto a
background thread. SDL (which uses Cocoa internally) on the other hand
uses a polling approach within Qemu's main event loop. Events are
polled during the SDL UI's dpy_refresh callback, which happens to run
on the main thread by default.

As UIs are mutually exclusive, this works OK as long as nothing else
needs platform-native event handling. In the next patch, a new device is
introduced based on the ParavirtualizedGraphics.framework in macOS.
This uses libdispatch internally, and only works when events are being
handled on the main runloop. With the current system, it works when
using either the Cocoa or the SDL UI. However, it does not when running
headless. Moreover, any attempt to install a similar scheme to the
Cocoa UI's main thread replacement fails when combined with the SDL
UI.

This change tidies up main thread management to be more flexible.

 * The qemu_main global function pointer is a custom function for the
   main thread, and it may now be NULL. When it is, the main thread
   runs the main Qemu loop. This represents the traditional setup.
 * When non-null, spawning the main Qemu event loop on a separate
   thread is now done centrally rather than inside the Cocoa UI code.
 * For most platforms, qemu_main is indeed NULL by default, but on
   Darwin, it defaults to a function that runs the CFRunLoop.
 * The Cocoa UI sets qemu_main to a function which runs the
   NSApplication event handling runloop, as is usual for a Cocoa app.
 * The SDL UI overrides the qemu_main function to NULL, thus
   specifying that Qemu's main loop must run on the main
   thread.
 * The GTK UI also overrides the qemu_main function to NULL.
 * For other UIs, or in the absence of UIs, the platform's default
   behaviour is followed.

This means that on macOS, the platform's runloop events are always
handled, regardless of chosen UI. The new PV graphics device will
thus work in all configurations. There is no functional change on other
operating systems.

Implementing this via a global function pointer variable is a bit
ugly, but it's probably worth investigating the existing UI thread rule
violations in the SDL (e.g. #2537) and GTK+ back-ends. Fixing those
issues might precipitate requirements similar but not identical to those
of the Cocoa UI; hopefully we'll see some kind of pattern emerge, which
can then be used as a basis for an overhaul. (In fact, it may turn
out to be simplest to split the UI/native platform event thread from the
QEMU main event loop on all platforms, with any UI or even none at all.)

Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Tested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-ID: <20241223221645.29911-2-phil@philjordan.eu>
[PMD: Declare 'qemu_main' symbol in tests/qtest/fuzz/fuzz.c,
      add missing g_assert_not_reached() call in main()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
2024-12-31 21:21:34 +01:00
..
icons configure: move directory options from config-host.mak to meson 2020-10-26 07:08:38 -04:00
shader meson: do not build shaders by default 2023-10-17 15:20:53 +02:00
clipboard.c ui/vdagent: notify clipboard peers of serial reset 2024-07-22 12:47:28 +04:00
cocoa.m ui & main loop: Redesign of system-specific main thread event handling 2024-12-31 21:21:34 +01:00
console-gl.c ui/console: remove redundant format field 2023-09-12 10:37:02 +04:00
console-priv.h ui/curses: Do not use console_select() 2024-03-20 10:27:58 +04:00
console-vc-stubs.c ui/curses: Do not use console_select() 2024-03-20 10:27:58 +04:00
console-vc.c ui: Replace type_register() with type_register_static() 2024-12-10 18:49:25 +01:00
console.c ui: refactor using a common qemu_pixman_shareable 2024-10-14 17:34:09 +04:00
curses.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
curses_keys.h For curses display, recognize a few more control keys 2023-07-25 10:56:51 +01:00
cursor.c ui/cursor: remove cursor_get_mono_image 2024-10-03 17:26:06 +03:00
cursor_hidden.xpm ui: move files to ui/ and include/ui/ 2012-12-19 08:31:30 +01:00
cursor_left_ptr.xpm ui: move files to ui/ and include/ui/ 2012-12-19 08:31:30 +01:00
dbus-chardev.c ui/dbus: win32 support 2023-06-27 17:08:56 +02:00
dbus-clipboard.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
dbus-console.c ui/dbus: do not limit to one listener per connection / bus name 2024-10-14 17:34:09 +04:00
dbus-display1.xml ui/dbus: add Listener.Unix.Map interface XML 2024-10-14 17:34:09 +04:00
dbus-error.c ui: add a D-Bus display backend 2021-12-21 10:50:22 +04:00
dbus-listener.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
dbus-module.c ui/dbus: add p2p=on/off option 2021-12-21 10:50:22 +04:00
dbus.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
dbus.h ui/dbus: win32 support 2023-06-27 17:08:56 +02:00
dmabuf.c ui/console: move QemuDmaBuf struct def to dmabuf.c 2024-05-14 17:14:12 +04:00
egl-context.c qapi/ui: Drop temporary 'prefix' 2024-09-10 13:22:47 +02:00
egl-headless.c qapi/ui: Drop temporary 'prefix' 2024-09-10 13:22:47 +02:00
egl-helpers.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
gtk-clipboard.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
gtk-egl.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
gtk-gl-area.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
gtk.c ui & main loop: Redesign of system-specific main thread event handling 2024-12-31 21:21:34 +01:00
input-barrier.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
input-barrier.h ui: add an embedded Barrier client 2019-09-17 13:43:22 +02:00
input-keymap.c meson: rename included C source files to .c.inc 2020-08-21 06:18:30 -04:00
input-legacy.c ui/input-legacy.c: remove unused legacy qemu_add_kbd_event_handler() function 2024-11-08 11:06:42 +01:00
input-linux.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
input.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
kbd-state.c ui/vnc: Do not use console_select() 2024-03-20 10:27:54 +04:00
keymaps.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
keymaps.h ui: spelling fixes 2023-08-31 19:47:43 +02:00
meson.build Revert "meson: Propagate gnutls dependency" 2024-07-03 18:41:26 +02:00
qemu-pixman.c ui: refactor using a common qemu_pixman_shareable 2024-10-14 17:34:09 +04:00
qemu-x509.h ui: move files to ui/ and include/ui/ 2012-12-19 08:31:30 +01:00
qemu.desktop ui: fix icon display for GTK frontend under GNOME Shell with Wayland 2019-01-21 09:43:13 +01:00
sdl2-2d.c ui+display: rename is_placeholder() -> surface_is_placeholder() 2024-06-19 12:42:03 +02:00
sdl2-gl.c qapi/ui: Drop temporary 'prefix' 2024-09-10 13:22:47 +02:00
sdl2-input.c ui/sdl2: release all modifiers 2024-09-13 20:12:16 +02:00
sdl2.c ui & main loop: Redesign of system-specific main thread event handling 2024-12-31 21:21:34 +01:00
shader.c ui/shader: free associated programs 2022-03-14 15:16:16 +04:00
spice-app.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
spice-core.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
spice-display.c ui/console: Convert mouse visibility parameter into bool 2024-07-16 20:04:08 +02:00
spice-input.c input: Allow to choose console with qemu_input_is_absolute 2023-10-03 15:04:56 +04:00
spice-module.c spice: wire up monitor in QemuSpiceOps. 2020-10-21 15:46:14 +02:00
trace-events ui/dbus: add trace for can_share_map 2024-10-14 17:34:09 +04:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
udmabuf.c Do not include "qemu/error-report.h" in headers that do not need it 2023-02-14 09:11:27 +01:00
ui-hmp-cmds.c qmp/hmp: disable screendump if PIXMAN is missing 2023-11-07 14:04:25 +04:00
ui-qmp-cmds.c ui/qmp-cmds: Improve two error messages 2023-11-17 10:07:52 +01:00
util.c include/hw/pci: Split pci_device.h off pci.h 2023-01-08 01:54:22 -05:00
vdagent.c ui/vdagent: send caps on fe_open 2024-07-22 12:47:28 +04:00
vgafont.h ui: fix tab indentation 2022-11-08 10:23:06 +01:00
vnc-auth-sasl.c ui: validate NUL byte padding in SASL client data more strictly 2024-10-22 13:02:31 +01:00
vnc-auth-sasl.h vnc: avoid deprecation warnings for SASL on OS X 2021-06-15 17:17:09 +02:00
vnc-auth-vencrypt.c vnc: fix resource leak when websocket channel error 2020-11-04 08:25:17 +01:00
vnc-auth-vencrypt.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
vnc-clipboard.c ui/vnc-clipboard: fix inflate_buffer 2023-12-04 11:28:26 +04:00
vnc-enc-hextile-template.h ui/vnc-enc-hextile: Use static rather than dynamic length stack array 2023-09-04 14:57:44 +04:00
vnc-enc-hextile.c Drop useless casts from g_malloc() & friends to pointer 2022-10-22 23:15:40 +02:00
vnc-enc-tight.c ui/vnc-enc-tight: Avoid dynamic stack allocation 2023-09-04 14:57:44 +04:00
vnc-enc-tight.h Clean up header guards that don't match their file name 2016-07-12 16:19:16 +02:00
vnc-enc-zlib.c vnc: fix memory leak when vnc disconnect 2019-09-17 13:45:10 +02:00
vnc-enc-zrle.c meson: rename included C source files to .c.inc 2020-08-21 06:18:30 -04:00
vnc-enc-zrle.c.inc ui: Clean up local variable shadowing 2023-09-29 08:13:57 +02:00
vnc-enc-zrle.h Clean up header guards that don't match their file name 2016-07-12 16:19:16 +02:00
vnc-enc-zywrle-template.c ui: fix tab indentation 2022-11-08 10:23:06 +01:00
vnc-enc-zywrle.h ui: spelling fixes 2023-08-31 19:47:43 +02:00
vnc-jobs.c vnc: move assert in vnc_worker_thread_loop 2023-06-10 00:00:24 +03:00
vnc-jobs.h ui/vnc: Drop unused vnc_has_job() and vnc_jobs_clear() 2017-02-08 14:59:36 +01:00
vnc-palette.c ui: Clean up local variable shadowing 2023-09-29 08:13:57 +02:00
vnc-palette.h Include qapi/qmp/qlist.h exactly where needed 2018-02-09 13:52:15 +01:00
vnc-stubs.c qemu-options: define -vnc only #ifdef CONFIG_VNC 2023-11-07 14:04:25 +04:00
vnc-ws.c bulk: Remove pointless QOM casts 2023-06-05 20:48:34 +02:00
vnc-ws.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
vnc.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
vnc.h ui/vnc: fix skipping SASL SSF on UNIX sockets 2024-10-22 11:44:23 +01:00
vnc_keysym.h ui: fix tab indentation 2022-11-08 10:23:06 +01:00
win32-kbd-hook.c include: Rename sysemu/ -> system/ 2024-12-20 17:44:56 +01:00
x_keymap.c ui: Fix memory leak in qemu_xkeymap_mapping_table() 2021-05-02 17:24:50 +02:00
x_keymap.h ui: convert GTK and SDL1 frontends to keycodemapdb 2018-01-25 15:02:00 +01:00