ui: add a D-Bus display backend

The "dbus" display backend exports the QEMU consoles and other
UI-related interfaces over D-Bus.

By default, the connection is established on the session bus, but you
can specify a different bus with the "addr" option.

The backend takes the "org.qemu" service name, while still allowing
further instances to queue on the same name (so you can lookup all the
available instances too). It accepts any number of clients at this
point, although this is expected to evolve with options to restrict
clients, or only accept p2p via fd passing.

The interface is intentionally very close to the internal QEMU API,
and can be introspected or interacted with busctl/dfeet etc:

$ ./qemu-system-x86_64 -name MyVM -display dbus
$ busctl --user introspect org.qemu /org/qemu/Display1/Console_0

org.qemu.Display1.Console           interface -         -               -
.RegisterListener                   method    h         -               -
.SetUIInfo                          method    qqiiuu    -               -
.DeviceAddress                      property  s         "pci/0000/01.0" emits-change
.Head                               property  u         0               emits-change
.Height                             property  u         480             emits-change
.Label                              property  s         "VGA"           emits-change
.Type                               property  s         "Graphic"       emits-change
.Width                              property  u         640             emits-change
[...]

See the interfaces XML source file and Sphinx docs for the generated API
documentations.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 486 insertions, 0 deletions

diff --git a/ui/dbus-listener.c b/ui/dbus-listener.c
new file mode 100644
index 0000000..20094fc
--- /dev/null
+++ b/ui/dbus-listener.c
@@ -0,0 +1,486 @@
+/*
+ * QEMU DBus display console
+ *
+ * Copyright (c) 2021 Marc-André Lureau <marcandre.lureau@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "sysemu/sysemu.h"
+#include "dbus.h"
+#include <gio/gunixfdlist.h>
+
+#include "ui/shader.h"
+#include "ui/egl-helpers.h"
+#include "ui/egl-context.h"
+#include "trace.h"
+
+struct _DBusDisplayListener {
+    GObject parent;
+
+    char *bus_name;
+    DBusDisplayConsole *console;
+    GDBusConnection *conn;
+
+    QemuDBusDisplay1Listener *proxy;
+
+    DisplayChangeListener dcl;
+    DisplaySurface *ds;
+    QemuGLShader *gls;
+    int gl_updates;
+};
+
+G_DEFINE_TYPE(DBusDisplayListener, dbus_display_listener, G_TYPE_OBJECT)
+
+static void dbus_update_gl_cb(GObject *source_object,
+                           GAsyncResult *res,
+                           gpointer user_data)
+{
+    g_autoptr(GError) err = NULL;
+    DBusDisplayListener *ddl = user_data;
+
+    if (!qemu_dbus_display1_listener_call_update_dmabuf_finish(ddl->proxy,
+                                                               res, &err)) {
+        error_report("Failed to call update: %s", err->message);
+    }
+
+    graphic_hw_gl_block(ddl->dcl.con, false);
+    g_object_unref(ddl);
+}
+
+static void dbus_call_update_gl(DBusDisplayListener *ddl,
+                                int x, int y, int w, int h)
+{
+    graphic_hw_gl_block(ddl->dcl.con, true);
+    glFlush();
+    qemu_dbus_display1_listener_call_update_dmabuf(ddl->proxy,
+        x, y, w, h,
+        G_DBUS_CALL_FLAGS_NONE,
+        DBUS_DEFAULT_TIMEOUT, NULL,
+        dbus_update_gl_cb,
+        g_object_ref(ddl));
+}
+
+static void dbus_scanout_disable(DisplayChangeListener *dcl)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    ddl->ds = NULL;
+    qemu_dbus_display1_listener_call_disable(
+        ddl->proxy, G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL);
+}
+
+static void dbus_scanout_dmabuf(DisplayChangeListener *dcl,
+                                QemuDmaBuf *dmabuf)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+    g_autoptr(GError) err = NULL;
+    g_autoptr(GUnixFDList) fd_list = NULL;
+
+    fd_list = g_unix_fd_list_new();
+    if (g_unix_fd_list_append(fd_list, dmabuf->fd, &err) != 0) {
+        error_report("Failed to setup dmabuf fdlist: %s", err->message);
+        return;
+    }
+
+    qemu_dbus_display1_listener_call_scanout_dmabuf(
+        ddl->proxy,
+        g_variant_new_handle(0),
+        dmabuf->width,
+        dmabuf->height,
+        dmabuf->stride,
+        dmabuf->fourcc,
+        dmabuf->modifier,
+        dmabuf->y0_top,
+        G_DBUS_CALL_FLAGS_NONE,
+        -1,
+        fd_list,
+        NULL, NULL, NULL);
+}
+
+static void dbus_scanout_texture(DisplayChangeListener *dcl,
+                                 uint32_t tex_id,
+                                 bool backing_y_0_top,
+                                 uint32_t backing_width,
+                                 uint32_t backing_height,
+                                 uint32_t x, uint32_t y,
+                                 uint32_t w, uint32_t h)
+{
+    QemuDmaBuf dmabuf = {
+        .width = backing_width,
+        .height = backing_height,
+        .y0_top = backing_y_0_top,
+    };
+
+    assert(tex_id);
+    dmabuf.fd = egl_get_fd_for_texture(
+        tex_id, (EGLint *)&dmabuf.stride,
+        (EGLint *)&dmabuf.fourcc,
+        &dmabuf.modifier);
+    if (dmabuf.fd < 0) {
+        error_report("%s: failed to get fd for texture", __func__);
+        return;
+    }
+
+    dbus_scanout_dmabuf(dcl, &dmabuf);
+    close(dmabuf.fd);
+}
+
+static void dbus_cursor_dmabuf(DisplayChangeListener *dcl,
+                               QemuDmaBuf *dmabuf, bool have_hot,
+                               uint32_t hot_x, uint32_t hot_y)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+    DisplaySurface *ds;
+    GVariant *v_data = NULL;
+    egl_fb cursor_fb;
+
+    if (!dmabuf) {
+        qemu_dbus_display1_listener_call_mouse_set(
+            ddl->proxy, 0, 0, false,
+            G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL);
+        return;
+    }
+
+    egl_dmabuf_import_texture(dmabuf);
+    if (!dmabuf->texture) {
+        return;
+    }
+    egl_fb_setup_for_tex(&cursor_fb, dmabuf->width, dmabuf->height,
+                         dmabuf->texture, false);
+    ds = qemu_create_displaysurface(dmabuf->width, dmabuf->height);
+    egl_fb_read(ds, &cursor_fb);
+
+    v_data = g_variant_new_from_data(
+        G_VARIANT_TYPE("ay"),
+        surface_data(ds),
+        surface_width(ds) * surface_height(ds) * 4,
+        TRUE,
+        (GDestroyNotify)qemu_free_displaysurface,
+        ds);
+    qemu_dbus_display1_listener_call_cursor_define(
+        ddl->proxy,
+        surface_width(ds),
+        surface_height(ds),
+        hot_x,
+        hot_y,
+        v_data,
+        G_DBUS_CALL_FLAGS_NONE,
+        -1,
+        NULL,
+        NULL,
+        NULL);
+}
+
+static void dbus_cursor_position(DisplayChangeListener *dcl,
+                                 uint32_t pos_x, uint32_t pos_y)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    qemu_dbus_display1_listener_call_mouse_set(
+        ddl->proxy, pos_x, pos_y, true,
+        G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL);
+}
+
+static void dbus_release_dmabuf(DisplayChangeListener *dcl,
+                                QemuDmaBuf *dmabuf)
+{
+    dbus_scanout_disable(dcl);
+}
+
+static void dbus_scanout_update(DisplayChangeListener *dcl,
+                                uint32_t x, uint32_t y,
+                                uint32_t w, uint32_t h)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    dbus_call_update_gl(ddl, x, y, w, h);
+}
+
+static void dbus_gl_refresh(DisplayChangeListener *dcl)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    graphic_hw_update(dcl->con);
+
+    if (!ddl->ds || qemu_console_is_gl_blocked(ddl->dcl.con)) {
+        return;
+    }
+
+    if (ddl->gl_updates) {
+        dbus_call_update_gl(ddl, 0, 0,
+                            surface_width(ddl->ds), surface_height(ddl->ds));
+        ddl->gl_updates = 0;
+    }
+}
+
+static void dbus_refresh(DisplayChangeListener *dcl)
+{
+    graphic_hw_update(dcl->con);
+}
+
+static void dbus_gl_gfx_update(DisplayChangeListener *dcl,
+                               int x, int y, int w, int h)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    if (ddl->ds) {
+        surface_gl_update_texture(ddl->gls, ddl->ds, x, y, w, h);
+    }
+
+    ddl->gl_updates++;
+}
+
+static void dbus_gfx_update(DisplayChangeListener *dcl,
+                            int x, int y, int w, int h)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+    pixman_image_t *img;
+    GVariant *v_data;
+    size_t stride;
+
+    assert(ddl->ds);
+    stride = w * DIV_ROUND_UP(PIXMAN_FORMAT_BPP(surface_format(ddl->ds)), 8);
+
+    trace_dbus_update(x, y, w, h);
+
+    /* make a copy, since gvariant only handles linear data */
+    img = pixman_image_create_bits(surface_format(ddl->ds),
+                                   w, h, NULL, stride);
+    pixman_image_composite(PIXMAN_OP_SRC, ddl->ds->image, NULL, img,
+                           x, y, 0, 0, 0, 0, w, h);
+
+    v_data = g_variant_new_from_data(
+        G_VARIANT_TYPE("ay"),
+        pixman_image_get_data(img),
+        pixman_image_get_stride(img) * h,
+        TRUE,
+        (GDestroyNotify)pixman_image_unref,
+        img);
+    qemu_dbus_display1_listener_call_update(ddl->proxy,
+        x, y, w, h, pixman_image_get_stride(img), pixman_image_get_format(img),
+        v_data,
+        G_DBUS_CALL_FLAGS_NONE,
+        DBUS_DEFAULT_TIMEOUT, NULL, NULL, NULL);
+}
+
+static void dbus_gl_gfx_switch(DisplayChangeListener *dcl,
+                               struct DisplaySurface *new_surface)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    if (ddl->ds) {
+        surface_gl_destroy_texture(ddl->gls, ddl->ds);
+    }
+    ddl->ds = new_surface;
+    if (ddl->ds) {
+        int width = surface_width(ddl->ds);
+        int height = surface_height(ddl->ds);
+
+        surface_gl_create_texture(ddl->gls, ddl->ds);
+        /* TODO: lazy send dmabuf (there are unnecessary sent otherwise) */
+        dbus_scanout_texture(&ddl->dcl, ddl->ds->texture, false,
+                             width, height, 0, 0, width, height);
+    }
+}
+
+static void dbus_gfx_switch(DisplayChangeListener *dcl,
+                            struct DisplaySurface *new_surface)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+    GVariant *v_data = NULL;
+
+    ddl->ds = new_surface;
+    if (!ddl->ds) {
+        /* why not call disable instead? */
+        return;
+    }
+
+    v_data = g_variant_new_from_data(
+        G_VARIANT_TYPE("ay"),
+        surface_data(ddl->ds),
+        surface_stride(ddl->ds) * surface_height(ddl->ds),
+        TRUE,
+        (GDestroyNotify)pixman_image_unref,
+        pixman_image_ref(ddl->ds->image));
+    qemu_dbus_display1_listener_call_scanout(ddl->proxy,
+        surface_width(ddl->ds),
+        surface_height(ddl->ds),
+        surface_stride(ddl->ds),
+        surface_format(ddl->ds),
+        v_data,
+        G_DBUS_CALL_FLAGS_NONE,
+        DBUS_DEFAULT_TIMEOUT, NULL, NULL, NULL);
+}
+
+static void dbus_mouse_set(DisplayChangeListener *dcl,
+                           int x, int y, int on)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+
+    qemu_dbus_display1_listener_call_mouse_set(
+        ddl->proxy, x, y, on, G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL);
+}
+
+static void dbus_cursor_define(DisplayChangeListener *dcl,
+                               QEMUCursor *c)
+{
+    DBusDisplayListener *ddl = container_of(dcl, DBusDisplayListener, dcl);
+    GVariant *v_data = NULL;
+
+    cursor_get(c);
+    v_data = g_variant_new_from_data(
+        G_VARIANT_TYPE("ay"),
+        c->data,
+        c->width * c->height * 4,
+        TRUE,
+        (GDestroyNotify)cursor_put,
+        c);
+
+    qemu_dbus_display1_listener_call_cursor_define(
+        ddl->proxy,
+        c->width,
+        c->height,
+        c->hot_x,
+        c->hot_y,
+        v_data,
+        G_DBUS_CALL_FLAGS_NONE,
+        -1,
+        NULL,
+        NULL,
+        NULL);
+}
+
+const DisplayChangeListenerOps dbus_gl_dcl_ops = {
+    .dpy_name                = "dbus-gl",
+    .dpy_gfx_update          = dbus_gl_gfx_update,
+    .dpy_gfx_switch          = dbus_gl_gfx_switch,
+    .dpy_gfx_check_format    = console_gl_check_format,
+    .dpy_refresh             = dbus_gl_refresh,
+    .dpy_mouse_set           = dbus_mouse_set,
+    .dpy_cursor_define       = dbus_cursor_define,
+
+    .dpy_gl_scanout_disable  = dbus_scanout_disable,
+    .dpy_gl_scanout_texture  = dbus_scanout_texture,
+    .dpy_gl_scanout_dmabuf   = dbus_scanout_dmabuf,
+    .dpy_gl_cursor_dmabuf    = dbus_cursor_dmabuf,
+    .dpy_gl_cursor_position  = dbus_cursor_position,
+    .dpy_gl_release_dmabuf   = dbus_release_dmabuf,
+    .dpy_gl_update           = dbus_scanout_update,
+};
+
+const DisplayChangeListenerOps dbus_dcl_ops = {
+    .dpy_name                = "dbus",
+    .dpy_gfx_update          = dbus_gfx_update,
+    .dpy_gfx_switch          = dbus_gfx_switch,
+    .dpy_refresh             = dbus_refresh,
+    .dpy_mouse_set           = dbus_mouse_set,
+    .dpy_cursor_define       = dbus_cursor_define,
+};
+
+static void
+dbus_display_listener_dispose(GObject *object)
+{
+    DBusDisplayListener *ddl = DBUS_DISPLAY_LISTENER(object);
+
+    unregister_displaychangelistener(&ddl->dcl);
+    g_clear_object(&ddl->conn);
+    g_clear_pointer(&ddl->bus_name, g_free);
+    g_clear_object(&ddl->proxy);
+    g_clear_pointer(&ddl->gls, qemu_gl_fini_shader);
+
+    G_OBJECT_CLASS(dbus_display_listener_parent_class)->dispose(object);
+}
+
+static void
+dbus_display_listener_constructed(GObject *object)
+{
+    DBusDisplayListener *ddl = DBUS_DISPLAY_LISTENER(object);
+
+    if (display_opengl) {
+        ddl->gls = qemu_gl_init_shader();
+        ddl->dcl.ops = &dbus_gl_dcl_ops;
+    } else {
+        ddl->dcl.ops = &dbus_dcl_ops;
+    }
+
+    G_OBJECT_CLASS(dbus_display_listener_parent_class)->constructed(object);
+}
+
+static void
+dbus_display_listener_class_init(DBusDisplayListenerClass *klass)
+{
+    GObjectClass *object_class = G_OBJECT_CLASS(klass);
+
+    object_class->dispose = dbus_display_listener_dispose;
+    object_class->constructed = dbus_display_listener_constructed;
+}
+
+static void
+dbus_display_listener_init(DBusDisplayListener *ddl)
+{
+}
+
+const char *
+dbus_display_listener_get_bus_name(DBusDisplayListener *ddl)
+{
+    return ddl->bus_name;
+}
+
+DBusDisplayConsole *
+dbus_display_listener_get_console(DBusDisplayListener *ddl)
+{
+    return ddl->console;
+}
+
+DBusDisplayListener *
+dbus_display_listener_new(const char *bus_name,
+                          GDBusConnection *conn,
+                          DBusDisplayConsole *console)
+{
+    DBusDisplayListener *ddl;
+    QemuConsole *con;
+    g_autoptr(GError) err = NULL;
+
+    ddl = g_object_new(DBUS_DISPLAY_TYPE_LISTENER, NULL);
+    ddl->proxy =
+        qemu_dbus_display1_listener_proxy_new_sync(conn,
+            G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START,
+            NULL,
+            "/org/qemu/Display1/Listener",
+            NULL,
+            &err);
+    if (!ddl->proxy) {
+        error_report("Failed to setup proxy: %s", err->message);
+        g_object_unref(conn);
+        g_object_unref(ddl);
+        return NULL;
+    }
+
+    ddl->bus_name = g_strdup(bus_name);
+    ddl->conn = conn;
+    ddl->console = console;
+
+    con = qemu_console_lookup_by_index(dbus_display_console_get_index(console));
+    assert(con);
+    ddl->dcl.con = con;
+    register_displaychangelistener(&ddl->dcl);
+
+    return ddl;
+}