diff --git a/hmp-commands.hx b/hmp-commands.hx
index cd068389de574bbd9baab5b3b6880025717287eb..ff2d7aa8f3e39a179ee2b340ac01ec30af3a3b91 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -254,6 +254,7 @@ ERST
.help = "save screen from head 'head' of display device 'device' "
"into PPM image 'filename'",
.cmd = hmp_screendump,
+ .coroutine = true,
},
SRST
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 56e9bad33d9431a378d8b5af5e75c7b35e0663f4..a6a6684df1c6b8a22bf05f71ba3afd0be2d75f8c 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -1762,7 +1762,8 @@ err_out:
goto out;
}
-void hmp_screendump(Monitor *mon, const QDict *qdict)
+void coroutine_fn
+hmp_screendump(Monitor *mon, const QDict *qdict)
{
const char *filename = qdict_get_str(qdict, "filename");
const char *id = qdict_get_try_str(qdict, "device");
diff --git a/qapi/ui.json b/qapi/ui.json
index 9d6721037f5b76427b7fba3e703408b14da4cd7b..6c7b33cb72389988ce71f291c863430ec4e32335 100644
--- a/qapi/ui.json
+++ b/qapi/ui.json
@@ -98,7 +98,8 @@
#
##
{ 'command': 'screendump',
- 'data': {'filename': 'str', '*device': 'str', '*head': 'int'} }
+ 'data': {'filename': 'str', '*device': 'str', '*head': 'int'},
+ 'coroutine': true }
##
# == Spice
diff --git a/ui/console.c b/ui/console.c
index 820e4081709db252ad08b274f0b8806d56d6f7c6..e8e59707d38c0c08d597d6d90bda2e344936b5df 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -168,6 +168,7 @@ struct QemuConsole {
QEMUFIFO out_fifo;
uint8_t out_fifo_buf[16];
QEMUTimer *kbd_timer;
+ CoQueue dump_queue;
QTAILQ_ENTRY(QemuConsole) next;
};
@@ -195,7 +196,6 @@ static void dpy_refresh(DisplayState *s);
static DisplayState *get_alloc_displaystate(void);
static void text_console_update_cursor_timer(void);
static void text_console_update_cursor(void *opaque);
-static bool ppm_save(int fd, DisplaySurface *ds, Error **errp);
static void gui_update(void *opaque)
{
@@ -264,6 +264,7 @@ static void gui_setup_refresh(DisplayState *ds)
void graphic_hw_update_done(QemuConsole *con)
{
+ qemu_co_queue_restart_all(&con->dump_queue);
}
void graphic_hw_update(QemuConsole *con)
@@ -311,16 +312,16 @@ void graphic_hw_invalidate(QemuConsole *con)
}
}
-static bool ppm_save(int fd, DisplaySurface *ds, Error **errp)
+static bool ppm_save(int fd, pixman_image_t *image, Error **errp)
{
- int width = pixman_image_get_width(ds->image);
- int height = pixman_image_get_height(ds->image);
+ int width = pixman_image_get_width(image);
+ int height = pixman_image_get_height(image);
g_autoptr(Object) ioc = OBJECT(qio_channel_file_new_fd(fd));
g_autofree char *header = NULL;
g_autoptr(pixman_image_t) linebuf = NULL;
int y;
- trace_ppm_save(fd, ds);
+ trace_ppm_save(fd, image);
header = g_strdup_printf("P6\n%d %d\n%d\n", width, height, 255);
if (qio_channel_write_all(QIO_CHANNEL(ioc),
@@ -330,7 +331,7 @@ static bool ppm_save(int fd, DisplaySurface *ds, Error **errp)
linebuf = qemu_pixman_linebuf_create(PIXMAN_BE_r8g8b8, width);
for (y = 0; y < height; y++) {
- qemu_pixman_linebuf_fill(linebuf, ds->image, width, 0, y);
+ qemu_pixman_linebuf_fill(linebuf, image, width, 0, y);
if (qio_channel_write_all(QIO_CHANNEL(ioc),
(char *)pixman_image_get_data(linebuf),
pixman_image_get_stride(linebuf), errp) < 0) {
@@ -341,9 +342,17 @@ static bool ppm_save(int fd, DisplaySurface *ds, Error **errp)
return true;
}
-void qmp_screendump(const char *filename, bool has_device, const char *device,
- bool has_head, int64_t head, Error **errp)
+static void graphic_hw_update_bh(void *con)
{
+ graphic_hw_update(con);
+}
+
+/* Safety: coroutine-only, concurrent-coroutine safe, main thread only */
+void coroutine_fn
+qmp_screendump(const char *filename, bool has_device, const char *device,
+ bool has_head, int64_t head, Error **errp)
+{
+ g_autoptr(pixman_image_t) image = NULL;
QemuConsole *con;
DisplaySurface *surface;
int fd;
@@ -366,12 +375,24 @@ void qmp_screendump(const char *filename, bool has_device, const char *device,
}
}
- graphic_hw_update(con);
+ if (qemu_co_queue_empty(&con->dump_queue)) {
+ /* Defer the update, it will restart the pending coroutines */
+ aio_bh_schedule_oneshot(qemu_get_aio_context(),
+ graphic_hw_update_bh, con);
+ }
+ qemu_co_queue_wait(&con->dump_queue, NULL);
+
+ /*
+ * All pending coroutines are woken up, while the BQL is held. No
+ * further graphic update are possible until it is released. Take
+ * an image ref before that.
+ */
surface = qemu_console_surface(con);
if (!surface) {
error_setg(errp, "no surface");
return;
}
+ image = pixman_image_ref(surface->image);
fd = qemu_open_old(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0666);
if (fd == -1) {
@@ -380,7 +401,12 @@ void qmp_screendump(const char *filename, bool has_device, const char *device,
return;
}
- if (!ppm_save(fd, surface, errp)) {
+ /*
+ * The image content could potentially be updated as the coroutine
+ * yields and releases the BQL. It could produce corrupted dump, but
+ * it should be otherwise safe.
+ */
+ if (!ppm_save(fd, image, errp)) {
qemu_unlink(filename);
}
}
@@ -1296,6 +1322,7 @@ static QemuConsole *new_console(DisplayState *ds, console_type_t console_type,
obj = object_new(TYPE_QEMU_CONSOLE);
s = QEMU_CONSOLE(obj);
+ qemu_co_queue_init(&s->dump_queue);
s->head = head;
object_property_add_link(obj, "device", TYPE_DEVICE,
(Object **)&s->device,
diff --git a/ui/trace-events b/ui/trace-events
index b7d7270c02c6d0a139ea7423ef72d5b049aa8bff..0ffcdb4408a6fd90ad6a9bc6db7168e0d616078b 100644
--- a/ui/trace-events
+++ b/ui/trace-events
@@ -15,7 +15,7 @@ displaysurface_create_pixman(void *display_surface) "surface=%p"
displaysurface_free(void *display_surface) "surface=%p"
displaychangelistener_register(void *dcl, const char *name) "%p [ %s ]"
displaychangelistener_unregister(void *dcl, const char *name) "%p [ %s ]"
-ppm_save(int fd, void *display_surface) "fd=%d surface=%p"
+ppm_save(int fd, void *image) "fd=%d image=%p"
# gtk-egl.c
# gtk-gl-area.c
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 36927b5f88d58e96531e0fdd13367f8e1272d08c..5816bf890094d4e87f72808abe0631a0cd5fb26f 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -85,15 +85,13 @@ static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
return true;
}
-bool coroutine_fn qemu_co_queue_next(CoQueue *queue)
+bool qemu_co_queue_next(CoQueue *queue)
{
- assert(qemu_in_coroutine());
return qemu_co_queue_do_restart(queue, true);
}
-void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
+void qemu_co_queue_restart_all(CoQueue *queue)
{
- assert(qemu_in_coroutine());
qemu_co_queue_do_restart(queue, false);
}