[PATCH] spice: delay starting until display are initialized

[marcandre.lureau@redhat.com]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

QEMU used to run qemu_spice.display_init() before vm_start(), and
QXL/display interfaces where started then. Now, vm_start() happens
before QXL/display interfaces are added and Spice server doesn't
automatically start them in this case (fixed in spice git)

Fixes Spice regression introduced after 5.2, with refactoring commits
b4e1a34211 ("vl: remove separate preconfig main_loop") and
facf7c60ee ("vl: initialize displays _after_ exiting preconfiguration"),
probably others.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/sysemu/runstate.h | 1 +
 include/ui/qemu-spice.h   | 1 +
 softmmu/runstate.c        | 5 +++++
 ui/spice-core.c           | 9 ++++++++-
 ui/spice-display.c        | 2 ++
 5 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/include/sysemu/runstate.h b/include/sysemu/runstate.h
index e557f470d4..40b3083008 100644
--- a/include/sysemu/runstate.h
+++ b/include/sysemu/runstate.h
@@ -6,6 +6,7 @@
 
 bool runstate_check(RunState state);
 void runstate_set(RunState new_state);
+RunState runstate_get(void);
 int runstate_is_running(void);
 bool runstate_needs_reset(void);
 bool runstate_store(char *str, size_t size);
diff --git a/include/ui/qemu-spice.h b/include/ui/qemu-spice.h
index 2beb792972..71ecd6cfd1 100644
--- a/include/ui/qemu-spice.h
+++ b/include/ui/qemu-spice.h
@@ -28,6 +28,7 @@
 
 void qemu_spice_input_init(void);
 void qemu_spice_display_init(void);
+void qemu_spice_display_init_done(void);
 bool qemu_spice_have_display_interface(QemuConsole *con);
 int qemu_spice_add_display_interface(QXLInstance *qxlin, QemuConsole *con);
 int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
diff --git a/softmmu/runstate.c b/softmmu/runstate.c
index beee050815..92ef7444d0 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -195,6 +195,11 @@ static void runstate_init(void)
     qemu_mutex_init(&vmstop_lock);
 }
 
+RunState runstate_get(void)
+{
+    return current_run_state;
+}
+
 /* This function will abort() on invalid state transitions */
 void runstate_set(RunState new_state)
 {
diff --git a/ui/spice-core.c b/ui/spice-core.c
index 5746d0aae7..b621dd86b6 100644
--- a/ui/spice-core.c
+++ b/ui/spice-core.c
@@ -46,6 +46,7 @@ static const char *auth = "spice";
 static char *auth_passwd;
 static time_t auth_expires = TIME_MAX;
 static int spice_migration_completed;
+static int spice_display_init_done;
 static int spice_display_is_running;
 static int spice_have_target_host;
 
@@ -625,13 +626,19 @@ static int add_channel(void *opaque, const char *name, const char *value,
 static void vm_change_state_handler(void *opaque, int running,
                                     RunState state)
 {
-    if (running) {
+    if (running && spice_display_init_done) {
         qemu_spice_display_start();
     } else if (state != RUN_STATE_PAUSED) {
         qemu_spice_display_stop();
     }
 }
 
+void qemu_spice_display_init_done(void)
+{
+    spice_display_init_done = true;
+    vm_change_state_handler(NULL, runstate_is_running(), runstate_get());
+}
+
 static void qemu_spice_init(void)
 {
     QemuOpts *opts = QTAILQ_FIRST(&qemu_spice_opts.head);
diff --git a/ui/spice-display.c b/ui/spice-display.c
index 0178d5766d..3d3e3bcb22 100644
--- a/ui/spice-display.c
+++ b/ui/spice-display.c
@@ -1188,4 +1188,6 @@ void qemu_spice_display_init(void)
         }
         qemu_spice_display_init_one(con);
     }
+
+    qemu_spice_display_init_done();
 }
-- 
2.29.0