replay: checkpoints

This patch introduces checkpoints that synchronize cpu thread and iothread.
When checkpoint is met in the code all asynchronous events from the queue
are executed.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20150917162444.8676.52916.stgit@PASHA-ISP.def.inno>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

1 files changed, 24 insertions, 5 deletions

diff --git a/vl.c b/vl.c
index f481a1e5aa..8806092551 100644
--- a/vl.c
+++ b/vl.c
@@ -1642,15 +1642,21 @@ static void qemu_kill_report(void)
 static int qemu_reset_requested(void)
 {
     int r = reset_requested;
-    reset_requested = 0;
-    return r;
+    if (r && replay_checkpoint(CHECKPOINT_RESET_REQUESTED)) {
+        reset_requested = 0;
+        return r;
+    }
+    return false;
 }
 
 static int qemu_suspend_requested(void)
 {
     int r = suspend_requested;
-    suspend_requested = 0;
-    return r;
+    if (r && replay_checkpoint(CHECKPOINT_SUSPEND_REQUESTED)) {
+        suspend_requested = 0;
+        return r;
+    }
+    return false;
 }
 
 static WakeupReason qemu_wakeup_requested(void)
@@ -1798,7 +1804,12 @@ void qemu_system_killed(int signal, pid_t pid)
     shutdown_signal = signal;
     shutdown_pid = pid;
     no_shutdown = 0;
-    qemu_system_shutdown_request();
+
+    /* Cannot call qemu_system_shutdown_request directly because
+     * we are in a signal handler.
+     */
+    shutdown_requested = 1;
+    qemu_notify_event();
 }
 
 void qemu_system_shutdown_request(void)
@@ -4483,6 +4494,10 @@ int main(int argc, char **argv, char **envp)
     }
     qemu_add_globals();
 
+    /* This checkpoint is required by replay to separate prior clock
+       reading from the other reads, because timer polling functions query
+       clock values from the log. */
+    replay_checkpoint(CHECKPOINT_INIT);
     qdev_machine_init();
 
     current_machine->ram_size = ram_size;
@@ -4601,6 +4616,10 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
+    /* This checkpoint is required by replay to separate prior clock
+       reading from the other reads, because timer polling functions query
+       clock values from the log. */
+    replay_checkpoint(CHECKPOINT_RESET);
     qemu_system_reset(VMRESET_SILENT);
     register_global_state();
     if (loadvm) {