replay: asynchronous events infrastructure

This patch adds module for saving and replaying asynchronous events.
These events include network packets, keyboard and mouse input,
USB packets, thread pool and bottom halves callbacks.
All events are stored in the queue to be processed at synchronization points
such as beginning of TB execution, or checkpoint in the iothread.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20150917162422.8676.88696.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, 227 insertions, 0 deletions

diff --git a/replay/replay-events.c b/replay/replay-events.c
new file mode 100644
index 0000000000..8dcc96d51e
--- /dev/null
+++ b/replay/replay-events.c
@@ -0,0 +1,227 @@
+/*
+ * replay-events.c
+ *
+ * Copyright (c) 2010-2015 Institute for System Programming
+ *                         of the Russian Academy of Sciences.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "qemu/error-report.h"
+#include "sysemu/replay.h"
+#include "replay-internal.h"
+
+typedef struct Event {
+    ReplayAsyncEventKind event_kind;
+    void *opaque;
+    void *opaque2;
+    uint64_t id;
+
+    QTAILQ_ENTRY(Event) events;
+} Event;
+
+static QTAILQ_HEAD(, Event) events_list = QTAILQ_HEAD_INITIALIZER(events_list);
+static unsigned int read_event_kind = -1;
+static uint64_t read_id = -1;
+static int read_checkpoint = -1;
+
+static bool events_enabled;
+
+/* Functions */
+
+static void replay_run_event(Event *event)
+{
+    switch (event->event_kind) {
+    default:
+        error_report("Replay: invalid async event ID (%d) in the queue",
+                    event->event_kind);
+        exit(1);
+        break;
+    }
+}
+
+void replay_enable_events(void)
+{
+    events_enabled = true;
+}
+
+bool replay_has_events(void)
+{
+    return !QTAILQ_EMPTY(&events_list);
+}
+
+void replay_flush_events(void)
+{
+    replay_mutex_lock();
+    while (!QTAILQ_EMPTY(&events_list)) {
+        Event *event = QTAILQ_FIRST(&events_list);
+        replay_mutex_unlock();
+        replay_run_event(event);
+        replay_mutex_lock();
+        QTAILQ_REMOVE(&events_list, event, events);
+        g_free(event);
+    }
+    replay_mutex_unlock();
+}
+
+void replay_disable_events(void)
+{
+    if (replay_mode != REPLAY_MODE_NONE) {
+        events_enabled = false;
+        /* Flush events queue before waiting of completion */
+        replay_flush_events();
+    }
+}
+
+void replay_clear_events(void)
+{
+    replay_mutex_lock();
+    while (!QTAILQ_EMPTY(&events_list)) {
+        Event *event = QTAILQ_FIRST(&events_list);
+        QTAILQ_REMOVE(&events_list, event, events);
+
+        g_free(event);
+    }
+    replay_mutex_unlock();
+}
+
+/*! Adds specified async event to the queue */
+#if 0
+static void replay_add_event(ReplayAsyncEventKind event_kind,
+                             void *opaque,
+                             void *opaque2, uint64_t id)
+{
+    assert(event_kind < REPLAY_ASYNC_COUNT);
+
+    if (!replay_file || replay_mode == REPLAY_MODE_NONE
+        || !events_enabled) {
+        Event e;
+        e.event_kind = event_kind;
+        e.opaque = opaque;
+        e.opaque2 = opaque2;
+        e.id = id;
+        replay_run_event(&e);
+        return;
+    }
+
+    Event *event = g_malloc0(sizeof(Event));
+    event->event_kind = event_kind;
+    event->opaque = opaque;
+    event->opaque2 = opaque2;
+    event->id = id;
+
+    replay_mutex_lock();
+    QTAILQ_INSERT_TAIL(&events_list, event, events);
+    replay_mutex_unlock();
+}
+#endif
+
+static void replay_save_event(Event *event, int checkpoint)
+{
+    if (replay_mode != REPLAY_MODE_PLAY) {
+        /* put the event into the file */
+        replay_put_event(EVENT_ASYNC);
+        replay_put_byte(checkpoint);
+        replay_put_byte(event->event_kind);
+
+        /* save event-specific data */
+        switch (event->event_kind) {
+        default:
+            error_report("Unknown ID %d of replay event", read_event_kind);
+            exit(1);
+            break;
+        }
+    }
+}
+
+/* Called with replay mutex locked */
+void replay_save_events(int checkpoint)
+{
+    while (!QTAILQ_EMPTY(&events_list)) {
+        Event *event = QTAILQ_FIRST(&events_list);
+        replay_save_event(event, checkpoint);
+
+        replay_mutex_unlock();
+        replay_run_event(event);
+        replay_mutex_lock();
+        QTAILQ_REMOVE(&events_list, event, events);
+        g_free(event);
+    }
+}
+
+static Event *replay_read_event(int checkpoint)
+{
+    Event *event;
+    if (read_event_kind == -1) {
+        read_checkpoint = replay_get_byte();
+        read_event_kind = replay_get_byte();
+        read_id = -1;
+        replay_check_error();
+    }
+
+    if (checkpoint != read_checkpoint) {
+        return NULL;
+    }
+
+    /* Events that has not to be in the queue */
+    switch (read_event_kind) {
+    default:
+        error_report("Unknown ID %d of replay event", read_event_kind);
+        exit(1);
+        break;
+    }
+
+    QTAILQ_FOREACH(event, &events_list, events) {
+        if (event->event_kind == read_event_kind
+            && (read_id == -1 || read_id == event->id)) {
+            break;
+        }
+    }
+
+    if (event) {
+        QTAILQ_REMOVE(&events_list, event, events);
+    } else {
+        return NULL;
+    }
+
+    /* Read event-specific data */
+
+    return event;
+}
+
+/* Called with replay mutex locked */
+void replay_read_events(int checkpoint)
+{
+    while (replay_data_kind == EVENT_ASYNC) {
+        Event *event = replay_read_event(checkpoint);
+        if (!event) {
+            break;
+        }
+        replay_mutex_unlock();
+        replay_run_event(event);
+        replay_mutex_lock();
+
+        g_free(event);
+        replay_finish_event();
+        read_event_kind = -1;
+    }
+}
+
+void replay_init_events(void)
+{
+    read_event_kind = -1;
+}
+
+void replay_finish_events(void)
+{
+    events_enabled = false;
+    replay_clear_events();
+}
+
+bool replay_events_enabled(void)
+{
+    return events_enabled;
+}