replay: allow replay stopping and restarting

This patch fixes bug with stopping and restarting replay
through monitor.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20160926080815.6992.71818.stgit@PASHA-ISP>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 13 insertions, 2 deletions

diff --git a/replay/replay-events.c b/replay/replay-events.c
index 4eb2ea3..c513913 100644
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -309,3 +309,11 @@ bool replay_events_enabled(void)
 {
     return events_enabled;
 }
+
+uint64_t blkreplay_next_id(void)
+{
+    if (replay_events_enabled()) {
+        return replay_state.block_request_id++;
+    }
+    return 0;
+}
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index e07eb7d..9117e44 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -68,6 +68,10 @@ typedef struct ReplayState {
     unsigned int has_unread_data;
     /*! Temporary variable for saving current log offset. */
     uint64_t file_offset;
+    /*! Next block operation id.
+        This counter is global, because requests from different
+        block devices should not get overlapping ids. */
+    uint64_t block_request_id;
 } ReplayState;
 extern ReplayState replay_state;
 
@@ -123,8 +127,6 @@ void replay_read_next_clock(unsigned int kind);
 void replay_init_events(void);
 /*! Clears internal data structures for events handling */
 void replay_finish_events(void);
-/*! Enables storing events in the queue */
-void replay_enable_events(void);
 /*! Flushes events queue */
 void replay_flush_events(void);
 /*! Clears events list before loading new VM state */
diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
index a17e80e..4980597 100644
--- a/replay/replay-snapshot.c
+++ b/replay/replay-snapshot.c
@@ -50,6 +50,7 @@ static const VMStateDescription vmstate_replay = {
         VMSTATE_UINT32(data_kind, ReplayState),
         VMSTATE_UINT32(has_unread_data, ReplayState),
         VMSTATE_UINT64(file_offset, ReplayState),
+        VMSTATE_UINT64(block_request_id, ReplayState),
         VMSTATE_END_OF_LIST()
     },
 };