[Qemu-devel] [PATCH v4 6/8] replay: vmstate for replay module

[Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>]

This patch introduces vmstate for replay data structures.
It allows saving and loading vmstate while replaying.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 replay/replay-internal.h |    9 +++++++++
 replay/replay-snapshot.c |   40 ++++++++++++++++++++++++++++++++++++++++
 replay/replay.c          |    1 +
 3 files changed, 50 insertions(+)

diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 3147d66..6040f4d 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -67,6 +67,8 @@ typedef struct ReplayState {
     unsigned int data_kind;
     /*! Flag which indicates that event is not processed yet. */
     unsigned int has_unread_data;
+    /*! Temporary variable for saving current log offset. */
+    uint64_t file_offset;
 } ReplayState;
 extern ReplayState replay_state;
 
@@ -167,4 +169,11 @@ void replay_event_net_save(void *opaque);
 /*! Reads network from the file. */
 void *replay_event_net_load(void);
 
+/* VMState-related functions */
+
+/* Registers replay VMState.
+   Should be called before virtual devices initialization
+   to make cached timers available for post_load functions. */
+void replay_vmstate_register(void);
+
 #endif
diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
index 970b893..eb3d70a 100644
--- a/replay/replay-snapshot.c
+++ b/replay/replay-snapshot.c
@@ -18,6 +18,46 @@
 #include "monitor/monitor.h"
 #include "qapi/qmp/qstring.h"
 #include "qemu/error-report.h"
+#include "migration/vmstate.h"
+
+static void replay_pre_save(void *opaque)
+{
+    ReplayState *state = opaque;
+    state->file_offset = ftello64(replay_file);
+}
+
+static int replay_post_load(void *opaque, int version_id)
+{
+    ReplayState *state = opaque;
+    fseeko64(replay_file, state->file_offset, SEEK_SET);
+    /* If this was a vmstate, saved in recording mode,
+       we need to initialize replay data fields. */
+    replay_fetch_data_kind();
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_replay = {
+    .name = "replay",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .pre_save = replay_pre_save,
+    .post_load = replay_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT64_ARRAY(cached_clock, ReplayState, REPLAY_CLOCK_COUNT),
+        VMSTATE_UINT64(current_step, ReplayState),
+        VMSTATE_INT32(instructions_count, ReplayState),
+        VMSTATE_UINT32(data_kind, ReplayState),
+        VMSTATE_UINT32(has_unread_data, ReplayState),
+        VMSTATE_UINT64(file_offset, ReplayState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+void replay_vmstate_register(void)
+{
+    vmstate_register(NULL, 0, &vmstate_replay, &replay_state);
+}
 
 void replay_vmstate_init(void)
 {
diff --git a/replay/replay.c b/replay/replay.c
index 9472d4c..46e5729 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -295,6 +295,7 @@ void replay_configure(QemuOpts *opts)
 
     replay_snapshot = g_strdup(qemu_opt_get(opts, "rrsnapshot"));
 
+    replay_vmstate_register();
     replay_enable(fname, mode);
 
 out: