[Qemu-devel] [PATCH v2 06/10] 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>
---
 include/sysemu/replay.h  |    4 ++++
 replay/replay-internal.h |    2 ++
 replay/replay-snapshot.c |   40 ++++++++++++++++++++++++++++++++++++++++
 vl.c                     |    1 +
 4 files changed, 47 insertions(+)

diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index aa378ce..1123fc2 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -147,6 +147,10 @@ void replay_net_packet_event(ReplayNetState *rns, unsigned flags,
 
 /* VM state operations */
 
+/* Registers replay VMState.
+   Should be called before virtual devices initialization
+   to make cached timers available for post_load functions. */
+void replay_vmstate_register(void);
 /*! Called at the start of execution.
     Loads or saves initial vmstate depending on execution mode. */
 void replay_vmstate_init(void);
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 3147d66..9bc4a29 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;
 
diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
index a48c6fc..4933bdd 100644
--- a/replay/replay-snapshot.c
+++ b/replay/replay-snapshot.c
@@ -17,6 +17,46 @@
 #include "sysemu/sysemu.h"
 #include "monitor/monitor.h"
 #include "qapi/qmp/qstring.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/vl.c b/vl.c
index 6698d88..f2193cb 100644
--- a/vl.c
+++ b/vl.c
@@ -4361,6 +4361,7 @@ int main(int argc, char **argv, char **envp)
         configure_icount(icount_opts, &error_abort);
         qemu_opts_del(icount_opts);
     }
+    replay_vmstate_register();
 
     if (default_net) {
         QemuOptsList *net = qemu_find_opts("net");