Re: [PATCH 3/4] replay: allow runstate shutdown->running when replaying trace

[Pavel Dovgalyuk]

Acked-by: Pavel Dovgalyuk <pavel.dovgal...@ispras.ru>

On 14.08.2023 19:31, Nicholas Piggin wrote:

When replaying a trace, it is possible to go from shutdown to
running with a reverse-debugging step. This can be useful if the
problem being debugged triggers a reset or shutdown.

Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
  include/sysemu/runstate.h |  1 +
  replay/replay.c           |  2 ++
  softmmu/runstate.c        | 19 +++++++++++++++++++
  3 files changed, 22 insertions(+)

diff --git a/include/sysemu/runstate.h b/include/sysemu/runstate.h
index 7beb29c2e2..85a1167ccb 100644
--- a/include/sysemu/runstate.h
+++ b/include/sysemu/runstate.h
@@ -9,6 +9,7 @@ void runstate_set(RunState new_state);
  RunState runstate_get(void);
  bool runstate_is_running(void);
  bool runstate_needs_reset(void);
+void runstate_replay_enable(void);

typedef void VMChangeStateHandler(void *opaque, bool running, RunState state); diff --git a/replay/replay.c b/replay/replay.c

index 0f7d766efe..e64f71209a 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -272,6 +272,8 @@ static void replay_enable(const char *fname, int mode)
          /* go to the beginning */
          fseek(replay_file, HEADER_SIZE, SEEK_SET);
          replay_fetch_data_kind();
+
+        runstate_replay_enable();
      }

replay_init_events();

diff --git a/softmmu/runstate.c b/softmmu/runstate.c
index f3bd862818..9fd3e57485 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -174,6 +174,12 @@ static const RunStateTransition runstate_transitions_def[] 
= {
      { RUN_STATE__MAX, RUN_STATE__MAX },
  };

+static const RunStateTransition replay_runstate_transitions_def[] = {

+    { RUN_STATE_SHUTDOWN, RUN_STATE_RUNNING},
+
+    { RUN_STATE__MAX, RUN_STATE__MAX },
+};
+
  static bool runstate_valid_transitions[RUN_STATE__MAX][RUN_STATE__MAX];

bool runstate_check(RunState state)

@@ -181,6 +187,19 @@ bool runstate_check(RunState state)
      return current_run_state == state;
  }

+void runstate_replay_enable(void)

+{
+    const RunStateTransition *p;
+
+    assert(replay_mode == REPLAY_MODE_PLAY);
+
+    for (p = &replay_runstate_transitions_def[0]; p->from != RUN_STATE__MAX;
+         p++) {
+        runstate_valid_transitions[p->from][p->to] = true;
+    }
+
+}
+
  static void runstate_init(void)
  {
      const RunStateTransition *p;