[Qemu-devel] [RFC PATCH v4 09/25] replay: introduce icount event

[Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>]

This patch adds icount event to the replay subsystem. This event corresponds
to execution of several instructions and used to synchronize input events
in the replay phase.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 replay/replay-internal.c |   14 ++++++++++++++
 replay/replay-internal.h |   18 ++++++++++++++++++
 replay/replay.c          |   45 +++++++++++++++++++++++++++++++++++++++++++++
 replay/replay.h          |    7 +++++++
 4 files changed, 84 insertions(+), 0 deletions(-)

diff --git a/replay/replay-internal.c b/replay/replay-internal.c
index 29f995d..14881b7 100755
--- a/replay/replay-internal.c
+++ b/replay/replay-internal.c
@@ -10,6 +10,7 @@
  */
 
 #include "qemu-common.h"
+#include "replay.h"
 #include "replay-internal.h"
 
 volatile unsigned int replay_data_kind = -1;
@@ -139,3 +140,16 @@ void replay_fetch_data_kind(void)
         }
     }
 }
+
+/*! Saves cached instructions. */
+void replay_save_instructions(void)
+{
+    if (replay_file && replay_mode == REPLAY_MODE_RECORD) {
+        int diff = (int)(replay_get_current_step() - replay_state.current_step);
+        if (first_cpu != NULL && diff > 0) {
+            replay_put_event(EVENT_INSTRUCTION);
+            replay_put_dword(diff);
+            replay_state.current_step += diff;
+        }
+    }
+}
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 45bb344..577d1e9 100755
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -14,6 +14,17 @@
 
 #include <stdio.h>
 
+/* for instruction event */
+#define EVENT_INSTRUCTION           32
+
+typedef struct ReplayState {
+    /*! Current step - number of processed instructions and timer events. */
+    uint64_t current_step;
+    /*! Number of instructions to be executed before other events happen. */
+    int instructions_count;
+} ReplayState;
+extern ReplayState replay_state;
+
 extern volatile unsigned int replay_data_kind;
 extern volatile unsigned int replay_has_unread_data;
 
@@ -47,4 +58,11 @@ void replay_save_instructions(void);
     Terminates the program in case of error. */
 void validate_data_kind(int kind);
 
+/*! Skips async events until some sync event will be found. */
+bool skip_async_events(int stop_event);
+/*! Skips async events invocations from the input,
+    until required data kind is found. If the requested data is not found
+    reports an error and stops the execution. */
+void skip_async_events_until(unsigned int kind);
+
 #endif
diff --git a/replay/replay.c b/replay/replay.c
index ac976b2..c305e0c 100755
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -9,7 +9,10 @@
  *
  */
 
+#include "qemu-common.h"
 #include "replay.h"
+#include "replay-internal.h"
+#include "qemu/timer.h"
 
 ReplayMode replay_mode = REPLAY_MODE_NONE;
 /*! Stores current submode for PLAY mode */
@@ -18,8 +21,50 @@ ReplaySubmode play_submode = REPLAY_SUBMODE_UNKNOWN;
 /* Suffix for the disk images filenames */
 char *replay_image_suffix;
 
+ReplayState replay_state;
 
 ReplaySubmode replay_get_play_submode(void)
 {
     return play_submode;
 }
+
+bool skip_async_events(int stop_event)
+{
+    /* nothing to skip - not all instructions used */
+    if (replay_state.instructions_count != 0
+        && replay_has_unread_data) {
+        return stop_event == EVENT_INSTRUCTION;
+    }
+
+    bool res = false;
+    while (true) {
+        replay_fetch_data_kind();
+        if (stop_event == replay_data_kind) {
+            res = true;
+        }
+        switch (replay_data_kind) {
+        case EVENT_INSTRUCTION:
+            replay_state.instructions_count = replay_get_dword();
+            return res;
+        default:
+            /* clock, time_t, checkpoint and other events */
+            return res;
+        }
+    }
+
+    return res;
+}
+
+void skip_async_events_until(unsigned int kind)
+{
+    if (!skip_async_events(kind)) {
+        fprintf(stderr, "%"PRId64": Read data kind %d instead of expected %d\n",
+            replay_get_current_step(), replay_data_kind, kind);
+        exit(1);
+    }
+}
+
+uint64_t replay_get_current_step(void)
+{
+    return cpu_get_instructions_counter();
+}
diff --git a/replay/replay.h b/replay/replay.h
index 51a18fe..e40daf5 100755
--- a/replay/replay.h
+++ b/replay/replay.h
@@ -12,6 +12,8 @@
  *
  */
 
+#include <stdbool.h>
+#include <stdint.h>
 #include "qapi-types.h"
 
 extern ReplayMode replay_mode;
@@ -20,4 +22,9 @@ extern char *replay_image_suffix;
 /*! Returns replay play submode */
 ReplaySubmode replay_get_play_submode(void);
 
+/* Processing the instructions */
+
+/*! Returns number of executed instructions. */
+uint64_t replay_get_current_step(void);
+
 #endif