[Qemu-devel] [RFC PATCH v8 19/21] replay: initialization and deinitialization

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

This patch introduces the functions for enabling the record/replay and for
freeing the resources when simulator closes.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 block.c                  |    2 -
 exec.c                   |    1 
 replay/replay-internal.c |    1 
 replay/replay-internal.h |    4 +
 replay/replay.c          |  140 ++++++++++++++++++++++++++++++++++++++++++++++
 replay/replay.h          |   13 ++++
 stubs/replay.c           |    1 
 vl.c                     |    5 ++
 8 files changed, 165 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index 7f6fa8b..9923a80 100644
--- a/block.c
+++ b/block.c
@@ -2010,7 +2010,7 @@ void bdrv_drain_all(void)
             aio_context_release(aio_context);
         }
     }
-    if (replay_mode == REPLAY_MODE_PLAY) {
+    if (replay_mode == REPLAY_MODE_PLAY && replay_checkpoints) {
         /* Skip checkpoints from the log */
         while (replay_checkpoint(CHECKPOINT_BDRV_DRAIN)) {
             /* Nothing */
diff --git a/exec.c b/exec.c
index 410371d..f70f03d 100644
--- a/exec.c
+++ b/exec.c
@@ -783,6 +783,7 @@ void cpu_abort(CPUState *cpu, const char *fmt, ...)
     }
     va_end(ap2);
     va_end(ap);
+    replay_finish();
 #if defined(CONFIG_USER_ONLY)
     {
         struct sigaction act;
diff --git a/replay/replay-internal.c b/replay/replay-internal.c
index 49b37a6..d608b71 100755
--- a/replay/replay-internal.c
+++ b/replay/replay-internal.c
@@ -33,6 +33,7 @@ void replay_put_byte(uint8_t byte)
 
 void replay_put_event(uint8_t event)
 {
+    assert(event <= EVENT_END);
     replay_put_byte(event);
 }
 
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 4d242aa..1e5d037 100755
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -34,7 +34,9 @@ enum ReplayEvents {
     EVENT_CLOCK,
     /* for checkpoint event */
     /* some of grteater codes are reserved for checkpoints */
-    EVENT_CHECKPOINT = EVENT_CLOCK + REPLAY_CLOCK_COUNT
+    EVENT_CHECKPOINT = EVENT_CLOCK + REPLAY_CLOCK_COUNT,
+    /* end of log event */
+    EVENT_END = EVENT_CHECKPOINT + CHECKPOINT_COUNT
 };
 
 /* Asynchronous events IDs */
diff --git a/replay/replay.c b/replay/replay.c
index 7c4a801..fa738c2 100755
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -15,9 +15,18 @@
 #include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 
+/* Current version of the replay mechanism.
+   Increase it when file format changes. */
+#define REPLAY_VERSION              0xe02002
+/* Size of replay log header */
+#define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))
+
 ReplayMode replay_mode = REPLAY_MODE_NONE;
 
+/* Name of replay file  */
+static char *replay_filename;
 ReplayState replay_state;
+bool replay_checkpoints;
 
 bool skip_async_events(int stop_event)
 {
@@ -167,6 +176,10 @@ void replay_shutdown_request(void)
 bool replay_checkpoint(ReplayCheckpoint checkpoint)
 {
     bool res = false;
+    if (!replay_checkpoints) {
+        return true;
+    }
+
     replay_save_instructions();
 
     if (replay_file) {
@@ -199,3 +212,130 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint)
 
     return true;
 }
+
+static void replay_enable(const char *fname, int mode)
+{
+    const char *fmode = NULL;
+    if (replay_file) {
+        fprintf(stderr,
+                "Replay: some record/replay operation is already started\n");
+        return;
+    }
+
+    switch (mode) {
+    case REPLAY_MODE_RECORD:
+        fmode = "wb";
+        break;
+    case REPLAY_MODE_PLAY:
+        fmode = "rb";
+        break;
+    default:
+        fprintf(stderr, "Replay: internal error: invalid replay mode\n");
+        exit(1);
+    }
+
+    atexit(replay_finish);
+
+    replay_mutex_init();
+
+    replay_file = fopen(fname, fmode);
+    if (replay_file == NULL) {
+        fprintf(stderr, "Replay: open %s: %s\n", fname, strerror(errno));
+        exit(1);
+    }
+
+    replay_filename = g_strdup(fname);
+
+    replay_mode = mode;
+    replay_has_unread_data = 0;
+    replay_data_kind = -1;
+    replay_state.instructions_count = 0;
+    replay_state.current_step = 0;
+
+    /* skip file header for RECORD and check it for PLAY */
+    if (replay_mode == REPLAY_MODE_RECORD) {
+        fseek(replay_file, HEADER_SIZE, SEEK_SET);
+    } else if (replay_mode == REPLAY_MODE_PLAY) {
+        unsigned int version = replay_get_dword();
+        uint64_t offset = replay_get_qword();
+        if (version != REPLAY_VERSION) {
+            fprintf(stderr, "Replay: invalid input log file version\n");
+            exit(1);
+        }
+        /* go to the beginning */
+        fseek(replay_file, 12, SEEK_SET);
+    }
+
+    replay_init_events();
+}
+
+void replay_configure(QemuOpts *opts)
+{
+    const char *fname;
+    const char *rr;
+    ReplayMode mode = REPLAY_MODE_NONE;
+
+    rr = qemu_opt_get(opts, "rr");
+    if (!rr) {
+        /* Just enabling icount */
+        return;
+    } else if (!strcmp(rr, "record")) {
+        mode = REPLAY_MODE_RECORD;
+    } else if (!strcmp(rr, "replay")) {
+        mode = REPLAY_MODE_PLAY;
+    } else {
+        fprintf(stderr, "Invalid icount rr option: %s\n", rr);
+        exit(1);
+    }
+
+    fname = qemu_opt_get(opts, "rrfname");
+    if (!fname) {
+        fprintf(stderr, "File name not specified for replay\n");
+        exit(1);
+    }
+
+    replay_enable(fname, mode);
+}
+
+void replay_init_timer(void)
+{
+    if (replay_mode == REPLAY_MODE_NONE) {
+        return;
+    }
+
+    replay_checkpoints = true;
+    replay_enable_events();
+}
+
+void replay_finish(void)
+{
+    if (replay_mode == REPLAY_MODE_NONE) {
+        return;
+    }
+
+    replay_save_instructions();
+
+    /* finalize the file */
+    if (replay_file) {
+        if (replay_mode == REPLAY_MODE_RECORD) {
+            uint64_t offset = 0;
+            /* write end event */
+            replay_put_event(EVENT_END);
+
+            /* write header */
+            fseek(replay_file, 0, SEEK_SET);
+            replay_put_dword(REPLAY_VERSION);
+            replay_put_qword(offset);
+        }
+
+        fclose(replay_file);
+        replay_file = NULL;
+    }
+    if (replay_filename) {
+        g_free(replay_filename);
+        replay_filename = NULL;
+    }
+
+    replay_mutex_destroy();
+    replay_finish_events();
+}
diff --git a/replay/replay.h b/replay/replay.h
index 3110d46..231b8ec 100755
--- a/replay/replay.h
+++ b/replay/replay.h
@@ -17,6 +17,8 @@
 #include <time.h>
 #include "qapi-types.h"
 
+struct QemuOpts;
+
 /* replay clock kinds */
 enum ReplayClockKind {
     /* rdtsc */
@@ -45,6 +47,17 @@ enum ReplayCheckpoint {
 typedef enum ReplayCheckpoint ReplayCheckpoint;
 
 extern ReplayMode replay_mode;
+/*! Is set to true after finishing initialization */
+extern bool replay_checkpoints;
+
+/* Replay process control functions */
+
+/*! Enables recording or saving event log with specified parameters */
+void replay_configure(struct QemuOpts *opts);
+/*! Initializes timers used for snapshotting and enables events recording */
+void replay_init_timer(void);
+/*! Closes replay log file and frees other resources. */
+void replay_finish(void);
 
 /* Processing the instructions */
 
diff --git a/stubs/replay.c b/stubs/replay.c
index 81eddae..7d87964 100755
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -2,6 +2,7 @@
 #include "sysemu/sysemu.h"
 
 ReplayMode replay_mode;
+bool replay_checkpoints;
 
 int64_t replay_save_clock(unsigned int kind, int64_t clock)
 {
diff --git a/vl.c b/vl.c
index 86ba385..ae3e97e 100644
--- a/vl.c
+++ b/vl.c
@@ -4376,7 +4376,12 @@ int main(int argc, char **argv, char **envp)
         }
     }
 
+    replay_init_timer();
+
     main_loop();
+    if (replay_mode != REPLAY_MODE_NONE) {
+        replay_disable_events();
+    }
     bdrv_close_all();
     pause_all_vcpus();
     res_free();