[Qemu-devel] [RFC PATCH v8 20/21] replay: command line options

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

This patch introduces command line options for enabling recording or replaying
virtual machine behavior. "-record" option starts recording of the execution
and saves it into the log, specified with "fname" parameter. "-replay" option
is intended for replaying previously saved log.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 cpus.c          |    3 ++-
 qemu-options.hx |    8 ++++++--
 vl.c            |   27 ++++++++++++++++++++++++++-
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/cpus.c b/cpus.c
index 9c32491..7689cec 100644
--- a/cpus.c
+++ b/cpus.c
@@ -912,9 +912,10 @@ static void qemu_wait_io_event_common(CPUState *cpu)
 static void qemu_tcg_wait_io_event(void)
 {
     CPUState *cpu;
+    GMainContext *context = g_main_context_default();
 
     while (all_cpu_threads_idle()) {
-       /* Start accounting real time to the virtual clock if the CPUs
+        /* Start accounting real time to the virtual clock if the CPUs
           are idle.  */
         qemu_clock_warp(QEMU_CLOCK_VIRTUAL);
         qemu_cond_wait(tcg_halt_cond, &qemu_global_mutex);
diff --git a/qemu-options.hx b/qemu-options.hx
index 10b9568..cb4b577 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3037,11 +3037,11 @@ re-inject them.
 ETEXI
 
 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
-    "-icount [shift=N|auto][,align=on|off]\n" \
+    "-icount [shift=N|auto][,align=on|off][,rr=record|replay,rrfname=<filename>]\n" \
     "                enable virtual instruction counter with 2^N clock ticks per\n" \
     "                instruction and enable aligning the host and virtual clocks\n", QEMU_ARCH_ALL)
 STEXI
-@item -icount [shift=@var{N}|auto]
+@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfname=@var{filename}]
 @findex -icount
 Enable virtual instruction counter.  The virtual cpu will execute one
 instruction every 2^@var{N} ns of virtual time.  If @code{auto} is specified
@@ -3063,6 +3063,10 @@ Currently this option does not work when @option{shift} is @code{auto}.
 Note: The sync algorithm will work for those shift values for which
 the guest clock runs ahead of the host clock. Typically this happens
 when the shift value is high (how high depends on the host machine).
+
+When @option{rr} option is specified deterministic record/replay is enabled.
+Replay log is written into @var{filename} file in record mode and
+read from this file in replay mode.
 ETEXI
 
 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
diff --git a/vl.c b/vl.c
index ae3e97e..39d9024 100644
--- a/vl.c
+++ b/vl.c
@@ -475,6 +475,12 @@ static QemuOptsList qemu_icount_opts = {
         }, {
             .name = "align",
             .type = QEMU_OPT_BOOL,
+        }, {
+            .name = "rr",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "rrfname",
+            .type = QEMU_OPT_STRING,
         },
         { /* end of list */ }
     },
@@ -2752,6 +2758,8 @@ int main(int argc, char **argv, char **envp)
 {
     int i;
     int snapshot, linux_boot;
+    int not_compatible_replay_param = 0;
+    const char *icount_option = NULL;
     const char *initrd_filename;
     const char *kernel_filename, *kernel_cmdline;
     const char *boot_order;
@@ -2949,6 +2957,7 @@ int main(int argc, char **argv, char **envp)
                 break;
             case QEMU_OPTION_pflash:
                 drive_add(IF_PFLASH, -1, optarg, PFLASH_OPTS);
+                not_compatible_replay_param++;
                 break;
             case QEMU_OPTION_snapshot:
                 snapshot = 1;
@@ -3105,6 +3114,7 @@ int main(int argc, char **argv, char **envp)
 #endif
             case QEMU_OPTION_bt:
                 add_device_config(DEV_BT, optarg);
+                not_compatible_replay_param++;
                 break;
             case QEMU_OPTION_audio_help:
                 AUD_help ();
@@ -3244,6 +3254,7 @@ int main(int argc, char **argv, char **envp)
                 if (!opts) {
                     exit(1);
                 }
+                not_compatible_replay_param++;
                 break;
             case QEMU_OPTION_fsdev:
                 olist = qemu_find_opts("fsdev");
@@ -3372,6 +3383,7 @@ int main(int argc, char **argv, char **envp)
                 if (strncmp(optarg, "mon:", 4) == 0) {
                     default_monitor = 0;
                 }
+                not_compatible_replay_param++;
                 break;
             case QEMU_OPTION_debugcon:
                 add_device_config(DEV_DEBUGCON, optarg);
@@ -3489,6 +3501,7 @@ int main(int argc, char **argv, char **envp)
                 if (!qemu_opts_parse(qemu_find_opts("smp-opts"), optarg, 1)) {
                     exit(1);
                 }
+                not_compatible_replay_param++;
                 break;
             case QEMU_OPTION_vnc:
 #ifdef CONFIG_VNC
@@ -3628,6 +3641,7 @@ int main(int argc, char **argv, char **envp)
                 if (!icount_opts) {
                     exit(1);
                 }
+                replay_configure(icount_opts);
                 break;
             case QEMU_OPTION_incoming:
                 incoming = optarg;
@@ -3786,6 +3800,12 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
+    if (not_compatible_replay_param && (replay_mode != REPLAY_MODE_NONE)) {
+        fprintf(stderr, "options -smp, -pflash, -chardev, -bt, -parallel "
+                        "are not compatible with record/replay\n");
+        exit(1);
+    }
+
     if (qemu_opts_foreach(qemu_find_opts("sandbox"), parse_sandbox, NULL, 0)) {
         exit(1);
     }
@@ -4136,6 +4156,11 @@ int main(int argc, char **argv, char **envp)
         qemu_opts_del(icount_opts);
     }
 
+    if (replay_mode != REPLAY_MODE_NONE && !use_icount) {
+        fprintf(stderr, "Please enable icount to use record/replay\n");
+        exit(1);
+    }
+
     /* clean up network at qemu process termination */
     atexit(&net_cleanup);
 
@@ -4172,7 +4197,7 @@ int main(int argc, char **argv, char **envp)
     }
 
     /* open the virtual block devices */
-    if (snapshot)
+    if (snapshot || replay_mode != REPLAY_MODE_NONE)
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot, NULL, 0);
     if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
                           &machine_class->block_default_type, 1) != 0) {