replay: command line options

This patch introduces command line options for enabling recording or replaying
virtual machine behavior. These options are added to icount command line
parameter. They include 'rr' which switches between record and replay
and 'rrfile' for specifying the filename for replay log.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20150917162518.8676.70792.stgit@PASHA-ISP.def.inno>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

3 files changed, 22 insertions, 5 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index 949db7f2ea..0eea4ee9e9 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3157,12 +3157,12 @@ re-inject them.
 ETEXI
 
 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
-    "-icount [shift=N|auto][,align=on|off][,sleep=no]\n" \
+    "-icount [shift=N|auto][,align=on|off][,sleep=no,rr=record|replay,rrfile=<filename>]\n" \
     "                enable virtual instruction counter with 2^N clock ticks per\n" \
     "                instruction, enable aligning the host and virtual clocks\n" \
     "                or disable real time cpu sleeping\n", QEMU_ARCH_ALL)
 STEXI
-@item -icount [shift=@var{N}|auto]
+@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@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
@@ -3191,6 +3191,10 @@ 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/replay/replay.c b/replay/replay.c
index 1373346cc3..0d33e82c95 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -295,6 +295,10 @@ void replay_start(void)
                      error_get_pretty(replay_blockers->data));
         exit(1);
     }
+    if (!use_icount) {
+        error_report("Please enable icount to use record/replay");
+        exit(1);
+    }
 
     /* Timer for snapshotting will be set up here. */
 
diff --git a/vl.c b/vl.c
index c1e54f46b5..bc4890b9c7 100644
--- a/vl.c
+++ b/vl.c
@@ -476,6 +476,12 @@ static QemuOptsList qemu_icount_opts = {
         }, {
             .name = "sleep",
             .type = QEMU_OPT_BOOL,
+        }, {
+            .name = "rr",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "rrfile",
+            .type = QEMU_OPT_STRING,
         },
         { /* end of list */ }
     },
@@ -4014,6 +4020,8 @@ int main(int argc, char **argv, char **envp)
         }
     }
 
+    replay_configure(icount_opts);
+
     opts = qemu_get_machine_opts();
     optarg = qemu_opt_get(opts, "type");
     if (optarg) {
@@ -4447,9 +4455,10 @@ int main(int argc, char **argv, char **envp)
     }
 
     /* open the virtual block devices */
-    if (snapshot)
-        qemu_opts_foreach(qemu_find_opts("drive"),
-                          drive_enable_snapshot, NULL, NULL);
+    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
+        qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
+                          NULL, NULL);
+    }
     if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
                           &machine_class->block_default_type, NULL)) {
         exit(1);