[Qemu-devel] [RFC PATCH v10 23/24] replay: command line options

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

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>
---
 qemu-options.hx |    8 ++++++--
 replay/replay.c |    4 ++++
 vl.c            |   15 +++++++++++++--
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 85ca3ad..c62661a 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3038,11 +3038,11 @@ 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,rrfile=<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,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
@@ -3064,6 +3064,10 @@ 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 a5ae58b..b8fdef5 100755
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -292,6 +292,10 @@ 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 f9c345d..89d6da6 100644
--- a/vl.c
+++ b/vl.c
@@ -472,6 +472,12 @@ static QemuOptsList qemu_icount_opts = {
         }, {
             .name = "align",
             .type = QEMU_OPT_BOOL,
+        }, {
+            .name = "rr",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "rrfile",
+            .type = QEMU_OPT_STRING,
         },
         { /* end of list */ }
     },
@@ -2751,6 +2757,7 @@ int main(int argc, char **argv, char **envp)
 {
     int i;
     int snapshot, linux_boot;
+    const char *icount_option = NULL;
     const char *initrd_filename;
     const char *kernel_filename, *kernel_cmdline;
     const char *boot_order;
@@ -3770,6 +3777,8 @@ 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) {
@@ -4173,8 +4182,10 @@ 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, 0);
+    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) {
         exit(1);