From: KONRAD Frederic <fred.kon...@greensocs.com>
This creates QEMU options for reverse execution.
Signed-off-by: KONRAD Frederic <fred.kon...@greensocs.com>
---
cpus.c | 15 +++++++++++++++
qemu-options.hx | 6 +++++-
vl.c | 6 ++++++
3 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/cpus.c b/cpus.c
index 740c6e5..ba5f8f5 100644
--- a/cpus.c
+++ b/cpus.c
@@ -498,6 +498,7 @@ static const VMStateDescription vmstate_timers = {
void configure_icount(QemuOpts *opts, Error **errp)
{
const char *option;
+ bool enable_rexec;
seqlock_init(&timers_state.vm_clock_seqlock, NULL);
vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
@@ -513,12 +514,26 @@ void configure_icount(QemuOpts *opts, Error **errp)
icount_warp_timer = timer_new_ns(QEMU_CLOCK_REALTIME,
icount_warp_rt, NULL);
+
+ enable_rexec = qemu_opt_get_bool(opts, "rexec", false);
+
if (strcmp(option, "auto") != 0) {
icount_time_shift = strtol(option, NULL, 0);
use_icount = 1;
+
+ if (enable_rexec) {
+ rexec_setup();
+ }
return;
}
+ /*
+ * We don't allow to run reverse execution with use_icount != 1.
+ */
+ if (enable_rexec) {
+ error_setg(errp, "Reverse execution requires icount in fixed mode.");
+ }
+
use_icount = 2;
/* 125MIPS seems a reasonable initial guess at the guest speed.
diff --git a/qemu-options.hx b/qemu-options.hx
index 143def4..ee1fdf4 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3011,7 +3011,7 @@ re-inject them.
ETEXI
DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
- "-icount [shift=N|auto]\n" \
+ "-icount [shift=N|auto][,rexec=on|off]\n" \
" enable virtual instruction counter with 2^N clock ticks
per\n" \
" instruction\n", QEMU_ARCH_ALL)
STEXI
@@ -3026,6 +3026,10 @@ Note that while this option can give deterministic
behavior, it does not
provide cycle accurate emulation. Modern CPUs contain superscalar out of
order cores with complex cache hierarchies. The number of instructions
executed often has little or no correlation with actual performance.
+
+@option{rexec=on} will enable reverse execution. A snapshot is taken regularly
+and will allow to replay the execution when gdb reverse-step or reverse-cont
+command are used. This requires shift!=auto.
ETEXI
DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
diff --git a/vl.c b/vl.c
index 18df07c..69924cd 100644
--- a/vl.c
+++ b/vl.c
@@ -548,6 +548,9 @@ static QemuOptsList qemu_icount_opts = {
{
.name = "shift",
.type = QEMU_OPT_STRING,
+ }, {
+ .name = "rexec",
+ .type = QEMU_OPT_BOOL,
},
{ /* end of list */ }
},
@@ -4561,5 +4564,8 @@ int main(int argc, char **argv, char **envp)
tpm_cleanup();
#endif
+ if (rexec_is_enabled()) {
+ rexec_cleanup();
+ }
return 0;
}
--
1.9.0
