diff mbox

[RFC,V7,10/10] rexec: allow to enable reverse execution.

Message ID 1410942410-32604-11-git-send-email-fred.konrad@greensocs.com
State New
Headers show

Commit Message

fred.konrad@greensocs.com Sept. 17, 2014, 8:26 a.m. UTC 
From: KONRAD Frederic <fred.konrad@greensocs.com>

This creates QEMU options for reverse execution.

Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
---
 cpus.c          | 15 +++++++++++++++
 qemu-options.hx |  5 ++++-
 vl.c            |  9 +++++++--
 3 files changed, 26 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/cpus.c b/cpus.c
index 742fc84..56da39b 100644
--- a/cpus.c
+++ b/cpus.c
@@ -519,6 +519,7 @@  void configure_icount(QemuOpts *opts, Error **errp)
 {
     const char *option;
     char *rem_str = NULL;
+    bool enable_rexec;
 
     seqlock_init(&timers_state.vm_clock_seqlock, NULL);
     vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
@@ -532,6 +533,9 @@  void configure_icount(QemuOpts *opts, Error **errp)
     icount_align_option = qemu_opt_get_bool(opts, "align", false);
     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) {
         errno = 0;
         icount_time_shift = strtol(option, &rem_str, 0);
@@ -539,11 +543,22 @@  void configure_icount(QemuOpts *opts, Error **errp)
             error_setg(errp, "icount: Invalid shift value");
         }
         use_icount = 1;
+
+        if (enable_rexec) {
+            rexec_setup();
+        }
         return;
     } else if (icount_align_option) {
         error_setg(errp, "shift=auto and align=on are incompatible");
     }
 
+    /*
+     * 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 365b56c..2273272 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3026,7 +3026,7 @@  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][,rexec=on,|off]\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
@@ -3052,6 +3052,9 @@  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).
+@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 f69d1f1..96588c8 100644
--- a/vl.c
+++ b/vl.c
@@ -556,8 +556,10 @@  static QemuOptsList qemu_icount_opts = {
         }, {
             .name = "align",
             .type = QEMU_OPT_BOOL,
-        },
-        { /* end of list */ }
+        }, {
+            .name = "rexec",
+            .type = QEMU_OPT_BOOL,
+        }, { /* end of list */ }
     },
 };
 
@@ -4582,5 +4584,8 @@  int main(int argc, char **argv, char **envp)
     tpm_cleanup();
 #endif
 
+    if (rexec_is_enabled()) {
+        rexec_cleanup();
+    }
     return 0;
 }