target/ppc: Fix timebase reset with record-replay

Timebase save uses a random number for a legacy vmstate field, which
makes rr snapshot loading unbalanced. The easiest way to deal with this
is just to skip the rng if record-replay is active.

Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

hw/ppc/ppc.c

@@ -32,6 +32,7 @@
 #include "qemu/main-loop.h"
 #include "qemu/error-report.h"
 #include "sysemu/kvm.h"
+#include "sysemu/replay.h"
 #include "sysemu/runstate.h"
 #include "kvm_ppc.h"
 #include "migration/vmstate.h"
@@ -974,8 +975,14 @@ static void timebase_save(PPCTimebase *tb)
         return;
     }
 
-    /* not used anymore, we keep it for compatibility */
-    tb->time_of_the_day_ns = qemu_clock_get_ns(QEMU_CLOCK_HOST);
+    if (replay_mode == REPLAY_MODE_NONE) {
+        /* not used anymore, we keep it for compatibility */
+        tb->time_of_the_day_ns = qemu_clock_get_ns(QEMU_CLOCK_HOST);
+    } else {
+        /* simpler for record-replay to avoid this event, compat not needed */
+        tb->time_of_the_day_ns = 0;
+    }
+
     /*
      * tb_offset is only expected to be changed by QEMU so
      * there is no need to update it from KVM here