[Qemu-devel] [RFC PATCH v6 20/32] timer: introduce new QEMU_CLOCK_VIRTUAL_RT clock

[Pavel Dovgalyuk]

This patch introduces new QEMU_CLOCK_VIRTUAL_RT clock, which
should be used for icount warping. Separate timer is needed
for replaying the execution, because warping callbacks should
be deterministic. We cannot make realtime clock deterministic
because it is used for screen updates and other simulator-specific
actions. That is why we added new clock which is recorded and
replayed when needed.

Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
---
 include/qemu/timer.h |    7 +++++++
 qemu-timer.c         |    2 ++
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 3dae414..5948c88 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -36,12 +36,19 @@
  * is suspended, and it will reflect system time changes the host may
  * undergo (e.g. due to NTP). The host clock has the same precision as
  * the virtual clock.
+ *
+ * @QEMU_CLOCK_VIRTUAL_RT: realtime clock used for icount warp
+ *
+ * This clock runs as a realtime clock, but is used for icount warp
+ * and thus should be traced with record/replay to make warp function
+ * behave deterministically.
  */
 
 typedef enum {
     QEMU_CLOCK_REALTIME = 0,
     QEMU_CLOCK_VIRTUAL = 1,
     QEMU_CLOCK_HOST = 2,
+    QEMU_CLOCK_VIRTUAL_RT = 3,
     QEMU_CLOCK_MAX
 } QEMUClockType;
 
diff --git a/qemu-timer.c b/qemu-timer.c
index 00a5d35..f4b4b6a 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -566,6 +566,8 @@ int64_t qemu_clock_get_ns(QEMUClockType type)
             notifier_list_notify(&clock->reset_notifiers, &now);
         }
         return now;
+    case QEMU_CLOCK_VIRTUAL_RT:
+        return cpu_get_clock();
     }
 }