[Qemu-devel] [RFC PATCH v5 07/31] icount: implement icount requesting

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

Replay uses number of executed instructions to determine corrent events
injection moments. This patch introduces new function for querying the
instructions counter.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 cpus.c               |   26 +++++++++++++++++++++++---
 include/qemu/timer.h |    1 +
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/cpus.c b/cpus.c
index a7b6c53..492e19a 100644
--- a/cpus.c
+++ b/cpus.c
@@ -136,8 +136,7 @@ typedef struct TimersState {
 
 static TimersState timers_state;
 
-/* Return the virtual CPU time, based on the instruction counter.  */
-static int64_t cpu_get_icount_locked(void)
+static int64_t cpu_get_instructions_counter_locked(void)
 {
     int64_t icount;
     CPUState *cpu = current_cpu;
@@ -145,10 +144,31 @@ static int64_t cpu_get_icount_locked(void)
     icount = timers_state.qemu_icount;
     if (cpu) {
         if (!cpu_can_do_io(cpu)) {
-            fprintf(stderr, "Bad clock read\n");
+            fprintf(stderr, "Bad icount read\n");
+            exit(1);
         }
         icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
     }
+    return icount;
+}
+
+int64_t cpu_get_instructions_counter(void)
+{
+    /* This function calls are synchnonized to timer changes,
+       calling cpu_get_instructions_counter_locked without lock is safe */
+    int64_t icount = timers_state.qemu_icount;
+    CPUState *cpu = current_cpu;
+
+    if (cpu) {
+        icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
+    }
+    return icount;
+}
+
+/* Return the virtual CPU time, based on the instruction counter.  */
+static int64_t cpu_get_icount_locked(void)
+{
+    int64_t icount = cpu_get_instructions_counter_locked();
     return timers_state.qemu_icount_bias + cpu_icount_to_ns(icount);
 }
 
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 5f5210d..38a02c5 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -743,6 +743,7 @@ static inline int64_t get_clock(void)
 #endif
 
 /* icount */
+int64_t cpu_get_instructions_counter(void);
 int64_t cpu_get_icount(void);
 int64_t cpu_get_clock(void);
 int64_t cpu_get_clock_offset(void);