From: Alex Bennée <alex.bennee@linaro.org>
Date: Wed, 5 Apr 2017 09:53:47 +0000 (+0100)
Subject: cpus: call cpu_update_icount on read
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1d05906b95e7f2a35be2392506f9af8f89ff39a5;p=qemu.git

cpus: call cpu_update_icount on read

This ensures each time the vCPU thread reads the icount we update the
master timer_state.qemu_icount field. This way as long as updates are
in BQL protected sections (which they should be) the main-loop can
never come to update the log and find time has gone backwards.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---

diff --git a/cpus.c b/cpus.c
index 9c8bd2c991..740b8dc3f8 100644
--- a/cpus.c
+++ b/cpus.c
@@ -253,19 +253,21 @@ void cpu_update_icount(CPUState *cpu)
 
 int64_t cpu_get_icount_raw(void)
 {
-    int64_t icount;
     CPUState *cpu = current_cpu;
 
-    icount = atomic_read(&timers_state.qemu_icount);
     if (cpu && cpu->running) {
         if (!cpu->can_do_io) {
             fprintf(stderr, "Bad icount read\n");
             exit(1);
         }
         /* Take into account what has run */
-        icount += cpu_get_icount_executed(cpu);
+        cpu_update_icount(cpu);
     }
-    return icount;
+#ifdef CONFIG_ATOMIC64
+    return atomic_read__nocheck(&timers_state.qemu_icount);
+#else /* FIXME: we need 64bit atomics to do this safely */
+    return timers_state.qemu_icount;
+#endif
 }
 
 /* Return the virtual CPU time, based on the instruction counter.  */