cpus: access .qemu_icount with atomic64

Signed-off-by: NEmilio G. Cota <cota@braap.org>
Message-Id: <20180910232752.31565-10-cota@braap.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

cpus.c

@@ -250,8 +250,8 @@ static void cpu_update_icount_locked(CPUState *cpu)
     int64_t executed = cpu_get_icount_executed(cpu);
     cpu->icount_budget -= executed;
 
-    atomic_set__nocheck(&timers_state.qemu_icount,
-                        timers_state.qemu_icount + executed);
+    atomic_set_i64(&timers_state.qemu_icount,
+                   timers_state.qemu_icount + executed);
 }
 
 /*
@@ -280,8 +280,8 @@ static int64_t cpu_get_icount_raw_locked(void)
         /* Take into account what has run */
         cpu_update_icount_locked(cpu);
     }
-    /* The read is protected by the seqlock, so __nocheck is okay.  */
-    return atomic_read__nocheck(&timers_state.qemu_icount);
+    /* The read is protected by the seqlock, but needs atomic64 to avoid UB */
+    return atomic_read_i64(&timers_state.qemu_icount);
 }
 
 static int64_t cpu_get_icount_locked(void)