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cpus: call cpu_update_icount on read

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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>
This commit is contained in:
Alex Bennée 2017-04-05 10:53:47 +01:00
parent eda5f7c6a1
commit 1d05906b95
1 changed files with 6 additions and 4 deletions
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10
cpus.c
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@ -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. */