> From: Alex Bennée [mailto:alex.ben...@linaro.org]
> Pavel Dovgalyuk <dovga...@ispras.ru> writes:
>
> >> From: Alex Bennée [mailto:alex.ben...@linaro.org]
> >
> > Sorry, this is another problem which occurs only in icount replay mode:
> > 1. cpu_handle_exception tries to force exception when is cannot occur due to
> > running out all the planned instructions:
> > } else if (replay_has_exception()
> > && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
> > /* try to cause an exception pending in the log */
> > cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0), true);
> > *ret = -1;
> > return true;
> >
> > 2. tb_find calls tb_gen_code, which cannot allocate new translation block
> > and calls tb_flush (which only queues the flushing) and cpu_loop_exit
> > 3. cpu_loop_exit returns to infinite loop of cpu_exec and the condition
> > if (cpu_handle_exception(cpu, &ret)) {
> > break;
> > }
> > is checked again causing an infinite loop.
> >
> > TB cache is not flushed because we never execute that break and real work
> > of tb_flush
> > is made outside this loop.
>
> I think what we need is a:
>
>
> if (cpu->exit_request)
> break;
Where this exit_request is supposed to be set?
>
> before the cpu_handle_exception() call to ensure any queued work gets
> processed first. Can you give me you current command line so I can
> reproduce this and check the fix works?
I solved the problem using following patch:
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -451,6 +451,10 @@ static inline bool cpu_handle_exception(CPUState *cpu, int
*ret)
#ifndef CONFIG_USER_ONLY
} else if (replay_has_exception()
&& cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
+ /* Break the execution loop in case of running out of TB cache.
+ This is needed to make flushing of the TB cache, because
+ real flush is queued to be executed outside the cpu loop. */
+ cpu->exception_index = EXCP_INTERRUPT;
/* try to cause an exception pending in the log */
cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0), true);
*ret = -1;
Pavel Dovgalyuk
