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Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix
From: |
Pavel Dovgalyuk |
Subject: |
Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix |
Date: |
Wed, 25 Jan 2017 15:27:45 +0300 |
> From: Paolo Bonzini [mailto:address@hidden
> On 25/01/2017 12:33, Pavel Dovgalyuk wrote:
> >> From: Paolo Bonzini [mailto:address@hidden
> >> On 25/01/2017 12:12, Pavel Dovgalyuk wrote:
> >>>> From: Paolo Bonzini [mailto:address@hidden
> >>>> On 24/01/2017 08:17, Pavel Dovgalyuk wrote:
> >>>>> @@ -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;
> >>>>
> >>>> Why is replay_has_exception() related to be running out of TB cache?
> >>>
> >>> It doesn't.
> >>> Calling tb_find when there is not space in cache causes tb_flush and
> >>> cpu_loop_exit.
> >>> But execution loop will continue, because there is no reason to break it
> >>> (like setting exception_index).
> >>
> >> What about setting cpu->exit_request? queue_work_on_cpu calls
> >> qemu_cpu_kick.
> >
> > cpu->exit_request does not checked in this loop.
> > We have to add this checking somewhere then?
>
> It's checked by cpu_handle_interrupt. Are you not reaching
> cpu_handle_interrupt then? Why?
Execution doesn't reach cpu_handle_interrupt, because tb_find
calls cpu_loop_exit. And the execution loop enters cpu_handle_exception again
and again.
Pavel Dovgalyuk
- [Qemu-devel] [PATCH v7 00/14] replay additions, Pavel Dovgalyuk, 2017/01/24
- [Qemu-devel] [PATCH v7 01/14] icount: update instruction counter on apic patching, Pavel Dovgalyuk, 2017/01/24
- [Qemu-devel] [PATCH v7 02/14] replay: improve interrupt handling, Pavel Dovgalyuk, 2017/01/24
- [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Pavel Dovgalyuk, 2017/01/24
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Paolo Bonzini, 2017/01/25
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Pavel Dovgalyuk, 2017/01/25
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Paolo Bonzini, 2017/01/25
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Pavel Dovgalyuk, 2017/01/25
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Paolo Bonzini, 2017/01/25
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix,
Pavel Dovgalyuk <=
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Paolo Bonzini, 2017/01/25
- Re: [Qemu-devel] [PATCH v7 03/14] replay: exception replay fix, Pavel Dovgalyuk, 2017/01/25
[Qemu-devel] [PATCH v7 04/14] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/24
[Qemu-devel] [PATCH v7 05/14] apic: save apic_delivered flag, Pavel Dovgalyuk, 2017/01/24