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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <edb33598-ba1e-883b-ed61-61b7a50f8f0c@redhat.com>
Date: Wed, 25 Jan 2017 13:00:46 +0100
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Subject: Re: [Qemu-devel] [PATCH v7 04/14] icount: exit cpu loop on expire
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To: Pavel Dovgalyuk <dovgaluk@ispras.ru>, 'Pavel Dovgalyuk' <pavel.dovgaluk@ispras.ru>, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, peter.maydell@linaro.org, mst@redhat.com, jasowang@redhat.com, quintela@redhat.com, kraxel@redhat.com



On 25/01/2017 12:50, Pavel Dovgalyuk wrote:
>>> +                /* icount has expired, we need to break the execution loop.
>>> +                   This check is needed before tb_find to make execution
>>> +                   deterministic - tb_find may cause an exception
>>> +                   while translating the code from non-mapped page. */
>>> +                if (use_icount && ((cpu->icount_extra == 0
>>> +                                    && cpu->icount_decr.u16.low == 0)
>>> +                                || (int32_t)cpu->icount_decr.u32 < 0)) {
>>> +                    if (cpu->exception_index == -1) {
>>> +                        cpu->exception_index = EXCP_INTERRUPT;
>>> +                    }
>>> +                    cpu_loop_exit(cpu);
>>> +                }
>> Can this can be placed in cpu_handle_interrupt itself?  
> I guess it could. I placed it here because it doesn't related to interrupts.

True, on the other hand neither is

    if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) {
        atomic_set(&cpu->exit_request, 0);
        cpu->exception_index = EXCP_INTERRUPT;
        cpu_loop_exit(cpu);
    }

Except for the replay_has_interrupt() that you added, but I don't understand
that one either...

Paolo