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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <2f57db92-25e0-362a-6130-dfa116fd43a2@redhat.com>
Date: Thu, 2 Nov 2017 15:43:26 +0100
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Subject: Re: [Qemu-devel] [RFC PATCH 19/26] cpu-exec: reset exit flag before
 calling cpu_exec_nocache
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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, boost.lists@gmail.com, quintela@redhat.com, jasowang@redhat.com, mst@redhat.com, zuban32s@gmail.com, maria.klimushenkova@ispras.ru, kraxel@redhat.com, alex.bennee@linaro.org

On 02/11/2017 13:45, Pavel Dovgalyuk wrote:
>> But if u16.high is -1, shouldn't you return EXCP_INTERRUPT first (via
>> "Finally, check if we need to exit to the main loop" in
>> cpu_handle_interrupt)?  Then only cause the exception when that one is
>> processed.
> The case is the following.
> 1. There are no pending instructions to execute, cpu_loop_exec_tb finished.
> 2. There are no interrupts and cpu_handle_interrupt sets cpu->exception_index = EXCP_INTERRUPT
> 3. There are no pending exceptions and cpu_handle_exception goes to the last branch,
>    because there is an exception flag in the log.
> 4. cpu_exec_nocache translates the block and tries to execute it, causing an exception
> 

Then the fix is indeed to clear u16.high in cpu_handle_interrupt instead
of cpu_loop_exec_tb---see my other reply.

Paolo