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From: Sergey Fedorov <serge.fdrv@gmail.com>
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Date: Fri, 16 Oct 2015 17:08:11 +0300
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Subject: Re: [Qemu-devel] [PATCH] target-*: Advance pc after recognizing a
 breakpoint
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To: Richard Henderson <rth@twiddle.net>, Peter Maydell <peter.maydell@linaro.org>
Cc: QEMU Developers <qemu-devel@nongnu.org>

On 16.10.2015 04:14, Richard Henderson wrote:
> On 10/16/2015 03:36 AM, Peter Maydell wrote:
>> On 14 October 2015 at 22:02, Richard Henderson <rth@twiddle.net> wrote:
>>> On 10/15/2015 06:34 AM, Peter Maydell wrote:
>>>>
>>>> This is still the same cryptic comment we have in the
>>>> targets which do do this. Can we have something
>>>> that is a bit more explanatory about what is going on and
>>>> why we need to do this, please?
>>>
>>>
>>> Suggestions?
>>
>> ...well, I don't entirely understand the problem it's
>> fixing, which is why I'm asking for a better comment :-)
>
> Heh.  Fair enough.  How about
>
>   /* The address covered by the breakpoint must be included in
>      [tb->pc, tb->pc + tb->size) in order to for it to be
>      properly cleared -- thus we increment the PC here so that
>      the logic setting tb->size below does the right thing.  */
>
> There are two edge cases that cause the problem with clearing that
> could be described, but I think that the comment becomes too bulky, as
> well as confuses the situation for someone cutting-and-pasting the
> logic to a new port.

Maybe we could rather fix that condition in
tb_invalidate_phys_page_range()? It seems weird that it can't handle a
zero-sized TB.

Best,
Sergey