Re: [RFC PATCH v2 0/7] tcg-plugins: add hooks for interrupts, exceptions and traps

[Pierrick Bouvier <pierrick.bouvier@linaro.org>]

On 10/21/24 11:47, Alex Bennée wrote:
> Pierrick Bouvier <pierrick.bouvier@linaro.org> writes:
> 
>> Hi Julian,
>>
>> On 10/19/24 09:39, Julian Ganz wrote:
>>> Some analysis greatly benefits, or depends on, information about
>>> interrupts. For example, we may need to handle the execution of a new
>>> translation block differently if it is not the result of normal program
>>> flow but of an interrupt.
>>> Even with the existing interfaces, it is more or less possible to
>>> discern these situations, e.g. as done by the cflow plugin. However,
>>> this process poses a considerable overhead to the core analysis one may
>>> intend to perform.
>>>
>>
>> I agree it would be useful. Beyond the scope of this series, it would
>> be nice if we could add a control flow related API instead of asking
>> to plugins to do it themselves.
> 
> I think there is a balance to be had here. We don't want to
> inadvertently expose QEMU internals to the plugin API. With this series
> at least we rely on stuff the front-end knows which can at least be
> tweaked relatively easily.
> 

You're right. Maybe a good way to find the balance is to identify the 
real use cases behind this need.

>> If we would provide something like this, is there still a value to add
>> an API to detect interrupt/exceptions/traps events?
>>
>> Note: It's not a critic against what you sent, just an open question
>> on *why* it's useful to access this QEMU implementation related
>> information vs something more generic.
> <snip>
> 
> It would be good to have the opinion of the front-end maintainers if
> this is too burdensome or easy enough to manage.
> 
>