Re: [Qemu-devel] [RFC PATCH 00/21] Trace updates and plugin RFC

["Alex Bennée" <alex.bennee@linaro.org>]

Pavel Dovgalyuk <dovgaluk@ispras.ru> writes:

>> From: Alex Bennée [mailto:alex.bennee@linaro.org]
>> Pavel Dovgalyuk <dovgaluk@ispras.ru> writes:
>>
>> >> From: Alex Bennée [mailto:alex.bennee@linaro.org]
>> >> Any serious analysis tool should allow for us to track all memory
>> >> accesses so I think the guest_mem_before trace point should probably
>> >> be split into guest_mem_before_store and guest_mem_after_load. We
>> >> could go the whole hog and add potential trace points for start/end of
>> >> all memory operations.
>> >
>> > I wanted to ask about memory tracing and found this one.
>> > Is it possible to use tracepoints for capturing all memory accesses?
>> > In our implementation we insert helpers before and after tcg
>> > read/write operations.
>>
>> The current tracepoint isn't enough but yes I think we could. The first
>> thing I need to do is de-macrofy the atomic helpers a little just to
>> make it a bit simpler to add the before/after tracepoints.
>
> But memory accesses can use 'fast path' without the helpers.
> Thus you still need inserting the new helper for that case.

trace_guest_mem_before_tcg in tcg-op.c already does this but currently
only before operations. That's why I want to split it and pass the
load/store value register values into the helpers.

>
> Pavel Dovgalyuk


--
Alex Bennée