Re: [Qemu-devel] Tracing guest virtual addresses

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

Peter Maydell <peter.maydell@linaro.org> writes:

> On 20 June 2017 at 12:02, Lluís Vilanova <vilanova@ac.upc.edu> wrote:
>> Jayanto Minocha writes:
>>> But that is only used to instrument the cpu_ld/cpu_st macros, which is only
>>> called in the case of a tlb miss.
>>
>>> I've been going over the archives, and it looks like I need to instrument
>>> tcg_out_tlb_load. Am I on the right path ?
>>
>> That event should trace all guest memory accesses performed by the CPU. If you
>> found any case where this does not hold, it is likely a bug and I'd appreciate
>> it if you can point me to the smallest possible failing example.
>
> Does it catch memory accesses that are performed via helper functions,
> or only ones done by inline TCG code?

AFAICT it inserts a helper call on the TCG ld/st ops. I wonder why not
just ensure we always take the slow path and put the helpers in the
access functions there? You could even apply an address mask if you only
want to look at certain address ranges.

>
> thanks
> -- PMM


--
Alex Bennée