Re: [Qemu-devel] memory trace with qemu

[Lluís]

malc  writes:
>> > 2) instrumentation: a set of generic macros that signal events that might 
>> > be
>> > of
>> >     interest.
>> 
>> Etc.
>> 
>> In the context of another simulator, we developed a different
>> technique, which would be quite general and might be of interest
>> for QEMU.  We communicate with the simulator via a "fake" *device*,
>> mapped into user-mode memory using an mmap call.  If someone
>> devised and coded such a device, then it could be used from any
>> guest.

> I'v done something similar a while ago:
> http://repo.or.cz/w/qemu/malc.git/shortlog/refs/heads/wctpci

Ah, although somewhat heavier, this is much more clever and generic :)

My only concern is on the need of running as root to mmap /dev/mem, but I could
write a dumb character device that can be mmaped by everybody.

Lluis

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