Ok, I now have a recent debian amd64 system running in bochs.
I have hacked the linux kernel to save in a special register the task id of the task running on the cpu.
By adding this support into bochs (which I am almost finishing) and using the memory instrumentation macros, I can generate memory traces of specific process.
I have already done this mod into qemu, but the results were weird, since qemu executes hundreds of thousands instructions of a cpu before switching to another cpu in smp environments.
I hope in bochs, by setting the cpu quantum to a small value, I get correct results.

But, sometimes, I get an annoying error.
I took a screenshot, you can see it here:
Bochs logs the error (left window), and the kernel detects it too (right window).
Sometimes, after this error appears, I get a segmentation fault.

It's not my hack's fault, since it was already happening before my modifications.

Eduardo Henrique Molina da Cruz
MSc student
Parallel and Distributed Processing Group
Federal University of Rio Grande do Sul (UFRGS)