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qemu/target-xtensa is a project aimed at development of a free simulator for Tensilica Xtensa processor family.
Although xtensa instruction set specification is open and there's even linux port for xtensa there were no free simulator available.
The project was initiated to lower cost and to speed up development of one of the Motorola Solutions projects and has been carried out exclusively by the OSLL. Started in March 2011 it took 2 months to provide initial ThreadX support, 2 more months to provide linux support and 2 more months to get accepted into the qemu mainline.
Our goal is to make it usable (and preferable:) in real development/production environment.
I guess you can just make sure you don't mark new registers as PRIVILEGED in ./gdb/xtensa-config.c