As an update to the nouveau development community, the downstream fork of Valgrind with a mmap tracing tool ("mmt") we maintain has been rebased against the latest upstream release of Valgrind, v3.16.1
Code branch: https://github.com/envytools/valgrind/tree/mmt-3.16.1
Features of upstream Valgrind 3.16.x: https://www.valgrind.org/docs/manual/dist.news.html
In selected highlights, the benefits of tracking the latest version of Valgrind is added support for AArch64 v8.1 and reduced memcheck false positive rate on highly optimised code. There are, as ever, many smaller refinements and bug fixes. v3.16.1 includes two bugs fixed after 3.16.0 was frozen. As our downstream valgrind-mmt was last released against v3.14, we also get the benefit of all bug fixes and features since then, including that the RDRAND and F16C insn set extensions are now supported.
For anyone unfamiliar with valgrind-mmt, it is a userspace mmio tracer that assists nouveau reverse engineering efforts by tracing the commands sent to the card. There is an accompanying demmt tool within the enytools repo to better understand these trace logs.
I would like to thank all the other nouveau developers who have worked on mmt over many years, including specifically airlied, mslusarz and kherbst.
Best, Rhys