This patch series are intended to test the POWER9 Nest
Accelerator (NX) GZIP engine that is being introduced by
https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-March/205659.html
More information about how to access the NX can be found in that patch, also a
complete userspace library and more documentation can be found at:
https://github.com/libnxz/power-gzip
Changes in V3:
- Defined a macro and increased the number of retries for page faults
to work in system with less memory, mentioning the issue on README.
- Returned to use volatile on the touch pages routine and a few structs
on inc/nxu.h as they are handled by hardware and some compilers could
optmize it wrongly.
- Moved common functions to gzip_vas.c.
