Looks like someone actually did the homework and read the linked papers 
Links from the previous thread:
https://lwn.net/Articles/685215/
AMD Memory Encryption whitepaper:
(Currently down)
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf
AMD64 Architecture Programmer's Manual:
http://support.amd.com/TechDocs/24593.pdf
SME is section 7.10
SEV is section 15.34
Support for the extension exists within the kernel
https://patchwork.kernel.org/patch/9612007/
AMD Memory Encryption Tutorial ISCA 2016
https://sites.google.com/site/metisca2016/
The Intel Equivalent technology
https://software.intel.com/en-us/blogs/2016/02/26/memory-encryption-an-intel-sgx-underpinning-technology
Regarding SEV
A Whole dump of everything else Ryzen technical