It seems to me, that no one has read anything about AMD's research other than the PR blurbs that is quoted as replies. It would take far too long to explain completely, but AMD is, for all practical purposes at this time, immune from Spectre 2 and Meltdown. The author links a story about proof of concepts appearing in the wild. Note that to date, Spectre 2 has NOT been demonstrated on the Zen architecture. This has to do with how AMD chose to execute branch prediction memory locations.
AMD is preparing an OPTIONAL microcode update, that will insert some instructions to keep branches "in their own lanes" so to speak, as a precaution. But, they are NOT going to implement the main instruction that has the performance hit to the Intel chips. Maybe, someday, someone may get Spectre 2 to run on Zen, but as of now, it's a non issue. To imply that there are proof of concept programs in the wild affecting the Zen cpus by omission is just not right. Near zero risk of Spectre 2, and a vulnerability to both Specter variants are NOT different statements. Near zero means a remote chance of vulnerability. Still, since there are NO examples......