According to a update to the security post on AMD’s newsroom section of the AMD website, AMD’s latest processors are not vulnerable for latest Spectre V3a variant also known as “Rogue System Register Read” as revealed by Microsoft and Google Project Zero.
From the AMD Processor Security update:
We have not identified any AMD x86 products susceptible to the Variant 3a vulnerability in our analysis to-date.
Spectre V4 “Speculative Store Bypass (SSB)”
AMD is, as are many chip architectures, affected by the new Spectre V4 variant labeled Speculative Store Bypass (SSB). Operating system mitigations are underway for Microsoft Windows and Linux.
AMD advises to keep BIOS up-to-date and adopt operating system mitigations for speculative execution side channel vulnerability (Speculative Store Bypass or SSB) as being released by Microsoft and other vendors. The semiconductor company also recommends leaving memory disambiguation on as the default setting.
AMD released a in-depth white paper describing ‘Speculative Store Bypass Disable’.