• AMD Preparing Linux Kernel For “RMPOPT” To Help Reduce Overhead On SEV-SNP Servers AMD sent out a set of Linux kernel patches today for enabling use of a new instruction dubbed RMPOPT. • Given the timing of these patches, RMPOPT is presumably a feature coming with next-gen AMD EPYC Zen 6 “Venice” processors. • RMPOPT is a new instruction to help minimize the performance overhead of RMP checks on the hypervisor and for non-SNP guests by letting RMP checks be skipped in certain scenarios. • With RMPOPT these checks can be skipped when 1G regions of memory are known not to contain any SEV-SNP guest memory. • Today is the first time I’m hearing of AMD RMPOPT and didn’t turn up any other search results hits for patches I may have missed. • Today’s patch series further describes RMPOPT as: The patches don’t explicitly call out what generation of EPYC server processors will introduce RMPOPT support and the code just checks for the presence of the feature.
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