The newest upstream-focused work around AMD SEV for Secure Encrypted Virtualization with EPYC server processors is a set of patches to better optimize cache flushing.
Sean Christopherson of Google sent out the set of patches last week that use the WBNOINVD instruction rather than WBINVD for better cache maintenance efficiency within the context of SEV. Additionally there are some cache flushing optimizations for flushing the cache only on CPUs running the SEV guest(s).
These build off patches posted by Google engineer Kevin Loughlin and Chinese engineer Zheyun Shen. No performance numbers were provided as part of this patch series, but any help to further optimize cache flushing tends to be useful and of measurable impact for helping with Linux VM performance.
Those interested in this latest cache flushing optimization work for AMD SEV can find the patches under review on the the kernel mailing list.
