AMD Ends Out 2023 Still Working To Get The Rest Of SEV-SNP Upstream In Linux

This New Year's weekend brought the latest AMD patches working on plumbing the mainline Linux kernel with the hypervisor support around AMD Secure Nested Paging (SNP) as part of their Secure Encrypted Virtualization (SEV). SEV-SNP has been supported since EPYC 7003 series and while some elements of the support have been upstreamed for securing VMs, some bits remain.

For such significant changes to the Linux kernel, getting all of the SEV-SNP code into the mainline Linux kernel has been slow going... Similar to Intel's Trust Domain Extensions (TDX) support also going through many rounds of revisions and a long time in the making. SEV-SNP premiered with the EPYC 7003 (Zen 3) server processors and continues to be supported with the latest EPYC 8004/9004 series processors.

On Saturday the 11th iteration of the SEV-SNP hypervisor support was sent out for review on the kernel mailing list. With this the patches for SEV-SNP initialization have been broken off into their own patch series.

The actual SEV-SNP initialization code was broken off into its own patch series. The patch series cover letter explains:

"These patches were originally included in v10 of the SNP KVM/hypervisor patches, but have been split off from the general KVM support for easier review and eventual merging into the x86 tree. They are based on linux-next to help stay in sync with both tip and kvm-next."

And then the v11 patches of the KVM hypervisor support include adapting to the split-off patch series, adjusting various ioctls, documentation improvements, code refactorings, and other improvements.

Hopefully it won't be too long into 2024 before all of the AMD SEV-SNP code is finally upstreamed for mainline Linux kernel builds.