The "KVM Chainsaw" Clean-Up Merged For Linux 7.3 Along With Other Fixes

The Kernel-based Virtual Machine "KVM" changes have landed for the Linux 7.3 merge window that is wrapping up later today.

The KVM code for this next version of the Linux kernel is mostly seeing bug fixes and code clean-ups with not much in the way of user-facing new features or direct improvements.

Most notable on the KVM side for Linux 7.3, the "KVM chainsaw" code was merged for splitting up one of the god data structures. The kvm_mmu code is now cleaned up for better handling modern KVM usage. There was also other "spring (summer) cleaning" to the KVM x86 code.

The AMD KVM code for Linux 7.3 now allocates full pages for SEV/SEV-ES ENCRYPT/DECRYPT ops to fix a data corruption issue due to the AMD PSP driver assigning to-be-written pages to firmware. This Linux kernel change aligns properly now with the AMD SEV-SNP specifications. The AMD SEV-SNP population ioctls have also been hardened against bad input, among other improvements for AMD Secure Encrypted Virtualization.

The Intel KVM code has also seen a number of fixes such as for servicing local TLB flushes on failed nested VM-Enter, which fixes a condition where KVM could miss a TLB on a future successful VM-Enter having the same L2 VPID. There is also a fix for VPID virtualization bugs where KVM would fail to flush hardware TLBs.

Meanwhile KVM on RISC-V added Svadu/Zicfiss/Zicfilp FWFT support for guests and optimized HFENCE request handling for SMP guests. LoongArch and ARM for KVM with Linux 7.3 is mostly about bug fixing.

More details on the Linux 7.3 KVM changes via this pull request.