KVM With Linux 6.8 Adds Intel LAM For Guests, More Confidential VMs Work

The KVM virtualization changes for the in-development Linux 6.8 kernel is quite heavy on the feature side.

There's a lot of KVM changes this cycle with some of the new v6.8 functionality including:

- Continued work around better supporting confidential VMs such as with the new KVM_SET_MEMORY_ATTRIBUTES ioctl for allowing user-space to specify per-page attributes for a given page of guest memory. This can be useful for confidential/secure VMs with the likes of AMD SEV-SNP, Intel TDX, and ARM pKVM.

- KVM on x86 also now supports "software-protected VMs" as currently a method of testing new interfaces around guest_memfd and the page attributes code.

- Advertising flush-by-ASID support for nSVM unconditionally on KVM to let the very latest versions of VMware Workstation work atop KVM.

- Intel Linear Address Masking (LAM) support for KVM guests.

- A new "CONFIG_KVM_HYPERV" Kconfig option to allow disabling KVM support for Microsoft Hyper-V emulation at build-time.

- ARM64 LPA2 support.

- KVM on LoongArch now allows for the LSX/LAX SIMD CPU instructions within KVM guest VMs.

- A variety of fixes and other improvements throughout the Kernel-based Virtual Machine code.

More details on the KVM changes for Linux 6.8 via this pull.