LoongArch KVM Support Extended To Allow LSX/LASX SIMD Support

With the Linux 6.7 kernel there is now KVM virtualization support for LoongArch CPUs. With the upcoming Linux 6.8 kernel cycle, that KVM support is being further extended for these RISC-V-inspired and MIPS64-derived Chinese processors.

Following the LoongArch KVM introduction in Linux 6.7, the succeeding kernel cycle will be adding a few more features. The LoongArch KVM changes for Linux 6.8 were sent out on Saturday and include an optimization for memslot hugepage checking, fixing a hardware/software timer issue, and LSX/LASX support.

The LSX/LASX support is for supporting the LoongArch architecture's 128-bit and 256-bit SIMD, respectively. LASX is akin to AVX2 and previously the Linux kernel and the open-source compiler toolchains saw work for supporting these vector instructions. KVM needs special handling for supporting LSX and LASX use by LoongArch guests, which will now be in place with Linux 6.8.

Aside from that the LoongArch KVM changes for this first kernel cycle of 2024 will be relatively minor. The list of patches can be found via this pull request.