LoongArch KVM To Speed-Up ARM/x86 Binary Translation

The LoongArch changes for the Kernel-based Virtual Machine (KVM) have been submitted ahead of the Linux 6.12 merge window opening. For enhancing KVM virtualization on these Chinese CPUs is enabling Loongson Binary Translation (LBT) for accelerating ARM/x86 binary translation.

Last year the Linux 6.6 kernel merged support for Loongson Binary Translation to help MIPS / x86 / ARM binaries on LoongArch. For the upcoming Linux 6.12 kernel the LBT functionality is being adapted for LoongArch KVM use.

Binary translation is accelerated by adding four scratch registers, x86/ARM eflags, and x87 FPU stack pointer support. This adaptation for KVM will help those wanting to run x86/x86_64 or ARM operating systems within the confines of KVM/QEMU. No benchmarks or other performance metrics for quantifying the LBT benefit were provided.

The LoongArch KVM changes for Linux 6.12 also add PMU support for guest VMs, enabling paravirt feature control from the VMM, and other features.