Summary

Add VM option for AArch64 to optionally select SVE feature

Problem

Arm SVE [1] and SVE2 [2] are optional extentions to Arm architecture. VM needs to detect SVE version in running hardware and generate code for non-SVE, SVE1 and SVE2 to get best performance. And we can also enable or disable SVE based on different applications or use cases.

[1] https://developer.arm.com/architectures/cpu-architecture/a-profile/docs/arm-architecture-reference-manual-supplement-armv8-a [2] https://developer.arm.com/tools-and-software/server-and-hpc/compile/arm-instruction-emulator/resources/tutorials/sve/sve-vs-sve2/introduction-to-sve2

Solution

We add a VM option UseSVE to control which SVE version is going to be used or not using SVE at all. This is similar to x86 UseAVX option.

Specification

We add a new VM option, UseSVE, which is an integer with the following valid values:

0: Do not use SVE, even when the hardware supports SVE.

1: Use SVE version 1

2: Use SVE version 2