Compilation options for Downfall mitigation

Elrod · October 22, 2023, 5:56pm

mitigations=off =P

Kidding.
You can try julia -Cnative,-fast-gather. However, I still saw vpgatherqq instructions in the test that I tried.

When Julia eventually upgrades to LLVM 17, you should be able to use julia -Cnative,+prefer-no-gather,+prefer-no-scatter.
I think the best place to look for these options is the .td files:

github.com

llvm/llvm-project/blob/release/17.x/llvm/lib/Target/X86/X86.td

//===-- X86.td - Target definition file for the Intel X86 --*- tablegen -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This is a target description file for the Intel i386 architecture, referred
// to here as the "X86" architecture.
//
//===----------------------------------------------------------------------===//

// Get the target-independent interfaces which we are implementing...
//
include "llvm/Target/Target.td"

//===----------------------------------------------------------------------===//
// X86 Subtarget state
//

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Compilation options for Downfall mitigation

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