Comment by sudosysgen

You can still do DMA cheating with IOMMU enabled. There are quite a few relatively widespread bugs with IOMMU that allow you to bypass it, for example https://cloud.google.com/blog/products/gcp/fuzzing-pci-expre.... So to be able to actually do IOMMU DMA protection you need to be willing to ban many popular devices. That may be viable for FACEIT and ESEA but it won't be for 99.9% of anticheat deployments.

The detection for DMA cheating is based on the DMA engines being unable to emulate 1:1 the actual behavior the hardware ID would be expected to have. This can be fixed by simply doing that properly.

But even besides that, DMA through PCIe is just one hardware cheat that fits a separate thread model and therefore has some countermeasures.

There are much more robust methods you can use, for example a PCIe interposer between the OS and GPU, or simply direct memory interposes if you want to do DMA without the protections afforded by the PCIe implementation. There are interposets along with machinery to get along memory encryption and other obfuscations that can be made for around 100$.