[tptacek]

You almost certainly know more about this than me, but hasn't macOS been breaking this attack --- malicious PCIE DMA --- for several years now with its IOMMU configuration? Ivan Krstic has a whole series of BH slides about this, and in the context of T2.

The point about attacking trusted devices and pre-cloning devices is well taken.

[redactions]

Yes. With MacOS and Thunderbolt 3 devices on Apple hardware the IOMMU is used as expected. This should handle DMA attacks when booted into MacOS.

An important caveat: the IOMMU alone will not handle every other issue that comes with malicious PCI(e) devices.