AML execution

[ethindp]

Sometime in the future the kernel is going to need to execute AML in a safe and secure way (e.g. I'd like to avoid an in-kernel VM if possible; preferably, that would be in userspace and would call out to the kernel when needed).

AML is the ACPI machine language. Its used for hardware and device control, and for the majority of devices its also used for device enumeration (e.g. for detecting UARTs).

There are a variety of implementations of AML interpreters, such as acpica
and LAI.
As it currently stands, we're using the acpi crate, which
means that, most likely, we might want to use the aml crate because
it easily fits the architecture of the acpi crate.