On 12/11/2014 12:34, Christoffer Dall wrote: > AFAIU ACPI already has a method for doing this
It's not defined in the spec. QEMU defines a bunch of registers to do that, and provides AML that works with those registers. While these registers can be separated from the ACPI code in QEMU... > and I speculate that there is some IRQ > assigned to an ACPI event that causes some AML code to be interpreted by > your OS. ... QEMU does exactly this, it uses the "general purpose event" (GPE) mechanism to trigger the parsing of the AML. When you hot-plug/unplug a CPU or memory, an SCI (system control interrupt - the ACPI IRQ) is triggered in the guest and that's not entirely disconnected from ACPI. Perhaps you could treat it as a shared level-triggered interrupt in DT? I don't know. > Wouldn't it be a matter of QEMU putting the right AML table > fragments in place to wire this up then? Yes. Paolo
