On 25/09/19 11:12, Gerd Hoffmann wrote: > Hi, > >> If you want to add hotplug to microvm, you can reuse the existing code >> for CPU and memory hotplug controllers, and write drivers for them in >> Linux's drivers/platform. The drivers would basically do what the ACPI >> AML tells the interpreter to do. > > How would the linux kernel detect those devices? > > I guess that wouldn't be ACPI, seems everyone wants avoid it[1]. > > So device tree on x86? Something else? Yes, device tree would be great. > [1] Not clear to me why, some minimal ACPI tables listing our > devices (isa-serial, fw_cfg, ...) doesn't look unreasonable > to me. It's not, but ACPI is dog slow and half of the boot time is cut if you remove it. > We could also make virtio-mmio discoverable that way. True, but the simplest way to plumb virtio-mmio into ACPI would be taking the device tree properties and representing them as _DSD[1]. So at this point it's just as easy to use directly the device tree. Paolo [1] https://kernel-recipes.org/en/2015/talks/representing-device-tree-peripherals-in-acpi/
