On Thu, Oct 10, 2019 at 06:23:00PM +0200, Laszlo Ersek wrote: > On 10/10/19 14:48, Igor Mammedov wrote: > > > it doesn't really matter if it's ACPI blob or fw_cfg, > > what firmware needs is a table of possible CPUs with APIC IDs. > > To repeat my previous point: > > Not necessarily taking sides between "data table" and "register block", > but *if* we opt for "data table", then it *must* be fw_cfg. > > > But if we go this route (i.e. not reuse CPU hotplug interface), > > the table alone is not enough, one would need to build a protocol > > between ACPI and firmware to communicate what CPUs to (un)hotplug. > > That's for sure, yes -- for finding out what CPU has been hotplugged, > the hotplug SMI handler in the firmware has to look at the register > block no matter what.
I thought all that's done by ACPI, with ACPI returning an event to the OSPM reporting what happened. > The "data table" vs "register block" question only arises *afterwards*, > for translating the CPU selector (fetched from the register block) to > the APIC-ID domain. (The generic edk2 infrastructure requires APIC-IDs). > > Thanks > Laszlo