[SeaBIOS] [PATCH] vcpu hotplug: Setup vcpu add/remove infrastructure

[Gleb Natapov]

On Sat, Jan 30, 2010 at 04:14:29AM +0800, Liu, Jinsong wrote:
> Gleb Natapov wrote:
> >> 
> > OK. Let me try to explain it one more time. Currently MADT table
> > resides in memory of type "ACPI DATA" and AML code reads and writes
> > this memory during CPU hot-plug. According to ACPI spec "ACPI DATA"
> > ares can be reused by an OS, so consider what will happen if OS puts
> > its data into memory area where MADT was and later gets cpu hotplug
> > event. Do you see the problem now?
> > 
> 
> I just hesitate ' if OS puts its data ...'.
What is not clear here? OS is free to reuse this memory for whatever it
wants.

> Per my understanding, os will not write madt after booting, only AML write madt when necessary (i.e. cpu hotplug).
Your understanding is wrong. Read spec.

> So is it necessary to mark madt as ACPI NVS?
> 
ACPI VNS or reserved. The difference is that OS should save/restore ACPI NVS
memory during S4 transition. Read the spec it is all there.

--
			Gleb.