Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation

[Christoffer Dall]

On Wed, Nov 12, 2014 at 1:27 PM, Paolo Bonzini <address@hidden> wrote:
>
>
> On 12/11/2014 13:18, Mark Rutland wrote:
>> On Wed, Nov 12, 2014 at 11:48:27AM +0000, Paolo Bonzini wrote:
>>>
>>> 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.
>>
>> Huh? SCI + AML is the method, and that's defined by the spec.
>
> I thought Christoffer meant a method to do the actual hotplug, not just
> to signal events.  If you want to "support the low-level interfaces in
> the kernel for this anyway", you certainly need to know the details
> underneath the AML.
>
I was being deliberately vague, because I don't know how this works (I
did use the word speculate, didn't I?).

But yes, one of the reasons why I would argue that we're not in a
hurry to accept these patches is that we don't know how the actual
underlying mechanisms to do the things we want ACPI to facilitate
(e.g. cpu and memory hotplug) really work, and thus we cannot verify
the implementation or benefit directly from it today.

-Christoffer