Re: [Qemu-devel] [PATCH 10/15] smbios: Add a function to directly add an entry

[Corey Minyard]

On 04/14/2015 01:31 AM, Michael S. Tsirkin wrote:
> On Mon, Apr 13, 2015 at 06:40:46PM +0200, Paolo Bonzini wrote:
>>
>> On 13/04/2015 18:34, Corey Minyard wrote:
>>>>> I made this the same as the ACPI code, which you have to have as a
>>>>> callback if you are adding it to a common SSDT.
>>>> Not really I think.
>>> The AML functions require that you have a tree to attach what you are
>>> adding.  If you did your own SSDT, you wouldn't need a callback.  You
>>> could add a binary blob that gets put into the SSDT, but I think that
>>> would require adding some AML functions.
>> I very much prefer the callback idea.  Long term it could be used by
>> more devices and possibly it could be turned into an AMLProvider QOM
>> interface.  Then the ACPI builder could iterate on all QOM devices and
>> just ask which of them can provide some AML.
> Yes, that would make sense. Devices which have a static
> AML could provide a static AML property, with very little code,
> those that have dynamic AML - dynamic AML property with more code.
>
> But I don't see callbacks as a step in that direction -
> more like code that will have to be ripped out later.
>
> I was looking for ways to remove dependencies for this patchset,
> not add them.

I don't see a dependency difference between the two.  Either way we are
adding something to the ACPI code to store these things, and adding
something to i386 (and arm64, when that happens) to get these entries
from ACPI and add them to the firmware.

>> Also, tables are rebuilt when the firmware loads them, and handing in a
>> blob makes it harder to achieve this on-the-fly modification, compared
>> to callbacks.
>>
>> Paolo
> Well that's not true for smbios, is it?

Both tables are dynamically built at runtime.  The SMBIOS table is fixed
size, but the contents will vary depending on what the user specifies
about IPMI.

-corey