[SeaBIOS] KVM call agenda for 2013-05-28
Gerd Hoffmann
kraxel at redhat.com
Wed May 29 11:42:34 CEST 2013
Hi,
>>> possible complexity of having to regenerate
>>> tables on a vm reboot,
>>
>> Why tables should be regenerated at reboot? I remember hotplug being
>> mentioned in the call. Hmm? Which hotplugged component needs acpi
>> table updates to work properly? And what is the point of hotplugging if
>> you must reboot the guest anyway to get the acpi updates needed?
>> Details please.
>
> I think it's a mistake. I sent a mail explaining this part.
Saw it meanwhile.
>> Also mentioned in the call: "architectural reasons", which I understand
>> as "real hardware works that way". Correct.
>
> Not exactly. Real hardware is very likely to have
> most of the tables pre-generated in ROM, load
> them and tweak them in the minor way.
>From a quick look it seems coreboot has a static (iasl-compiled) dsdt
and generates everything else.
http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/mainboard/emulation/qemu-x86/acpi_tables.c
>> Agree on this one. Ideally the acpi table generation code should be
>> able to gather all information it needs from the qom tree, so it can be
>> a standalone C file instead of being scattered over all qemu.
>
> Did you look at the patchset I posted?
Very briefly only.
> Generation is in a standalone C file there.
Good.
> However, if you mean we should do things like
>
> if (Device_id == foobar) {
> }
> in once central place, I disagree.
> I think that's nasty, adding devices would
> mean touching this central registry.
No, I mean more "lookup PIIX4_PM object + check disable_s3 property"
instead of having code for it in hw/acpi/piix4.c or using global variables.
cheers,
Gerd
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