Re: [Xen-devel] [PATCH] hvmloader / qemu-xen: Getting rid of resource conflict for OpRegion.

["G.R." <firemeteor@xxxxxxxxxxxxxxxxxxxxx>]

>> >> Just one more question -- is the layout specific to the bios, or
>> common?
>> >> I wonder how can we judge the security risk if the layout is not
>> >> constant.
>> >
>> > I would say the layout of the IGD stuff is common per the Intel spec
>> for it and the OEMs have to follow that spec when writing the BIOS. But
>> it could change for newer hardware (with a new rev of the spec for
>> example that extended the IGD functionality).
>>
>>
>> I understand that the layout within OpRegion  is defined by the spec
>> and should be common.
>> But I don't see any words (may be I missed something) about the layout
>> of the outside world (e.g. what region is adjacent to OpRegion?).
>> So my question is actually can we expect a constant layout with regard
>> to OpRegion's neighbors?
>
> Ok sorry, I did not understand the question fully. We may be able to sort
> out what is in those NVS areas.
>

If we need to sort out ourselves, I guess we need more samples from
different vendors / bios versions.
Do we need to dump them from a live system, or this can be easily
extracted from the bios rom file?

>>
>> My impression from Ian's feedback is that the patch cannot be accepted
>> before the concern being resolved.
>> (Let alone the existing code in the tree has already open a hole
>> (first 18 bytes in my example))
>> And you mentioned that such info can be obtained from my host bios.
>> I've dumped the ACPI table from my host system and had it disassembled
>> by iasl.
>> But I lack of the knowledge to interpret the content.
>> Could you lend me a hand in case that's a trivial task for you?
>> You can find the DSDT.dsl file attached in my previous mail (@2012-12-
>> 23).
>
> Sure I can take a look. Can you send me a dump of your e820 map on the
> system in question (and an lspci dump while you are at it)? Also I think
> you may have mentioned it but what base address is the ASLS register
> reporting?

First of all, are you asking for the guest or the host? Host, I guess?
I'm not sure how to dump the e820 map.
Previously I used acpidump to get acpitables and use iasl to disassemble them.
Are you talking about the same work flow?

Thanks,
Timothy

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