Re: [Xen-devel] [PATCH v2 18/30] xen/x86: setup PVHv2 Dom0 ACPI tables

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 27.10.16 at 16:15, <boris.ostrovsky@xxxxxxxxxx> wrote:
> On 10/27/2016 10:02 AM, Jan Beulich wrote:
>>>>> On 27.10.16 at 15:51, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>> I re-read this thread and I am not sure I understand why we can't keep
>>> host's RSDP descriptor. We are not mapping dom0 memory 1:1 (right?) so
>>> we can place our versions of RSDT/XSDT at the address that the
>>> descriptor points to.
>>>
>>> Unless that address is beyond dom0 memory allocation so that could be a
>>> problem I guess.
>>
>> Also eventually we may want to add tables, not just remove some,
>> and then there may not be enough space at the original location.
>> Plus I think nothing precludes the XSDT living below 1Mb, and then
>> we're back into the same problems discussed in another branch of
>> this thread.
> 
> Yes, that is a problem.
> 
> I guess we will need to do something in Linux to override descriptor 
> search. There is already some cruft for this but it appears to be 
> kexec-specific.

As Roger pointed out - there should be kexec-independent logic
to avoid that lookup on EFI systems (by finding the pointer earlier
another way).

Jan

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