[Xen-devel] [PATCH RFC 09/13] xen: change quality of the MADT ACPI enumerator

[Roger Pau Monné]

On 14/02/14 18:51, John Baldwin wrote:
> On Thursday, February 13, 2014 8:49:24 pm Andrew Cooper wrote:
>> On 08/02/2014 21:42, John Baldwin wrote:
>>> On Tuesday, December 24, 2013 12:20:58 PM Roger Pau Monne wrote:
>>>> Lower the quality of the MADT ACPI enumerator, so on Xen Dom0 we can
>>>> force the usage of the Xen mptable enumerator even when ACPI is
>>>> detected.
>>> Hmm, so I think one question is why does the existing MADT parser
>>> not work with the MADT table provided by Xen?  This may very well
>>> be correct, but if it's only a small change to make the existing
>>> MADT parser work with Xen's MADT table, that route might be
>>> preferable.
>>>
>>
>> For dom0, the MADT seen is the system MADT, which does not bear any
>> reality to dom0's topology.  For PV domU, no MADT will be found.  For
>> HVM domU, the MADT seen ought to represent (virtual) reality.
> 
> Hmm, the other changes suggested that you do want to use the I/O APIC
> entries and interrupt overrides from the system MADT for dom0?  Just
> not the CPU entries.  Is that correct?

Yes, we need the interrupt entries in order to interact with the
underlying hardware, but not the CPU entries/topology.

Roger.