On 21.10.2024 13:10, Andrew Cooper wrote:
> On 18/10/2024 9:08 am, Roger Pau Monne wrote:
>> When using AMD-VI interrupt remapping the vector field in the IO-APIC RTE is
>> repurposed to contain part of the offset into the remapping table. Previous
>> to
>> 2ca9fbd739b8 Xen had logic so that the offset into the interrupt remapping
>> table would match the vector. Such logic was mandatory for end of interrupt
>> to
>> work, since the vector field (even when not containing a vector) is used by
>> the
>> IO-APIC to find for which pin the EOI must be performed.
>>
>> Introduce a table to store the EOI handlers when using interrupt remapping,
>> so
>> that the IO-APIC driver can translate pins into EOI handlers without having
>> to
>> read the IO-APIC RTE entry. Note that to simplify the logic such table is
>> used
>> unconditionally when interrupt remapping is enabled, even if strictly it
>> would
>> only be required for AMD-Vi.
>>
>> Reported-by: Willi Junga <xenproj...@ymy.be>
>> Suggested-by: David Woodhouse <d...@amazon.co.uk>
>> Fixes: 2ca9fbd739b8 ('AMD IOMMU: allocate IRTE entries instead of using a
>> static mapping')
>> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
>
> Yet more fallout from the multi-MSI work. That really has been a giant
> source of bugs.
If there's a connection to the multi-MSI work (which I don't see), the Fixes:
tag would likely need adjusting.
Jan
