Re: [PATCH v7 9/9] iommu/dma: Reserve any RMR regions associated with a dev

Robin Murphy
2021-10-11T15:00:58Z

On 2021-10-09 08:07, Jon Nettleton wrote:
> On Fri, Oct 8, 2021 at 3:10 PM Robin Murphy <robin.murphy@arm.com> wrote:
>>
>> On 2021-08-05 09:07, Shameer Kolothum wrote:
>>> Get ACPI IORT RMR regions associated with a dev reserved
>>> so that there is a unity mapping for them in SMMU.
>>
>> This feels like most of it belongs in the IORT code rather than
>> iommu-dma (which should save the temporary list copy as well).
>
> See previous comment. The original intent was for device-tree to also
> be able to use these mechanisms to create RMR's and support them
> in the SMMU.

Can you clarify how code behind an "if (!is_of_node(...))" check
alongside other IORT-specific code is expected to be useful for DT?

Yes, iommu_dma_get_resv_regions() itself wants to end up serving as an
abstraction layer, but that still doesn't mean it has to do much more
than dispatch into firmware-specific backends as appropriate.

Robin.