Re: [PATCH v4 3/8] iommu/vt-d: Put iopf enablement in domain attach path

[Baolu Lu <baolu.lu@linux.intel.com>]

On 3/18/2025 5:58 PM, Yi Liu wrote:
> On 2025/3/13 13:19, Lu Baolu wrote:
>> Update iopf enablement in the driver to use the new method, similar to
>> the arm-smmu-v3 driver. Enable iopf support when any domain with an
>> iopf_handler is attached, and disable it when the domain is removed.
>>
>> Place all the logic for controlling the PRI and iopf queue in the domain
>> set/remove/replace paths. Keep track of the number of domains set to the
>> device and PASIDs that require iopf. When the first domain requiring iopf
>> is attached, add the device to the iopf queue and enable PRI. When the
>> last domain is removed, remove it from the iopf queue and disable PRI.
> 
> Reviewed-by: Yi Liu <yi.l.liu@intel.com>
> 
> a nit. It appears to me the PRI cap and IOMMU PRI enable bit is set in the
> probe_device() now after the below patch. This commit now is more dealing
> with iopf_refcount and adding the device to the iopf queue.
> 
> https://lore.kernel.org/linux-iommu/20250228092631.3425464-6- 
> baolu.lu@linux.intel.com/

Yes. With the device not adding to the iommu iopf queue, the IOMMU core
will respond to the device with IOMMU_PAGE_RESP_INVALID.

Thanks,
baolu