Re: [PATCH 5/6] iommu: init pasid array while doing domain_replace and iopf is active

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

On 9/4/24 9:17 PM, Joel Granados via B4 Relay wrote:
> From: Joel Granados<j.granados@samsung.com>
> 
> iommu_report_device_fault expects a pasid array to have an
> iommu_attach_handle when a fault is detected.

The iommu_attach_handle is expected only when an iopf-capable domain is
attached to the device or PASID. The iommu_report_device_fault() treats
it as a fault when a fault occurs, but no iopf-capable domain is
attached.

> Add this handle when the
> replacing hwpt has a valid iommufd fault object. Remove it when we
> release ownership of the group.

The iommu_attach_handle is managed by the caller (iommufd here for
example). Therefore, before iommu_attach_handle tries to attach a domain
to an iopf-capable device or pasid, it should allocate the handle and
pass it to the domain attachment interfaces. Conversely, the handle can
only be freed after the domain is detached.

Thanks,
baolu