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

[Joel Granados]

On Thu, Sep 05, 2024 at 11:30:05AM +0800, Baolu Lu wrote:
> On 9/4/24 9:17 PM, Joel Granados via B4 Relay wrote:
> > From: Joel Granados<j.granados@xxxxxxxxxxx>
> > 
> > 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.
I don't follow. The way that I read it: if the pasid_array x-array does
not have an iommu_attach_handle indexed by either fault->prm.pasid or
IOMMU_NO_PASID, it will follow the err_bad_iopf and return -EINVAL
(please correct me if I'm wrong). So the iommu_attach_handle is *always*
expected.

Would it be more clear for it to be:
"""
The iommu_report_device_fault function expects the pasid_array x-array
to have an iommu_attach_handle indexed by a PASID. Add one indexed with
IOMMU_NO_PASID when the replacing HWPT has a valid iommufd fault object.
Remove it when we release ownership of the group.
"""

best

-- 

Joel Granados