Re: [PATCH v5 3/9] iommu: Add attachment handle to struct iopf_group

[Baolu Lu]

On 5/8/24 8:04 AM, Jason Gunthorpe wrote:

On Tue, Apr 30, 2024 at 10:57:04PM +0800, Lu Baolu wrote:

@@ -206,8 +197,11 @@ void iommu_report_device_fault(struct device *dev, struct 
iopf_fault *evt)
        if (group == &abort_group)
                goto err_abort;

- group->domain = get_domain_for_iopf(dev, fault);

-       if (!group->domain)
+       if (!(fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) ||
+           get_attach_handle_for_iopf(dev, fault->prm.pasid, group))
+               get_attach_handle_for_iopf(dev, IOMMU_NO_PASID, group);

That seems a bit weird looking?

Agreed.

get_attach_handle_for_iopf(dev,
    (fault->prm.flags &
    IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) ? fault->prm.pasid : IOMMU_NO_PASID,
    group);

The logic here is that it tries the PASID domain and if it doesn't
exist, then tries the RID domain as well. I explained this in the commit
message:

"
... if the pasid table of a device is wholly managed by user space,
there is no domain attached to the PASID of the device ...
"

Perhaps I can improve it like this,

        int rc = -EINVAL;
        ...
        if (fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)
                rc = get_attach_handle_for_iopf(dev, fault->prm.pasid, group);
        if (rc)
                rc = get_attach_handle_for_iopf(dev, IOMMU_NO_PASID, group);

        if (rc || !group->attach_handle->domain->iopf_handler)
                goto err_abort;

Best regards,
baolu