Re: [PATCH v5 7/9] iommufd: Associate fault object with iommufd_hw_pgtable

[Baolu Lu]

On 5/15/24 4:50 PM, Tian, Kevin wrote:
From: Lu Baolu <baolu...@linux.intel.com>
Sent: Tuesday, April 30, 2024 10:57 PM
@@ -227,7 +233,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx
*ictx,
        refcount_inc(&parent->common.obj.users);
        hwpt_nested->parent = parent;

-       hwpt->domain = ops->domain_alloc_user(idev->dev, flags,
+       hwpt->domain = ops->domain_alloc_user(idev->dev, 0,
                                              parent->common.domain,
user_data);

it reads slightly better to clear the fault bit and still pass in flags.


Done.

-       hwpt->domain = ops->domain_alloc_user(idev->dev, 0,
+       hwpt->domain = ops->domain_alloc_user(idev->dev,
+                                             flags & 
~IOMMU_HWPT_FAULT_ID_VALID,
                                              parent->common.domain, 
user_data);

@@ -308,6 +314,19 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd
*ucmd)
                goto out_put_pt;
        }

+       if (cmd->flags & IOMMU_HWPT_FAULT_ID_VALID) {
+               struct iommufd_fault *fault;
+
+               fault = iommufd_get_fault(ucmd, cmd->fault_id);
+               if (IS_ERR(fault)) {
+                       rc = PTR_ERR(fault);
+                       goto out_hwpt;
+               }
+               hwpt->fault = fault;
+               hwpt->domain->iopf_handler = iommufd_fault_iopf_handler;
+               hwpt->domain->fault_data = hwpt;
+       }

this is nesting specific. why not moving it to the nested_alloc()?

Nesting is currently a use case for userspace I/O page faults, but this
design should be general enough to support other scenarios as well.

Best regards,
baolu