On 3/3/23 10:36 AM, Tian, Kevin wrote:
From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
Sent: Thursday, March 2, 2023 10:07 PM
+
+ if (!sm_supported(iommu) || !info)
@info has been referenced. !info check makes no sense.
Add pasid_supported(iommu).
Do you need to check whether the domain is compatible for this rid
pasid?
what kind of compatibility is concerned here? In concept a pasid
can be attached to any domain if it has been successfully attached
to rid. Probably we can add a check here that RID2PASID must
point to the domain already.
"...if it has been successfully attached to rid..."
We should not have this assumption in iommu driver's callback. The iommu
driver has no (and should not have) knowledge about the history of any
domain.
+ return -ENODEV;
+
+ if (WARN_ON(pasid == PASID_RID2PASID))
+ return -EINVAL;
Add a call to domain_attach_iommu() here to get a refcount of the domain
ID. And call domain_detach_iommu() in intel_iommu_remove_dev_pasid().
Is it necessary? iommu core doesn't allow taking ownership
if !xa_empty(&group->pasid_array) so if this pasid attach succeeds
this device cannot be attached to another domain before pasid
detach is done on the current domain.
It's not about the pasid, but the domain id.
This domain's id will be set to a field of the device's pasid entry. It
must get a refcount of that domain id to avoid use after free.
Best regards,
baolu
