iommu: Detaching pasid by attaching to the blocked_domain

The iommu drivers are on the way to detach pasid by attaching to the blocked
domain. However, this cannot be done in one shot. During the transition, iommu
core would select between the remove_dev_pasid op and the blocked domain.

Suggested-by: Kevin Tian <[email protected]>
Suggested-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Vasant Hegde <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Signed-off-by: Yi Liu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: yiliu1765

drivers/iommu/iommu.c

@@ -3316,8 +3316,18 @@ static void iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid,
 				   struct iommu_domain *domain)
 {
 	const struct iommu_ops *ops = dev_iommu_ops(dev);
+	struct iommu_domain *blocked_domain = ops->blocked_domain;
+	int ret = 1;
 
-	ops->remove_dev_pasid(dev, pasid, domain);
+	if (blocked_domain && blocked_domain->ops->set_dev_pasid) {
+		ret = blocked_domain->ops->set_dev_pasid(blocked_domain,
+							 dev, pasid, domain);
+	} else {
+		ops->remove_dev_pasid(dev, pasid, domain);
+		ret = 0;
+	}
+
+	WARN_ON(ret);
 }
 
 static int __iommu_set_group_pasid(struct iommu_domain *domain,
@@ -3380,7 +3390,9 @@ int iommu_attach_device_pasid(struct iommu_domain *domain,
 	ops = dev_iommu_ops(dev);
 
 	if (!domain->ops->set_dev_pasid ||
-	    !ops->remove_dev_pasid)
+	    (!ops->remove_dev_pasid &&
+	     (!ops->blocked_domain ||
+	      !ops->blocked_domain->ops->set_dev_pasid)))
 		return -EOPNOTSUPP;
 
 	if (ops != domain->owner || pasid == IOMMU_NO_PASID)