iommufd: Allow allocating PASID-compatible domain

The underlying infrastructure has supported the PASID attach and related
enforcement per the requirement of the IOMMU_HWPT_ALLOC_PASID flag. This
extends iommufd to support PASID compatible domain requested by userspace.

Link: https://patch.msgid.link/r/[email protected]
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Nicolin Chen <[email protected]>
Signed-off-by: Yi Liu <[email protected]>
Tested-by: Nicolin Chen <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

Author: yiliu1765

drivers/iommu/iommufd/hw_pagetable.c

@@ -112,7 +112,8 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 {
 	const u32 valid_flags = IOMMU_HWPT_ALLOC_NEST_PARENT |
 				IOMMU_HWPT_ALLOC_DIRTY_TRACKING |
-				IOMMU_HWPT_FAULT_ID_VALID;
+				IOMMU_HWPT_FAULT_ID_VALID |
+				IOMMU_HWPT_ALLOC_PASID;
 	const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
 	struct iommufd_hwpt_paging *hwpt_paging;
 	struct iommufd_hw_pagetable *hwpt;
@@ -233,7 +234,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 	struct iommufd_hw_pagetable *hwpt;
 	int rc;
 
-	if ((flags & ~IOMMU_HWPT_FAULT_ID_VALID) ||
+	if ((flags & ~(IOMMU_HWPT_FAULT_ID_VALID | IOMMU_HWPT_ALLOC_PASID)) ||
 	    !user_data->len || !ops->domain_alloc_nested)
 		return ERR_PTR(-EOPNOTSUPP);
 	if (parent->auto_domain || !parent->nest_parent ||
@@ -290,7 +291,7 @@ iommufd_viommu_alloc_hwpt_nested(struct iommufd_viommu *viommu, u32 flags,
 	struct iommufd_hw_pagetable *hwpt;
 	int rc;
 
-	if (flags & ~IOMMU_HWPT_FAULT_ID_VALID)
+	if (flags & ~(IOMMU_HWPT_FAULT_ID_VALID | IOMMU_HWPT_ALLOC_PASID))
 		return ERR_PTR(-EOPNOTSUPP);
 	if (!user_data->len)
 		return ERR_PTR(-EOPNOTSUPP);

include/uapi/linux/iommufd.h

@@ -393,6 +393,9 @@ struct iommu_vfio_ioas {
  *                          Any domain attached to the non-PASID part of the
  *                          device must also be flagged, otherwise attaching a
  *                          PASID will blocked.
+ *                          For the user that wants to attach PASID, ioas is
+ *                          not recommended for both the non-PASID part
+ *                          and PASID part of the device.
  *                          If IOMMU does not support PASID it will return
  *                          error (-EOPNOTSUPP).
  */