iommufd: Enforce PASID-compatible domain in PASID path

JIRA: https://issues.redhat.com/browse/RHEL-114131
Upstream-Status: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

commit ff3f014
Author: Yi Liu <yi.l.liu@intel.com>
Date: Fri Mar 21 10:19:32 2025 -0700

    iommufd: Enforce PASID-compatible domain in PASID path

    AMD IOMMU requires attaching PASID-compatible domains to PASID-capable
    devices. This includes the domains attached to RID and PASIDs. Related
    discussions in link [1] and [2]. ARM also has such a requirement, Intel
    does not need it, but can live up with it. Hence, iommufd is going to
    enforce this requirement as it is not harmful to vendors that do not
    need it.

    Mark the PASID-compatible domains and enforce it in the PASID path.

    [1] https://lore.kernel.org/linux-iommu/20240709182303.GK14050@ziepe.ca/
    [2] https://lore.kernel.org/linux-iommu/20240822124433.GD3468552@ziepe.ca/

    Link: https://patch.msgid.link/r/20250321171940.7213-11-yi.l.liu@intel.com
    Reviewed-by: Kevin Tian <kevin.tian@intel.com>
    Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
    Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
    Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
    Signed-off-by: Yi Liu <yi.l.liu@intel.com>
    Tested-by: Nicolin Chen <nicolinc@nvidia.com>
    Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

(cherry picked from commit ff3f014)
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Author: snits

drivers/iommu/iommufd/device.c

@@ -395,6 +395,15 @@ static bool iommufd_device_is_attached(struct iommufd_device *idev,
 	return xa_load(&attach->device_array, idev->obj.id);
 }
 
+static int iommufd_hwpt_pasid_compat(struct iommufd_hw_pagetable *hwpt,
+				     struct iommufd_device *idev,
+				     ioasid_t pasid)
+{
+	if (pasid != IOMMU_NO_PASID && !hwpt->pasid_compat)
+		return -EINVAL;
+	return 0;
+}
+
 static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
 				      struct iommufd_device *idev,
 				      ioasid_t pasid)
@@ -404,6 +413,10 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
 
 	lockdep_assert_held(&idev->igroup->lock);
 
+	rc = iommufd_hwpt_pasid_compat(hwpt, idev, pasid);
+	if (rc)
+		return rc;
+
 	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
 	if (!handle)
 		return -ENOMEM;
@@ -472,6 +485,10 @@ static int iommufd_hwpt_replace_device(struct iommufd_device *idev,
 
 	WARN_ON(pasid != IOMMU_NO_PASID);
 
+	rc = iommufd_hwpt_pasid_compat(hwpt, idev, pasid);
+	if (rc)
+		return rc;
+
 	old_handle = iommufd_device_get_attach_handle(idev, pasid);
 
 	handle = kzalloc(sizeof(*handle), GFP_KERNEL);

drivers/iommu/iommufd/hw_pagetable.c

@@ -136,6 +136,7 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 	if (IS_ERR(hwpt_paging))
 		return ERR_CAST(hwpt_paging);
 	hwpt = &hwpt_paging->common;
+	hwpt->pasid_compat = flags & IOMMU_HWPT_ALLOC_PASID;
 
 	INIT_LIST_HEAD(&hwpt_paging->hwpt_item);
 	/* Pairs with iommufd_hw_pagetable_destroy() */
@@ -244,6 +245,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 	if (IS_ERR(hwpt_nested))
 		return ERR_CAST(hwpt_nested);
 	hwpt = &hwpt_nested->common;
+	hwpt->pasid_compat = flags & IOMMU_HWPT_ALLOC_PASID;
 
 	refcount_inc(&parent->common.obj.users);
 	hwpt_nested->parent = parent;
@@ -300,6 +302,7 @@ iommufd_viommu_alloc_hwpt_nested(struct iommufd_viommu *viommu, u32 flags,
 	if (IS_ERR(hwpt_nested))
 		return ERR_CAST(hwpt_nested);
 	hwpt = &hwpt_nested->common;
+	hwpt->pasid_compat = flags & IOMMU_HWPT_ALLOC_PASID;
 
 	hwpt_nested->viommu = viommu;
 	refcount_inc(&viommu->obj.users);

drivers/iommu/iommufd/iommufd_private.h

@@ -299,6 +299,7 @@ struct iommufd_hw_pagetable {
 	struct iommufd_object obj;
 	struct iommu_domain *domain;
 	struct iommufd_fault *fault;
+	bool pasid_compat : 1;
 };
 
 struct iommufd_hwpt_paging {