[PATCH v10 12/18] iommufd: Enforce PASID-compatible domain for RID

[Yi Liu <yi.l.liu@intel.com>]

Per the definition of IOMMU_HWPT_ALLOC_PASID, iommufd needs to enforce
the RID to use PASID-compatible domain if PASID has been attached, and
vice versa. The PASID path has already enforced it. This adds the
enforcement in the RID path.

This enforcement requires a lock across the RID and PASID attach path,
the idev->igroup->lock is used as both the RID and the PASID path holds
it.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
v9 -> v10: split the hwpt->pasid_compat check to a separate if in the
           else statement.
---
 drivers/iommu/iommufd/device.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 17c424d9a355..54ffef9c17f7 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -514,8 +514,28 @@ 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;
+	struct iommufd_group *igroup = idev->igroup;
+
+	lockdep_assert_held(&igroup->lock);
+
+	if (pasid == IOMMU_NO_PASID) {
+		unsigned long start = IOMMU_NO_PASID;
+
+		if (!hwpt->pasid_compat &&
+		    xa_find_after(&igroup->pasid_attach,
+				  &start, UINT_MAX, XA_PRESENT))
+			return -EINVAL;
+	} else {
+		struct iommufd_attach *attach;
+
+		if (!hwpt->pasid_compat)
+			return -EINVAL;
+
+		attach = xa_load(&igroup->pasid_attach, IOMMU_NO_PASID);
+		if (attach && attach->hwpt && !attach->hwpt->pasid_compat)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -526,8 +546,6 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
 	struct iommufd_attach_handle *handle;
 	int rc;
 
-	lockdep_assert_held(&idev->igroup->lock);
-
 	rc = iommufd_hwpt_pasid_compat(hwpt, idev, pasid);
 	if (rc)
 		return rc;
-- 
2.34.1