[PATCH v7 07/13] 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>
---
 drivers/iommu/iommufd/device.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 30dd2f79491a..e0f097b04467 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -357,6 +357,22 @@ iommufd_device_attach_reserved_iova(struct iommufd_device *idev,
 
 /* The device attach/detach/replace helpers for attach_handle */
 
+static int iommufd_hwpt_pasid_compat(struct iommufd_hw_pagetable *hwpt,
+				     struct iommufd_device *idev,
+				     ioasid_t pasid)
+{
+	lockdep_assert_held(&idev->igroup->lock);
+
+	if (pasid == IOMMU_NO_PASID &&
+	    !xa_empty(&idev->pasid_hwpts) && !hwpt->pasid_compat)
+		return -EINVAL;
+
+	if (pasid != IOMMU_NO_PASID &&
+	    (!idev->igroup->hwpt->pasid_compat || !hwpt->pasid_compat))
+		return -EINVAL;
+	return 0;
+}
+
 int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
 			       struct iommufd_device *idev,
 			       ioasid_t pasid)
@@ -364,10 +380,9 @@ int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
 	struct iommufd_attach_handle *handle;
 	int rc;
 
-	lockdep_assert_held(&idev->igroup->lock);
-
-	if (pasid != IOMMU_NO_PASID && !hwpt->pasid_compat)
-		return -EINVAL;
+	rc = iommufd_hwpt_pasid_compat(hwpt, idev, pasid);
+	if (rc)
+		return rc;
 
 	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
 	if (!handle)
@@ -441,8 +456,9 @@ int iommufd_hwpt_replace_device(struct iommufd_device *idev,
 	struct iommufd_attach_handle *handle, *old_handle;
 	int rc;
 
-	if (pasid != IOMMU_NO_PASID && !hwpt->pasid_compat)
-		return -EINVAL;
+	rc = iommufd_hwpt_pasid_compat(hwpt, idev, pasid);
+	if (rc)
+		return rc;
 
 	old_handle = iommufd_device_get_attach_handle(idev, pasid);
 
-- 
2.34.1