@@ -352,16 +352,41 @@ iommufd_hw_pagetable_detach(struct iommufd_device *idev)
return hwpt;
}
+static struct iommufd_hw_pagetable *
+iommufd_device_do_attach(struct iommufd_device *idev,
+ struct iommufd_hw_pagetable *hwpt)
+{
+ int rc;
+
+ rc = iommufd_hw_pagetable_attach(hwpt, idev);
+ if (rc)
+ return ERR_PTR(rc);
+ return NULL;
+}
+
+typedef struct iommufd_hw_pagetable *(*attach_fn)(
+ struct iommufd_device *idev, struct iommufd_hw_pagetable *hwpt);
+
/*
* When automatically managing the domains we search for a compatible domain in
* the iopt and if one is found use it, otherwise create a new domain.
* Automatic domain selection will never pick a manually created domain.
*/
-static int iommufd_device_auto_get_domain(struct iommufd_device *idev,
- struct iommufd_ioas *ioas, u32 *pt_id)
+static struct iommufd_hw_pagetable *
+iommufd_device_auto_get_domain(struct iommufd_device *idev,
+ struct iommufd_ioas *ioas, u32 *pt_id,
+ attach_fn do_attach)
{
+ /*
+ * iommufd_hw_pagetable_attach() is called by
+ * iommufd_hw_pagetable_alloc() in immediate attachment mode, same as
+ * iommufd_device_do_attach(). So if we are in this mode then we prefer
+ * to use the immediate_attach path as it supports drivers that can't
+ * directly allocate a domain.
+ */
+ bool immediate_attach = do_attach == iommufd_device_do_attach;
+ struct iommufd_hw_pagetable *destroy_hwpt;
struct iommufd_hw_pagetable *hwpt;
- int rc;
/*
* There is no differentiation when domains are allocated, so any domain
@@ -375,52 +400,58 @@ static int iommufd_device_auto_get_domain(struct iommufd_device *idev,
if (!iommufd_lock_obj(&hwpt->obj))
continue;
- rc = iommufd_hw_pagetable_attach(hwpt, idev);
- iommufd_put_object(&hwpt->obj);
-
- /*
- * -EINVAL means the domain is incompatible with the device.
- * Other error codes should propagate to userspace as failure.
- * Success means the domain is attached.
- */
- if (rc == -EINVAL)
- continue;
+ destroy_hwpt = (*do_attach)(idev, hwpt);
+ if (IS_ERR(destroy_hwpt)) {
+ iommufd_put_object(&hwpt->obj);
+ /*
+ * -EINVAL means the domain is incompatible with the
+ * device. Other error codes should propagate to
+ * userspace as failure. Success means the domain is
+ * attached.
+ */
+ if (PTR_ERR(destroy_hwpt) == -EINVAL)
+ continue;
+ goto out_unlock;
+ }
*pt_id = hwpt->obj.id;
+ iommufd_put_object(&hwpt->obj);
goto out_unlock;
}
- hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev, true);
+ hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev,
+ immediate_attach);
if (IS_ERR(hwpt)) {
- rc = PTR_ERR(hwpt);
+ destroy_hwpt = ERR_CAST(hwpt);
goto out_unlock;
}
+
+ if (!immediate_attach) {
+ destroy_hwpt = (*do_attach)(idev, hwpt);
+ if (IS_ERR(destroy_hwpt))
+ goto out_abort;
+ } else {
+ destroy_hwpt = NULL;
+ }
+
hwpt->auto_domain = true;
*pt_id = hwpt->obj.id;
mutex_unlock(&ioas->mutex);
iommufd_object_finalize(idev->ictx, &hwpt->obj);
- return 0;
+ return destroy_hwpt;
+
+out_abort:
+ iommufd_object_abort_and_destroy(idev->ictx, &hwpt->obj);
out_unlock:
mutex_unlock(&ioas->mutex);
- return rc;
+ return destroy_hwpt;
}
-/**
- * iommufd_device_attach - Connect a device from an iommu_domain
- * @idev: device to attach
- * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HW_PAGETABLE
- * Output the IOMMUFD_OBJ_HW_PAGETABLE ID
- *
- * This connects the device to an iommu_domain, either automatically or manually
- * selected. Once this completes the device could do DMA.
- *
- * The caller should return the resulting pt_id back to userspace.
- * This function is undone by calling iommufd_device_detach().
- */
-int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
+static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
+ attach_fn do_attach)
{
+ struct iommufd_hw_pagetable *destroy_hwpt;
struct iommufd_object *pt_obj;
- int rc;
pt_obj = iommufd_get_object(idev->ictx, *pt_id, IOMMUFD_OBJ_ANY);
if (IS_ERR(pt_obj))
@@ -431,8 +462,8 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
struct iommufd_hw_pagetable *hwpt =
container_of(pt_obj, struct iommufd_hw_pagetable, obj);
- rc = iommufd_hw_pagetable_attach(hwpt, idev);
- if (rc)
+ destroy_hwpt = (*do_attach)(idev, hwpt);
+ if (IS_ERR(destroy_hwpt))
goto out_put_pt_obj;
break;
}
@@ -440,22 +471,54 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
struct iommufd_ioas *ioas =
container_of(pt_obj, struct iommufd_ioas, obj);
- rc = iommufd_device_auto_get_domain(idev, ioas, pt_id);
- if (rc)
+ destroy_hwpt = iommufd_device_auto_get_domain(idev, ioas, pt_id,
+ do_attach);
+ if (IS_ERR(destroy_hwpt))
goto out_put_pt_obj;
break;
}
default:
- rc = -EINVAL;
+ destroy_hwpt = ERR_PTR(-EINVAL);
goto out_put_pt_obj;
}
+ iommufd_put_object(pt_obj);
- refcount_inc(&idev->obj.users);
- rc = 0;
+ /* This destruction has to be after we unlock everything */
+ if (destroy_hwpt)
+ iommufd_hw_pagetable_put(idev->ictx, destroy_hwpt);
+ return 0;
out_put_pt_obj:
iommufd_put_object(pt_obj);
- return rc;
+ return PTR_ERR(destroy_hwpt);
+}
+
+/**
+ * iommufd_device_attach - Connect a device to an iommu_domain
+ * @idev: device to attach
+ * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HW_PAGETABLE
+ * Output the IOMMUFD_OBJ_HW_PAGETABLE ID
+ *
+ * This connects the device to an iommu_domain, either automatically or manually
+ * selected. Once this completes the device could do DMA.
+ *
+ * The caller should return the resulting pt_id back to userspace.
+ * This function is undone by calling iommufd_device_detach().
+ */
+int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
+{
+ int rc;
+
+ rc = iommufd_device_change_pt(idev, pt_id, &iommufd_device_do_attach);
+ if (rc)
+ return rc;
+
+ /*
+ * Pairs with iommufd_device_detach() - catches caller bugs attempting
+ * to destroy a device with an attachment.
+ */
+ refcount_inc(&idev->obj.users);
+ return 0;
}
EXPORT_SYMBOL_NS_GPL(iommufd_device_attach, IOMMUFD);