[PATCH 2/2] vhost: forbid IOTLB invalidation when not enabled

[Jason Wang]

When IOTLB is not enabled, we should forbid IOTLB invalidation to
avoid a NULL pointer dereference.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 drivers/vhost/vhost.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c6f2d89..7d338d5 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -959,6 +959,10 @@ int vhost_process_iotlb_msg(struct vhost_dev *dev,
 		vhost_iotlb_notify_vq(dev, msg);
 		break;
 	case VHOST_IOTLB_INVALIDATE:
+		if (!dev->iotlb) {
+			ret = -EFAULT;
+			break;
+		}
 		vhost_del_umem_range(dev->iotlb, msg->iova,
 				     msg->iova + msg->size - 1);
 		break;
-- 
2.7.4