diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index ed71b5347a766ee26c95039638a028ece31b53de..cb807d0ea498df3a197d0c3ed70d5548e57d97b7 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -713,9 +713,13 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
 			r = -EFAULT;
 			break;
 		}
-		if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) ||
-		    (a.used_user_addr & (sizeof *vq->used->ring - 1)) ||
-		    (a.log_guest_addr & (sizeof *vq->used->ring - 1))) {
+
+		/* Make sure it's safe to cast pointers to vring types. */
+		BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
+		BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
+		if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
+		    (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
+		    (a.log_guest_addr & (sizeof(u64) - 1))) {
 			r = -EINVAL;
 			break;
 		}
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
index 61c818a7fe70dfca4d26b2ef7f4269e9da22233f..a3318f31e8e7fd05f317c595e8c4ce3bc3595fac 100644
--- a/include/uapi/linux/virtio_ring.h
+++ b/include/uapi/linux/virtio_ring.h
@@ -101,6 +101,13 @@ struct vring {
 	struct vring_used *used;
 };
 
+/* Alignment requirements for vring elements.
+ * When using pre-virtio 1.0 layout, these fall out naturally.
+ */
+#define VRING_AVAIL_ALIGN_SIZE 2
+#define VRING_USED_ALIGN_SIZE 4
+#define VRING_DESC_ALIGN_SIZE 16
+
 /* The standard layout for the ring is a continuous chunk of memory which looks
  * like this.  We assume num is a power of 2.
  *