On 2018/12/29 上午3:34, David Miller wrote:
From: Jason Wang
Date: Fri, 28 Dec 2018 15:55:37 +0800
+static int vhost_invalidate_vmap(struct vhost_virtqueue *vq,
+struct vhost_vmap *map,
+unsigned long uaddr,
+
From: Jason Wang
Date: Fri, 28 Dec 2018 15:55:37 +0800
> +static int vhost_invalidate_vmap(struct vhost_virtqueue *vq,
> + struct vhost_vmap *map,
> + unsigned long uaddr,
> + unsigned long start,
> +
It was noticed that the copy_user() friends that was used to access
virtqueue metdata tends to be very expensive for dataplane
implementation like vhost since it involves lots of software checks,
speculation barrier, hardware feature toggling (e.g SMAP). The
extra cost will be more obvious when tra
