Subject: Re: [PATCH net] virtio-net: alloc big buffers also when guest can receive UFO

From: Jason Wang <[email-masked]>
Date: Thu, 13 Feb 2014 11:02:13 +0800

On 02/12/2014 07:59 PM, Michael S. Tsirkin wrote:
> On Wed, Feb 12, 2014 at 01:43:28PM +0800, Jason Wang wrote:
>> > We should alloc big buffers also when guest can receive UFO
>> > pakcets. Otherwise the big packets will be truncated when mergeable rx
>> > buffer is disabled.
> Not truncated, they will be dropped.
>

Why dropped? We enable the ufo on tap0 if VIRTIO_NET_F_GUEST_UFO is
negotiated. So skb was queued on the receive queue. But since the
receive buffer is small, it will be truncated during tun_put_user().