From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtio-dev@lists.oasis-open.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Sridhar Samudrala <sri@us.ibm.com>
Subject: Re: [PATCH net] virtio-net: alloc big buffers also when guest can receive UFO
Date: Thu, 13 Feb 2014 13:40:59 +0800 [thread overview]
Message-ID: <52FC5AEB.3090503@redhat.com> (raw)
In-Reply-To: <20140213051559.GB31352@redhat.com>
On 02/13/2014 01:15 PM, Michael S. Tsirkin wrote:
> On Thu, Feb 13, 2014 at 11:02:13AM +0800, Jason Wang wrote:
>> 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().
> Hypervisor shouldn't truncate packets silently - if it does
> it's a hypervisor bug. Passing malformed packets to guest is
> a bad idea.
>
Yes, but the commit log describes the current behaviour so it was ok?
Btw, dropping the packets silently is still not good. Virito needs a
method to report rx errors to guest.
prev parent reply other threads:[~2014-02-13 5:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-12 5:43 [PATCH net] virtio-net: alloc big buffers also when guest can receive UFO Jason Wang
2014-02-12 11:59 ` Michael S. Tsirkin
2014-02-13 3:02 ` Jason Wang
2014-02-13 5:15 ` Michael S. Tsirkin
2014-02-13 5:40 ` Jason Wang [this message]
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