Hi Qian,
> > -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Liu, Jijiang > Sent: Wednesday, November 11, 2015 4:53 PM > To: Yuanhan Liu > Cc: dev at dpdk.org; Michael S. Tsirkin > Subject: Re: [dpdk-dev] [PATCH v4 7/8] virtio/lib:add virtio guest offload > capabilities > > > > > -----Original Message----- > > From: Yuanhan Liu [mailto:yuanhan.liu at linux.intel.com] > > Sent: Wednesday, November 11, 2015 4:44 PM > > To: Liu, Jijiang > > Cc: Michael S. Tsirkin; dev at dpdk.org > > Subject: Re: [dpdk-dev] [PATCH v4 7/8] virtio/lib:add virtio guest > > offload capabilities > > > > On Wed, Nov 11, 2015 at 08:38:29AM +0000, Liu, Jijiang wrote: > > > > > > > > > > -----Original Message----- > > > > From: Yuanhan Liu [mailto:yuanhan.liu at linux.intel.com] > > > > Sent: Wednesday, November 11, 2015 4:31 PM > > > > To: Liu, Jijiang; Michael S. Tsirkin > > > > Cc: dev at dpdk.org > > > > Subject: Re: [dpdk-dev] [PATCH v4 7/8] virtio/lib:add virtio guest > > > > offload capabilities > > > > > > > > I don't think we need that, and it might be wrong to set those > > > > fields at > > vhost. > > > > > > > > And, TBH, I am not 100% sure that I understand what those flags > > > > truely are and for. All I know is that they seem have something to > > > > do with QEMU/TAP device. > > > > > > According to virtio standard, those fileds should be set. > > > > If so, you'd better quote them here, or even to your patch commit. > > In the Virtual I/O Device (VIRTIO) Version 1.0 Committee Specification 02, > > > [QIAN] Do we support virtio 1.0 in the vhost offload case? Currently it's > virtio > 0.95 Spec that we are testing. > There are almost same description in 0.95 Spec, (1)VIRTIO_NET_F_GUEST_CSUM (1) Guest handles packets with partial checksum (2) If the VIRTIO_NET_F_GUEST_CSUM feature was negotiated, the VIRTIO_NET_HDR_F_NEEDS_CSUM bit in the ags eld may be set: if so, the checksum on the packet is incomplete and the csum_start and csum_oset elds indicate how to calculate it (see 1). (3) The converse features are also available: a driver can save the virtual device some work by negotiating these features.8 The VIRTIO_NET_F_GUEST_CSUM feature indicates that partially checksummed packets can be received, and if it can do that then the VIRTIO_NET_F_GUEST_TSO4, VIRTIO_ NET_F_GUEST_TSO6, VIRTIO_NET_F_GUEST_UFO and VIRTIO_NET_F_GUEST_ECN are the input equivalents of the features described above. See Receiving Packets below.
