[dpdk-dev] [PATCH v4 7/8] virtio/lib:add virtio guest offload capabilities

[Xu, Qian Q]

Frank, 


Thanks
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
> > >
> > > On Wed, Nov 11, 2015 at 02:40:45PM +0800, Jijiang Liu wrote:
> > > > Add virtio guest offload capabilities.
> > > >
> > > > Signed-off-by: Jijiang Liu <jijiang.liu at intel.com>
> > > > ---
> > > >  lib/librte_vhost/virtio-net.c |    5 ++++-
> > > >  1 files changed, 4 insertions(+), 1 deletions(-)
> > > >
> > > > diff --git a/lib/librte_vhost/virtio-net.c 
> > > > b/lib/librte_vhost/virtio-net.c index 81bd309..839a333 100644
> > > > --- a/lib/librte_vhost/virtio-net.c
> > > > +++ b/lib/librte_vhost/virtio-net.c
> > > > @@ -80,7 +80,10 @@ static struct virtio_net_config_ll *ll_root;
> > > >  				(1ULL <<
> > > VHOST_USER_F_PROTOCOL_FEATURES) | \
> > > >  				(1ULL << VIRTIO_NET_F_HOST_TSO4) | \
> > > >  				(1ULL << VIRTIO_NET_F_HOST_TSO6) | \
> > > > -				(1ULL << VIRTIO_NET_F_CSUM))
> > > > +				(1ULL << VIRTIO_NET_F_CSUM)    | \
> > > > +				(1ULL << VIRTIO_NET_F_GUEST_CSUM) | \
> > > > +				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
> > > > +				(1ULL << VIRTIO_NET_F_GUEST_TSO6))
> > >
> > > 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. 


(1) VIRTIO_NET_F_GUEST_CSUM (1) Driver 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 flags MAY be set: if so, the checksum on the packet is incomplete and csum_start and csum_offset indicate how to calculate it (see Packet Transmission point 1).

(3) If the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options were negotiated, then gso_type MAY be something other than VIRTIO_NET_HDR_GSO_NONE, and gso_size field indicates the desired MSS (see Packet Transmission point 2).

The information can be included in the next version of patch set.

> 	--yliu
> 
> > Yes, I'd like to listen other guys comments.
> >
> > > Hopefully the virtio expert, Michael, could shine some lights on that.
> > >
> > > 	--yliu
> > >
> > > >
> > > >  static uint64_t VHOST_FEATURES = VHOST_SUPPORTED_FEATURES;
> > > >
> > > > --
> > > > 1.7.7.6