Re: [PATCH] vhost: fix checking of device features

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> Sent: Thursday, June 29, 2017 3:27 PM
> To: Tan, Jianfeng; Ivan Dyukov; yliu@fridaylinux.org; dev@dpdk.org
> Cc: i.maximets@samsung.com; heetae82.ahn@samsung.com;
> stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] vhost: fix checking of device features
> 
> 
> 
> On 06/29/2017 08:13 AM, Tan, Jianfeng wrote:
> >
> >
> >> -----Original Message-----
> >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ivan Dyukov
> >> Sent: Wednesday, June 28, 2017 8:41 PM
> >> To: yliu@fridaylinux.org; maxime.coquelin@redhat.com; dev@dpdk.org
> >> Cc: i.maximets@samsung.com; heetae82.ahn@samsung.com; Ivan
> Dyukov;
> >> stable@dpdk.org
> >> Subject: [dpdk-dev] [PATCH] vhost: fix checking of device features
> >>
> >> To compare enabled features in current device we must use bit
> >> mask instead of bit position.
> >>
> >> CC: stable@dpdk.org
> >> Fixes: c843af3aa13e ("vhost: access header only")
> >>
> >> Signed-off-by: Ivan Dyukov <i.dyukov@samsung.com>
> >> ---
> >>   lib/librte_vhost/virtio_net.c | 8 +++++---
> >>   1 file changed, 5 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> >> index ebfda1c..4fae4c1 100644
> >> --- a/lib/librte_vhost/virtio_net.c
> >> +++ b/lib/librte_vhost/virtio_net.c
> >> @@ -601,9 +601,11 @@ static inline bool
> >>   virtio_net_with_host_offload(struct virtio_net *dev)
> >>   {
> >>   	if (dev->features &
> >> -			(VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_ECN |
> >> -			 VIRTIO_NET_F_HOST_TSO4 |
> >> VIRTIO_NET_F_HOST_TSO6 |
> >> -			 VIRTIO_NET_F_HOST_UFO))
> >> +			((1ULL << VIRTIO_NET_F_CSUM) |
> >> +			 (1ULL << VIRTIO_NET_F_HOST_ECN) |
> >> +			 (1ULL << VIRTIO_NET_F_HOST_TSO4) |
> >> +			 (1ULL << VIRTIO_NET_F_HOST_TSO6) |
> >> +			 (1ULL << VIRTIO_NET_F_HOST_UFO)))
> >
> > Another problem in this piece of code, we don't support
> VIRTIO_NET_F_HOST_ECN and VIRTIO_NET_F_HOST_UFO in vhost-user. We
> might consider to remove those two lines?
> 
> It is not really a problem as the feature is never negotiated as not
> supported, it would just be a clean-up.

Yes, it's a clean-up to avoid confusion.


> 
> I think we should stick with this version as it targets also -stable.
> 
> Another patch could be sent on top to remove these unsupported feature
> bits.

Agreed.

Thanks,
Jianfeng

> 
> Thanks,
> Maxime
> 
> > Thanks,
> > Jianfeng
> >
> >
> >>   		return true;
> >>
> >>   	return false;
> >> --
> >> 2.7.4
> >