On Fri, Apr 14, 2017 at 04:35:57AM +0000, Tan, Jianfeng wrote:
>
>
> > -----Original Message-----
> > From: Yuanhan Liu [mailto:yuanhan....@linux.intel.com]
> > Sent: Friday, April 14, 2017 12:24 PM
> > To: Tan, Jianfeng
> > Cc: dev@dpdk.org; maxime.coque...@redhat.com
> > Subject: Re: [PATCH v2] net/virtio-user: fix cannot get initialized
> >
> > On Thu, Apr 13, 2017 at 10:11:27AM +0000, Jianfeng Tan wrote:
> > > The feature negotiation in virtio-user is proven to be broken,
> > > which results in device initialization failure.
> > >
> > > Originally, we get features from vhost backend, and remove those
> > > that are not supported. But when new feature is added, for example,
> > > VIRTIO_NET_F_MTU, we fail to remove this new feature. Then, this
> > > new feature will be negotiated, as both frontend and backend claim
> > > to support this feature.
> > >
> > > To fix it, we add a macro to record supported featues, as a filter
> > > to remove newly added features.
> >
> > Yes, this is much better! You now don't have to worry that virtio-user
> > will be broken every time we add a new feature.
> >
> > Applied to dpdk-next-virtio, with the title changed to "fix feature
> > negotitation".
> >
>
> Thanks. By the way, it's better backporting it to stable branches, however, I
> forget to CC sta...@dpdk.org.
As long as we don't backport new features to a stable release, there
should be no problem.
Besides, the virtio-user features supported in this patch may not match
those supported by a stable release (say 16.11 LTS). For example, F_STATUS
is just added in this feature. Thus, I don't think it's a good candidate
for a stable release (though a backport could fix it).
--yliu
