> -----Original Message-----
> From: Bie, Tiwei
> Sent: Wednesday, July 25, 2018 10:19 AM
> To: Liu, Yong <yong....@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [PATCH v2] examples/vhost: workaround qemu abort
>
> On Wed, Jul 25, 2018 at 05:56:54PM +0800, Marvin Liu wrote:
> > Current qemu vhost net ring start has a dependency on feature bit
> > VHOST_USER_F_PROTOCOL_FEATURES. If vhost device start without it, stop
> > action will be skipped. Consequently, same ioevent fd will be added
> > twice after reloading driver and then cause qemu abort. However, ring
> > should be initialized in an enabled state when this feature bit not
> > negotiated. Work around qemu issue by enabling this feature bit in vhost
> > user backend.
> >
> > Signed-off-by: Marvin Liu <yong....@intel.com>
> >
> > diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> > index 2175c1186..4b87331fc 100644
> > --- a/examples/vhost/main.c
> > +++ b/examples/vhost/main.c
> > @@ -1519,8 +1519,12 @@ main(int argc, char *argv[])
> > "vhost driver register failure.\n");
> > }
> >
> > - if (builtin_net_driver)
> > + if (builtin_net_driver) {
> > rte_vhost_driver_set_features(file,
> > VIRTIO_NET_FEATURES);
> > + /* Workaround for qemu vhost net device startup */
> > + rte_vhost_driver_set_features(file,
> > + 1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
>
> rte_vhost_driver_set_features() will overwrite the
> existing value. You need to OR VIRTIO_NET_FEATURES
> and (1ULL << VHOST_USER_F_PROTOCOL_FEATURES).
>
>
Tiwei,
Thanks for point out the error, I have sent v3 for correcting this.
Regards,
Marvin
>
> > + }
> >
> > if (mergeable == 0) {
> > rte_vhost_driver_disable_features(file,
> > --
> > 2.17.0
> >
