Re: [PATCH v2] hw/virtio/vhost-user: support obtain vdpa device's mac address automatically

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Sep 21, 2022 at 07:23:12PM +0100, Alex Bennée wrote:
> 
> chenh <chenh@yusur.tech> writes:
> 
> > From: Hao Chen <chenh@yusur.tech>
> >
> > When use dpdk-vdpa tests vdpa device. You need to specify the mac address to
> > start the virtual machine through libvirt or qemu, but now, the libvirt or
> > qemu can call dpdk vdpa vendor driver's ops .get_config through vhost_net_get_config
> > to get the mac address of the vdpa hardware without manual configuration.
> >
> > v1->v2:
> > Only copy ETH_ALEN data of netcfg for some vdpa device such as
> > NVIDIA BLUEFIELD DPU(BF2)'s netcfg->status is not right.
> > We only need the mac address and don't care about the status field.
> >
> > Signed-off-by: Hao Chen <chenh@yusur.tech>
> > ---
> >  hw/block/vhost-user-blk.c |  1 -
> >  hw/net/virtio-net.c       |  7 +++++++
> >  hw/virtio/vhost-user.c    | 19 -------------------
> >  3 files changed, 7 insertions(+), 20 deletions(-)
> >
> > diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> > index 9117222456..5dca4eab09 100644
> > --- a/hw/block/vhost-user-blk.c
> > +++ b/hw/block/vhost-user-blk.c
> > @@ -337,7 +337,6 @@ static int vhost_user_blk_connect(DeviceState *dev, Error **errp)
> >  
> >      vhost_dev_set_config_notifier(&s->dev, &blk_ops);
> >  
> > -    s->vhost_user.supports_config = true;
> 
> <snip>
> 
> NACK from me. The supports_config flag is there for a reason.


Alex please, do not send NACKs. If you feel compelled to stress
your point, provide extra justification instead. Thanks!

> >  
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index bd24741be8..8b01078249 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -2013,8 +2013,6 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
> >      }
> >  
> >      if (virtio_has_feature(features, VHOST_USER_F_PROTOCOL_FEATURES)) {
> > -        bool supports_f_config = vus->supports_config ||
> > -            (dev->config_ops && dev->config_ops->vhost_dev_config_notifier);
> >          uint64_t protocol_features;
> >  
> >          dev->backend_features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
> > @@ -2033,23 +2031,6 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque,
> >           */
> >          protocol_features &= VHOST_USER_PROTOCOL_FEATURE_MASK;
> >  
> > -        if (supports_f_config) {
> > -            if (!virtio_has_feature(protocol_features,
> > -                                    VHOST_USER_PROTOCOL_F_CONFIG)) {
> > -                error_setg(errp, "vhost-user device expecting "
> > -                           "VHOST_USER_PROTOCOL_F_CONFIG but the vhost-user backend does "
> > -                           "not support it.");
> > -                return -EPROTO;
> > -            }
> > -        } else {
> > -            if (virtio_has_feature(protocol_features,
> > -                                   VHOST_USER_PROTOCOL_F_CONFIG)) {
> > -                warn_reportf_err(*errp, "vhost-user backend supports "
> > -                                 "VHOST_USER_PROTOCOL_F_CONFIG but QEMU does not.");
> > -                protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG);
> > -            }
> > -        }
> > -
> >          /* final set of protocol features */
> >          dev->protocol_features = protocol_features;
> >          err = vhost_user_set_protocol_features(dev, dev->protocol_features);
> 
> 
> -- 
> Alex Bennée