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From:   Jason Wang <jasowang@redhat.com>
Date:   Fri, 23 Sep 2022 12:20:12 +0800
Message-ID: <CACGkMEvRL3iN8iAP_1dZXLfOhRKv4573DYK6=C9gwME-85=03Q@mail.gmail.com>
Subject: Re: [PATCH V2 2/3] vdpa_sim_net: support feature provisioning
To:     Eli Cohen <elic@nvidia.com>
Cc:     "mst@redhat.com" <mst@redhat.com>,
        "si-wei.liu@oracle.com" <si-wei.liu@oracle.com>,
        Parav Pandit <parav@nvidia.com>,
        "wuzongyong@linux.alibaba.com" <wuzongyong@linux.alibaba.com>,
        "virtualization@lists.linux-foundation.org" 
        <virtualization@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "eperezma@redhat.com" <eperezma@redhat.com>,
        "lingshan.zhu@intel.com" <lingshan.zhu@intel.com>,
        "gdawar@xilinx.com" <gdawar@xilinx.com>,
        "lulu@redhat.com" <lulu@redhat.com>,
        "xieyongji@bytedance.com" <xieyongji@bytedance.com>
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On Thu, Sep 22, 2022 at 1:14 PM Eli Cohen <elic@nvidia.com> wrote:
>
> > From: Jason Wang <jasowang@redhat.com>
> > Sent: Thursday, 22 September 2022 5:43
> > To: mst@redhat.com; jasowang@redhat.com
> > Cc: Eli Cohen <elic@nvidia.com>; si-wei.liu@oracle.com; Parav Pandit
> > <parav@nvidia.com>; wuzongyong@linux.alibaba.com;
> > virtualization@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
> > eperezma@redhat.com; lingshan.zhu@intel.com; gdawar@xilinx.com;
> > lulu@redhat.com; xieyongji@bytedance.com
> > Subject: [PATCH V2 2/3] vdpa_sim_net: support feature provisioning
> >
> > This patch implements features provisioning for vdpa_sim_net.
> >
> > 1) validating the provisioned features to be a subset of the parent
> >    features.
> > 2) clearing the features that is not wanted by the userspace
> >
> > For example:
> >
> > # vdpa mgmtdev show
> > vdpasim_net:
> >   supported_classes net
> >   max_supported_vqs 3
> >   dev_features MTU MAC CTRL_VQ CTRL_MAC_ADDR ANY_LAYOUT
> > VERSION_1 ACCESS_PLATFORM
> >
> > 1) provision vDPA device with all features that are supported by the
> >    net simulator
> >
> > # vdpa dev add name dev1 mgmtdev vdpasim_net
> > # vdpa dev config show
> > dev1: mac 00:00:00:00:00:00 link up link_announce false mtu 1500
> >   negotiated_features MTU MAC CTRL_VQ CTRL_MAC_ADDR VERSION_1
> > ACCESS_PLATFORM
> >
> > 2) provision vDPA device with a subset of the features
> >
> > # vdpa dev add name dev1 mgmtdev vdpasim_net device_features
> > 0x300020000
>
> How about "features_mask" instead of "device_features"? Could avoid confusion.

It's device_feautres not a mask (the kernel code is probably confusing
per Michael's comment), so I tend to tweak the kernel code and keep
the name.

Thanks

>
> > # vdpa dev config show
> > dev1: mac 00:00:00:00:00:00 link up link_announce false mtu 1500
> >   negotiated_features CTRL_VQ VERSION_1 ACCESS_PLATFORM
> >
> > Reviewed-by: Eli Cohen <elic@nvidia.com>
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> >  drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 11 ++++++++++-
> >  1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> > b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> > index 886449e88502..a9ba02be378b 100644
> > --- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> > @@ -254,6 +254,14 @@ static int vdpasim_net_dev_add(struct
> > vdpa_mgmt_dev *mdev, const char *name,
> >       dev_attr.work_fn = vdpasim_net_work;
> >       dev_attr.buffer_size = PAGE_SIZE;
> >
> > +     if (config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
> > +             if (config->device_features &
> > +                 ~dev_attr.supported_features)
> > +                     return -EINVAL;
> > +             dev_attr.supported_features &=
> > +                      config->device_features;
> > +     }
> > +
> >       simdev = vdpasim_create(&dev_attr);
> >       if (IS_ERR(simdev))
> >               return PTR_ERR(simdev);
> > @@ -294,7 +302,8 @@ static struct vdpa_mgmt_dev mgmt_dev = {
> >       .id_table = id_table,
> >       .ops = &vdpasim_net_mgmtdev_ops,
> >       .config_attr_mask = (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR |
> > -                          1 << VDPA_ATTR_DEV_NET_CFG_MTU),
> > +                          1 << VDPA_ATTR_DEV_NET_CFG_MTU |
> > +                          1 << VDPA_ATTR_DEV_FEATURES),
> >       .max_supported_vqs = VDPASIM_NET_VQ_NUM,
> >       .supported_features = VDPASIM_NET_FEATURES,
> >  };
> > --
> > 2.25.1
>