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From:   Jason Wang <jasowang@redhat.com>
Date:   Mon, 26 Sep 2022 15:11:53 +0800
Message-ID: <CACGkMEt22w2rK058Bm692sb1xXsNRULcjgeCpoc6Fimn7suheA@mail.gmail.com>
Subject: Re: [PATCH V2 2/3] vdpa_sim_net: support feature provisioning
To:     Si-Wei Liu <si-wei.liu@oracle.com>
Cc:     mst <mst@redhat.com>, Eli Cohen <elic@nvidia.com>,
        Parav Pandit <parav@nvidia.com>,
        Wu Zongyong <wuzongyong@linux.alibaba.com>,
        virtualization <virtualization@lists.linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        eperezma <eperezma@redhat.com>,
        Zhu Lingshan <lingshan.zhu@intel.com>,
        Gautam Dawar <gdawar@xilinx.com>, Cindy Lu <lulu@redhat.com>,
        Yongji Xie <xieyongji@bytedance.com>
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On Mon, Sep 26, 2022 at 3:11 PM Jason Wang <jasowang@redhat.com> wrote:
>
> On Sat, Sep 24, 2022 at 4:01 AM Si-Wei Liu <si-wei.liu@oracle.com> wrote:
> >
> >
> >
> > On 9/21/2022 7:43 PM, Jason Wang wrote:
> > > 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
> > Sighs, not to blame any one and it's perhaps too late, but this
> > "dev_features" attr in "mgmtdev show" command output should have been
> > called "supported_features" in the first place.
>
> Not sure I get this, but I guess this is the negotiated features actually.
>
> I think Ling Shan is working on reporting both negotiated features
> with the device features.
>
> >
> > >
> > > 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
> > Maybe not in this patch, but for completeness for the whole series,
> > could we also add device_features to the output?
>
> Lingshan, could you please share your thoughts or patch on this?
>
> >
> > When simply look at the "vdpa dev config show" output, I cannot really
> > tell the actual device_features that was used in vdpa creation. For e.g.
> > there is a missing feature ANY_LAYOUT from negotiated_features compared
> > with supported_features in mgmtdev, but the orchestration software
> > couldn't tell if the vdpa device on destination host should be created
> > with or without the ANY_LAYOUT feature.

Btw, it might be helpful to show those features in hex as well.

>
> I think VERSION_1 implies ANY_LAYOUT. But it should be sufficient to
> use features_src & feature_dst in this case. Actually, it should work
> similar as to the cpu flags, the management software should introduce
> the concept of cluster which means the maximal set of common features
> is calculated and provisioned during device creation to allow
> migration among the nodes inside the cluster.
>
> Thanks
>
> >
> > Thanks,
> > -Siwei
> >
> >
> > >
> > > 2) provision vDPA device with a subset of the features
> > >
> > > # vdpa dev add name dev1 mgmtdev vdpasim_net device_features 0x300020000
> > > # 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,
> > >   };
> >