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From:   Cindy Lu <lulu@redhat.com>
Date:   Mon, 25 Sep 2023 12:15:08 +0800
Message-ID: <CACLfguVRPV_8HOy3mQbKvpWRGpM_tnjmC=oQqrEbvEz6YkMi0w@mail.gmail.com>
Subject: Re: [RFC v2 3/4] vduse: update the vq_info in ioctl
To:     Jason Wang <jasowang@redhat.com>
Cc:     mst@redhat.com, maxime.coquelin@redhat.com,
        xieyongji@bytedance.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        stable@vger.kernel.org
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On Tue, Sep 12, 2023 at 3:39=E2=80=AFPM Jason Wang <jasowang@redhat.com> wr=
ote:
>
> On Tue, Sep 12, 2023 at 11:00=E2=80=AFAM Cindy Lu <lulu@redhat.com> wrote=
:
> >
> > In VDUSE_VQ_GET_INFO, the driver will sync the last_avail_idx
> > with reconnect info, After mapping the reconnect pages to userspace
> > The userspace App will update the reconnect_time in
> > struct vhost_reconnect_vring, If this is not 0 then it means this
> > vq is reconnected and will update the last_avail_idx
> >
> > Signed-off-by: Cindy Lu <lulu@redhat.com>
> > ---
> >  drivers/vdpa/vdpa_user/vduse_dev.c | 13 +++++++++++++
> >  include/uapi/linux/vduse.h         |  6 ++++++
> >  2 files changed, 19 insertions(+)
> >
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_use=
r/vduse_dev.c
> > index 2c69f4004a6e..680b23dbdde2 100644
> > --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > @@ -1221,6 +1221,8 @@ static long vduse_dev_ioctl(struct file *file, un=
signed int cmd,
> >                 struct vduse_vq_info vq_info;
> >                 struct vduse_virtqueue *vq;
> >                 u32 index;
> > +               struct vdpa_reconnect_info *area;
> > +               struct vhost_reconnect_vring *vq_reconnect;
> >
> >                 ret =3D -EFAULT;
> >                 if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
> > @@ -1252,6 +1254,17 @@ static long vduse_dev_ioctl(struct file *file, u=
nsigned int cmd,
> >
> >                 vq_info.ready =3D vq->ready;
> >
> > +               area =3D &vq->reconnect_info;
> > +
> > +               vq_reconnect =3D (struct vhost_reconnect_vring *)area->=
vaddr;
> > +               /*check if the vq is reconnect, if yes then update the =
last_avail_idx*/
> > +               if ((vq_reconnect->last_avail_idx !=3D
> > +                    vq_info.split.avail_index) &&
> > +                   (vq_reconnect->reconnect_time !=3D 0)) {
> > +                       vq_info.split.avail_index =3D
> > +                               vq_reconnect->last_avail_idx;
> > +               }
> > +
> >                 ret =3D -EFAULT;
> >                 if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
> >                         break;
> > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> > index 11bd48c72c6c..d585425803fd 100644
> > --- a/include/uapi/linux/vduse.h
> > +++ b/include/uapi/linux/vduse.h
> > @@ -350,4 +350,10 @@ struct vduse_dev_response {
> >         };
> >  };
> >
> > +struct vhost_reconnect_vring {
> > +       __u16 reconnect_time;
> > +       __u16 last_avail_idx;
> > +       _Bool avail_wrap_counter;
>
> Please add a comment for each field.
>
Sure will do

> And I never saw _Bool is used in uapi before, maybe it's better to
> pack it with last_avail_idx into a __u32.
>
Thanks will fix this
> Btw, do we need to track inflight descriptors as well?
>
I will check this
Thanks

cindy
> Thanks
>
> > +};
> > +
> >  #endif /* _UAPI_VDUSE_H_ */
> > --
> > 2.34.3
> >
>