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From:   Cindy Lu <lulu@redhat.com>
Date:   Sun, 8 Oct 2023 20:55:12 +0800
Message-ID: <CACLfguU5_8u-n5UopwzDKEEtFJ1GJ9NezEU7LGG=BY3BrZdhrg@mail.gmail.com>
Subject: Re: [RFC v2 3/4] vduse: update the vq_info in ioctl
To:     Jason Wang <jasowang@redhat.com>
Cc:     Maxime Coquelin <maxime.coquelin@redhat.com>, mst@redhat.com,
        xieyongji@bytedance.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org
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On Sun, Oct 8, 2023 at 1:17=E2=80=AFPM Jason Wang <jasowang@redhat.com> wro=
te:
>
> On Fri, Sep 29, 2023 at 5:12=E2=80=AFPM Maxime Coquelin
> <maxime.coquelin@redhat.com> wrote:
> >
> >
> >
> > On 9/12/23 09:39, Jason Wang wrote:
> > > On Tue, Sep 12, 2023 at 11:00=E2=80=AFAM Cindy Lu <lulu@redhat.com> w=
rote:
> > >>
> > >> 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_=
user/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,=
 unsigned 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=
, unsigned int cmd,
> > >>
> > >>                  vq_info.ready =3D vq->ready;
> > >>
> > >> +               area =3D &vq->reconnect_info;
> > >> +
> > >> +               vq_reconnect =3D (struct vhost_reconnect_vring *)are=
a->vaddr;
> > >> +               /*check if the vq is reconnect, if yes then update t=
he 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.
> > >
> > > And I never saw _Bool is used in uapi before, maybe it's better to
> > > pack it with last_avail_idx into a __u32.
> >
> > Better as two distincts __u16 IMHO.
>
> Fine with me.
>
> Thanks
>

sure will fix  this
Thanks
Cindy
> >
> > Thanks,
> > Maxime
> >
> > >
> > > Btw, do we need to track inflight descriptors as well?
> > >
> > > Thanks
> > >
> > >> +};
> > >> +
> > >>   #endif /* _UAPI_VDUSE_H_ */
> > >> --
> > >> 2.34.3
> > >>
> > >
> >
>