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From:   Jason Wang <jasowang@redhat.com>
Date:   Wed, 18 Oct 2023 13:08:55 +0800
Message-ID: <CACGkMEtF+dLbWPvYjmGL2RZssK6uo1Lg-hQd=R_-McYA1pMSCg@mail.gmail.com>
Subject: Re: [PATCH v1 4/4] vduse: update the vq_info in ioctl
To:     Cindy Lu <lulu@redhat.com>
Cc:     mst@redhat.com, xieyongji@bytedance.com,
        linux-kernel@vger.kernel.org, maxime.coquelin@redhat.com
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On Wed, Oct 11, 2023 at 2:42=E2=80=AFPM 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 | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/=
vduse_dev.c
> index 0f15e7ac716b..42e7a90ab74c 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1213,6 +1213,9 @@ static long vduse_dev_ioctl(struct file *file, unsi=
gned 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;
> +               struct vhost_reconnect_data *dev_reconnect;
>
>                 ret =3D -EFAULT;
>                 if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
> @@ -1244,6 +1247,19 @@ static long vduse_dev_ioctl(struct file *file, uns=
igned int cmd,
>
>                 vq_info.ready =3D vq->ready;
>
> +               area =3D &dev->reconnect_status;
> +               dev_reconnect =3D (struct vhost_reconnect_data *)area->va=
ddr;
> +
> +               area =3D &vq->reconnect_info;
> +               vq_reconnect =3D (struct vhost_reconnect_vring *)area->va=
ddr;
> +               /*check if the vq is reconnect, if yes then update the la=
st_avail_idx*/
> +               if ((vq_reconnect->last_avail_idx !=3D
> +                    vq_info.split.avail_index) &&
> +                   (dev_reconnect->reconnect_time !=3D 0)) {
> +                       vq_info.split.avail_index =3D
> +                               vq_reconnect->last_avail_idx;
> +               }

This may work only for split, how about packed? And I wonder when such
synchronization is not done at set_vq_state() but get_vq_info()?

Thanks

> +
>                 ret =3D -EFAULT;
>                 if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
>                         break;
> --
> 2.34.3
>