Re: [PATCH v10 05/17] vhost-vdpa: Fail the vhost_vdpa_set_status() on reset failure

[Yongji Xie]

On Tue, Aug 3, 2021 at 4:10 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
>
> 在 2021/7/29 下午3:34, Xie Yongji 写道:
> > Re-read the device status to ensure it's set to zero during
> > resetting. Otherwise, fail the vhost_vdpa_set_status() after timeout.
> >
> > Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
> > ---
> >   drivers/vhost/vdpa.c | 11 ++++++++++-
> >   1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index b07aa161f7ad..dd05c1e1133c 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -157,7 +157,7 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
> >       struct vdpa_device *vdpa = v->vdpa;
> >       const struct vdpa_config_ops *ops = vdpa->config;
> >       u8 status, status_old;
> > -     int nvqs = v->nvqs;
> > +     int timeout = 0, nvqs = v->nvqs;
> >       u16 i;
> >
> >       if (copy_from_user(&status, statusp, sizeof(status)))
> > @@ -173,6 +173,15 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
> >               return -EINVAL;
> >
> >       ops->set_status(vdpa, status);
> > +     if (status == 0) {
> > +             while (ops->get_status(vdpa)) {
> > +                     timeout += 20;
> > +                     if (timeout > VDPA_RESET_TIMEOUT_MS)
> > +                             return -EIO;
> > +
> > +                     msleep(20);
> > +             }
>
>
> Spec has introduced the reset a one of the basic facility. And consider
> we differ reset here.
>
> This makes me think if it's better to introduce a dedicated vdpa ops for
> reset?
>

Do you mean replace the ops.set_status(vdev, 0) with the ops.reset()?
Then we can remove the timeout processing which is device specific
stuff.

Thanks,
Yongji