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

[Jason Wang]

在 2021/8/3 下午5:50, Yongji Xie 写道:
> 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.


Exactly.

Thanks


> Thanks,
> Yongji