Re: [PATCH v4 1/4] vdpa: Add stop operation

[Eugenio Perez Martin]

On Wed, Jun 1, 2022 at 7:35 AM Eli Cohen <elic@xxxxxxxxxx> wrote:
>
> > From: Eugenio Pérez <eperezma@xxxxxxxxxx>
> > Sent: Thursday, May 26, 2022 3:44 PM
> > To: Michael S. Tsirkin <mst@xxxxxxxxxx>; kvm@xxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > Jason Wang <jasowang@xxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx
> > Cc: martinh@xxxxxxxxxx; Stefano Garzarella <sgarzare@xxxxxxxxxx>; martinpo@xxxxxxxxxx; lvivier@xxxxxxxxxx; pabloc@xxxxxxxxxx;
> > Parav Pandit <parav@xxxxxxxxxx>; Eli Cohen <elic@xxxxxxxxxx>; Dan Carpenter <dan.carpenter@xxxxxxxxxx>; Xie Yongji
> > <xieyongji@xxxxxxxxxxxxx>; Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>; Zhang Min <zhang.min9@xxxxxxxxxx>; Wu Zongyong
> > <wuzongyong@xxxxxxxxxxxxxxxxx>; lulu@xxxxxxxxxx; Zhu Lingshan <lingshan.zhu@xxxxxxxxx>; Piotr.Uminski@xxxxxxxxx; Si-Wei Liu <si-
> > wei.liu@xxxxxxxxxx>; ecree.xilinx@xxxxxxxxx; gautam.dawar@xxxxxxx; habetsm.xilinx@xxxxxxxxx; tanuj.kamde@xxxxxxx;
> > hanand@xxxxxxxxxx; dinang@xxxxxxxxxx; Longpeng <longpeng2@xxxxxxxxxx>
> > Subject: [PATCH v4 1/4] vdpa: Add stop operation
> >
> > This operation is optional: It it's not implemented, backend feature bit
> > will not be exposed.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> > ---
> >  include/linux/vdpa.h | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 15af802d41c4..ddfebc4e1e01 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -215,6 +215,11 @@ struct vdpa_map_file {
> >   * @reset:                   Reset device
> >   *                           @vdev: vdpa device
> >   *                           Returns integer: success (0) or error (< 0)
> > + * @stop:                    Stop or resume the device (optional, but it must
> > + *                           be implemented if require device stop)
> > + *                           @vdev: vdpa device
> > + *                           @stop: stop (true), not stop (false)
> > + *                           Returns integer: success (0) or error (< 0)
>
> I assume after successful "stop" the device is guaranteed to stop processing descriptors and after resume it may process descriptors?
> If that is so, I think it should be clear in the change log.
>

Yes.

It's better described in the changelog of vdpa sim change, maybe it's
better to move here.

Thanks!

> >   * @get_config_size:         Get the size of the configuration space includes
> >   *                           fields that are conditional on feature bits.
> >   *                           @vdev: vdpa device
> > @@ -316,6 +321,7 @@ struct vdpa_config_ops {
> >       u8 (*get_status)(struct vdpa_device *vdev);
> >       void (*set_status)(struct vdpa_device *vdev, u8 status);
> >       int (*reset)(struct vdpa_device *vdev);
> > +     int (*stop)(struct vdpa_device *vdev, bool stop);
> >       size_t (*get_config_size)(struct vdpa_device *vdev);
> >       void (*get_config)(struct vdpa_device *vdev, unsigned int offset,
> >                          void *buf, unsigned int len);
> > --
> > 2.31.1
>