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From:   Eugenio Perez Martin <eperezma@redhat.com>
Date:   Wed, 1 Jun 2022 08:53:18 +0200
Message-ID: <CAJaqyWfHLtcFokus3PB1K+19gcD1yeazox426Ur0LoMqOPy7FQ@mail.gmail.com>
Subject: Re: [PATCH v4 1/4] vdpa: Add stop operation
To:     Eli Cohen <elic@nvidia.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
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        Stefano Garzarella <sgarzare@redhat.com>,
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On Wed, Jun 1, 2022 at 7:35 AM Eli Cohen <elic@nvidia.com> wrote:
>
> > From: Eugenio P=C3=A9rez <eperezma@redhat.com>
> > Sent: Thursday, May 26, 2022 3:44 PM
> > To: Michael S. Tsirkin <mst@redhat.com>; kvm@vger.kernel.org; virtualiz=
ation@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
> > Jason Wang <jasowang@redhat.com>; netdev@vger.kernel.org
> > Cc: martinh@xilinx.com; Stefano Garzarella <sgarzare@redhat.com>; marti=
npo@xilinx.com; lvivier@redhat.com; pabloc@xilinx.com;
> > Parav Pandit <parav@nvidia.com>; Eli Cohen <elic@nvidia.com>; Dan Carpe=
nter <dan.carpenter@oracle.com>; Xie Yongji
> > <xieyongji@bytedance.com>; Christophe JAILLET <christophe.jaillet@wanad=
oo.fr>; Zhang Min <zhang.min9@zte.com.cn>; Wu Zongyong
> > <wuzongyong@linux.alibaba.com>; lulu@redhat.com; Zhu Lingshan <lingshan=
.zhu@intel.com>; Piotr.Uminski@intel.com; Si-Wei Liu <si-
> > wei.liu@oracle.com>; ecree.xilinx@gmail.com; gautam.dawar@amd.com; habe=
tsm.xilinx@gmail.com; tanuj.kamde@amd.com;
> > hanand@xilinx.com; dinang@xilinx.com; Longpeng <longpeng2@huawei.com>
> > Subject: [PATCH v4 1/4] vdpa: Add stop operation
> >
> > This operation is optional: It it's not implemented, backend feature bi=
t
> > will not be exposed.
> >
> > Signed-off-by: Eugenio P=C3=A9rez <eperezma@redhat.com>
> > ---
> >  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 process=
ing 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 i=
ncludes
> >   *                           fields that are conditional on feature bi=
ts.
> >   *                           @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
>