Re: [PATCH v6 1/4] vdpa: Add suspend operation

From: Eugenio Perez Martin <eperezma@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: netdev <netdev@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	virtualization <virtualization@lists.linux-foundation.org>,
	kvm <kvm@vger.kernel.org>, "Michael S. Tsirkin" <mst@redhat.com>,
	Parav Pandit <parav@nvidia.com>,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	Cindy Lu <lulu@redhat.com>, "Kamde, Tanuj" <tanuj.kamde@amd.com>,
	Si-Wei Liu <si-wei.liu@oracle.com>,
	"Uminski, Piotr" <Piotr.Uminski@intel.com>,
	habetsm.xilinx@gmail.com, "Dawar, Gautam" <gautam.dawar@amd.com>,
	Pablo Cascon Katchadourian <pabloc@xilinx.com>,
	Zhu Lingshan <lingshan.zhu@intel.com>,
	Laurent Vivier <lvivier@redhat.com>,
	Longpeng <longpeng2@huawei.com>,
	Dinan Gunawardena <dinang@xilinx.com>,
	Martin Petrus Hubertus Habets <martinh@xilinx.com>,
	Martin Porter <martinpo@xilinx.com>, Eli Cohen <elic@nvidia.com>,
	ecree.xilinx@gmail.com,
	Wu Zongyong <wuzongyong@linux.alibaba.com>,
	Stefano Garzarella <sgarzare@redhat.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Harpreet Singh Anand <hanand@xilinx.com>,
	Xie Yongji <xieyongji@bytedance.com>,
	Zhang Min <zhang.min9@zte.com.cn>
Subject: Re: [PATCH v6 1/4] vdpa: Add suspend operation
Date: Fri, 8 Jul 2022 13:30:19 +0200	[thread overview]
Message-ID: <CAJaqyWcsesMV5DSs7sCrsJmZX=QED7p7UXa_7H=1UHfQTnKS6w@mail.gmail.com> (raw)
In-Reply-To: <CACGkMEv+yFLCzo-K7eSaVPJqLCa5SxfVCmB=piQ3+6R3=oDz-w@mail.gmail.com>

On Wed, Jun 29, 2022 at 6:10 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Fri, Jun 24, 2022 at 12:07 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > This operation is optional: It it's not implemented, backend feature bit
> > will not be exposed.
>
> A question, do we allow suspending a device without DRIVER_OK?
>

That should be invalid. In particular, vdpa_sim will resume in that
case, but I guess it would depend on the device.

Do you think it should be controlled in the vdpa frontend code?

Thanks!

> Thanks
>
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> >  include/linux/vdpa.h | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 7b4a13d3bd91..d282f464d2f1 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -218,6 +218,9 @@ struct vdpa_map_file {
> >   * @reset:                     Reset device
> >   *                             @vdev: vdpa device
> >   *                             Returns integer: success (0) or error (< 0)
> > + * @suspend:                   Suspend or resume the device (optional)
> > + *                             @vdev: vdpa device
> > + *                             Returns integer: success (0) or error (< 0)
> >   * @get_config_size:           Get the size of the configuration space includes
> >   *                             fields that are conditional on feature bits.
> >   *                             @vdev: vdpa device
> > @@ -319,6 +322,7 @@ 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 (*suspend)(struct vdpa_device *vdev);
> >         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
> >
>