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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 2/4] vhost-vdpa: introduce SUSPEND backend feature bit
Date: Fri, 8 Jul 2022 13:44:57 +0200	[thread overview]
Message-ID: <CAJaqyWdciXkbtpBmGugDsr+0Nh3X50r2Fa5i9Yk2NyQaXBLKtg@mail.gmail.com> (raw)
In-Reply-To: <CACGkMEtNC=4KeigQXr4NuaiuVGkxK2ruQTk6-Fbr3B1MqHieTA@mail.gmail.com>

On Wed, Jun 29, 2022 at 6:12 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Fri, Jun 24, 2022 at 12:08 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > Userland knows if it can suspend the device or not by checking this feature
> > bit.
> >
> > It's only offered if the vdpa driver backend implements the suspend()
> > operation callback, and to offer it or userland to ack it if the backend
> > does not offer that callback is an error.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> >  drivers/vhost/vdpa.c             | 16 +++++++++++++++-
> >  include/uapi/linux/vhost_types.h |  2 ++
> >  2 files changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index 23dcbfdfa13b..3d636e192061 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -347,6 +347,14 @@ static long vhost_vdpa_set_config(struct vhost_vdpa *v,
> >         return 0;
> >  }
> >
> > +static bool vhost_vdpa_can_suspend(const struct vhost_vdpa *v)
> > +{
> > +       struct vdpa_device *vdpa = v->vdpa;
> > +       const struct vdpa_config_ops *ops = vdpa->config;
> > +
> > +       return ops->suspend;
> > +}
> > +
> >  static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
> >  {
> >         struct vdpa_device *vdpa = v->vdpa;
> > @@ -577,7 +585,11 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> >         if (cmd == VHOST_SET_BACKEND_FEATURES) {
> >                 if (copy_from_user(&features, featurep, sizeof(features)))
> >                         return -EFAULT;
> > -               if (features & ~VHOST_VDPA_BACKEND_FEATURES)
> > +               if (features & ~(VHOST_VDPA_BACKEND_FEATURES |
> > +                                BIT_ULL(VHOST_BACKEND_F_SUSPEND)))
> > +                       return -EOPNOTSUPP;
> > +               if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
> > +                    !vhost_vdpa_can_suspend(v))
>
> Do we need to advertise this to the management?
>

Not sure if I follow, the feature bit is not exposed if the backend
cannot suspend.

Thanks!

> Thanks
>
> >                         return -EOPNOTSUPP;
> >                 vhost_set_backend_features(&v->vdev, features);
> >                 return 0;
> > @@ -628,6 +640,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> >                 break;
> >         case VHOST_GET_BACKEND_FEATURES:
> >                 features = VHOST_VDPA_BACKEND_FEATURES;
> > +               if (vhost_vdpa_can_suspend(v))
> > +                       features |= BIT_ULL(VHOST_BACKEND_F_SUSPEND);
> >                 if (copy_to_user(featurep, &features, sizeof(features)))
> >                         r = -EFAULT;
> >                 break;
> > diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
> > index 634cee485abb..1bdd6e363f4c 100644
> > --- a/include/uapi/linux/vhost_types.h
> > +++ b/include/uapi/linux/vhost_types.h
> > @@ -161,5 +161,7 @@ struct vhost_vdpa_iova_range {
> >   * message
> >   */
> >  #define VHOST_BACKEND_F_IOTLB_ASID  0x3
> > +/* Device can be suspended */
> > +#define VHOST_BACKEND_F_SUSPEND  0x4
> >
> >  #endif
> > --
> > 2.31.1
> >
>


  reply	other threads:[~2022-07-08 11:45 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-23 16:07 [PATCH v6 0/4] Implement vdpasim suspend operation Eugenio Pérez
2022-06-23 16:07 ` [PATCH v6 1/4] vdpa: Add " Eugenio Pérez
2022-06-28 13:39   ` Stefano Garzarella
2022-07-08 11:28     ` Eugenio Perez Martin
2022-06-29  4:10   ` Jason Wang
2022-07-08 11:30     ` Eugenio Perez Martin
2022-07-12  8:04       ` Jason Wang
2022-06-23 16:07 ` [PATCH v6 2/4] vhost-vdpa: introduce SUSPEND backend feature bit Eugenio Pérez
2022-06-28 13:43   ` Stefano Garzarella
2022-07-08 11:38     ` Eugenio Perez Martin
2022-07-08 13:51       ` Stefano Garzarella
2022-06-29  4:12   ` Jason Wang
2022-07-08 11:44     ` Eugenio Perez Martin [this message]
2022-06-23 16:07 ` [PATCH v6 3/4] vhost-vdpa: uAPI to suspend the device Eugenio Pérez
2022-06-28 13:44   ` Stefano Garzarella
2022-07-08 11:47     ` Eugenio Perez Martin
2022-06-29  4:15   ` Jason Wang
2022-07-08 11:53     ` Eugenio Perez Martin
2022-07-12  8:08       ` Jason Wang
2022-06-23 16:07 ` [PATCH v6 4/4] vdpa_sim: Implement suspend vdpa op Eugenio Pérez
2022-06-29  4:18   ` Jason Wang
2022-07-08 12:20     ` Eugenio Perez Martin

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