On Thu, Oct 13, 2022 at 11:35 PM <sebastien.boeuf@xxxxxxxxx> wrote:
>
> From: Sebastien Boeuf <sebastien.boeuf@xxxxxxxxx>
>
> Userspace knows if the device can be resumed or not by checking this
> feature bit.
>
> It's only exposed if the vdpa driver backend implements the resume()
> operation callback. Userspace trying to negotiate this feature when it
> hasn't been exposed will result in an error.
>
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@xxxxxxxxx>
> ---
> drivers/vhost/vdpa.c | 19 ++++++++++++++++++-
> include/uapi/linux/vhost_types.h | 2 ++
> 2 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 166044642fd5..161727e1a9a5 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -355,6 +355,14 @@ static bool vhost_vdpa_can_suspend(const struct vhost_vdpa *v)
> return ops->suspend;
> }
>
> +static bool vhost_vdpa_can_resume(const struct vhost_vdpa *v)
> +{
> + struct vdpa_device *vdpa = v->vdpa;
> + const struct vdpa_config_ops *ops = vdpa->config;
> +
> + return ops->resume;
> +}
> +
> static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
> {
> struct vdpa_device *vdpa = v->vdpa;
> @@ -602,11 +610,18 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> if (copy_from_user(&features, featurep, sizeof(features)))
> return -EFAULT;
> if (features & ~(VHOST_VDPA_BACKEND_FEATURES |
> - BIT_ULL(VHOST_BACKEND_F_SUSPEND)))
> + BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
> + BIT_ULL(VHOST_BACKEND_F_RESUME)))
> return -EOPNOTSUPP;
> if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
> !vhost_vdpa_can_suspend(v))
> return -EOPNOTSUPP;
> + if ((features & BIT_ULL(VHOST_BACKEND_F_RESUME)) &&
> + !vhost_vdpa_can_resume(v))
> + return -EOPNOTSUPP;
> + if (!(features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
> + (features & BIT_ULL(VHOST_BACKEND_F_RESUME)))
> + return -EINVAL;
Is it better to do the check during the probe? It should be a bug that
we're having a parent that can only do resume but not suspend.
Thanks
> vhost_set_backend_features(&v->vdev, features);
> return 0;
> }
> @@ -658,6 +673,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> features = VHOST_VDPA_BACKEND_FEATURES;
> if (vhost_vdpa_can_suspend(v))
> features |= BIT_ULL(VHOST_BACKEND_F_SUSPEND);
> + if (vhost_vdpa_can_resume(v))
> + features |= BIT_ULL(VHOST_BACKEND_F_RESUME);
> 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 53601ce2c20a..c5690a8992d8 100644
> --- a/include/uapi/linux/vhost_types.h
> +++ b/include/uapi/linux/vhost_types.h
> @@ -163,5 +163,7 @@ struct vhost_vdpa_iova_range {
> #define VHOST_BACKEND_F_IOTLB_ASID 0x3
> /* Device can be suspended */
> #define VHOST_BACKEND_F_SUSPEND 0x4
> +/* Device can be resumed */
> +#define VHOST_BACKEND_F_RESUME 0x5
>
> #endif
> --
> 2.34.1
>
> ---------------------------------------------------------------------
> Intel Corporation SAS (French simplified joint stock company)
> Registered headquarters: "Les Montalets"- 2, rue de Paris,
> 92196 Meudon Cedex, France
> Registration Number: 302 456 199 R.C.S. NANTERRE
> Capital: 5 208 026.16 Euros
>
> This e-mail and any attachments may contain confidential material for
> the sole use of the intended recipient(s). Any review or distribution
> by others is strictly prohibited. If you are not the intended
> recipient, please contact the sender and delete all copies.
>
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
