Jason Wang
2022-Jun-29 04:12 UTC
[PATCH v6 2/4] vhost-vdpa: introduce SUSPEND backend feature bit
On Fri, Jun 24, 2022 at 12:08 AM Eugenio P?rez <eperezma at 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 P?rez <eperezma at 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? 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 >