Re: [PATCH v1 1/7] vdpa: Provide interface to read driver features

[Si-Wei Liu <si-wei.liu@xxxxxxxxxx>]

On 12/8/2021 12:14 PM, Eli Cohen wrote:
> Provide an interface to read the negotiated features. This is needed
> when building the netlink message in vdpa_dev_net_config_fill().
>
> Also fix the implementation of vdpa_dev_net_config_fill() to use the
> negotiated features instead of the device features.
Are we sure the use of device feature is a bug rather than expected 
behavior? How do users determine the configured number of queue pairs at 
any point in case of a non-multiqueue supporting guest/driver or that 
the device is being reset (where actual_features == 0)? Maybe we should 
differentiate the static device config against driver/device running 
state here. I thought the change to vdpa_dev_net_config_fill() in this 
patch would break vdpa tool user's expectation that the value of max_vqp 
config is a fixed value since the vdpa creation time.

Perhaps worth adding another attribute to represent the running state 
(cur_max_qps) based on the negotiated features.

-Siwei

> To make APIs clearer, make the following name changes to struct
> vdpa_config_ops so they better describe their operations:
>
> get_features -> get_device_features
> set_features -> set_driver_features
>
> Finally, add get_driver_features to return the negotiated features and
> add implementation to all the upstream drivers.
>
> Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> ---
>   drivers/vdpa/alibaba/eni_vdpa.c    | 16 ++++++++++++----
>   drivers/vdpa/ifcvf/ifcvf_main.c    | 16 ++++++++++++----
>   drivers/vdpa/mlx5/net/mlx5_vnet.c  | 16 ++++++++++++----
>   drivers/vdpa/vdpa.c                |  2 +-
>   drivers/vdpa/vdpa_sim/vdpa_sim.c   | 21 +++++++++++++++------
>   drivers/vdpa/vdpa_user/vduse_dev.c | 16 ++++++++++++----
>   drivers/vdpa/virtio_pci/vp_vdpa.c  | 16 ++++++++++++----
>   drivers/vhost/vdpa.c               |  2 +-
>   drivers/virtio/virtio_vdpa.c       |  2 +-
>   include/linux/vdpa.h               | 14 +++++++++-----
>   10 files changed, 87 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/vdpa/alibaba/eni_vdpa.c b/drivers/vdpa/alibaba/eni_vdpa.c
> index 3f788794571a..ac0975660f4d 100644
> --- a/drivers/vdpa/alibaba/eni_vdpa.c
> +++ b/drivers/vdpa/alibaba/eni_vdpa.c
> @@ -58,7 +58,7 @@ static struct virtio_pci_legacy_device *vdpa_to_ldev(struct vdpa_device *vdpa)
>   	return &eni_vdpa->ldev;
>   }
>   
> -static u64 eni_vdpa_get_features(struct vdpa_device *vdpa)
> +static u64 eni_vdpa_get_device_features(struct vdpa_device *vdpa)
>   {
>   	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
>   	u64 features = vp_legacy_get_features(ldev);
> @@ -69,7 +69,7 @@ static u64 eni_vdpa_get_features(struct vdpa_device *vdpa)
>   	return features;
>   }
>   
> -static int eni_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> +static int eni_vdpa_set_driver_features(struct vdpa_device *vdpa, u64 features)
>   {
>   	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
>   
> @@ -84,6 +84,13 @@ static int eni_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
>   	return 0;
>   }
>   
> +static u64 eni_vdpa_get_driver_features(struct vdpa_device *vdpa)
> +{
> +	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
> +
> +	return vp_legacy_get_driver_features(ldev);
> +}
> +
>   static u8 eni_vdpa_get_status(struct vdpa_device *vdpa)
>   {
>   	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
> @@ -401,8 +408,9 @@ static void eni_vdpa_set_config_cb(struct vdpa_device *vdpa,
>   }
>   
>   static const struct vdpa_config_ops eni_vdpa_ops = {
> -	.get_features	= eni_vdpa_get_features,
> -	.set_features	= eni_vdpa_set_features,
> +	.get_device_features = eni_vdpa_get_device_features,
> +	.set_driver_features = eni_vdpa_set_driver_features,
> +	.get_driver_features = eni_vdpa_get_driver_features,
>   	.get_status	= eni_vdpa_get_status,
>   	.set_status	= eni_vdpa_set_status,
>   	.reset		= eni_vdpa_reset,
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index 6dc75ca70b37..6a6a0a462392 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -169,7 +169,7 @@ static struct ifcvf_hw *vdpa_to_vf(struct vdpa_device *vdpa_dev)
>   	return &adapter->vf;
>   }
>   
> -static u64 ifcvf_vdpa_get_features(struct vdpa_device *vdpa_dev)
> +static u64 ifcvf_vdpa_get_device_features(struct vdpa_device *vdpa_dev)
>   {
>   	struct ifcvf_adapter *adapter = vdpa_to_adapter(vdpa_dev);
>   	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
> @@ -187,7 +187,7 @@ static u64 ifcvf_vdpa_get_features(struct vdpa_device *vdpa_dev)
>   	return features;
>   }
>   
> -static int ifcvf_vdpa_set_features(struct vdpa_device *vdpa_dev, u64 features)
> +static int ifcvf_vdpa_set_driver_features(struct vdpa_device *vdpa_dev, u64 features)
>   {
>   	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
>   	int ret;
> @@ -201,6 +201,13 @@ static int ifcvf_vdpa_set_features(struct vdpa_device *vdpa_dev, u64 features)
>   	return 0;
>   }
>   
> +static u64 ifcvf_vdpa_get_driver_features(struct vdpa_device *vdpa_dev)
> +{
> +	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
> +
> +	return vf->req_features;
> +}
> +
>   static u8 ifcvf_vdpa_get_status(struct vdpa_device *vdpa_dev)
>   {
>   	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
> @@ -443,8 +450,9 @@ static struct vdpa_notification_area ifcvf_get_vq_notification(struct vdpa_devic
>    * implemented set_map()/dma_map()/dma_unmap()
>    */
>   static const struct vdpa_config_ops ifc_vdpa_ops = {
> -	.get_features	= ifcvf_vdpa_get_features,
> -	.set_features	= ifcvf_vdpa_set_features,
> +	.get_device_features = ifcvf_vdpa_get_device_features,
> +	.set_driver_features = ifcvf_vdpa_set_driver_features,
> +	.get_driver_features = ifcvf_vdpa_get_driver_features,
>   	.get_status	= ifcvf_vdpa_get_status,
>   	.set_status	= ifcvf_vdpa_set_status,
>   	.reset		= ifcvf_vdpa_reset,
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 63813fbb5f62..ce2e13135dd8 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1880,7 +1880,7 @@ static u64 mlx_to_vritio_features(u16 dev_features)
>   	return result;
>   }
>   
> -static u64 mlx5_vdpa_get_features(struct vdpa_device *vdev)
> +static u64 mlx5_vdpa_get_device_features(struct vdpa_device *vdev)
>   {
>   	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>   	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> @@ -1972,7 +1972,7 @@ static void update_cvq_info(struct mlx5_vdpa_dev *mvdev)
>   	}
>   }
>   
> -static int mlx5_vdpa_set_features(struct vdpa_device *vdev, u64 features)
> +static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
>   {
>   	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>   	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> @@ -2339,6 +2339,13 @@ static int mlx5_get_vq_irq(struct vdpa_device *vdv, u16 idx)
>   	return -EOPNOTSUPP;
>   }
>   
> +static u64 mlx5_vdpa_get_driver_features(struct vdpa_device *vdev)
> +{
> +	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> +
> +	return mvdev->actual_features;
> +}
> +
>   static const struct vdpa_config_ops mlx5_vdpa_ops = {
>   	.set_vq_address = mlx5_vdpa_set_vq_address,
>   	.set_vq_num = mlx5_vdpa_set_vq_num,
> @@ -2351,8 +2358,9 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
>   	.get_vq_notification = mlx5_get_vq_notification,
>   	.get_vq_irq = mlx5_get_vq_irq,
>   	.get_vq_align = mlx5_vdpa_get_vq_align,
> -	.get_features = mlx5_vdpa_get_features,
> -	.set_features = mlx5_vdpa_set_features,
> +	.get_device_features = mlx5_vdpa_get_device_features,
> +	.set_driver_features = mlx5_vdpa_set_driver_features,
> +	.get_driver_features = mlx5_vdpa_get_driver_features,
>   	.set_config_cb = mlx5_vdpa_set_config_cb,
>   	.get_vq_num_max = mlx5_vdpa_get_vq_num_max,
>   	.get_device_id = mlx5_vdpa_get_device_id,
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 7332a74a4b00..c37d384c0f33 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -733,7 +733,7 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
>   	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
>   		return -EMSGSIZE;
>   
> -	features = vdev->config->get_features(vdev);
> +	features = vdev->config->get_driver_features(vdev);
>   
>   	return vdpa_dev_net_mq_config_fill(vdev, msg, features, &config);
>   }
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index 41b0cd17fcba..ddbe142af09a 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -399,14 +399,14 @@ static u32 vdpasim_get_vq_align(struct vdpa_device *vdpa)
>   	return VDPASIM_QUEUE_ALIGN;
>   }
>   
> -static u64 vdpasim_get_features(struct vdpa_device *vdpa)
> +static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
>   {
>   	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>   
>   	return vdpasim->dev_attr.supported_features;
>   }
>   
> -static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features)
> +static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features)
>   {
>   	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>   
> @@ -419,6 +419,13 @@ static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features)
>   	return 0;
>   }
>   
> +static u64 vdpasim_get_driver_features(struct vdpa_device *vdpa)
> +{
> +	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> +
> +	return vdpasim->features;
> +}
> +
>   static void vdpasim_set_config_cb(struct vdpa_device *vdpa,
>   				  struct vdpa_callback *cb)
>   {
> @@ -613,8 +620,9 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
>   	.set_vq_state           = vdpasim_set_vq_state,
>   	.get_vq_state           = vdpasim_get_vq_state,
>   	.get_vq_align           = vdpasim_get_vq_align,
> -	.get_features           = vdpasim_get_features,
> -	.set_features           = vdpasim_set_features,
> +	.get_device_features    = vdpasim_get_device_features,
> +	.set_driver_features    = vdpasim_set_driver_features,
> +	.get_driver_features    = vdpasim_get_driver_features,
>   	.set_config_cb          = vdpasim_set_config_cb,
>   	.get_vq_num_max         = vdpasim_get_vq_num_max,
>   	.get_device_id          = vdpasim_get_device_id,
> @@ -642,8 +650,9 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
>   	.set_vq_state           = vdpasim_set_vq_state,
>   	.get_vq_state           = vdpasim_get_vq_state,
>   	.get_vq_align           = vdpasim_get_vq_align,
> -	.get_features           = vdpasim_get_features,
> -	.set_features           = vdpasim_set_features,
> +	.get_device_features    = vdpasim_get_device_features,
> +	.set_driver_features    = vdpasim_set_driver_features,
> +	.get_driver_features    = vdpasim_get_driver_features,
>   	.set_config_cb          = vdpasim_set_config_cb,
>   	.get_vq_num_max         = vdpasim_get_vq_num_max,
>   	.get_device_id          = vdpasim_get_device_id,
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index c9204c62f339..1e65af6ab9ae 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -573,14 +573,14 @@ static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
>   	return dev->vq_align;
>   }
>   
> -static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
> +static u64 vduse_vdpa_get_device_features(struct vdpa_device *vdpa)
>   {
>   	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>   
>   	return dev->device_features;
>   }
>   
> -static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> +static int vduse_vdpa_set_driver_features(struct vdpa_device *vdpa, u64 features)
>   {
>   	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>   
> @@ -588,6 +588,13 @@ static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
>   	return 0;
>   }
>   
> +static u64 vduse_vdpa_get_driver_features(struct vdpa_device *vdpa)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	return dev->driver_features;
> +}
> +
>   static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
>   				  struct vdpa_callback *cb)
>   {
> @@ -720,8 +727,9 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = {
>   	.set_vq_state		= vduse_vdpa_set_vq_state,
>   	.get_vq_state		= vduse_vdpa_get_vq_state,
>   	.get_vq_align		= vduse_vdpa_get_vq_align,
> -	.get_features		= vduse_vdpa_get_features,
> -	.set_features		= vduse_vdpa_set_features,
> +	.get_device_features	= vduse_vdpa_get_device_features,
> +	.set_driver_features	= vduse_vdpa_set_driver_features,
> +	.get_driver_features	= vduse_vdpa_get_driver_features,
>   	.set_config_cb		= vduse_vdpa_set_config_cb,
>   	.get_vq_num_max		= vduse_vdpa_get_vq_num_max,
>   	.get_device_id		= vduse_vdpa_get_device_id,
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index e3ff7875e123..97285bc05e47 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -53,14 +53,14 @@ static struct virtio_pci_modern_device *vdpa_to_mdev(struct vdpa_device *vdpa)
>   	return &vp_vdpa->mdev;
>   }
>   
> -static u64 vp_vdpa_get_features(struct vdpa_device *vdpa)
> +static u64 vp_vdpa_get_device_features(struct vdpa_device *vdpa)
>   {
>   	struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>   
>   	return vp_modern_get_features(mdev);
>   }
>   
> -static int vp_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> +static int vp_vdpa_set_driver_features(struct vdpa_device *vdpa, u64 features)
>   {
>   	struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>   
> @@ -69,6 +69,13 @@ static int vp_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
>   	return 0;
>   }
>   
> +static u64 vp_vdpa_get_driver_features(struct vdpa_device *vdpa)
> +{
> +	struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
> +
> +	return vp_modern_get_features(mdev);
> +}
> +
>   static u8 vp_vdpa_get_status(struct vdpa_device *vdpa)
>   {
>   	struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
> @@ -415,8 +422,9 @@ vp_vdpa_get_vq_notification(struct vdpa_device *vdpa, u16 qid)
>   }
>   
>   static const struct vdpa_config_ops vp_vdpa_ops = {
> -	.get_features	= vp_vdpa_get_features,
> -	.set_features	= vp_vdpa_set_features,
> +	.get_device_features = vp_vdpa_get_device_features,
> +	.set_driver_features = vp_vdpa_set_driver_features,
> +	.get_driver_features = vp_vdpa_get_driver_features,
>   	.get_status	= vp_vdpa_get_status,
>   	.set_status	= vp_vdpa_set_status,
>   	.reset		= vp_vdpa_reset,
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 29cced1cd277..6d087a4fb581 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -262,7 +262,7 @@ static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
>   	const struct vdpa_config_ops *ops = vdpa->config;
>   	u64 features;
>   
> -	features = ops->get_features(vdpa);
> +	features = ops->get_device_features(vdpa);
>   
>   	if (copy_to_user(featurep, &features, sizeof(features)))
>   		return -EFAULT;
> diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> index f85f860bc10b..a84b04ba3195 100644
> --- a/drivers/virtio/virtio_vdpa.c
> +++ b/drivers/virtio/virtio_vdpa.c
> @@ -308,7 +308,7 @@ static u64 virtio_vdpa_get_features(struct virtio_device *vdev)
>   	struct vdpa_device *vdpa = vd_get_vdpa(vdev);
>   	const struct vdpa_config_ops *ops = vdpa->config;
>   
> -	return ops->get_features(vdpa);
> +	return ops->get_device_features(vdpa);
>   }
>   
>   static int virtio_vdpa_finalize_features(struct virtio_device *vdev)
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index c3011ccda430..db24317d61b6 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -169,14 +169,17 @@ struct vdpa_map_file {
>    *				for the device
>    *				@vdev: vdpa device
>    *				Returns virtqueue algin requirement
> - * @get_features:		Get virtio features supported by the device
> + * @get_device_features:	Get virtio features supported by the device
>    *				@vdev: vdpa device
>    *				Returns the virtio features support by the
>    *				device
> - * @set_features:		Set virtio features supported by the driver
> + * @set_driver_features:	Set virtio features supported by the driver
>    *				@vdev: vdpa device
>    *				@features: feature support by the driver
>    *				Returns integer: success (0) or error (< 0)
> + * @get_driver_features:	Get virtio features in action
> + *				@vdev: vdpa device
> + *				Returns the virtio features accepted
>    * @set_config_cb:		Set the config interrupt callback
>    *				@vdev: vdpa device
>    *				@cb: virtio-vdev interrupt callback structure
> @@ -276,8 +279,9 @@ struct vdpa_config_ops {
>   
>   	/* Device ops */
>   	u32 (*get_vq_align)(struct vdpa_device *vdev);
> -	u64 (*get_features)(struct vdpa_device *vdev);
> -	int (*set_features)(struct vdpa_device *vdev, u64 features);
> +	u64 (*get_device_features)(struct vdpa_device *vdev);
> +	int (*set_driver_features)(struct vdpa_device *vdev, u64 features);
> +	u64 (*get_driver_features)(struct vdpa_device *vdev);
>   	void (*set_config_cb)(struct vdpa_device *vdev,
>   			      struct vdpa_callback *cb);
>   	u16 (*get_vq_num_max)(struct vdpa_device *vdev);
> @@ -395,7 +399,7 @@ static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)
>   	const struct vdpa_config_ops *ops = vdev->config;
>   
>   	vdev->features_valid = true;
> -	return ops->set_features(vdev, features);
> +	return ops->set_driver_features(vdev, features);
>   }
>   
>   void vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,

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