Re: [PATCH V2 2/3] vdpa_sim_net: support feature provisioning

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

On 9/21/2022 7:43 PM, Jason Wang wrote:
> This patch implements features provisioning for vdpa_sim_net.
>
> 1) validating the provisioned features to be a subset of the parent
>     features.
> 2) clearing the features that is not wanted by the userspace
>
> For example:
>
> # vdpa mgmtdev show
> vdpasim_net:
>    supported_classes net
>    max_supported_vqs 3
>    dev_features MTU MAC CTRL_VQ CTRL_MAC_ADDR ANY_LAYOUT VERSION_1 ACCESS_PLATFORM
Sighs, not to blame any one and it's perhaps too late, but this 
"dev_features" attr in "mgmtdev show" command output should have been 
called "supported_features" in the first place.

>
> 1) provision vDPA device with all features that are supported by the
>     net simulator
>
> # vdpa dev add name dev1 mgmtdev vdpasim_net
> # vdpa dev config show
> dev1: mac 00:00:00:00:00:00 link up link_announce false mtu 1500
>    negotiated_features MTU MAC CTRL_VQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM
Maybe not in this patch, but for completeness for the whole series, 
could we also add device_features to the output?

When simply look at the "vdpa dev config show" output, I cannot really 
tell the actual device_features that was used in vdpa creation. For e.g. 
there is a missing feature ANY_LAYOUT from negotiated_features compared 
with supported_features in mgmtdev, but the orchestration software 
couldn't tell if the vdpa device on destination host should be created 
with or without the ANY_LAYOUT feature.

Thanks,
-Siwei


>
> 2) provision vDPA device with a subset of the features
>
> # vdpa dev add name dev1 mgmtdev vdpasim_net device_features 0x300020000
> # vdpa dev config show
> dev1: mac 00:00:00:00:00:00 link up link_announce false mtu 1500
>    negotiated_features CTRL_VQ VERSION_1 ACCESS_PLATFORM
>
> Reviewed-by: Eli Cohen <elic@nvidia.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>   drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> index 886449e88502..a9ba02be378b 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> @@ -254,6 +254,14 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
>   	dev_attr.work_fn = vdpasim_net_work;
>   	dev_attr.buffer_size = PAGE_SIZE;
>   
> +	if (config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
> +		if (config->device_features &
> +		    ~dev_attr.supported_features)
> +			return -EINVAL;
> +		dev_attr.supported_features &=
> +			 config->device_features;
> +	}
> +
>   	simdev = vdpasim_create(&dev_attr);
>   	if (IS_ERR(simdev))
>   		return PTR_ERR(simdev);
> @@ -294,7 +302,8 @@ static struct vdpa_mgmt_dev mgmt_dev = {
>   	.id_table = id_table,
>   	.ops = &vdpasim_net_mgmtdev_ops,
>   	.config_attr_mask = (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR |
> -			     1 << VDPA_ATTR_DEV_NET_CFG_MTU),
> +			     1 << VDPA_ATTR_DEV_NET_CFG_MTU |
> +		             1 << VDPA_ATTR_DEV_FEATURES),
>   	.max_supported_vqs = VDPASIM_NET_VQ_NUM,
>   	.supported_features = VDPASIM_NET_FEATURES,
>   };