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

[Jason Wang <jasowang@redhat.com>]

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

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

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,
 };
-- 
2.25.1