vdpa_sim_net: support feature provisioning

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:

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

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

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>
Message-Id: <20220927074810.28627-3-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

drivers/vdpa/vdpa_sim/vdpa_sim.c

@@ -18,6 +18,7 @@
 #include <linux/vdpa.h>
 #include <linux/vhost_iotlb.h>
 #include <linux/iova.h>
+#include <uapi/linux/vdpa.h>
 
 #include "vdpa_sim.h"
 
@@ -245,13 +246,22 @@ static const struct dma_map_ops vdpasim_dma_ops = {
 static const struct vdpa_config_ops vdpasim_config_ops;
 static const struct vdpa_config_ops vdpasim_batch_config_ops;
 
-struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
+struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
+			       const struct vdpa_dev_set_config *config)
 {
 	const struct vdpa_config_ops *ops;
 	struct vdpasim *vdpasim;
 	struct device *dev;
 	int i, ret = -ENOMEM;
 
+	if (config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
+		if (config->device_features &
+		    ~dev_attr->supported_features)
+			return ERR_PTR(-EINVAL);
+		dev_attr->supported_features =
+			config->device_features;
+	}
+
 	if (batch_mapping)
 		ops = &vdpasim_batch_config_ops;
 	else

drivers/vdpa/vdpa_sim/vdpa_sim.h

@@ -71,7 +71,8 @@ struct vdpasim {
 	spinlock_t iommu_lock;
 };
 
-struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *attr);
+struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *attr,
+			       const struct vdpa_dev_set_config *config);
 
 /* TODO: cross-endian support */
 static inline bool vdpasim_is_little_endian(struct vdpasim *vdpasim)

drivers/vdpa/vdpa_sim/vdpa_sim_blk.c

@@ -383,7 +383,7 @@ static int vdpasim_blk_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	dev_attr.work_fn = vdpasim_blk_work;
 	dev_attr.buffer_size = VDPASIM_BLK_CAPACITY << SECTOR_SHIFT;
 
-	simdev = vdpasim_create(&dev_attr);
+	simdev = vdpasim_create(&dev_attr, config);
 	if (IS_ERR(simdev))
 		return PTR_ERR(simdev);
 

drivers/vdpa/vdpa_sim/vdpa_sim_net.c

@@ -254,7 +254,7 @@ 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;
 
-	simdev = vdpasim_create(&dev_attr);
+	simdev = vdpasim_create(&dev_attr, config);
 	if (IS_ERR(simdev))
 		return PTR_ERR(simdev);
 
@@ -294,7 +294,8 @@ 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,
 };