vDPA: conditionally read MTU and MAC in dev cfg space

The spec says:
mtu only exists if VIRTIO_NET_F_MTU is set
The mac address field always exists (though
is only valid if VIRTIO_NET_F_MAC is set)

So vdpa_dev_net_config_fill() should read MTU and MAC
conditionally on the feature bits.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220929014555.112323-7-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index e5e18124ed12bc954f73661f00eacbbdcfd920c7..d4b05cd0f2fbfa5fe9558352174e0cfc8f6e4ee8 100644 (file)
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -818,6 +818,29 @@ static int vdpa_dev_net_mq_config_fill(struct sk_buff *msg, u64 features,
        return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, val_u16);
 }
 
+static int vdpa_dev_net_mtu_config_fill(struct sk_buff *msg, u64 features,
+                                       const struct virtio_net_config *config)
+{
+       u16 val_u16;
+
+       if ((features & BIT_ULL(VIRTIO_NET_F_MTU)) == 0)
+               return 0;
+
+       val_u16 = __virtio16_to_cpu(true, config->mtu);
+
+       return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16);
+}
+
+static int vdpa_dev_net_mac_config_fill(struct sk_buff *msg, u64 features,
+                                       const struct virtio_net_config *config)
+{
+       if ((features & BIT_ULL(VIRTIO_NET_F_MAC)) == 0)
+               return 0;
+
+       return  nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR,
+                       sizeof(config->mac), config->mac);
+}
+
 static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
 {
        struct virtio_net_config config = {};
@@ -826,24 +849,22 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
 
        vdev->config->get_config(vdev, 0, &config, sizeof(config));
 
-       if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac),
-                   config.mac))
-               return -EMSGSIZE;
-
        val_u16 = __virtio16_to_cpu(true, config.status);
        if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16))
                return -EMSGSIZE;
 
-       val_u16 = __virtio16_to_cpu(true, config.mtu);
-       if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
-               return -EMSGSIZE;
-
        features_device = vdev->config->get_device_features(vdev);
 
        if (nla_put_u64_64bit(msg, VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, features_device,
                              VDPA_ATTR_PAD))
                return -EMSGSIZE;
 
+       if (vdpa_dev_net_mtu_config_fill(msg, features_device, &config))
+               return -EMSGSIZE;
+
+       if (vdpa_dev_net_mac_config_fill(msg, features_device, &config))
+               return -EMSGSIZE;
+
        return vdpa_dev_net_mq_config_fill(msg, features_device, &config);
 }