vDPA: only report driver features if FEATURES_OK is set

This commit reports driver features to user space
only after FEATURES_OK is features negotiation is done.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Message-Id: <20220929014555.112323-3-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 d0a7b76..1bed527 100644 (file)
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -820,7 +820,7 @@ static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
 static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
 {
        struct virtio_net_config config = {};
-       u64 features_device, features_driver;
+       u64 features_device;
        u16 val_u16;
 
        vdev->config->get_config(vdev, 0, &config, sizeof(config));
@@ -837,11 +837,6 @@ 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_driver = vdev->config->get_driver_features(vdev);
-       if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features_driver,
-                             VDPA_ATTR_PAD))
-               return -EMSGSIZE;
-
        features_device = vdev->config->get_device_features(vdev);
 
        if (nla_put_u64_64bit(msg, VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, features_device,
@@ -855,6 +850,8 @@ static int
 vdpa_dev_config_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq,
                     int flags, struct netlink_ext_ack *extack)
 {
+       u64 features_driver;
+       u8 status = 0;
        u32 device_id;
        void *hdr;
        int err;
@@ -878,6 +875,17 @@ vdpa_dev_config_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid,
                goto msg_err;
        }
 
+       /* only read driver features after the feature negotiation is done */
+       status = vdev->config->get_status(vdev);
+       if (status & VIRTIO_CONFIG_S_FEATURES_OK) {
+               features_driver = vdev->config->get_driver_features(vdev);
+               if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features_driver,
+                                     VDPA_ATTR_PAD)) {
+                       err = -EMSGSIZE;
+                       goto msg_err;
+               }
+       }
+
        switch (device_id) {
        case VIRTIO_ID_NET:
                err = vdpa_dev_net_config_fill(vdev, msg);