virtio-net: validate features during probe

We currently trigger BUG when VIRTIO_NET_F_CTRL_VQ
is not set but one of features depending on it is.
That's not a friendly way to report errors to
hypervisors.
Let's check, and fail probe instead.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ec2a8b4..b0bc8ea 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1673,6 +1673,40 @@ static const struct attribute_group virtio_net_mrg_rx_group = {
 };
 #endif
 
+static bool virtnet_fail_on_feature(struct virtio_device *vdev,
+                                   unsigned int fbit,
+                                   const char *fname, const char *dname)
+{
+       if (!virtio_has_feature(vdev, fbit))
+               return false;
+
+       dev_err(&vdev->dev, "device advertises feature %s but not %s",
+               fname, dname);
+
+       return true;
+}
+
+#define VIRTNET_FAIL_ON(vdev, fbit, dbit)                      \
+       virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
+
+static bool virtnet_validate_features(struct virtio_device *vdev)
+{
+       if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
+           (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
+                            "VIRTIO_NET_F_CTRL_VQ") ||
+            VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
+                            "VIRTIO_NET_F_CTRL_VQ") ||
+            VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
+                            "VIRTIO_NET_F_CTRL_VQ") ||
+            VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
+            VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
+                            "VIRTIO_NET_F_CTRL_VQ"))) {
+               return false;
+       }
+
+       return true;
+}
+
 static int virtnet_probe(struct virtio_device *vdev)
 {
        int i, err;
@@ -1680,6 +1714,9 @@ static int virtnet_probe(struct virtio_device *vdev)
        struct virtnet_info *vi;
        u16 max_queue_pairs;
 
+       if (!virtnet_validate_features(vdev))
+               return -EINVAL;
+
        /* Find if host supports multiqueue virtio_net device */
        err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
                                   struct virtio_net_config,