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>

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ec2a8b41ed41..b0bc8ead47de 100644
--- 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,