This patch validates feature dependencies during probe and fail the probing
if a dependency is missed. This fixes the issues of hitting BUG()
when qemu fails to advertise features correctly. One example is booting
guest with ctrl_vq=off through qemu.
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Cc: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/net/virtio_net.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 93 insertions(+)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ec2a8b4..4a0ad46 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1673,6 +1673,95 @@ static const struct attribute_group virtio_net_mrg_rx_group = {
};
#endif
+static int virtnet_validate_features(struct virtio_device *dev,
+ unsigned int *table,
+ int table_size,
+ unsigned int feature)
+{
+ int i;
+
+ if (!virtio_has_feature(dev, feature)) {
+ for (i = 0; i < table_size; i++) {
+ unsigned int f = table[i];
+
+ if (virtio_has_feature(dev, f)) {
+ dev_err(&dev->dev,
+ "buggy hyperviser: feature 0x%x was advertised but its dependency 0x%x was not",
+ f, feature);
+ return -EINVAL;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int virtnet_check_features(struct virtio_device *dev)
+{
+ unsigned int features_for_ctrl_vq[] = {
+ VIRTIO_NET_F_CTRL_RX,
+ VIRTIO_NET_F_CTRL_VLAN,
+ VIRTIO_NET_F_GUEST_ANNOUNCE,
+ VIRTIO_NET_F_MQ,
+ VIRTIO_NET_F_CTRL_MAC_ADDR
+ };
+ unsigned int features_for_guest_csum[] = {
+ VIRTIO_NET_F_GUEST_TSO4,
+ VIRTIO_NET_F_GUEST_TSO6,
+ VIRTIO_NET_F_GUEST_ECN,
+ VIRTIO_NET_F_GUEST_UFO,
+ };
+ unsigned int features_for_host_csum[] = {
+ VIRTIO_NET_F_HOST_TSO4,
+ VIRTIO_NET_F_HOST_TSO6,
+ VIRTIO_NET_F_HOST_ECN,
+ VIRTIO_NET_F_HOST_UFO,
+ };
+ int err;
+
+ err = virtnet_validate_features(dev, features_for_ctrl_vq,
+ ARRAY_SIZE(features_for_ctrl_vq),
+ VIRTIO_NET_F_CTRL_VQ);
+ if (err)
+ return err;
+
+ err = virtnet_validate_features(dev, features_for_guest_csum,
+ ARRAY_SIZE(features_for_guest_csum),
+ VIRTIO_NET_F_GUEST_CSUM);
+ if (err)
+ return err;
+
+ err = virtnet_validate_features(dev, features_for_host_csum,
+ ARRAY_SIZE(features_for_host_csum),
+ VIRTIO_NET_F_CSUM);
+ if (err)
+ return err;
+
+ if (virtio_has_feature(dev, VIRTIO_NET_F_GUEST_ECN) &&
+ (!virtio_has_feature(dev, VIRTIO_NET_F_GUEST_TSO4) ||
+ !virtio_has_feature(dev, VIRTIO_NET_F_GUEST_TSO6))) {
+ dev_err(&dev->dev,
+ "buggy hyperviser: feature 0x%x was advertised but its dependency 0x%x or 0x%x was not",
+ VIRTIO_NET_F_GUEST_ECN,
+ VIRTIO_NET_F_GUEST_TSO4,
+ VIRTIO_NET_F_GUEST_TSO6);
+ return -EINVAL;
+ }
+
+ if (virtio_has_feature(dev, VIRTIO_NET_F_HOST_ECN) &&
+ (!virtio_has_feature(dev, VIRTIO_NET_F_HOST_TSO4) ||
+ !virtio_has_feature(dev, VIRTIO_NET_F_HOST_TSO6))) {
+ dev_err(&dev->dev,
+ "buggy hyperviser: feature 0x%x was advertised but its dependency 0x%x or 0x%x was not",
+ VIRTIO_NET_F_HOST_ECN,
+ VIRTIO_NET_F_HOST_TSO4,
+ VIRTIO_NET_F_HOST_TSO6);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int virtnet_probe(struct virtio_device *vdev)
{
int i, err;
@@ -1680,6 +1769,10 @@ static int virtnet_probe(struct virtio_device *vdev)
struct virtnet_info *vi;
u16 max_queue_pairs;
+ err = virtnet_check_features(vdev);
+ if (err)
+ return -EINVAL;
+
/* Find if host supports multiqueue virtio_net device */
err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
struct virtio_net_config,
--
1.9.1
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