Negotiating VIRTIO_NET_F_CTRL_GUEST_OFFLOADS indicates the device allows control over offload support, but the offloads that can be controlled may have nothing to do with GRO (e.g., if neither GUEST_TSO4 nor GUEST_TSO6 is supported). In such a setup, reporting NETIF_F_GRO_HW as available for the device is too optimistic and misleading to the user. Improve the situation by masking off NETIF_F_GRO_HW unless the device possesses actual GRO-related offload capabilities. Out of an abundance of caution, this does not change the current behaviour for hardware with just v6 or just v4 GRO: current interfaces do not allow distinguishing between v6/v4 GRO, so we can't expose them to userspace precisely. Fixes: dbcf24d15388 ("virtio-net: use NETIF_F_GRO_HW instead of NETIF_F_LRO") Signed-off-by: Di Zhu --- /* v3 */ -Update Fixes tag to dbcf24d15388 -Refine commit message using Maintainer's "too optimistic" phrasing to clarify the risk of misleading configurations. /* v2 */ -make the modified logic clearer --- drivers/net/virtio_net.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 72d6a9c6a5a2..b233c99925e9 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -6781,8 +6781,6 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)) dev->features |= NETIF_F_GRO_HW; - if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) - dev->hw_features |= NETIF_F_GRO_HW; dev->vlan_features = dev->features; dev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT | @@ -7058,6 +7056,10 @@ static int virtnet_probe(struct virtio_device *vdev) } vi->guest_offloads_capable = vi->guest_offloads; + if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS) && + (vi->guest_offloads_capable & GUEST_OFFLOAD_GRO_HW_MASK)) + dev->hw_features |= NETIF_F_GRO_HW; + rtnl_unlock(); err = virtnet_cpu_notif_add(vi); -- 2.34.1