On 2017年01月03日 06:30, John Fastabend wrote:
XDP programs can not consume multiple pages so we cap the MTU to avoid this case. Virtio-net however only checks the MTU at XDP program load and does not block MTU changes after the program has loaded. This patch sets/clears the max_mtu value at XDP load/unload time. Signed-off-by: John Fastabend <john.r.fastab...@intel.com> --- drivers/net/virtio_net.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 5deeda6..783e842 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1699,6 +1699,9 @@ static void virtnet_init_settings(struct net_device *dev) .set_settings = virtnet_set_settings, };+#define MIN_MTU ETH_MIN_MTU+#define MAX_MTU ETH_MAX_MTU + static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog) { unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr); @@ -1748,6 +1751,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog) virtnet_set_queues(vi, curr_qp); return PTR_ERR(prog); } + dev->max_mtu = max_sz; + } else { + dev->max_mtu = ETH_MAX_MTU;
Or use ETH_DATA_LEN here consider we only allocate a size of GOOD_PACKET_LEN for each small buffer?
Thanks
}vi->xdp_queue_pairs = xdp_qp;@@ -2133,9 +2139,6 @@ static bool virtnet_validate_features(struct virtio_device *vdev) return true; }-#define MIN_MTU ETH_MIN_MTU-#define MAX_MTU ETH_MAX_MTU - static int virtnet_probe(struct virtio_device *vdev) { int i, err;
