Commit e918085a authored by Alex Williamson's avatar Alex Williamson Committed by David S. Miller

virtio_net: Fix MAX_PACKET_LEN to support 802.1Q VLANs

802.1Q expanded the maximum ethernet frame size by 4 bytes for the
VLAN tag.  We're not taking this into account in virtio_net, which
means the buffers we provide to the backend in the virtqueue RX ring
aren't big enough to hold a full MTU VLAN packet.  For QEMU/KVM,
this results in the backend exiting with a packet truncation error.
Signed-off-by: default avatarAlex Williamson <alex.williamson@hp.com>
Acked-by: default avatarMark McLoughlin <markmc@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 801599b0
......@@ -24,6 +24,7 @@
#include <linux/virtio.h>
#include <linux/virtio_net.h>
#include <linux/scatterlist.h>
#include <linux/if_vlan.h>
static int napi_weight = 128;
module_param(napi_weight, int, 0444);
......@@ -33,7 +34,7 @@ module_param(csum, bool, 0444);
module_param(gso, bool, 0444);
/* FIXME: MTU in config. */
#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
#define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
#define GOOD_COPY_LEN 128
struct virtnet_info
......
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