@@ -44,6 +44,7 @@
#define VIRTIO_NET_F_CTRL_RX 18 /* Control channel RX mode support */
#define VIRTIO_NET_F_CTRL_VLAN 19 /* Control channel VLAN filtering */
#define VIRTIO_NET_F_CTRL_RX_EXTRA 20 /* Extra RX mode control support */
+#define VIRTIO_NET_F_ANY_HEADER_SG 22 /* Host can handle any header s/g */
#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
@@ -186,5 +187,6 @@ struct virtio_net_ctrl_mac {
DEFINE_PROP_BIT("ctrl_vq", _state, _field, VIRTIO_NET_F_CTRL_VQ, true), \
DEFINE_PROP_BIT("ctrl_rx", _state, _field, VIRTIO_NET_F_CTRL_RX, true), \
DEFINE_PROP_BIT("ctrl_vlan", _state, _field, VIRTIO_NET_F_CTRL_VLAN, true), \
- DEFINE_PROP_BIT("ctrl_rx_extra", _state, _field, VIRTIO_NET_F_CTRL_RX_EXTRA, true)
+ DEFINE_PROP_BIT("ctrl_rx_extra", _state, _field, VIRTIO_NET_F_CTRL_RX_EXTRA, true), \
+ DEFINE_PROP_BIT("any_header_sg", _state, _field, VIRTIO_NET_F_ANY_HEADER_SG, true)
#endif
Old qemu versions required that 1st s/g entry is the header. My recent patchset titled "virtio-net: iovec handling cleanup" removed this limitation but a feature bit is needed so guests know it's safe to lay out header differently. This patch applies on top and adds such a feature bit. virtio net header inline with the data is beneficial for latency and small packet bandwidth. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- hw/virtio-net.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)