forked from mirrors/linux
10a8d94a95
There's no need for the guest to validate the checksum if it have been validated by host nics. So this patch introduces a new flag - VIRTIO_NET_HDR_F_DATA_VALID which is used to bypass the checksum examing in guest. The backend (tap/macvtap) may set this flag when met skbs with CHECKSUM_UNNECESSARY to save cpu utilization. No feature negotiation is needed as old driver just ignore this flag. Iperf shows 12%-30% performance improvement for UDP traffic. For TCP, when gro is on no difference as it produces skb with partial checksum. But when gro is disabled, 20% or even higher improvement could be measured by netperf. Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
155 lines
6.6 KiB
C
155 lines
6.6 KiB
C
#ifndef _LINUX_VIRTIO_NET_H
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#define _LINUX_VIRTIO_NET_H
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/* This header is BSD licensed so anyone can use the definitions to implement
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* compatible drivers/servers.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of IBM nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE. */
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#include <linux/types.h>
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#include <linux/virtio_ids.h>
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#include <linux/virtio_config.h>
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#include <linux/if_ether.h>
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/* The feature bitmap for virtio net */
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#define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */
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#define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */
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#define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */
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#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
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#define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */
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#define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */
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#define VIRTIO_NET_F_GUEST_ECN 9 /* Guest can handle TSO[6] w/ ECN in. */
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#define VIRTIO_NET_F_GUEST_UFO 10 /* Guest can handle UFO in. */
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#define VIRTIO_NET_F_HOST_TSO4 11 /* Host can handle TSOv4 in. */
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#define VIRTIO_NET_F_HOST_TSO6 12 /* Host can handle TSOv6 in. */
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#define VIRTIO_NET_F_HOST_ECN 13 /* Host can handle TSO[6] w/ ECN in. */
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#define VIRTIO_NET_F_HOST_UFO 14 /* Host can handle UFO in. */
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#define VIRTIO_NET_F_MRG_RXBUF 15 /* Host can merge receive buffers. */
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#define VIRTIO_NET_F_STATUS 16 /* virtio_net_config.status available */
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#define VIRTIO_NET_F_CTRL_VQ 17 /* Control channel available */
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#define VIRTIO_NET_F_CTRL_RX 18 /* Control channel RX mode support */
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#define VIRTIO_NET_F_CTRL_VLAN 19 /* Control channel VLAN filtering */
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#define VIRTIO_NET_F_CTRL_RX_EXTRA 20 /* Extra RX mode control support */
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#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
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struct virtio_net_config {
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/* The config defining mac address (if VIRTIO_NET_F_MAC) */
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__u8 mac[6];
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/* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
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__u16 status;
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} __attribute__((packed));
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/* This is the first element of the scatter-gather list. If you don't
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* specify GSO or CSUM features, you can simply ignore the header. */
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struct virtio_net_hdr {
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#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 // Use csum_start, csum_offset
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#define VIRTIO_NET_HDR_F_DATA_VALID 2 // Csum is valid
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__u8 flags;
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#define VIRTIO_NET_HDR_GSO_NONE 0 // Not a GSO frame
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#define VIRTIO_NET_HDR_GSO_TCPV4 1 // GSO frame, IPv4 TCP (TSO)
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#define VIRTIO_NET_HDR_GSO_UDP 3 // GSO frame, IPv4 UDP (UFO)
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#define VIRTIO_NET_HDR_GSO_TCPV6 4 // GSO frame, IPv6 TCP
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#define VIRTIO_NET_HDR_GSO_ECN 0x80 // TCP has ECN set
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__u8 gso_type;
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__u16 hdr_len; /* Ethernet + IP + tcp/udp hdrs */
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__u16 gso_size; /* Bytes to append to hdr_len per frame */
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__u16 csum_start; /* Position to start checksumming from */
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__u16 csum_offset; /* Offset after that to place checksum */
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};
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/* This is the version of the header to use when the MRG_RXBUF
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* feature has been negotiated. */
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struct virtio_net_hdr_mrg_rxbuf {
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struct virtio_net_hdr hdr;
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__u16 num_buffers; /* Number of merged rx buffers */
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};
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/*
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* Control virtqueue data structures
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*
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* The control virtqueue expects a header in the first sg entry
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* and an ack/status response in the last entry. Data for the
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* command goes in between.
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*/
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struct virtio_net_ctrl_hdr {
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__u8 class;
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__u8 cmd;
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} __attribute__((packed));
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typedef __u8 virtio_net_ctrl_ack;
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#define VIRTIO_NET_OK 0
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#define VIRTIO_NET_ERR 1
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/*
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* Control the RX mode, ie. promisucous, allmulti, etc...
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* All commands require an "out" sg entry containing a 1 byte
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* state value, zero = disable, non-zero = enable. Commands
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* 0 and 1 are supported with the VIRTIO_NET_F_CTRL_RX feature.
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* Commands 2-5 are added with VIRTIO_NET_F_CTRL_RX_EXTRA.
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*/
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#define VIRTIO_NET_CTRL_RX 0
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#define VIRTIO_NET_CTRL_RX_PROMISC 0
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#define VIRTIO_NET_CTRL_RX_ALLMULTI 1
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#define VIRTIO_NET_CTRL_RX_ALLUNI 2
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#define VIRTIO_NET_CTRL_RX_NOMULTI 3
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#define VIRTIO_NET_CTRL_RX_NOUNI 4
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#define VIRTIO_NET_CTRL_RX_NOBCAST 5
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/*
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* Control the MAC filter table.
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*
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* The MAC filter table is managed by the hypervisor, the guest should
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* assume the size is infinite. Filtering should be considered
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* non-perfect, ie. based on hypervisor resources, the guest may
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* received packets from sources not specified in the filter list.
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*
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* In addition to the class/cmd header, the TABLE_SET command requires
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* two out scatterlists. Each contains a 4 byte count of entries followed
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* by a concatenated byte stream of the ETH_ALEN MAC addresses. The
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* first sg list contains unicast addresses, the second is for multicast.
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* This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
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* is available.
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*/
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struct virtio_net_ctrl_mac {
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__u32 entries;
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__u8 macs[][ETH_ALEN];
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} __attribute__((packed));
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#define VIRTIO_NET_CTRL_MAC 1
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#define VIRTIO_NET_CTRL_MAC_TABLE_SET 0
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/*
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* Control VLAN filtering
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*
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* The VLAN filter table is controlled via a simple ADD/DEL interface.
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* VLAN IDs not added may be filterd by the hypervisor. Del is the
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* opposite of add. Both commands expect an out entry containing a 2
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* byte VLAN ID. VLAN filterting is available with the
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* VIRTIO_NET_F_CTRL_VLAN feature bit.
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*/
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#define VIRTIO_NET_CTRL_VLAN 2
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#define VIRTIO_NET_CTRL_VLAN_ADD 0
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#define VIRTIO_NET_CTRL_VLAN_DEL 1
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#endif /* _LINUX_VIRTIO_NET_H */
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