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Diffstat (limited to 'static/freebsd/man4/vtnet.4')
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diff --git a/static/freebsd/man4/vtnet.4 b/static/freebsd/man4/vtnet.4 new file mode 100644 index 00000000..926f504d --- /dev/null +++ b/static/freebsd/man4/vtnet.4 @@ -0,0 +1,298 @@ +.\" Copyright (c) 2011 Bryan Venteicher +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.Dd December 19, 2025 +.Dt VTNET 4 +.Os +.Sh NAME +.Nm vtnet +.Nd VirtIO Ethernet driver +.Sh SYNOPSIS +To compile this driver into the kernel, +place the following lines in your +kernel configuration file: +.Bd -ragged -offset indent +.Cd "device vtnet" +.Ed +.Pp +Alternatively, to load the driver as a +module at boot time, place the following line in +.Xr loader.conf 5 : +.Bd -literal -offset indent +if_vtnet_load="YES" +.Ed +.Sh DESCRIPTION +The +.Nm +device driver provides support for VirtIO Ethernet devices. +.Pp +If the hypervisor advertises the appropriate features, the +.Nm +driver supports TCP/UDP checksum offload for both transmit and receive, +TCP segmentation offload (TSO), TCP large receive offload (LRO), +hardware VLAN tag stripping/insertion features, a multicast hash filter, +as well as Jumbo Frames (up to 9216 bytes), which can be +configured via the interface MTU setting. +.Pp +Two flavors of TCP LRO are supported: +Hardware TCP LRO, which is performed by the host providing TCP segments larger +than the MTU to the guest, and Software TCP LRO, which is performed by the +network stack of the guest processing TCP segments in an optimized way. +Only one flavour of TCP LRO should be used. +Since hardware TCP LRO can have bad interactions with IP forwarding and +software TCP LRO mitigates several drawbacks of hardware TCP LRO, the default +setting is to disable hardware TCP LRO. +See the loader tunable +.Va hw.vtnet. Ns Ar X Ns Va .lro_disable . +.Pp +TCP/UDP receive checksum offload cannot be configured independently for IPv4 +and IPv6. +Selecting an MTU larger than 1500 bytes with the +.Xr ifconfig 8 +utility configures the adapter to receive and transmit Jumbo Frames. +.Pp +For more information on configuring this device, see +.Xr ifconfig 8 . +.Sh LOADER TUNABLES +Tunables can be set at the +.Xr loader 8 +prompt before booting the kernel or stored in +.Xr loader.conf 5 . +.Bl -tag -width "xxxxxx" +.It Va hw.vtnet.csum_disable +.It Va hw.vtnet. Ns Ar X Ns Va .csum_disable +This tunable disables receive and transmit checksum offloading for TCP and +UDP. +This also implies that TCP segmentation offloading and large receive offload +are disabled. +The default value is 0. +.It Va hw.vtnet.fixup_needs_csum +.It Va hw.vtnet. Ns Ar X Ns Va .fixup_needs_csum +This tunable enforces the calculation of a valid TCP or UDP checksum for +packets received with +.Dv VIRTIO_NET_HDR_F_NEEDS_CSUM +being set in the +.Va flags +field of the structure +.Vt struct virtio_net_hdr . +It also marks the checksum as being correct in the mbuf packet header. +The default value is 0. +This tunable is deprecated and will be removed in +.Fx 16 . +.It Va hw.vtnet.tso_disable +.It Va hw.vtnet. Ns Ar X Ns Va .tso_disable +This tunable disables TCP segmentation offloading. +The default value is 0. +.It Va hw.vtnet.lro_disable +.It Va hw.vtnet. Ns Ar X Ns Va .lro_disable +This tunable disables hardware TCP LRO. +The default value is 1. +.It Va hw.vtnet.mq_disable +.It Va hw.vtnet. Ns Ar X Ns Va .mq_disable +This tunable disables multiqueue. +The default value is 0. +.It Va hw.vtnet.mq_max_pairs +.It Va hw.vtnet. Ns Ar X Ns Va .mq_max_pairs +This tunable sets the maximum number of transmit and receive queue pairs. +Multiple queues are only supported when the Multiqueue feature is negotiated. +This driver supports a maximum of 8 queue pairs. +The number of queue pairs used is the lesser of the maximum supported by the +driver and the hypervisor, the number of CPUs present in the guest, and this +tunable if not zero. +The default value is 0. +.It Va hw.vtnet.tso_maxlen +.It Va hw.vtnet. Ns Ar X Ns Va .tso_maxlen +This tunable sets the TSO burst limit. +The default value is 65535. +.It Va hw.vtnet.rx_process_limit +.It Va hw.vtnet. Ns Ar X Ns Va .rx_process_limit +This tunable sets the number of RX segments processed in one pass. +The default value is 1024. +.It Va hw.vtnet.lro_entry_count +.It Va hw.vtnet. Ns Ar X Ns Va .lro_entry_count +This tunable sets the software TCP LRO entry count. +The default value is 128, the minimum value is 8. +.It Va hw.vtnet.lro_mbufq_depth +.It Va hw.vtnet. Ns Ar X Ns Va .lro_mbufq_depth +This tunable sets the depth of the software TCP LRO mbuf queue. +The default value is 0. +.It Va hw.vtnet.altq_disable +This tunable disables ALTQ support, allowing the use of multiqueue instead. +This option applies to all interfaces. +The default value is 0. +.El +.Sh TRANSMIT QUEUE STATISTICS +For each transmit queue of each interface the following read-only statistics +are provided: +.Bl -tag -width "xxxxxx" +.It Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .rescheduled +The number of times the transmit interrupt handler was rescheduled. +.It Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .tso +The number of times TCP segment offloading was performed. +.It Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .csum +The number of times transmit checksum offloading for UDP or TCP was +performed. +.It Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .omcasts +The number of multicast packets that were transmitted. +.It Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .obytes +The number of bytes that were transmitted (based on Ethernet frames). +.It Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .opackets +The number of packets that were transmitted (Ethernet frames). +.El +.Sh RECEIVE QUEUE STATISTICS +For each receive queue of each interface the following read-only statistics +are provided: +.Bl -tag -width "xxxxxx" +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .rescheduled +The number of times the receive interrupt handler was rescheduled. +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .host_lro +The number of times TCP large receive offload was performed. +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .csum_failed +The number of times a packet with a request for receive or transmit checksum +offloading was received and this request failed. +The different reasons for the failure are counted by +.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_inaccessible_ipproto , +.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ipproto , +.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ethtype , +and +.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_offset . +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .csum +The number of times receive checksum offloading for UDP or TCP was performed. +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .ierrors +The number of times an error occurred during input processing. +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .iqdrops +The number of times a packet was dropped during input processing. +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .ibytes +The number of bytes that were received (based on Ethernet frames). +.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .ipackets +The number of packets that were received (Ethernet frames). +.El +.Sh INTERFACE TRANSMIT STATISTICS +For each interface the following read-only transmit statistics are provided: +.Bl -tag -width "xxxxxx" +.It Va dev.vtnet. Ns Ar X Ns Va .tx_task_rescheduled +The sum of +.Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .rescheduled +over all transmit queues of the interface. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_tso_offloaded +The sum of +.Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .tso +over all transmit queues of the interface. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_csum_offloaded +The sum of +.Va dev.vtnet. Ns Ar X Ns Va .txq Ns Ar Y Ns Va .csum +over all transmit queues of the interface. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_defrag_failed +The number of times an attempt to defragment an mbuf chain failed during a +transmit operation. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_defragged +The number of times an mbuf chain was defragmented during a transmit operation. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_tso_without_csum +The number of times TCP segment offloading was attempted without transmit +checksum offloading. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_tso_not_tcp +The number of times TCP segment offloading was attempted for a non-TCP packet. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_csum_proto_mismatch +The number of times the IP protocol version of the transmit checksum +offloading request did not match the IP protocol version of the packet. +.It Va dev.vtnet. Ns Ar X Ns Va .tx_csum_unknown_ethtype +The number of times a transmit offload operation was requested for an +ethernet frame for which the EtherType was neither IPv4 nor IPv6 +(considering simple VLAN tagging). +.El +.Sh INTERFACE RECEIVE STATISTICS +For each interface the following read-only receive statistics are provided: +.Bl -tag -width "xxxxxx" +.It Va dev.vtnet. Ns Ar X Ns Va .rx_task_rescheduled +The sum of +.Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .rescheduled +over all receive queues of the interface. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_offloaded +The sum of +.Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .csum +over all receive queues of the interface. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_failed +The sum of +.Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .csum_failed +over all receive queues of the interface. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_inaccessible_ipproto +The number of times a packet with a request for receive or transmit checksum +offloading was received where the IP protocol was not accessible. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_offset +The number of times fixing the checksum required by +.Va hw.vtnet.fixup_needs_csum +or +.Va hw.vtnet. Ns Ar X Ns Va .fixup_needs_csum +was attempted for a packet where the csum is not located in the first mbuf. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ipproto +The number of times a packet with a request for receive or transmit checksum +offloading was received where the IP protocol was neither TCP nor UDP. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ethtype +The number of times a packet with a request for receive or transmit checksum +offloading was received where the EtherType was neither IPv4 nor IPv6. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_mergeable_failed +The number of times receiving a mergable buffer failed. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_enq_replacement_failed +The number of times the enqueuing the replacement receive mbuf chain failed. +.It Va dev.vtnet. Ns Ar X Ns Va .rx_frame_too_large +The number of times the frame was loger than the mbuf chain during large +receive offload without mergeable buffers. +.It Va dev.vtnet. Ns Ar X Ns Va .mbuf_alloc_failed +The number of times an mbuf cluster allocation for the receive buffer failed. +.El +.Sh INTERFACE CONFIGURATION PARAMETER +For each interface the following read-only configuration parameters are +provided: +.Bl -tag -width "xxxxxx" +.It Va dev.vtnet. Ns Ar X Ns Va .act_vq_pairs +The number of active virtqueue pairs. +.It Va dev.vtnet. Ns Ar X Ns Va .req_vq_pairs +The number of requested virtqueue pairs. +.It Va dev.vtnet. Ns Ar X Ns Va .max_vq_pairs +The maximum number of supported virtqueue pairs. +.It Va dev.vtnet. Ns Ar X Ns Va .flags +The flags of the interface. +Mostly for debugging purposes. +.It Va dev.vtnet. Ns Ar X Ns Va .features +The features of the interface as defined by the virtio specification. +.El +.Sh SEE ALSO +.Xr arp 4 , +.Xr netintro 4 , +.Xr ng_ether 4 , +.Xr virtio 4 , +.Xr vlan 4 , +.Xr ifconfig 8 +.Sh HISTORY +The +.Nm +driver was written by +.An Bryan Venteicher Aq Mt bryanv@FreeBSD.org . +It first appeared in +.Fx 9.0 . +.Sh CAVEATS +The +.Nm +driver only supports LRO when the hypervisor advertises the +mergeable buffer feature. |