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authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 14:45:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 14:45:08 -0700
commitaae3dbb4776e7916b6cd442d00159bea27a695c1 (patch)
treed074c5d783a81e7e2e084b1eba77f57459da7e37 /Documentation/networking/netvsc.txt
parentec3604c7a5aae8953545b0d05495357009a960e5 (diff)
parent66bed8465a808400eb14562510e26c8818082cb8 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: 1) Support ipv6 checksum offload in sunvnet driver, from Shannon Nelson. 2) Move to RB-tree instead of custom AVL code in inetpeer, from Eric Dumazet. 3) Allow generic XDP to work on virtual devices, from John Fastabend. 4) Add bpf device maps and XDP_REDIRECT, which can be used to build arbitrary switching frameworks using XDP. From John Fastabend. 5) Remove UFO offloads from the tree, gave us little other than bugs. 6) Remove the IPSEC flow cache, from Florian Westphal. 7) Support ipv6 route offload in mlxsw driver. 8) Support VF representors in bnxt_en, from Sathya Perla. 9) Add support for forward error correction modes to ethtool, from Vidya Sagar Ravipati. 10) Add time filter for packet scheduler action dumping, from Jamal Hadi Salim. 11) Extend the zerocopy sendmsg() used by virtio and tap to regular sockets via MSG_ZEROCOPY. From Willem de Bruijn. 12) Significantly rework value tracking in the BPF verifier, from Edward Cree. 13) Add new jump instructions to eBPF, from Daniel Borkmann. 14) Rework rtnetlink plumbing so that operations can be run without taking the RTNL semaphore. From Florian Westphal. 15) Support XDP in tap driver, from Jason Wang. 16) Add 32-bit eBPF JIT for ARM, from Shubham Bansal. 17) Add Huawei hinic ethernet driver. 18) Allow to report MD5 keys in TCP inet_diag dumps, from Ivan Delalande. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1780 commits) i40e: point wb_desc at the nvm_wb_desc during i40e_read_nvm_aq i40e: avoid NVM acquire deadlock during NVM update drivers: net: xgene: Remove return statement from void function drivers: net: xgene: Configure tx/rx delay for ACPI drivers: net: xgene: Read tx/rx delay for ACPI rocker: fix kcalloc parameter order rds: Fix non-atomic operation on shared flag variable net: sched: don't use GFP_KERNEL under spin lock vhost_net: correctly check tx avail during rx busy polling net: mdio-mux: add mdio_mux parameter to mdio_mux_init() rxrpc: Make service connection lookup always check for retry net: stmmac: Delete dead code for MDIO registration gianfar: Fix Tx flow control deactivation cxgb4: Ignore MPS_TX_INT_CAUSE[Bubble] for T6 cxgb4: Fix pause frame count in t4_get_port_stats cxgb4: fix memory leak tun: rename generic_xdp to skb_xdp tun: reserve extra headroom only when XDP is set net: dsa: bcm_sf2: Configure IMP port TC2QOS mapping net: dsa: bcm_sf2: Advertise number of egress queues ...
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+Hyper-V network driver
+======================
+
+Compatibility
+=============
+
+This driver is compatible with Windows Server 2012 R2, 2016 and
+Windows 10.
+
+Features
+========
+
+ Checksum offload
+ ----------------
+ The netvsc driver supports checksum offload as long as the
+ Hyper-V host version does. Windows Server 2016 and Azure
+ support checksum offload for TCP and UDP for both IPv4 and
+ IPv6. Windows Server 2012 only supports checksum offload for TCP.
+
+ Receive Side Scaling
+ --------------------
+ Hyper-V supports receive side scaling. For TCP, packets are
+ distributed among available queues based on IP address and port
+ number.
+
+ For UDP, we can switch UDP hash level between L3 and L4 by ethtool
+ command. UDP over IPv4 and v6 can be set differently. The default
+ hash level is L4. We currently only allow switching TX hash level
+ from within the guests.
+
+ On Azure, fragmented UDP packets have high loss rate with L4
+ hashing. Using L3 hashing is recommended in this case.
+
+ For example, for UDP over IPv4 on eth0:
+ To include UDP port numbers in hashing:
+ ethtool -N eth0 rx-flow-hash udp4 sdfn
+ To exclude UDP port numbers in hashing:
+ ethtool -N eth0 rx-flow-hash udp4 sd
+ To show UDP hash level:
+ ethtool -n eth0 rx-flow-hash udp4
+
+ Generic Receive Offload, aka GRO
+ --------------------------------
+ The driver supports GRO and it is enabled by default. GRO coalesces
+ like packets and significantly reduces CPU usage under heavy Rx
+ load.
+
+ SR-IOV support
+ --------------
+ Hyper-V supports SR-IOV as a hardware acceleration option. If SR-IOV
+ is enabled in both the vSwitch and the guest configuration, then the
+ Virtual Function (VF) device is passed to the guest as a PCI
+ device. In this case, both a synthetic (netvsc) and VF device are
+ visible in the guest OS and both NIC's have the same MAC address.
+
+ The VF is enslaved by netvsc device. The netvsc driver will transparently
+ switch the data path to the VF when it is available and up.
+ Network state (addresses, firewall, etc) should be applied only to the
+ netvsc device; the slave device should not be accessed directly in
+ most cases. The exceptions are if some special queue discipline or
+ flow direction is desired, these should be applied directly to the
+ VF slave device.
+
+ Receive Buffer
+ --------------
+ Packets are received into a receive area which is created when device
+ is probed. The receive area is broken into MTU sized chunks and each may
+ contain one or more packets. The number of receive sections may be changed
+ via ethtool Rx ring parameters.
+
+ There is a similar send buffer which is used to aggregate packets for sending.
+ The send area is broken into chunks of 6144 bytes, each of section may
+ contain one or more packets. The send buffer is an optimization, the driver
+ will use slower method to handle very large packets or if the send buffer
+ area is exhausted.