From: Jan Klemkow Subject: Re: vio(4): use hardware offload with vlan(4) To: sf@openbsd.org Cc: tech@openbsd.org Date: Fri, 7 Jun 2024 16:04:52 +0200 On Fri, Jun 07, 2024 at 08:39:44AM +0200, sf@openbsd.org wrote: > On Thu, 6 Jun 2024, Jan Klemkow wrote: > On my system, this diff speeds up sending from a VM to the host with VLAN > from ~ 410 MByte/s to ~ 660 MByte/s, which is approx. the same speed as > without VLAN. > > The diff looks good to me, but I am not very familiar with the VLAN code. > For IFCAP_VLAN_HWTAGGING, drivers wrap the if_capabilities bit with #if > NVLAN > 0 . Do we want that for IFCAP_VLAN_HWOFFLOAD, too? Its not that important here, but I put the ifdef around both VLAN macros for consistency. ok? Thanks, Jan Index: sbin/ifconfig/ifconfig.8 =================================================================== RCS file: /cvs/src/sbin/ifconfig/ifconfig.8,v diff -u -p -r1.399 ifconfig.8 --- sbin/ifconfig/ifconfig.8 11 Jan 2024 17:22:04 -0000 1.399 +++ sbin/ifconfig/ifconfig.8 7 Jun 2024 13:56:53 -0000 @@ -294,6 +294,9 @@ tag. On transmit, the device can add the .Xr vlan 4 tag. +.It Sy VLAN_HWOFFLOAD +On transmit, the device can handle checksum or TSO offload without +.Sy VLAN_HWTAGGING . .It Sy WOL The device supports Wake on LAN (WoL). .It Sy hardmtu Index: sbin/ifconfig/ifconfig.c =================================================================== RCS file: /cvs/src/sbin/ifconfig/ifconfig.c,v diff -u -p -r1.472 ifconfig.c --- sbin/ifconfig/ifconfig.c 18 May 2024 02:44:22 -0000 1.472 +++ sbin/ifconfig/ifconfig.c 7 Jun 2024 13:56:53 -0000 @@ -125,7 +125,7 @@ #define HWFEATURESBITS \ "\024\1CSUM_IPv4\2CSUM_TCPv4\3CSUM_UDPv4" \ - "\5VLAN_MTU\6VLAN_HWTAGGING\10CSUM_TCPv6" \ + "\5VLAN_MTU\6VLAN_HWTAGGING\7VLAN_HWOFFLOAD\10CSUM_TCPv6" \ "\11CSUM_UDPv6\15TSOv4\16TSOv6\17LRO\20WOL" struct ifencap { Index: sys/dev/pv/if_vio.c =================================================================== RCS file: /cvs/src/sys/dev/pv/if_vio.c,v diff -u -p -r1.37 if_vio.c --- sys/dev/pv/if_vio.c 4 Jun 2024 09:51:52 -0000 1.37 +++ sys/dev/pv/if_vio.c 7 Jun 2024 13:56:53 -0000 @@ -604,7 +604,11 @@ vio_attach(struct device *parent, struct ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; ifp->if_start = vio_start; ifp->if_ioctl = vio_ioctl; - ifp->if_capabilities = IFCAP_VLAN_MTU; + ifp->if_capabilities = 0; +#if NVLAN > 0 + ifp->if_capabilities |= IFCAP_VLAN_MTU; + ifp->if_capabilities |= IFCAP_VLAN_HWOFFLOAD; +#endif if (virtio_has_feature(vsc, VIRTIO_NET_F_CSUM)) ifp->if_capabilities |= IFCAP_CSUM_TCPv4|IFCAP_CSUM_UDPv4| IFCAP_CSUM_TCPv6|IFCAP_CSUM_UDPv6; Index: sys/net/if.h =================================================================== RCS file: /cvs/src/sys/net/if.h,v diff -u -p -r1.216 if.h --- sys/net/if.h 11 Apr 2024 15:08:18 -0000 1.216 +++ sys/net/if.h 7 Jun 2024 13:56:53 -0000 @@ -249,6 +249,7 @@ struct if_status_description { #define IFCAP_CSUM_UDPv4 0x00000004 /* can do IPv4/UDP csum */ #define IFCAP_VLAN_MTU 0x00000010 /* VLAN-compatible MTU */ #define IFCAP_VLAN_HWTAGGING 0x00000020 /* hardware VLAN tag support */ +#define IFCAP_VLAN_HWOFFLOAD 0x00000040 /* hw offload w/ inline tag */ #define IFCAP_CSUM_TCPv6 0x00000080 /* can do IPv6/TCP checksums */ #define IFCAP_CSUM_UDPv6 0x00000100 /* can do IPv6/UDP checksums */ #define IFCAP_TSOv4 0x00001000 /* IPv4/TCP segment offload */ Index: sys/net/if_vlan.c =================================================================== RCS file: /cvs/src/sys/net/if_vlan.c,v diff -u -p -r1.218 if_vlan.c --- sys/net/if_vlan.c 23 Dec 2023 10:52:54 -0000 1.218 +++ sys/net/if_vlan.c 7 Jun 2024 13:56:53 -0000 @@ -523,7 +523,7 @@ vlan_up(struct vlan_softc *sc) /* * Note: In cases like vio(4) and em(4) where the offsets of the * csum can be freely defined, we could actually do csum offload - * for VLAN and QINQ packets. + * for QINQ packets. */ if (sc->sc_type != ETHERTYPE_VLAN) { /* @@ -531,10 +531,14 @@ vlan_up(struct vlan_softc *sc) * ethernet type (0x8100). */ ifp->if_capabilities = 0; - } else if (ISSET(ifp0->if_capabilities, IFCAP_VLAN_HWTAGGING)) { + } else if (ISSET(ifp0->if_capabilities, IFCAP_VLAN_HWTAGGING) || + ISSET(ifp0->if_capabilities, IFCAP_VLAN_HWOFFLOAD)) { /* * Chips that can do hardware-assisted VLAN encapsulation, can * calculate the correct checksum for VLAN tagged packets. + * + * Hardware which does checksum offloading, but not VLAN tag + * injection, have to set IFCAP_VLAN_HWOFFLOAD. */ ifp->if_capabilities = ifp0->if_capabilities & (IFCAP_CSUM_MASK | IFCAP_TSOv4 | IFCAP_TSOv6);