Download raw body.
ice(4) Tx checksum offloading
On Tue, May 20, 2025 at 10:13:42PM +0200, Stefan Sperling wrote:
> This patch adds support for Tx checksum offloading to the ice(4) driver.
>
> As with the earlier Rx patch, I have tested this diff both with and
> without ice-ddp firmware loaded. It seems to work in both cases.
>
> The only case where software checksumming is still being used is when
> I send iperf UDP packets over IPv6. Offloading UDP checkums works in
> the IPv4 case, though, per counters shown by netstat -s.
> Does this indicate a bug in this diff? Or is the IPv6 stack deciding to
> clear M_UDP_CSUM_OUT in some cases for some reason? I could not yet see
> anything wrong comparing my changes to ixl(4) and to FreeBSD ice(4).
Works for me. I don't see software checksumming counters going up.
Please commit, and I can have an eye on this in more test cases.
OK bluhm@
> M sys/dev/pci/if_ice.c | 23+ 6-
>
> 1 file changed, 23 insertions(+), 6 deletions(-)
>
> commit - 2e4fc07e79d7ea65b71425f1af53c3c7c9d88bb3
> commit + 0f813f93bd053e12f651681399505c576b4cc14e
> blob - ed64ea74bb85a0d5c2750114ed461c94028f295e
> blob + 7cb43b5931c74d075d351458dff0c13b70c582ed
> --- sys/dev/pci/if_ice.c
> +++ sys/dev/pci/if_ice.c
> @@ -84,6 +84,7 @@
>
> #include <netinet/in.h>
> #include <netinet/if_ether.h>
> +#include <netinet/udp.h>
>
> #define STRUCT_HACK_VAR_LEN
>
> @@ -13683,18 +13684,31 @@ ice_tx_setup_offload(struct mbuf *m0, struct ice_tx_qu
> hlen = ext.iphlen;
>
> if (ext.ip4) {
> - /* TODO: ipv4 checksum offload */
> - offload |= ICE_TX_DESC_CMD_IIPT_IPV4 << ICE_TXD_QW1_CMD_S;
> + if (ISSET(m0->m_pkthdr.csum_flags, M_IPV4_CSUM_OUT))
> + offload |= ICE_TX_DESC_CMD_IIPT_IPV4_CSUM <<
> + ICE_TXD_QW1_CMD_S;
> + else
> + offload |= ICE_TX_DESC_CMD_IIPT_IPV4 <<
> + ICE_TXD_QW1_CMD_S;
> } else if (ext.ip6)
> offload |= ICE_TX_DESC_CMD_IIPT_IPV6 << ICE_TXD_QW1_CMD_S;
> + else
> + return offload;
>
> offload |= ((ETHER_HDR_LEN >> 1) << ICE_TX_DESC_LEN_MACLEN_S) <<
> ICE_TXD_QW1_OFFSET_S;
> - if (ext.ip4 || ext.ip6)
> - offload |= ((hlen >> 2) << ICE_TX_DESC_LEN_IPLEN_S) <<
> - ICE_TXD_QW1_OFFSET_S;
> + offload |= ((hlen >> 2) << ICE_TX_DESC_LEN_IPLEN_S) <<
> + ICE_TXD_QW1_OFFSET_S;
>
> - /* TODO: enable offloading features */
> + if (ext.tcp && ISSET(m0->m_pkthdr.csum_flags, M_TCP_CSUM_OUT)) {
> + offload |= ICE_TX_DESC_CMD_L4T_EOFT_TCP << ICE_TXD_QW1_CMD_S;
> + offload |= ((uint64_t)(ext.tcphlen >> 2) <<
> + ICE_TX_DESC_LEN_L4_LEN_S) << ICE_TXD_QW1_OFFSET_S;
> + } else if (ext.udp && ISSET(m0->m_pkthdr.csum_flags, M_UDP_CSUM_OUT)) {
> + offload |= ICE_TX_DESC_CMD_L4T_EOFT_UDP << ICE_TXD_QW1_CMD_S;
> + offload |= ((uint64_t)(sizeof(*ext.udp) >> 2) <<
> + ICE_TX_DESC_LEN_L4_LEN_S) << ICE_TXD_QW1_OFFSET_S;
> + }
>
> return offload;
> }
> @@ -29809,6 +29823,9 @@ ice_attach_hook(struct device *self)
> #if NVLAN > 0
> ifp->if_capabilities |= IFCAP_VLAN_HWTAGGING;
> #endif
> + ifp->if_capabilities |= IFCAP_CSUM_IPv4 |
> + IFCAP_CSUM_TCPv4 | IFCAP_CSUM_UDPv4 |
> + IFCAP_CSUM_TCPv6 | IFCAP_CSUM_UDPv6;
>
> if_attach(ifp);
> ether_ifattach(ifp);
ice(4) Tx checksum offloading