Cathy Zhou wrote: > Sebastien Roy wrote: >> Cathy Zhou wrote: >>> I am adding this in the PSARC fast-track, and the diffs are posted >>> below. The following link is also updated >>> >>> http://opensolaris.org/os/project/clearview/uv_addendum_fasttrack >> ... >> >>> + ** HCKSUM_VLANCKSUM bit of MAC_CAPAB_HCKSUM >>> + >>> + The HCKSUM_VLANCKSUM bit can be set in combination with other >>> + MAC_CAPAB_HCKSUM bits (HCKSUM_INET_PARTIAL, HCKSUM_INET_FULL_V4, >>> + HCKSUM_INET_FULL_V6, or/and HCKSUM_IPHDRCKSUM), to indicate that >>> + a MAC is capable of doing the specified hardware checksum >>> offloading >>> + for VLAN frames. >> Can you add to the specification an explanation of why this is needed? >> In other words, GLDv3 previously (wrongly) assumed that all devices >> which claimed to support various flavors of hardware checksum offload >> could so with VLAN-tagged frames. This flag is presumably needed for >> some potential drivers out there that do hardware checksum, but only for >> non-vlan-tagged frames (correct?). >> > How about this: > > > ** HCKSUM_VLANCKSUM bit of MAC_CAPAB_HCKSUM > > Today, GLDv3 assumes that all Ethernet MACs that claim HW checksum > offloading capabilities could do HW checksum for both untagged > and VLAN-tagged packets. But in reality, there are some drivers that > can only support HW checksum for packets whose true payload is at the > right offset (reported in DL_INFO_ACK). For example, they will not be > able to handle HW checksum for VLAN-tagged packets, as VLAN tag are > embeded at the start of the payload section, which result in the true > payload starting at a different offset. > > The HCKSUM_VLANCKSUM bit can be set in combination with other > MAC_CAPAB_HCKSUM bits (HCKSUM_INET_PARTIAL, HCKSUM_INET_FULL_V4, > HCKSUM_INET_FULL_V6, or/and HCKSUM_IPHDRCKSUM), to indicate that > a MAC is not capable of doing the specified HW checksum offloading > for packets with extra VLAN tag headers.
And this is related to UV how?... (you put the answer below, and that's useful information for the specification) > >> Do we know of any such drivers offhand? > > I don't know NICs enough to know whether there is such hardware. > > But for those legacy drivers unified to GLDv3, UV always chooses not to > advertise there HW checksum capability on VLAN streams, unless they support > VLAN PPA access themselves. Therefore, we need a bit to indicate it is > different from the traditional GLDv3 drivers (that can support HW checksum > for VLAN frames). Got it. -Seb _______________________________________________ networking-discuss mailing list [email protected]
