| Message ID | 20230112201554.752144-1-daniel.machon@microchip.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce new DCB rewrite table | expand |
Daniel Machon <daniel.machon@microchip.com> writes: > There is currently no support for per-port egress mapping of priority to PCP and > priority to DSCP. Some support for expressing egress mapping of PCP is supported > through ip link, with the 'egress-qos-map', however this command only maps > priority to PCP, and for vlan interfaces only. DCB APP already has support for > per-port ingress mapping of PCP/DEI, DSCP and a bunch of other stuff. So why not > take advantage of this fact, and add a new table that does the reverse. > > This patch series introduces the new DCB rewrite table. Whereas the DCB > APP table deals with ingress mapping of PID (protocol identifier) to priority, > the rewrite table deals with egress mapping of priority to PID. > > It is indeed possible to integrate rewrite in the existing APP table, by > introducing new dedicated rewrite selectors, and altering existing functions > to treat rewrite entries specially. However, I feel like this is not a good > solution, and will pollute the APP namespace. APP is well-defined in IEEE, and > some userspace relies of advertised entries - for this fact, separating APP and > rewrite into to completely separate objects, seems to me the best solution. > > The new table shares much functionality with the APP table, and as such, much > existing code is reused, or slightly modified, to work for both. > > ================================================================================ > DCB rewrite table in a nutshell > ================================================================================ > The table is implemented as a simple linked list, and uses the same lock as the > APP table. New functions for getting, setting and deleting entries have been > added, and these are exported, so they can be used by the stack or drivers. > Additionnaly, new dcbnl_setrewr and dcnl_delrewr hooks has been added, to > support hardware offload of the entries. Looks good to me overall. I just want to add that to configure rewrite, mlxsw currently reverses the APP prioritization table. That's not ideal, and is lossy as well--certain configurations simply can't be expressed however you set up in-driver heuristics. The proposed interfaces would make configuration of the rewrite functionality very straightforward.
There is currently no support for per-port egress mapping of priority to PCP and priority to DSCP. Some support for expressing egress mapping of PCP is supported through ip link, with the 'egress-qos-map', however this command only maps priority to PCP, and for vlan interfaces only. DCB APP already has support for per-port ingress mapping of PCP/DEI, DSCP and a bunch of other stuff. So why not take advantage of this fact, and add a new table that does the reverse. This patch series introduces the new DCB rewrite table. Whereas the DCB APP table deals with ingress mapping of PID (protocol identifier) to priority, the rewrite table deals with egress mapping of priority to PID. It is indeed possible to integrate rewrite in the existing APP table, by introducing new dedicated rewrite selectors, and altering existing functions to treat rewrite entries specially. However, I feel like this is not a good solution, and will pollute the APP namespace. APP is well-defined in IEEE, and some userspace relies of advertised entries - for this fact, separating APP and rewrite into to completely separate objects, seems to me the best solution. The new table shares much functionality with the APP table, and as such, much existing code is reused, or slightly modified, to work for both. ================================================================================ DCB rewrite table in a nutshell ================================================================================ The table is implemented as a simple linked list, and uses the same lock as the APP table. New functions for getting, setting and deleting entries have been added, and these are exported, so they can be used by the stack or drivers. Additionnaly, new dcbnl_setrewr and dcnl_delrewr hooks has been added, to support hardware offload of the entries. ================================================================================ Sparx5 per-port PCP rewrite support ================================================================================ Sparx5 supports PCP egress mapping through two eight-entry switch tables. One table maps QoS class 0-7 to PCP for DE0 (DP levels mapped to drop-eligibility 0) and the other for DE1. DCB does currently not have support for expressing DP/color, so instead, the tagged DEI bit will reflect the DP levels, for any rewrite entries> 7 ('de'). The driver will take apptrust (contributed earlier) into consideration, so that the mapping tables only be used, if PCP is trusted *and* the rewrite table has active mappings, otherwise classified PCP (same as frame PCP) will be used instead. ================================================================================ Sparx5 per-port DSCP rewrite support ================================================================================ Sparx5 support DSCP egress mapping through a single 32-entry table. This table maps classified QoS class and DP level to classified DSCP, and is consulted by the switch Analyzer Classifier at ingress. At egress, the frame DSCP can either be rewritten to classified DSCP to frame DSCP. The driver will take apptrust into consideration, so that the mapping tables only be used, if DSCP is trusted *and* the rewrite table has active mappings, otherwise frame DSCP will be used instead. ================================================================================ Patches ================================================================================ Patch #1 modifies dcb_app_add to work for both APP and rewrite Patch #2 adds dcbnl_apprewr_setdel() for setting and deleting both APP and rewrite entries. Patch #3 adds the rewrite table and all required functions, offload hooks and bookkeeping for maintaining it. Patch #4 adds two new helper functions for getting a priority to PCP bitmask map, and a priority to DSCP bitmask map. Patch #5 adds support for PCP rewrite in the Sparx5 driver Patch #6 adds support for DSCP rewrite in the Sparx5 driver Daniel Machon (6): net: dcb: modify dcb_app_add to take list_head ptr as parameter net: dcb: add new common function for set/del of app/rewr entries net: dcb: add new rewrite table net: dcb: add helper functions to retrieve PCP and DSCP rewrite maps net: microchip: sparx5: add support for PCP rewrite net: microchip: sparx5: add support for DSCP rewrite .../ethernet/microchip/sparx5/sparx5_dcb.c | 121 +++++++- .../microchip/sparx5/sparx5_main_regs.h | 70 ++++- .../ethernet/microchip/sparx5/sparx5_port.c | 97 ++++++ .../ethernet/microchip/sparx5/sparx5_port.h | 41 +++ include/net/dcbnl.h | 18 ++ include/uapi/linux/dcbnl.h | 1 + net/dcb/dcbnl.c | 275 ++++++++++++++---- 7 files changed, 550 insertions(+), 73 deletions(-) -- 2.34.1