| Message ID | 20220316192117.2568261-1-vladimir.oltean@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8e0341aefcc9133f3f48683873284b169581315b |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: mscc: ocelot: fix backwards compatibility with single-chain tc-flower offload | expand |
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Wed, 16 Mar 2022 21:21:17 +0200 you wrote: > ACL rules can be offloaded to VCAP IS2 either through chain 0, or, since > the blamed commit, through a chain index whose number encodes a specific > PAG (Policy Action Group) and lookup number. > > The chain number is translated through ocelot_chain_to_pag() into a PAG, > and through ocelot_chain_to_lookup() into a lookup number. > > [...] Here is the summary with links: - [net] net: mscc: ocelot: fix backwards compatibility with single-chain tc-flower offload https://git.kernel.org/netdev/net/c/8e0341aefcc9 You are awesome, thank you!
diff --git a/drivers/net/ethernet/mscc/ocelot_flower.c b/drivers/net/ethernet/mscc/ocelot_flower.c index cc74d20634e5..03b5e59d033e 100644 --- a/drivers/net/ethernet/mscc/ocelot_flower.c +++ b/drivers/net/ethernet/mscc/ocelot_flower.c @@ -61,6 +61,12 @@ static int ocelot_chain_to_block(int chain, bool ingress) */ static int ocelot_chain_to_lookup(int chain) { + /* Backwards compatibility with older, single-chain tc-flower + * offload support in Ocelot + */ + if (chain == 0) + return 0; + return (chain / VCAP_LOOKUP) % 10; } @@ -69,7 +75,15 @@ static int ocelot_chain_to_lookup(int chain) */ static int ocelot_chain_to_pag(int chain) { - int lookup = ocelot_chain_to_lookup(chain); + int lookup; + + /* Backwards compatibility with older, single-chain tc-flower + * offload support in Ocelot + */ + if (chain == 0) + return 0; + + lookup = ocelot_chain_to_lookup(chain); /* calculate PAG value as chain index relative to the first PAG */ return chain - VCAP_IS2_CHAIN(lookup, 0);
ACL rules can be offloaded to VCAP IS2 either through chain 0, or, since the blamed commit, through a chain index whose number encodes a specific PAG (Policy Action Group) and lookup number. The chain number is translated through ocelot_chain_to_pag() into a PAG, and through ocelot_chain_to_lookup() into a lookup number. The problem with the blamed commit is that the above 2 functions don't have special treatment for chain 0. So ocelot_chain_to_pag(0) returns filter->pag = 224, which is in fact -32, but the "pag" field is an u8. So we end up programming the hardware with VCAP IS2 entries having a PAG of 224. But the way in which the PAG works is that it defines a subset of VCAP IS2 filters which should match on a packet. The default PAG is 0, and previous VCAP IS1 rules (which we offload using 'goto') can modify it. So basically, we are installing filters with a PAG on which no packet will ever match. This is the hardware equivalent of adding filters to a chain which has no 'goto' to it. Restore the previous functionality by making ACL filters offloaded to chain 0 go to PAG 0 and lookup number 0. The choice of PAG is clearly correct, but the choice of lookup number isn't "as before" (which was to leave the lookup a "don't care"). However, lookup 0 should be fine, since even though there are ACL actions (policers) which have a requirement to be used in a specific lookup, that lookup is 0. Fixes: 226e9cd82a96 ("net: mscc: ocelot: only install TCAM entries into a specific lookup and PAG") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> --- drivers/net/ethernet/mscc/ocelot_flower.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)