From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit 8e0341aefcc9133f3f48683873284b169581315b ]
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 Link: https://lore.kernel.org/r/20220316192117.2568261-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mscc/ocelot_flower.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mscc/ocelot_flower.c b/drivers/net/ethernet/mscc/ocelot_flower.c index 738dd2be79dc..a3f1f1fbaf7d 100644 --- a/drivers/net/ethernet/mscc/ocelot_flower.c +++ b/drivers/net/ethernet/mscc/ocelot_flower.c @@ -54,6 +54,12 @@ 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; }
@@ -62,7 +68,15 @@ 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);