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author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2022-03-16 22:21:17 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-23 11:16:43 +0300 |
commit | 800a17adb531d417b8d219b25e37b4de4c3a6a8c (patch) | |
tree | c4b27f60d3cb77a44074ac8f0ec76c30fc215572 /drivers/net/ethernet | |
parent | 2d7cff7e1fee5a00115f5afcb185e8f8c765d407 (diff) | |
download | linux-800a17adb531d417b8d219b25e37b4de4c3a6a8c.tar.xz |
net: mscc: ocelot: fix backwards compatibility with single-chain tc-flower offload
[ 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>
Diffstat (limited to 'drivers/net/ethernet')
-rw-r--r-- | drivers/net/ethernet/mscc/ocelot_flower.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/net/ethernet/mscc/ocelot_flower.c b/drivers/net/ethernet/mscc/ocelot_flower.c index afa062c5f82d..f1323af99b0c 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); |