From d682d2bdc30650a5c7ce9908ab83ab674b658744 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 22 Sep 2015 17:04:58 -0700 Subject: [PATCH] bnx2x: byte swap rss_key to comply to Toeplitz specs After a good amount of debugging, I found bnx2x was byte swaping the 40 bytes of rss_key. If we byte swap the key, then bnx2x generates hashes matching MSDN specs as documented in (Verifying the RSS Hash Calculation) https://msdn.microsoft.com/en-us/library/windows/hardware/ff571021% 28v=vs.85%29.aspx It is mostly a non issue, unless we want to mix different NIC in a host, and want consistent hashing among all of them, ie if they all use the boot time generated rss key, or if some application is choosing specific tuple(s) so that incoming traffic lands into known rx queue(s). Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c index c9bd7f16018e..ff702a707a91 100644 --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c @@ -4319,8 +4319,16 @@ static int bnx2x_setup_rss(struct bnx2x *bp, /* RSS keys */ if (test_bit(BNX2X_RSS_SET_SRCH, &p->rss_flags)) { - memcpy(&data->rss_key[0], &p->rss_key[0], - sizeof(data->rss_key)); + u8 *dst = (u8 *)(data->rss_key) + sizeof(data->rss_key); + const u8 *src = (const u8 *)p->rss_key; + int i; + + /* Apparently, bnx2x reads this array in reverse order + * We need to byte swap rss_key to comply with Toeplitz specs. + */ + for (i = 0; i < sizeof(data->rss_key); i++) + *--dst = *src++; + caps |= ETH_RSS_UPDATE_RAMROD_DATA_UPDATE_RSS_KEY; } -- 2.34.1