netdev - RE: [net-next,PATCH] net: dsa: microchip: Do not count RX/TX Bytes and discards on KSZ87xx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20250813070321.1608086-1-vtpieter@gmail.com>
Date: Wed, 13 Aug 2025 09:03:21 +0200
From: vtpieter@...il.com
To: tristram.ha@...rochip.com
Cc: Arun.Ramadoss@...rochip.com,
	UNGLinuxDriver@...rochip.com,
	Woojung.Huh@...rochip.com,
	andrew@...n.ch,
	edumazet@...gle.com,
	kuba@...nel.org,
	marek.vasut@...lbox.org,
	netdev@...r.kernel.org,
	olteanv@...il.com,
	pabeni@...hat.com
Subject: RE: [net-next,PATCH] net: dsa: microchip: Do not count RX/TX Bytes and discards on KSZ87xx

> > > Actually that many rx_discards may be a problem I need to find out.
> > >
> > > I think you are confused about how those MIB counters are read from
> > > KSZ8795.  They are not using the code in ksz9477.c but in ksz8.c.
> > 
> > See [1] TABLE 4-26: PORT MIB COUNTER INDIRECT MEMORY OFFSETS (CONTINUED)
> > , page 108 at the very end . Notice the table ends at 0x1F
> > TxMultipleCollision .
> > 
> > See [2] TABLE 5-6: MIB COUNTERS (CONTINUED) , page 219 at the end of the
> > table . Notice the table contains four extra entries , 0x80 RxByteCnt ,
> > 0x81 TxByteCnt , 0x82 RxDropPackets , 0x83 TXDropPackets .
> > 
> > These entries are present on KSZ9477 and missing on KSZ8795 .
> > 
> > This is what this patch attempts to address.
> 
> As I said KSZ8795 MIB counters are not using the code in ksz9477.c and
> their last counter locations are not the same as KSZ9477.  KSZ9477 uses
> ksz9477_r_mib_pkt while KSZ8795 uses ksz8795_r_mib_pkt.  The other
> KSZ8895 and KSZ8863 switches uses ksz8863_r_mib_pkt.
> 
> The 0x80 and such registers are not used in KSZ8795.  Its registers start
> at 0x100, 0x101, ...
> 
> They are in table 4-28.
 
Just wanted to chip in that for me, with a KSZ8794, the iproute2
statistics work as expected as well after commit 0d3edc90c4a0 ("net:
dsa: microchip: fix KSZ87xx family structure wrt the datasheet"). I'm
on a 6.12 kernel and I see the following:

ip -s -h a
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1501 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:d3:36:00:38:06 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::ad3:36ff:fe00:3806/64 scope link 
       valid_lft forever preferred_lft forever
    RX:  bytes packets errors dropped  missed   mcast           
         2.22G   30.3M      0       0       0    922k 
    TX:  bytes packets errors dropped carrier collsns           
         3.70G   19.3M      0       0       0       0 
4: lan1@...0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN group default qlen 1000
    link/ether 08:d3:36:00:38:06 brd ff:ff:ff:ff:ff:ff
    RX:  bytes packets errors dropped  missed   mcast           
             0       0      0       0       0       0 
    TX:  bytes packets errors dropped carrier collsns           
             0       0      0       0       0       0 
5: lan2@...0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP group default qlen 1000
    link/ether 08:d3:36:00:38:06 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::ad3:36ff:fe00:3806/64 scope link 
       valid_lft forever preferred_lft forever
    RX:  bytes packets errors dropped  missed   mcast           
         2.62G   30.3M    250     247       0    922k 
    TX:  bytes packets errors dropped carrier collsns           
         3.61G   19.3M      0       0       0       0 
6: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 08:d3:36:00:38:06 brd ff:ff:ff:ff:ff:ff
    inet 172.18.210.112/26 brd 172.18.210.127 scope global br0
       valid_lft forever preferred_lft forever
    inet6 fe80::ad3:36ff:fe00:3806/64 scope link 
       valid_lft forever preferred_lft forever
    RX:  bytes packets errors dropped  missed   mcast           
         2.19G   30.3M      0    252k       0    922k 
    TX:  bytes packets errors dropped carrier collsns           
         3.60G   19.3M      0       0       0       0 

ethtool -S lan2
NIC statistics:
     tx_packets: 19385247
     tx_bytes: 3615291269
     rx_packets: 30391568
     rx_bytes: 2623613208
     rx_hi: 0
     rx_undersize: 0
     rx_fragments: 0
     rx_oversize: 0
     rx_jabbers: 0
     rx_symbol_err: 3
     rx_crc_err: 3
     rx_align_err: 0
     rx_mac_ctrl: 0
     rx_pause: 0
     rx_bcast: 3985303
     rx_mcast: 924951
     rx_ucast: 25481561
     rx_64_or_less: 5781438
     rx_65_127: 24601395
     rx_128_255: 8744
     rx_256_511: 231
     rx_512_1023: 10
     rx_1024_1522: 3
     rx_1523_2000: 0
     rx_2001: 0
     tx_hi: 0
     tx_late_col: 0
     tx_pause: 0
     tx_bcast: 3
     tx_mcast: 5128
     tx_ucast: 19380278
     tx_deferred: 0
     tx_total_col: 0
     tx_exc_col: 0
     tx_single_col: 0
     tx_mult_col: 0
     rx_total: 2745200072
     tx_total: 3693245281
     rx_discards: 247
     tx_discards: 0