Re: [PATCH v5 4/5] i40e: Fix broken support for floating VEBs

[Simon Horman]

On Fri, Nov 24, 2023 at 04:03:42PM +0100, Ivan Vecera wrote:
> Although the i40e supports so-called floating VEB (VEB without
> an uplink connection to external network), this support is
> broken. This functionality is currently unused (except debugfs)
> but it will be used by subsequent series for switchdev mode
> slow-path. Fix this by following:
> 
> 1) Handle correctly floating VEB (VEB with uplink_seid == 0)
>    in i40e_reconstitute_veb() and look for owner VSI and
>    create it only for non-floating VEBs and also set bridge
>    mode only for such VEBs as the floating ones are using
>    always VEB mode.
> 2) Handle correctly floating VEB in i40e_veb_release() and
>    disallow its release when there are some VSIs. This is
>    different from regular VEB that have owner VSI that is
>    connected to VEB's uplink after VEB deletion by FW.
> 3) Fix i40e_add_veb() to handle 'vsi' that is NULL for floating
>    VEBs. For floating VEB use 0 for downlink SEID and 'true'
>    for 'default_port' parameters as per datasheet.
> 4) Fix 'add relay' command in i40e_dbg_command_write() to allow
>    to create floating VEB by 'add relay 0 0' or 'add relay'
> 
> Tested using debugfs:
> 1) Initial state
> [root@host net-next]# echo dump switch > $CMD
> [root@host net-next]# dmesg -c
> [  173.701286] i40e 0000:02:00.0: header: 3 reported 3 total
> [  173.706701] i40e 0000:02:00.0: type=19 seid=392 uplink=160 downlink=16
> [  173.713241] i40e 0000:02:00.0: type=17 seid=160 uplink=2 downlink=0
> [  173.719507] i40e 0000:02:00.0: type=19 seid=390 uplink=160 downlink=16
> 
> 2) Add floating VEB
> [root@host net-next]# CMD="/sys/kernel/debug/i40e/0000:02:00.0/command"
> [root@host net-next]# echo add relay > $CMD
> [root@host net-next]# dmesg -c
> [  245.551720] i40e 0000:02:00.0: added relay 162
> [root@host net-next]# echo dump switch > $CMD
> [root@host net-next]# dmesg -c
> [  276.984371] i40e 0000:02:00.0: header: 4 reported 4 total
> [  276.989779] i40e 0000:02:00.0: type=19 seid=392 uplink=160 downlink=16
> [  276.996302] i40e 0000:02:00.0: type=17 seid=160 uplink=2 downlink=0
> [  277.002569] i40e 0000:02:00.0: type=19 seid=390 uplink=160 downlink=16
> [  277.009091] i40e 0000:02:00.0: type=17 seid=162 uplink=0 downlink=0
> 
> 3) Add VMDQ2 VSI to this new VEB
> [root@host net-next]# echo add vsi 162 > $CMD
> [root@host net-next]# dmesg -c
> [  332.314030] i40e 0000:02:00.0: added VSI 394 to relay 162
> [  332.337486] enp2s0f0np0v0: NIC Link is Up, 40 Gbps Full Duplex, Flow Control: None
> [root@host net-next]# echo dump switch > $CMD
> [root@host net-next]# dmesg -c
> [  387.284490] i40e 0000:02:00.0: header: 5 reported 5 total
> [  387.289904] i40e 0000:02:00.0: type=19 seid=394 uplink=162 downlink=16
> [  387.296446] i40e 0000:02:00.0: type=17 seid=162 uplink=0 downlink=0
> [  387.302708] i40e 0000:02:00.0: type=19 seid=392 uplink=160 downlink=16
> [  387.309234] i40e 0000:02:00.0: type=17 seid=160 uplink=2 downlink=0
> [  387.315500] i40e 0000:02:00.0: type=19 seid=390 uplink=160 downlink=16
> 
> 4) Try to delete the VEB
> [root@host net-next]# echo del relay 162 > $CMD
> [root@host net-next]# dmesg -c
> [  428.749297] i40e 0000:02:00.0: deleting relay 162
> [  428.754011] i40e 0000:02:00.0: can't remove VEB 162 with 1 VSIs left
> 
> 5) Do PF reset and check switch status after rebuild
> [root@host net-next]# echo pfr > $CMD
> [root@host net-next]# echo dump switch > $CMD
> [root@host net-next]# dmesg -c
> [  738.056172] i40e 0000:02:00.0: header: 5 reported 5 total
> [  738.061577] i40e 0000:02:00.0: type=19 seid=394 uplink=162 downlink=16
> [  738.068104] i40e 0000:02:00.0: type=17 seid=162 uplink=0 downlink=0
> [  738.074367] i40e 0000:02:00.0: type=19 seid=392 uplink=160 downlink=16
> [  738.080892] i40e 0000:02:00.0: type=17 seid=160 uplink=2 downlink=0
> [  738.087160] i40e 0000:02:00.0: type=19 seid=390 uplink=160 downlink=16
> 
> 6) Delete VSI and delete VEB
> [root@host net-next]# echo del vsi 394 > $CMD
> [root@host net-next]# echo del relay 162 > $CMD
> [root@host net-next]# echo dump switch > $CMD
> [root@host net-next]# dmesg -c
> [ 1233.081126] i40e 0000:02:00.0: deleting VSI 394
> [ 1239.345139] i40e 0000:02:00.0: deleting relay 162
> [ 1244.886920] i40e 0000:02:00.0: header: 3 reported 3 total
> [ 1244.892328] i40e 0000:02:00.0: type=19 seid=392 uplink=160 downlink=16
> [ 1244.898853] i40e 0000:02:00.0: type=17 seid=160 uplink=2 downlink=0
> [ 1244.905119] i40e 0000:02:00.0: type=19 seid=390 uplink=160 downlink=16
> 
> Reviewed-by: Wojciech Drewek <wojciech.drewek@xxxxxxxxx>
> Signed-off-by: Ivan Vecera <ivecera@xxxxxxxxxx>

Reviewed-by: Simon Horman <horms@xxxxxxxxxx>