VF is still resetting

[Nobin Mathew <nobin.mathew@gmail.com>]

Hi,

We are running a dpdk app inside a pod, and orchestrating the app very
frequently(test app).

1/100 or so we are getting an error:

2022-07-17T22:34:24.620291289+03:00 iavf_check_vf_reset_done(): reset
VFR value: 3
2022-07-17T22:34:24.620310455+03:00 iavf_init_vf(): VF is still resetting
2022-07-17T22:34:24.620339697+03:00 iavf_dev_init(): Init vf failed
2022-07-17T22:34:24.620390802+03:00 EAL: Releasing PCI mapped resource
for 0000:3b:0f.5
2022-07-17T22:34:24.620397381+03:00 EAL: Calling pci_unmap_resource
for 0000:3b:0f.5 at 0x2101000000
2022-07-17T22:34:24.620442514+03:00 EAL: Calling pci_unmap_resource
for 0000:3b:0f.5 at 0x2101010000
2022-07-17T22:34:24.729012277+03:00 EAL: Requested device 0000:3b:0f.5
cannot be used
2022-07-17T22:34:24.729028758+03:00 EAL: Bus (pci) probe failed.

we added one log in dpdk lib to print the VFGEN_RSTAT register of the
VF. In problematic cases, we are seeing the value 3 which maps to
0xDEADBEEF

/ VF reset states - these are written into the RSTAT register:
* VFGEN_RSTAT on the VF
* When the PF initiates a reset, it writes 0
* When the reset is complete, it writes 1
* When the PF detects that the VF has recovered, it writes 2
* VF checks this register periodically to determine if a reset has occurred,
* then polls it to know when the reset is complete.
* If either the PF or VF reads the register while the hardware
* is in a reset state, it will return DEADBEEF, which, when masked
* will result in 3.
/
enum virtchnl_vfr_states {
VIRTCHNL_VFR_INPROGRESS = 0,
VIRTCHNL_VFR_COMPLETED,
VIRTCHNL_VFR_VFACTIVE,
};

We tried this patch also, increasing the poll time, no help.
https://github.com/DPDK/dpdk/commit/be7226980c9ad4963b92b489c8afb17f08899953

Details of the setup:

DPDK library version
21.11
VF Driver:-
intel-iavf version 4.0.1-3.2
PF driver:-
sudo ethtool -i enp94s0f1
driver: i40e
version: 2.14.13
firmware-version: 8.15 0x800096ca 20.0.17

Since we are seeing 0xDEADBEEF, I am assuming VF-PF reset mailbox msg
is received by PF, and PF initiated the RESET sequence by writing
VFSWR to VPGEN_VFRTRIG register.

I am not seeing
" dev_err(&pf->pdev->dev, "VF reset check timeout on VF %d\n", "
anywhere in syslog.

Any pointers?, why does this happen(why VF reset is not complete)?...

One more question, what is the sequence of calls in the reset path?
i40e_vc_process_vf_msg() -> VIRTCHNL_OP_RESET_VF i40e_vc_reset_vf() ->
i40e_reset_vf() -> i40e_trigger_vf_reset() & i40e_cleanup_reset_vf()

this one?

-Nobin