Re: [PATCH 0/8] nic: thunderx: fix communication races betwen VF & PF

Vadim Lomovtsev
2019-02-06T14:18:38Z

self-NACK here, some emails get's corrupted for some reasons,
along with some typos found.

sorry for inconvenience.

Vadim

On Wed, Feb 06, 2019 at 10:13:54AM +0000, Vadim Lomovtsev wrote:
> The ThunderX CN88XX NIC Virtual Function driver uses mailbox interface
> to communicate to physical function driver. Each of VF has it's own pair
> of mailbox registers to read from and write to. The mailbox registers
> has no protection from possible races, so it has to be implemented
> at software side.
>
> After long term testing by loop of 'ip link set <ifname> up/down'
> command it was found that there are two possible scenarios when
> race condition appears:
> 1. VF receives link change message from PF and VF send RX mode
> configuration message to PF in the same time from separate thread.
> 2. PF receives RX mode configuration from VF and in the same time,
> in separate thread PF detects link status change and sends appropriate
> message to particular VF.
>
> Both cases leads to mailbox data to be rewritten, NIC VF messaging control
> data to be updated incorrectly and communication sequence gets broken.
>
> This patch series is to address race condition with VF & PF communication.
>
> Vadim Lomovtsev (8):
> net: thunderx: correct typo in macro name
> net: thunderx: replace global nicvf_rx_mode_wq work queue for all VFs
> to private for each of them.
> net: thunderx: make CFG_DONE message to run through generic send-ack
> sequence
> net: thunderx: add nicvf_send_msg_to_pf result check for
> set_rx_mode_task
> net: thunderx: rework xcast message structure to make it fit into 64
> bit
> net: thunderx: add mutex to protect mailbox from concurrent calls for
> same VF
> net: thunderx: implement helpers to read mailbox IRQ status
> net: thunderx: check status of mailbox IRQ before sending a message
>
> drivers/net/ethernet/cavium/thunder/nic.h | 12 +--
> .../net/ethernet/cavium/thunder/nic_main.c | 58 +++++++------
> .../net/ethernet/cavium/thunder/nicvf_main.c | 82 +++++++++++++------
> .../ethernet/cavium/thunder/nicvf_queues.c | 14 ++++
> .../ethernet/cavium/thunder/nicvf_queues.h | 1 +
> .../net/ethernet/cavium/thunder/thunder_bgx.c | 2 +-
> .../net/ethernet/cavium/thunder/thunder_bgx.h | 2 +-
> 7 files changed, 112 insertions(+), 59 deletions(-)
>
> --
> 2.17.2