Re: [PATCH v3 0/8] nic: thunderx: fix communication races between VF & PF
From: Vadim Lomovtsev
Date: Wed Feb 20 2019 - 06:19:38 EST
sorry for occasionally reply to old thread.
On Wed, Feb 20, 2019 at 11:02:42AM +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.
> v1 -> v2
> - 0000: correct typo in cover letter subject: 'betwen' -> 'between';
> - move link state polling request task from pf to vf
> instead of cheking status of mailbox irq;
> v2 -> v3
> - 0003: change return type of nicvf_send_cfg_done() function
> from int to void;
> - 0007: update subject and remove unused variable 'netdev'
> from nicvf_link_status_check_task() function;
> 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
> net: thunderx: add nicvf_send_msg_to_pf result check for
> net: thunderx: rework xcast message structure to make it fit into 64
> net: thunderx: add mutex to protect mailbox from concurrent calls for
> same VF
> net: thunderx: add LINK_CHANGE message handler at nicpf
> net: thunderx: remove link change polling code and info from nicpf
> drivers/net/ethernet/cavium/thunder/nic.h | 14 +-
> .../net/ethernet/cavium/thunder/nic_main.c | 149 ++++++------------
> .../net/ethernet/cavium/thunder/nicvf_main.c | 130 ++++++++++-----
> .../net/ethernet/cavium/thunder/thunder_bgx.c | 2 +-
> .../net/ethernet/cavium/thunder/thunder_bgx.h | 2 +-
> 5 files changed, 144 insertions(+), 153 deletions(-)