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

Message

Vadim Lomovtsev Feb. 6, 2019, 10:13 a.m. UTC

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(-)

Comments

Vadim Lomovtsev Feb. 6, 2019, 2:18 p.m. UTC | #1

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