[dpdk-stable] [PATCH v2 5/5] net/bnxt: enforce io barrier for doorbell command

[Ajit Khaparde]

On Mon, Sep 16, 2019 at 4:27 AM Gavin Hu <gavin.hu at arm.com> wrote:

> The doorbell ringing operation requires a rte_io_mb immediately to make
> the command complete and visible to the device before reading the
> response, otherwise it may read stale or invalid responses.
>
> Fixes: ca241d9a0952 ("net/bnxt: use I/O device memory read/write API")
> Cc: stable at dpdk.org
>
> Signed-off-by: Gavin Hu <gavin.hu at arm.com>
>
Acked-by: Ajit Khaparde <ajit.khaparde at broadcom.com>


> ---
>  drivers/net/bnxt/bnxt_hwrm.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/bnxt/bnxt_hwrm.c b/drivers/net/bnxt/bnxt_hwrm.c
> index 2d5dc00..7d192e3 100644
> --- a/drivers/net/bnxt/bnxt_hwrm.c
> +++ b/drivers/net/bnxt/bnxt_hwrm.c
> @@ -134,6 +134,12 @@ static int bnxt_hwrm_send_message(struct bnxt *bp,
> void *msg,
>         /* Ring channel doorbell */
>         bar = (uint8_t *)bp->bar0 + mb_trigger_offset;
>         rte_write32(1, bar);
> +       /*
> +        * Make sure the channel doorbell ring command complete before
> +        * reading the response to avoid getting stale or invalid
> +        * responses.
> +        */
> +       rte_io_mb();
>
>         /* Poll for the valid bit */
>         for (i = 0; i < HWRM_CMD_TIMEOUT; i++) {
> --
> 2.7.4
>
>