Re: [dpdk-dev] [DPDK] net/e1000: fix buffer overrun while i219 processing DMA transactions

["Zhao1, Wei" <wei.zhao1@intel.com>]

Acked-by: Wei Zhao <wei.zhao1@intel.com>


> -----Original Message-----
> From: Zhang, Xiao
> Sent: Monday, July 8, 2019 9:37 PM
> To: dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Zhao1, Wei <wei.zhao1@intel.com>;
> Zhang, Xiao <xiao.zhang@intel.com>
> Subject: [DPDK] net/e1000: fix buffer overrun while i219 processing DMA
> transactions
> 
> Intel® 100/200 Series Chipset platforms reduced the round-trip latency for the
> LAN Controller DMA accesses, causing in some high performance cases a
> buffer overrun while the I219 LAN Connected Device is processing the DMA
> transactions. I219LM and I219V devices can fall into unrecovered Tx hang
> under very stressfully UDP traffic and multiple reconnection of Ethernet cable.
> This Tx hang of the LAN Controller is only recovered if the system is rebooted.
> Slightly slow down DMA access by reducing the number of outstanding requests.
> This workaround could have an impact on TCP traffic performance on the
> platform. Disabling TSO eliminates performance loss for TCP traffic without a
> noticeable impact on CPU performance.
> 
> Please, refer to I218/I219 specification update:
> https://www.intel.com/content/www/us/en/embedded/products/networking/
> ethernet-connection-i218-family-documentation.html
> 
> Signed-off-by: Xiao Zhang <xiao.zhang@intel.com>
> ---
>  drivers/net/e1000/base/e1000_ich8lan.h |  1 +
>  drivers/net/e1000/igb_rxtx.c           | 16 ++++++++++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/drivers/net/e1000/base/e1000_ich8lan.h
> b/drivers/net/e1000/base/e1000_ich8lan.h
> index 1f2a3f8..084eb9c 100644
> --- a/drivers/net/e1000/base/e1000_ich8lan.h
> +++ b/drivers/net/e1000/base/e1000_ich8lan.h
> @@ -134,6 +134,7 @@ POSSIBILITY OF SUCH DAMAGE.
>  #define E1000_FLASH_BASE_ADDR 0xE000 /*offset of NVM access regs*/
> #define E1000_CTRL_EXT_NVMVS 0x3 /*NVM valid sector */
>  #define E1000_TARC0_CB_MULTIQ_3_REQ	(1 << 28 | 1 << 29)
> +#define E1000_TARC0_CB_MULTIQ_2_REQ	(1 << 29)
>  #define PCIE_ICH8_SNOOP_ALL	PCIE_NO_SNOOP_ALL
> 
>  #define E1000_ICH_RAR_ENTRIES	7
> diff --git a/drivers/net/e1000/igb_rxtx.c b/drivers/net/e1000/igb_rxtx.c index
> 33eeb4e..5d45e62 100644
> --- a/drivers/net/e1000/igb_rxtx.c
> +++ b/drivers/net/e1000/igb_rxtx.c
> @@ -2627,6 +2627,22 @@ eth_igb_tx_init(struct rte_eth_dev *dev)
> 
>  	e1000_config_collision_dist(hw);
> 
> +	/* SPT and CNP Si errata workaround to avoid data corruption */
> +	if (hw->mac.type == e1000_pch_spt) {
> +		uint32_t reg_val;
> +		reg_val = E1000_READ_REG(hw, E1000_IOSFPC);
> +		reg_val |= E1000_RCTL_RDMTS_HEX;
> +		E1000_WRITE_REG(hw, E1000_IOSFPC, reg_val);
> +
> +		/* Dropping the number of outstanding requests from
> +		 * 3 to 2 in order to avoid a buffer overrun.
> +		 */
> +		reg_val = E1000_READ_REG(hw, E1000_TARC(0));
> +		reg_val &= ~E1000_TARC0_CB_MULTIQ_3_REQ;
> +		reg_val |= E1000_TARC0_CB_MULTIQ_2_REQ;
> +		E1000_WRITE_REG(hw, E1000_TARC(0), reg_val);
> +	}
> +
>  	/* This write will effectively turn on the transmit unit. */
>  	E1000_WRITE_REG(hw, E1000_TCTL, tctl);  }
> --
> 2.7.4