Hi, jiaqi
> -----Original Message-----
> From: dev <dev-boun...@dpdk.org> On Behalf Of Guinan Sun
> Sent: Friday, May 8, 2020 12:46 PM
> To: dev@dpdk.org
> Cc: Sun, GuinanX <guinanx....@intel.com>; sta...@dpdk.org
> Subject: [dpdk-dev] [PATCH v2 2/2] net/e1000: fix defects of macro in VF
>
> The defects in the macros UPDATE_VF_STAT and UPDATE_VF_STAT_36BIT
> exist.
> If latest is less than last, we will get wrong result.
> The patch fixes the defect.
>
> Fixes: d15fcf76c8b7 ("e1000: move to drivers/net/")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Guinan Sun <guinanx....@intel.com>
> ---
> v2 changes:
> * Aligned line-continuation character "\".
> ---
> drivers/net/e1000/igb_ethdev.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
> index 520fba8fa..4cd4e55c0 100644
> --- a/drivers/net/e1000/igb_ethdev.c
> +++ b/drivers/net/e1000/igb_ethdev.c
> @@ -47,6 +47,8 @@
> #define IGB_4_BIT_MASK RTE_LEN2MASK(IGB_4_BIT_WIDTH, uint8_t)
> #define IGB_8_BIT_WIDTH CHAR_BIT
> #define IGB_8_BIT_MASK UINT8_MAX
> +#define IGB_32_BIT_WIDTH (CHAR_BIT * 4) #define IGB_32_BIT_MASK
> +RTE_LEN2MASK(IGB_32_BIT_WIDTH, uint32_t)
>
> /* Additional timesync values. */
> #define E1000_CYCLECOUNTER_MASK 0xffffffffffffffffULL
> @@ -261,11 +263,17 @@ static int igb_filter_restore(struct rte_eth_dev
> *dev);
> /*
> * Define VF Stats MACRO for Non "cleared on read" register
> */
> -#define UPDATE_VF_STAT(reg, last, cur) \
> -{ \
> - u32 latest = E1000_READ_REG(hw, reg); \
> - cur += (latest - last) & UINT_MAX; \
> - last = latest; \
> +#define UPDATE_VF_STAT(reg, last, cur) \
> +{
> \
> + uint64_t latest = E1000_READ_REG(hw, reg); \
> + uint64_t stat = 0; \
Why do use 64 bit for register read？
Igb register only 32 bit width?
> + if (latest >= last) \
> + stat = latest - last; \
> + else \
> + stat = (uint64_t)((latest + \
> + ((uint64_t)1 << IGB_32_BIT_WIDTH)) - last);\
> + cur += stat & IGB_32_BIT_MASK; \
> + last = latest; \
> }
>
> #define IGB_FC_PAUSE_TIME 0x0680
> --
> 2.17.1
