Re: [dpdk-dev] [dpdk-stable] [PATCH v2 2/2] net/e1000: fix defects of macro in VF

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

Hi, xiaolong

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Ye Xiaolong
> Sent: Monday, May 18, 2020 9:25 AM
> To: Sun, GuinanX <guinanx.sun@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org
> Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH v2 2/2] net/e1000: fix defects of
> macro in VF
> 
> Hi, guinan
> 
> On 05/08, Guinan Sun wrote:
> >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.
> 
> There was similar patch before, https://patches.dpdk.org/patch/65131/, if I
> understand it correctly, you are trying to solve the rollover issue, right?
> Could you find the Ferruh's comment and check if this is a real issue?

this issue has not been fixed by now, we need this patch to fix it.
If (latest < last), there will be issue, is that right?


> 
> >
> >Fixes: d15fcf76c8b7 ("e1000: move to drivers/net/")
> 
> This fix commit isn't correct.
> 
> Thanks,
> Xiaolong
> 
> >Cc: stable@dpdk.org
> 
> 
> 
> >
> >Signed-off-by: Guinan Sun <guinanx.sun@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;                                         \
> >+	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
> >