[dpdk-dev] [PATCH v2] net/e1000: update UPDATE_VF_STAT to handle rollover

[David Harton]

Modified UPDATE_VF_STAT to properly handle rollover conditions.

Fixes: d82170d27918 ("igb: add VF support")
Cc: intel.com

Signed-off-by: David Harton <dharton at cisco.com>
---
 drivers/net/e1000/igb_ethdev.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
index a3e30dbe5..825663267 100644
--- a/drivers/net/e1000/igb_ethdev.c
+++ b/drivers/net/e1000/igb_ethdev.c
@@ -261,11 +261,15 @@ 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)                          \
+{                                                               \
+	u32 latest = E1000_READ_REG(hw, reg);                   \
+	if (latest >= last)                                     \
+		cur += (latest - last);                         \
+	else                                                    \
+		cur += ((latest + ((uint64_t)1 << 32)) - last); \
+	cur &= UINT_MAX;                                        \
+	last = latest;                                          \
 }
 
 #define IGB_FC_PAUSE_TIME 0x0680
-- 
2.19.1