[PATCH v2] net/ixgbe: consider DCB/VMDq conf when getting RSS conf

[PATCH v2] net/ixgbe: consider DCB/VMDq conf when getting RSS conf

[Min Zhou]

The mrqe field of MRQC register is an enum. From the Intel 82599 datasheet,
we know that these values below for the mrqe field are all related to RSS
configuration:
	0000b = RSS disabled.
	0001b = RSS only -- Single set of RSS 16 queues.
	0010b = DCB enabled and RSS disabled -- 8 TCs, each allocated 1 queue.
 	0011b = DCB enabled and RSS disabled -- 4 TCs, each allocated 1 queue.
	0100b = DCB and RSS -- 8 TCs, each allocated 16 RSS queues.
	0101b = DCB and RSS -- 4 TCs, each allocated 16 RSS queues.
	1000b = Virtualization only -- 64 pools, no RSS, each pool allocated
		2 queues.
	1010b = Virtualization and RSS -- 32 pools, each allocated 4 RSS queues.
	1011b = Virtualization and RSS -- 64 pools, each allocated 2 RSS queues.

The ixgbe pmd will check whether the rss is enabled or not when getting
rss conf. So, beside comparing the value of mrqe field with xxx0b and
xxx1b, we also need to consider the other configurations, such as
DCB + RSS or VMDQ + RSS. Otherwise, we may not get the correct rss conf
in some cases, such as when we use DCB and RSS with 8 TCs which corresponds
to 0100b for the mrqe field.

Signed-off-by: Min Zhou <zhoumin@loongson.cn>
---
v2:
- Add warning messages when removing RSS for virtualization and RSS with
  32 pools
---
 drivers/net/ixgbe/ixgbe_rxtx.c | 94 ++++++++++++++++++++++++++++++----
 1 file changed, 83 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index c9d6ca9efe..6b3d3a4d1a 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -3461,18 +3461,92 @@ static uint8_t rss_intel_key[40] = {
 	0x6A, 0x42, 0xB7, 0x3B, 0xBE, 0xAC, 0x01, 0xFA,
 };
 
+/*
+ * This function removes the rss configuration in the mrqe field of MRQC
+ * register and tries to maintain other configurations in the field, such
+ * DCB and Virtualization.
+ *
+ * The MRQC register supplied in section 8.2.3.7.12 of the Intel 82599
+ * datasheet. From the datasheet, we know that the mrqe field is an enum. So,
+ * masking the mrqe field with '~IXGBE_MRQC_RSSEN' may not completely disable
+ * rss configuration. For example, the value of mrqe is equal to 0101b when DCB
+ * and RSS with 4 TCs configured, however 'mrqe &= ~0x01' is equal to 0100b
+ * which corresponds to DCB and RSS with 8 TCs.
+ */
+static void
+ixgbe_mrqc_rss_remove(struct ixgbe_hw *hw)
+{
+	uint32_t mrqc;
+	uint32_t mrqc_reg;
+	uint32_t mrqe_val;
+
+	mrqc_reg = ixgbe_mrqc_reg_get(hw->mac.type);
+	mrqc = IXGBE_READ_REG(hw, mrqc_reg);
+	mrqe_val = mrqc & IXGBE_MRQC_MRQE_MASK;
+
+	switch (mrqe_val) {
+	case IXGBE_MRQC_RSSEN:
+		/* Completely disable rss */
+		mrqe_val = 0;
+		break;
+	case IXGBE_MRQC_RTRSS8TCEN:
+		mrqe_val = IXGBE_MRQC_RT8TCEN;
+		break;
+	case IXGBE_MRQC_RTRSS4TCEN:
+		mrqe_val = IXGBE_MRQC_RT4TCEN;
+		break;
+	case IXGBE_MRQC_VMDQRSS64EN:
+		mrqe_val = IXGBE_MRQC_VMDQEN;
+		break;
+	case IXGBE_MRQC_VMDQRSS32EN:
+		PMD_DRV_LOG(WARNING, "There is no regression for virtualization"
+			" and RSS with 32 pools among the MRQE configurations"
+			" after removing RSS, and left it unchanged.");
+		break;
+	default:
+		/* No rss configured, leave it as it is */
+		break;
+	}
+	mrqc = (mrqc & ~IXGBE_MRQC_MRQE_MASK) | mrqe_val;
+	IXGBE_WRITE_REG(hw, mrqc_reg, mrqc);
+}
+
 static void
 ixgbe_rss_disable(struct rte_eth_dev *dev)
 {
 	struct ixgbe_hw *hw;
+
+	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+	/* Remove the rss configuration and maintain the other configurations */
+	ixgbe_mrqc_rss_remove(hw);
+}
+
+/*
+ * This function checks whether the rss is enabled or not by comparing the mrqe
+ * field with some RSS related enums and also considers the configurations for
+ * DCB + RSS and Virtualization + RSS. It is necessary for getting the correct
+ * rss hash configurations from the RSS Field Enable field of MRQC register
+ * when both RSS and DCB/VMDQ are used.
+ */
+static bool
+ixgbe_rss_enabled(struct ixgbe_hw *hw)
+{
 	uint32_t mrqc;
 	uint32_t mrqc_reg;
+	uint32_t mrqe_val;
 
-	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 	mrqc_reg = ixgbe_mrqc_reg_get(hw->mac.type);
 	mrqc = IXGBE_READ_REG(hw, mrqc_reg);
-	mrqc &= ~IXGBE_MRQC_RSSEN;
-	IXGBE_WRITE_REG(hw, mrqc_reg, mrqc);
+	mrqe_val = mrqc & IXGBE_MRQC_MRQE_MASK;
+
+	if (mrqe_val == IXGBE_MRQC_RSSEN ||
+		mrqe_val == IXGBE_MRQC_RTRSS8TCEN ||
+		mrqe_val == IXGBE_MRQC_RTRSS4TCEN ||
+		mrqe_val == IXGBE_MRQC_VMDQRSS64EN ||
+		mrqe_val == IXGBE_MRQC_VMDQRSS32EN)
+		return true;
+
+	return false;
 }
 
 static void
@@ -3530,9 +3604,7 @@ ixgbe_dev_rss_hash_update(struct rte_eth_dev *dev,
 			  struct rte_eth_rss_conf *rss_conf)
 {
 	struct ixgbe_hw *hw;
-	uint32_t mrqc;
 	uint64_t rss_hf;
-	uint32_t mrqc_reg;
 
 	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 
@@ -3541,7 +3613,6 @@ ixgbe_dev_rss_hash_update(struct rte_eth_dev *dev,
 			"NIC.");
 		return -ENOTSUP;
 	}
-	mrqc_reg = ixgbe_mrqc_reg_get(hw->mac.type);
 
 	/*
 	 * Excerpt from section 7.1.2.8 Receive-Side Scaling (RSS):
@@ -3553,8 +3624,7 @@ ixgbe_dev_rss_hash_update(struct rte_eth_dev *dev,
 	 * disabled at initialization time.
 	 */
 	rss_hf = rss_conf->rss_hf & IXGBE_RSS_OFFLOAD_ALL;
-	mrqc = IXGBE_READ_REG(hw, mrqc_reg);
-	if (!(mrqc & IXGBE_MRQC_RSSEN)) { /* RSS disabled */
+	if (!ixgbe_rss_enabled(hw)) { /* RSS disabled */
 		if (rss_hf != 0) /* Enable RSS */
 			return -(EINVAL);
 		return 0; /* Nothing to do */
@@ -3594,12 +3664,14 @@ ixgbe_dev_rss_hash_conf_get(struct rte_eth_dev *dev,
 		}
 	}
 
-	/* Get RSS functions configured in MRQC register */
-	mrqc = IXGBE_READ_REG(hw, mrqc_reg);
-	if ((mrqc & IXGBE_MRQC_RSSEN) == 0) { /* RSS is disabled */
+	if (!ixgbe_rss_enabled(hw)) { /* RSS is disabled */
 		rss_conf->rss_hf = 0;
 		return 0;
 	}
+
+	/* Get RSS functions configured in MRQC register */
+	mrqc = IXGBE_READ_REG(hw, mrqc_reg);
+
 	rss_hf = 0;
 	if (mrqc & IXGBE_MRQC_RSS_FIELD_IPV4)
 		rss_hf |= RTE_ETH_RSS_IPV4;
-- 
2.31.1

RE: [PATCH v2] net/ixgbe: consider DCB/VMDq conf when getting RSS conf

[Zhang, Qi Z]

> -----Original Message-----
> From: Min Zhou <zhoumin@loongson.cn>
> Sent: Friday, April 28, 2023 4:43 PM
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Yang, Qiming
> <qiming.yang@intel.com>; Wu, Wenjun1 <wenjun1.wu@intel.com>;
> zhoumin@loongson.cn
> Cc: dev@dpdk.org; maobibo@loongson.cn
> Subject: [PATCH v2] net/ixgbe: consider DCB/VMDq conf when getting RSS
> conf
> 
> The mrqe field of MRQC register is an enum. From the Intel 82599 datasheet,
> we know that these values below for the mrqe field are all related to RSS
> configuration:
> 	0000b = RSS disabled.
> 	0001b = RSS only -- Single set of RSS 16 queues.
> 	0010b = DCB enabled and RSS disabled -- 8 TCs, each allocated 1
> queue.
>  	0011b = DCB enabled and RSS disabled -- 4 TCs, each allocated 1
> queue.
> 	0100b = DCB and RSS -- 8 TCs, each allocated 16 RSS queues.
> 	0101b = DCB and RSS -- 4 TCs, each allocated 16 RSS queues.
> 	1000b = Virtualization only -- 64 pools, no RSS, each pool allocated
> 		2 queues.
> 	1010b = Virtualization and RSS -- 32 pools, each allocated 4 RSS
> queues.
> 	1011b = Virtualization and RSS -- 64 pools, each allocated 2 RSS
> queues.
> 
> The ixgbe pmd will check whether the rss is enabled or not when getting rss
> conf. So, beside comparing the value of mrqe field with xxx0b and xxx1b, we
> also need to consider the other configurations, such as DCB + RSS or VMDQ +
> RSS. Otherwise, we may not get the correct rss conf in some cases, such as
> when we use DCB and RSS with 8 TCs which corresponds to 0100b for the
> mrqe field.
> 
> Signed-off-by: Min Zhou <zhoumin@loongson.cn>

Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Applied to dpdk-next-net-intel.

Thanks
Qi