[dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

[dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

[Alexander Kozyrev]

The modify_field Flow API assumes that the META item is 32 bits wide.
But the C Register that is used for Meta item can be 16 or 32 bits
wide depending on kernel and firmware configurations.
Take this into consideration and use the appropriate META width.

Fixes: 641dbe4fb0 ("net/mlx5: support modify field flow action")
Cc: stable@dpdk.org

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
---
 drivers/net/mlx5/mlx5_flow_dv.c | 48 ++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 13 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 935a55ef75..c50649a107 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1356,7 +1356,8 @@ flow_dv_convert_action_modify_ipv6_dscp
 }
 
 static int
-mlx5_flow_item_field_width(enum rte_flow_field_id field)
+mlx5_flow_item_field_width(struct mlx5_dev_config *config,
+			   enum rte_flow_field_id field)
 {
 	switch (field) {
 	case RTE_FLOW_FIELD_START:
@@ -1404,7 +1405,12 @@ mlx5_flow_item_field_width(enum rte_flow_field_id field)
 	case RTE_FLOW_FIELD_MARK:
 		return 24;
 	case RTE_FLOW_FIELD_META:
-		return 32;
+		if (config->dv_xmeta_en == MLX5_XMETA_MODE_META16)
+			return 16;
+		else if (config->dv_xmeta_en == MLX5_XMETA_MODE_META32)
+			return 32;
+		else
+			return 0;
 	case RTE_FLOW_FIELD_POINTER:
 	case RTE_FLOW_FIELD_VALUE:
 		return 64;
@@ -1424,6 +1430,8 @@ mlx5_flow_field_id_to_modify_info
 		 const struct rte_flow_attr *attr,
 		 struct rte_flow_error *error)
 {
+	struct mlx5_priv *priv = dev->data->dev_private;
+	struct mlx5_dev_config *config = &priv->config;
 	uint32_t idx = 0;
 	uint64_t val = 0;
 	switch (data->field) {
@@ -1777,17 +1785,28 @@ mlx5_flow_field_id_to_modify_info
 		break;
 	case RTE_FLOW_FIELD_META:
 		{
+			unsigned int xmeta = config->dv_xmeta_en;
 			int reg = flow_dv_get_metadata_reg(dev, attr, error);
 			if (reg < 0)
 				return;
 			MLX5_ASSERT(reg != REG_NON);
 			MLX5_ASSERT((unsigned int)reg < RTE_DIM(reg_to_field));
-			info[idx] = (struct field_modify_info){4, 0,
-						reg_to_field[reg]};
-			if (mask)
-				mask[idx] =
-					rte_cpu_to_be_32(0xffffffff >>
-							 (32 - width));
+			if (xmeta == MLX5_XMETA_MODE_META16) {
+				info[idx] = (struct field_modify_info){2, 0,
+							reg_to_field[reg]};
+				if (mask)
+					mask[idx] = rte_cpu_to_be_16(0xffff >>
+								(16 - width));
+			} else if (xmeta == MLX5_XMETA_MODE_META32) {
+				info[idx] = (struct field_modify_info){4, 0,
+							reg_to_field[reg]};
+				if (mask)
+					mask[idx] =
+						rte_cpu_to_be_32(0xffffffff >>
+								(32 - width));
+			} else {
+				MLX5_ASSERT(false);
+			}
 		}
 		break;
 	case RTE_FLOW_FIELD_POINTER:
@@ -1845,6 +1864,8 @@ flow_dv_convert_action_modify_field
 			 const struct rte_flow_attr *attr,
 			 struct rte_flow_error *error)
 {
+	struct mlx5_priv *priv = dev->data->dev_private;
+	struct mlx5_dev_config *config = &priv->config;
 	const struct rte_flow_action_modify_field *conf =
 		(const struct rte_flow_action_modify_field *)(action->conf);
 	struct rte_flow_item item;
@@ -1855,7 +1876,8 @@ flow_dv_convert_action_modify_field
 	uint32_t mask[MLX5_ACT_MAX_MOD_FIELDS] = {0, 0, 0, 0, 0};
 	uint32_t value[MLX5_ACT_MAX_MOD_FIELDS] = {0, 0, 0, 0, 0};
 	uint32_t type;
-	uint32_t dst_width = mlx5_flow_item_field_width(conf->dst.field);
+	uint32_t dst_width = mlx5_flow_item_field_width(config,
+							conf->dst.field);
 
 	if (conf->src.field == RTE_FLOW_FIELD_POINTER ||
 		conf->src.field == RTE_FLOW_FIELD_VALUE) {
@@ -4710,10 +4732,10 @@ flow_dv_validate_action_modify_field(struct rte_eth_dev *dev,
 	struct mlx5_dev_config *config = &priv->config;
 	const struct rte_flow_action_modify_field *action_modify_field =
 		action->conf;
-	uint32_t dst_width =
-		mlx5_flow_item_field_width(action_modify_field->dst.field);
-	uint32_t src_width =
-		mlx5_flow_item_field_width(action_modify_field->src.field);
+	uint32_t dst_width = mlx5_flow_item_field_width(config,
+				action_modify_field->dst.field);
+	uint32_t src_width = mlx5_flow_item_field_width(config,
+				action_modify_field->src.field);
 
 	ret = flow_dv_validate_action_modify_hdr(action_flags, action, error);
 	if (ret)
-- 
2.18.2

Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

[Slava Ovsiienko]

> -----Original Message-----
> From: Alexander Kozyrev <akozyrev@nvidia.com>
> Sent: Thursday, May 13, 2021 22:55
> To: dev@dpdk.org
> Cc: stable@dpdk.org; Raslan Darawsheh <rasland@nvidia.com>; Slava
> Ovsiienko <viacheslavo@nvidia.com>; Matan Azrad <matan@nvidia.com>
> Subject: [PATCH] net/mlx5: check meta register width for modify field
> 
> The modify_field Flow API assumes that the META item is 32 bits wide.
> But the C Register that is used for Meta item can be 16 or 32 bits wide
> depending on kernel and firmware configurations.
> Take this into consideration and use the appropriate META width.
> 
> Fixes: 641dbe4fb0 ("net/mlx5: support modify field flow action")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

[Thomas Monjalon]

> > The modify_field Flow API assumes that the META item is 32 bits wide.
> > But the C Register that is used for Meta item can be 16 or 32 bits wide
> > depending on kernel and firmware configurations.
> > Take this into consideration and use the appropriate META width.
> > 
> > Fixes: 641dbe4fb0 ("net/mlx5: support modify field flow action")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Applied in next-net-mlx, thanks.

Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

[Asaf Penso]

I didn't plan to have it in this release since it's not critical and I'm afraid of such changes... I didn't mention this in the status mail today.
@Raslan Darawsheh<mailto:rasland@nvidia.com> can we check tomorrow regression result?
If not good we'll need to revert it.

Regards,
Asaf Penso
________________________________
From: Thomas Monjalon <thomas@monjalon.net>
Sent: Tuesday, May 18, 2021 12:43:34 PM
To: Alexander Kozyrev <akozyrev@nvidia.com>
Cc: dev@dpdk.org <dev@dpdk.org>; stable@dpdk.org <stable@dpdk.org>; Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad <matan@nvidia.com>; Slava Ovsiienko <viacheslavo@nvidia.com>; Asaf Penso <asafp@nvidia.com>
Subject: Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

> > The modify_field Flow API assumes that the META item is 32 bits wide.
> > But the C Register that is used for Meta item can be 16 or 32 bits wide
> > depending on kernel and firmware configurations.
> > Take this into consideration and use the appropriate META width.
> >
> > Fixes: 641dbe4fb0 ("net/mlx5: support modify field flow action")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Applied in next-net-mlx, thanks.

Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

[Slava Ovsiienko]

Yes, It is palliative, it is not perfect, and, IMO, it is crucial - with always applying 32-bit wide values we can destroy the kernel part of reg_c0
in some extended metadata modes and this would lead to steering malfunction.

With best regards,
Slava

From: Asaf Penso <asafp@nvidia.com>
Sent: Tuesday, May 18, 2021 14:33
To: NBU-Contact-Thomas Monjalon <thomas@monjalon.net>; Alexander Kozyrev <akozyrev@nvidia.com>; Raslan Darawsheh <rasland@nvidia.com>
Cc: dev@dpdk.org; stable@dpdk.org; Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad <matan@nvidia.com>; Slava Ovsiienko <viacheslavo@nvidia.com>
Subject: Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

I didn't plan to have it in this release since it's not critical and I'm afraid of such changes... I didn't mention this in the status mail today.
@Raslan Darawsheh<mailto:rasland@nvidia.com> can we check tomorrow regression result?
If not good we'll need to revert it.

Regards,
Asaf Penso
________________________________
From: Thomas Monjalon <thomas@monjalon.net<mailto:thomas@monjalon.net>>
Sent: Tuesday, May 18, 2021 12:43:34 PM
To: Alexander Kozyrev <akozyrev@nvidia.com<mailto:akozyrev@nvidia.com>>
Cc: dev@dpdk.org<mailto:dev@dpdk.org> <dev@dpdk.org<mailto:dev@dpdk.org>>; stable@dpdk.org<mailto:stable@dpdk.org> <stable@dpdk.org<mailto:stable@dpdk.org>>; Raslan Darawsheh <rasland@nvidia.com<mailto:rasland@nvidia.com>>; Matan Azrad <matan@nvidia.com<mailto:matan@nvidia.com>>; Slava Ovsiienko <viacheslavo@nvidia.com<mailto:viacheslavo@nvidia.com>>; Asaf Penso <asafp@nvidia.com<mailto:asafp@nvidia.com>>
Subject: Re: [dpdk-dev] [PATCH] net/mlx5: check meta register width for modify field

> > The modify_field Flow API assumes that the META item is 32 bits wide.
> > But the C Register that is used for Meta item can be 16 or 32 bits wide
> > depending on kernel and firmware configurations.
> > Take this into consideration and use the appropriate META width.
> >
> > Fixes: 641dbe4fb0 ("net/mlx5: support modify field flow action")
> > Cc: stable@dpdk.org<mailto:stable@dpdk.org>
> >
> > Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com<mailto:akozyrev@nvidia.com>>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com<mailto:viacheslavo@nvidia.com>>

Applied in next-net-mlx, thanks.