ethdev: make representor parameter more explicit

PATCH Superseded Gregory Etelson 5 participants 15 messages Oct 28, 2025 – Nov 13, 2025 Network drivers

Share & tools

Gregory Etelson

author

2025-10-28 10:00 UTC #0 lore raw

PATCH 1/2 ethdev: make representor parameter more explicit

The current format for a port representor parameter is '-a DBDF,representor=pfXvfY'.
That parameter syntax describes port representor relative to PCI device DBDF.
In that notation VF Y belongs to PF X and PF X is relative to DBDF.

The syntax 'pfXvfY' will probe 2 port representors: PF X and VF Y. If we want to refer only to VF Y related to PF X, the parameter must be '(pfX)vfY'.
In this case only VF Y representor will be probed.

Signed-off-by Gregory Etelson <[email protected]>

---
 doc/guides/prog_guide/ethdev/ethdev.rst | 27 ++++++++++++++++++++-----
 lib/ethdev/ethdev_driver.h              |  4 ++++
 lib/ethdev/ethdev_private.c             | 13 ++++++++++--
 3 files changed, 37 insertions(+), 7 deletions(-)

doc/guides/prog_guide/ethdev/ethdev.rst +22 -5

index 89eb31a48d..69f84325c7 100644
@@ -379,18 +379,35 @@ parameters to those ports.
    -a DBDF,representor=vf[0,4,6,9]
    -a DBDF,representor=vf[0-31]
    -a DBDF,representor=vf[0,2-4,7,9-11]
+
+  These example will attach VF representors relative to DBDF.
+  The VF IDs can be a list, a range or a mix.
+  SF representors follow the same syntax::
+
    -a DBDF,representor=sf0
    -a DBDF,representor=sf[1,3,5]
    -a DBDF,representor=sf[0-1023]
    -a DBDF,representor=sf[0,2-4,7,9-11]
+
+  If there are multiple PFs associated with the same PCI device,
+  the PF ID must be used to distinguish between representors relative to different PFs::
+
    -a DBDF,representor=pf1vf0
-   -a DBDF,representor=pf[0-1]sf[0-127]
-   -a DBDF,representor=pf1
+   -a DBDF,representor=pf[0-1]vf0
+
+  The example above will attach 4 representors pf0vf0, pf1vf0, pf0 and pf1.
+  If only VF representors are required, the PF part must be enclosed with parenthesis::
+
+   -a DBDF,representor=(pf[0-1])vf0
+
+  The example above will attach 2 representors pf0vf0, pf1vf0.
+
+  List of representors for the same PCI device is enclosed in square brackets::
+
    -a DBDF,representor=[pf[0-1],pf2vf[0-2],pf3[3,5-8]]
-   (Multiple representors in one device argument can be represented as a list)
 
-Note: PMDs are not required to support the standard device arguments and users
-should consult the relevant PMD documentation to see support devargs.
+  Note: PMDs may have additional extensions for the representor parameter, and users
+  should consult the relevant PMD documentation to see support devargs.
 
 Extended Statistics API
 ~~~~~~~~~~~~~~~~~~~~~~~

lib/ethdev/ethdev_driver.h +4 -0

index db0b3d2c40..645e76015a 100644
@@ -2012,6 +2012,8 @@ __rte_internal
 int
 rte_eth_switch_domain_free(uint16_t domain_id);
 
+#define RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR RTE_BIT32(1)
+
 /**
  * Generic Ethernet device arguments
  *

@@ -2024,6 +2026,8 @@ struct rte_eth_devargs {
 	/** number of controllers in multi-host controllers field */
 	uint16_t ports[RTE_MAX_ETHPORTS];
 	/** port/s number to enable on a multi-port single function */
+	uint32_t port_flags;
+	/** ports flags for special processing */
 	uint16_t nb_ports;
 	/** number of ports in ports field */
 	uint16_t representor_ports[RTE_MAX_ETHPORTS];

lib/ethdev/ethdev_private.c +11 -2

index a881e9c003..df5fdf25ec 100644
@@ -152,11 +152,20 @@ rte_eth_devargs_parse_representor_ports(char *str, void *data)
 		if (str == NULL)
 			goto done;
 	}
-	if (str[0] == 'p' && str[1] == 'f') {
+	/* pfX... or (pfX)... */
+	if ((str[0] == 'p' && str[1] == 'f') ||
+	    (str[0] == '(' && str[1] == 'p' && str[2] == 'f')) {
 		eth_da->type = RTE_ETH_REPRESENTOR_PF;
-		str += 2;
+		if (str[0] == '(')
+			str++; /* advance past leading "(" */
+		str += 2; /* advance past "pf" */
 		str = rte_eth_devargs_process_list(str, eth_da->ports,
 				&eth_da->nb_ports, RTE_DIM(eth_da->ports));
+		if (str[0] == ')') {
+			str++; /* advance past ")" */
+			eth_da->port_flags =
+				RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR;
+		}
 		if (str == NULL || str[0] == '\0')
 			goto done;
 	} else if (eth_da->nb_mh_controllers > 0) {

Signature · 1 line

2.51.0

Gregory Etelson

author

2025-10-28 10:00 UTC #1 lore raw

PATCH 2/2 net/mlx5: support PF representor suppresion in multi-port E-Switch

In multi-port E-Switch setup, the MLX5 PMD always added
PF representor port.
For example, representor=pf1vf[0,1] implicitly added PF1 representor port:

```
Port     Name
0        p0
1        p1
2        representor_c0pf1vf0
3        representor_c0pf1vf1
```

The patch adds support for the new representor format that suppresses PF representor attachment:

Example: representor=(pf1)vf[0,1]

```
Port     Name
0        p0
1        representor_c0pf1vf0
2        representor_c0pf1vf1
```

Signed-off-by Gregory Etelson <[email protected]>

---
 drivers/net/mlx5/linux/mlx5_os.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

drivers/net/mlx5/linux/mlx5_os.c +12 -2

index 8d11b1ac3a..92084b4cdd 100644
@@ -2284,6 +2284,12 @@ mlx5_device_mpesw_pci_match(struct ibv_device *ibv,
 	return -1;
 }
 
+static inline bool
+mlx5_ingnore_pf_representor(const struct rte_eth_devargs *eth_da)
+{
+	return (eth_da->port_flags & RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR) != 0;
+}
+
 /**
  * Register a PCI device within bonding.
  *

@@ -2593,8 +2599,12 @@ mlx5_os_pci_probe_pf(struct mlx5_common_device *cdev,
 						list[ns].info.master = 1;
 						list[ns].info.representor = 0;
 					} else {
-						list[ns].info.master = 0;
-						list[ns].info.representor = 1;
+						if (mlx5_ingnore_pf_representor(req_eth_da)) {
+							continue;
+						} else {
+							list[ns].info.master = 0;
+							list[ns].info.representor = 1;
+						}
 					}
 					/*
 					 * Ports of this type have uplink port index

Signature · 1 line

2.51.0

Gregory Etelson

author

2025-11-05 17:39 UTC #2 lore raw

PATCH v2 1/2 ethdev: make representor parameter more explicit

In reply to Gregory Etelson

Signed-off-by Gregory Etelson <[email protected]>

---
v2: Add comments.

    In rte_eth_devargs structure rename port_flags -> flags. 
---
 doc/guides/prog_guide/ethdev/ethdev.rst | 27 ++++++++++++++++++++-----
 lib/ethdev/ethdev_driver.h              |  5 +++++
 lib/ethdev/ethdev_private.c             | 13 ++++++++++--
 3 files changed, 38 insertions(+), 7 deletions(-)

doc/guides/prog_guide/ethdev/ethdev.rst +22 -5

index 89eb31a48d..daaf43ea3b 100644
@@ -379,18 +379,35 @@ parameters to those ports.
    -a DBDF,representor=vf[0,4,6,9]
    -a DBDF,representor=vf[0-31]
    -a DBDF,representor=vf[0,2-4,7,9-11]
+
+  These examples will attach VF representors relative to DBDF.
+  The VF IDs can be a list, a range or a mix.
+  SF representors follow the same syntax::
+
    -a DBDF,representor=sf0
    -a DBDF,representor=sf[1,3,5]
    -a DBDF,representor=sf[0-1023]
    -a DBDF,representor=sf[0,2-4,7,9-11]
+
+  If there are multiple PFs associated with the same PCI device,
+  the PF ID must be used to distinguish between representors relative to different PFs::
+
    -a DBDF,representor=pf1vf0
-   -a DBDF,representor=pf[0-1]sf[0-127]
-   -a DBDF,representor=pf1
+   -a DBDF,representor=pf[0-1]vf0
+
+  The example above will attach 4 representors pf0vf0, pf1vf0, pf0 and pf1.
+  If only VF representors are required, the PF part must be enclosed with parentheses::
+
+   -a DBDF,representor=(pf[0-1])vf0
+
+  The example above will attach 2 representors pf0vf0, pf1vf0.
+
+  List of representors for the same PCI device is enclosed in square brackets::
+
    -a DBDF,representor=[pf[0-1],pf2vf[0-2],pf3[3,5-8]]
-   (Multiple representors in one device argument can be represented as a list)
 
-Note: PMDs are not required to support the standard device arguments and users
-should consult the relevant PMD documentation to see support devargs.
+  Note: PMDs may have additional extensions for the representor parameter, and users
+  should consult the relevant PMD documentation to see support devargs.
 
 Extended Statistics API
 ~~~~~~~~~~~~~~~~~~~~~~~

lib/ethdev/ethdev_driver.h +5 -0

index db0b3d2c40..31674210fe 100644
@@ -2012,6 +2012,10 @@ __rte_internal
 int
 rte_eth_switch_domain_free(uint16_t domain_id);
 
+/* Flags for rte_eth_devargs::flags. */
+/* When enclosed in parentheses, the PF representor is not required. */
+#define RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR RTE_BIT32(0)
+
 /**
  * Generic Ethernet device arguments
  *

@@ -2026,6 +2030,7 @@ struct rte_eth_devargs {
 	/** port/s number to enable on a multi-port single function */
 	uint16_t nb_ports;
 	/** number of ports in ports field */
+	uint32_t flags; /* see RTE_ETH_DEVARG_* */
 	uint16_t representor_ports[RTE_MAX_ETHPORTS];
 	/** representor port/s identifier to enable on device */
 	uint16_t nb_representor_ports;

lib/ethdev/ethdev_private.c +11 -2

index a881e9c003..d332654f00 100644
@@ -152,11 +152,20 @@ rte_eth_devargs_parse_representor_ports(char *str, void *data)
 		if (str == NULL)
 			goto done;
 	}
-	if (str[0] == 'p' && str[1] == 'f') {
+	/* pfX... or (pfX)... */
+	if ((str[0] == 'p' && str[1] == 'f') ||
+	    (str[0] == '(' && str[1] == 'p' && str[2] == 'f')) {
 		eth_da->type = RTE_ETH_REPRESENTOR_PF;
-		str += 2;
+		if (str[0] == '(')
+			str++; /* advance past leading "(" */
+		str += 2; /* advance past "pf" */
 		str = rte_eth_devargs_process_list(str, eth_da->ports,
 				&eth_da->nb_ports, RTE_DIM(eth_da->ports));
+		if (str != NULL && str[0] == ')') {
+			str++; /* advance past ")" */
+			eth_da->flags =
+				RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR;
+		}
 		if (str == NULL || str[0] == '\0')
 			goto done;
 	} else if (eth_da->nb_mh_controllers > 0) {

Signature · 1 line

2.51.0

Gregory Etelson

author

2025-11-05 17:39 UTC #3 lore raw

PATCH v2 2/2 net/mlx5: support PF representor suppresion in multi-port E-Switch

In multi-port E-Switch setup, the MLX5 PMD always added
PF representor port.
For example, representor=pf1vf[0,1] implicitly added PF1 representor port:

```
Port     Name
0        p0
1        p1
2        representor_c0pf1vf0
3        representor_c0pf1vf1
```

The patch adds support for the new representor format that suppresses PF representor attachment:

Example: representor=(pf1)vf[0,1]

```
Port     Name
0        p0
1        representor_c0pf1vf0
2        representor_c0pf1vf1
```

Signed-off-by Gregory Etelson <[email protected]>

---
 drivers/net/mlx5/linux/mlx5_os.c | 8 ++++++++
 1 file changed, 8 insertions(+)

drivers/net/mlx5/linux/mlx5_os.c +8 -0

index c742e0f282..fe80773d49 100644
@@ -2284,6 +2284,12 @@ mlx5_device_mpesw_pci_match(struct ibv_device *ibv,
 	return -1;
 }
 
+static inline bool
+mlx5_ignore_pf_representor(const struct rte_eth_devargs *eth_da)
+{
+	return (eth_da->flags & RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR) != 0;
+}
+
 /**
  * Register a PCI device within bonding.
  *

@@ -2592,6 +2598,8 @@ mlx5_os_pci_probe_pf(struct mlx5_common_device *cdev,
 					if (list[ns].info.port_name == mpesw) {
 						list[ns].info.master = 1;
 						list[ns].info.representor = 0;
+					} else if (mlx5_ignore_pf_representor(&eth_da)) {
+						continue;
 					} else {
 						list[ns].info.master = 0;
 						list[ns].info.representor = 1;

Signature · 1 line

2.51.0

Gregory Etelson

author

2025-11-05 17:50 UTC #4 lore raw

PATCH v3 1/2 ethdev: make representor parameter more explicit

In reply to Gregory Etelson

Signed-off-by Gregory Etelson <[email protected]>

---
v2: Add comments.

    In rte_eth_devargs structure rename port_flags -> flags. 
---
 doc/guides/prog_guide/ethdev/ethdev.rst | 27 ++++++++++++++++++++-----
 lib/ethdev/ethdev_driver.h              |  5 +++++
 lib/ethdev/ethdev_private.c             | 13 ++++++++++--
 3 files changed, 38 insertions(+), 7 deletions(-)

doc/guides/prog_guide/ethdev/ethdev.rst +22 -5

index 89eb31a48d..daaf43ea3b 100644
@@ -379,18 +379,35 @@ parameters to those ports.
    -a DBDF,representor=vf[0,4,6,9]
    -a DBDF,representor=vf[0-31]
    -a DBDF,representor=vf[0,2-4,7,9-11]
+
+  These examples will attach VF representors relative to DBDF.
+  The VF IDs can be a list, a range or a mix.
+  SF representors follow the same syntax::
+
    -a DBDF,representor=sf0
    -a DBDF,representor=sf[1,3,5]
    -a DBDF,representor=sf[0-1023]
    -a DBDF,representor=sf[0,2-4,7,9-11]
+
+  If there are multiple PFs associated with the same PCI device,
+  the PF ID must be used to distinguish between representors relative to different PFs::
+
    -a DBDF,representor=pf1vf0
-   -a DBDF,representor=pf[0-1]sf[0-127]
-   -a DBDF,representor=pf1
+   -a DBDF,representor=pf[0-1]vf0
+
+  The example above will attach 4 representors pf0vf0, pf1vf0, pf0 and pf1.
+  If only VF representors are required, the PF part must be enclosed with parentheses::
+
+   -a DBDF,representor=(pf[0-1])vf0
+
+  The example above will attach 2 representors pf0vf0, pf1vf0.
+
+  List of representors for the same PCI device is enclosed in square brackets::
+
    -a DBDF,representor=[pf[0-1],pf2vf[0-2],pf3[3,5-8]]
-   (Multiple representors in one device argument can be represented as a list)
 
-Note: PMDs are not required to support the standard device arguments and users
-should consult the relevant PMD documentation to see support devargs.
+  Note: PMDs may have additional extensions for the representor parameter, and users
+  should consult the relevant PMD documentation to see support devargs.
 
 Extended Statistics API
 ~~~~~~~~~~~~~~~~~~~~~~~

lib/ethdev/ethdev_driver.h +5 -0

index db0b3d2c40..31674210fe 100644
@@ -2012,6 +2012,10 @@ __rte_internal
 int
 rte_eth_switch_domain_free(uint16_t domain_id);
 
+/* Flags for rte_eth_devargs::flags. */
+/* When enclosed in parentheses, the PF representor is not required. */
+#define RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR RTE_BIT32(0)
+
 /**
  * Generic Ethernet device arguments
  *

@@ -2026,6 +2030,7 @@ struct rte_eth_devargs {
 	/** port/s number to enable on a multi-port single function */
 	uint16_t nb_ports;
 	/** number of ports in ports field */
+	uint32_t flags; /* see RTE_ETH_DEVARG_* */
 	uint16_t representor_ports[RTE_MAX_ETHPORTS];
 	/** representor port/s identifier to enable on device */
 	uint16_t nb_representor_ports;

lib/ethdev/ethdev_private.c +11 -2

index a881e9c003..d332654f00 100644
@@ -152,11 +152,20 @@ rte_eth_devargs_parse_representor_ports(char *str, void *data)
 		if (str == NULL)
 			goto done;
 	}
-	if (str[0] == 'p' && str[1] == 'f') {
+	/* pfX... or (pfX)... */
+	if ((str[0] == 'p' && str[1] == 'f') ||
+	    (str[0] == '(' && str[1] == 'p' && str[2] == 'f')) {
 		eth_da->type = RTE_ETH_REPRESENTOR_PF;
-		str += 2;
+		if (str[0] == '(')
+			str++; /* advance past leading "(" */
+		str += 2; /* advance past "pf" */
 		str = rte_eth_devargs_process_list(str, eth_da->ports,
 				&eth_da->nb_ports, RTE_DIM(eth_da->ports));
+		if (str != NULL && str[0] == ')') {
+			str++; /* advance past ")" */
+			eth_da->flags =
+				RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR;
+		}
 		if (str == NULL || str[0] == '\0')
 			goto done;
 	} else if (eth_da->nb_mh_controllers > 0) {

Signature · 1 line

2.51.0

Gregory Etelson

author

2025-11-05 17:50 UTC #5 lore raw

PATCH v3 2/2 net/mlx5: support PF representor suppression in multi-port E-Switch

In multi-port E-Switch setup, the MLX5 PMD always added
PF representor port.
For example, representor=pf1vf[0,1] implicitly added PF1 representor port:

```
Port     Name
0        p0
1        p1
2        representor_c0pf1vf0
3        representor_c0pf1vf1
```

The patch adds support for the new representor format that suppresses PF representor attachment:

Example: representor=(pf1)vf[0,1]

```
Port     Name
0        p0
1        representor_c0pf1vf0
2        representor_c0pf1vf1
```

Signed-off-by Gregory Etelson <[email protected]>

---
v2: Use updated rte_eth_devargs::flags.
v3: Fix typo in comment.

---
 drivers/net/mlx5/linux/mlx5_os.c | 8 ++++++++
 1 file changed, 8 insertions(+)

drivers/net/mlx5/linux/mlx5_os.c +8 -0

index c742e0f282..fe80773d49 100644
@@ -2284,6 +2284,12 @@ mlx5_device_mpesw_pci_match(struct ibv_device *ibv,
 	return -1;
 }
 
+static inline bool
+mlx5_ignore_pf_representor(const struct rte_eth_devargs *eth_da)
+{
+	return (eth_da->flags & RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR) != 0;
+}
+
 /**
  * Register a PCI device within bonding.
  *

@@ -2592,6 +2598,8 @@ mlx5_os_pci_probe_pf(struct mlx5_common_device *cdev,
 					if (list[ns].info.port_name == mpesw) {
 						list[ns].info.master = 1;
 						list[ns].info.representor = 0;
+					} else if (mlx5_ignore_pf_representor(&eth_da)) {
+						continue;
 					} else {
 						list[ns].info.master = 0;
 						list[ns].info.representor = 1;

Signature · 1 line

2.51.0

Stephen Hemminger

2025-11-05 19:20 UTC #6 lore raw

In reply to Gregory Etelson

Looks good as is, a couple of minor observations.

lib/ethdev/ethdev_private.c rte_eth_devargs_parse_representor_ports(char *str, void *data) · line 157

Quoted 3 lines

lib/ethdev/ethdev_private.c +3 -0

+	/* pfX... or (pfX)... */
+	if ((str[0] == 'p' && str[1] == 'f') ||
+	    (str[0] == '(' && str[1] == 'p' && str[2] == 'f')) {

This is correct but seem like it is getting verbose. If there are more cases than this looking for prefix, might be useful to have helper function.

Looks like devargs could use some better pattern matching, lots of string handling already in this code. String processing in C is often an error trap.

lib/ethdev/ethdev_private.c rte_eth_devargs_parse_representor_ports(char *str, void *data) · line 167

Quoted 4 lines

lib/ethdev/ethdev_private.c +4 -0

+		if (str != NULL && str[0] == ')') {
+			str++; /* advance past ")" */
+			eth_da->flags =
+				RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR;

Can't that go on one line, max line length in DPDK is 100. Is there a case where there could be multiple devargs flags?

Thomas Monjalon

2025-11-05 21:18 UTC #7 lore raw

05/11/2025 20:20, Stephen Hemminger:

Quoted 14 lines

Looks good as is, a couple of minor observations.
lib/ethdev/ethdev_private.c rte_eth_devargs_parse_representor_ports(char *str, void *data) · line 157
Quoted 3 lines
lib/ethdev/ethdev_private.c +3 -0
+	/* pfX... or (pfX)... */
+	if ((str[0] == 'p' && str[1] == 'f') ||
+	    (str[0] == '(' && str[1] == 'p' && str[2] == 'f')) {
This is correct but seem like it is getting verbose. If there are more cases than this looking for prefix, might be useful to have helper function.
Looks like devargs could use some better pattern matching, lots of string handling already in this code. String processing in C is often an error trap.

Quoted 7 lines

lib/ethdev/ethdev_private.c rte_eth_devargs_parse_representor_ports(char *str, void *data) · line 167
Quoted 4 lines
lib/ethdev/ethdev_private.c +4 -0
+		if (str != NULL && str[0] == ')') {
+			str++; /* advance past ")" */
+			eth_da->flags =
+				RTE_ETH_DEVARG_IGNORE_PF_REPRESENTOR;
Can't that go on one line, max line length in DPDK is 100. Is there a case where there could be multiple devargs flags?

It is the first flag.
I would prefer this flag to be named RTE_ETH_DEVARG_REPRESENTOR_IGNORE_PF.

Gregory Etelson

author

2025-11-06 05:54 UTC #8 lore raw

PATCH v4 1/2 ethdev: make representor parameter more explicit

In reply to Gregory Etelson

Signed-off-by Gregory Etelson <[email protected]>

---
v2: Add comments.

    In rte_eth_devargs structure rename port_flags -> flags.
v4: Rename devargs flag macro.	 
---
 doc/guides/prog_guide/ethdev/ethdev.rst | 27 ++++++++++++++++++++-----
 lib/ethdev/ethdev_driver.h              |  5 +++++
 lib/ethdev/ethdev_private.c             | 13 ++++++++++--
 3 files changed, 38 insertions(+), 7 deletions(-)

doc/guides/prog_guide/ethdev/ethdev.rst +22 -5

index 89eb31a48d..daaf43ea3b 100644
@@ -379,18 +379,35 @@ parameters to those ports.
    -a DBDF,representor=vf[0,4,6,9]
    -a DBDF,representor=vf[0-31]
    -a DBDF,representor=vf[0,2-4,7,9-11]
+
+  These examples will attach VF representors relative to DBDF.
+  The VF IDs can be a list, a range or a mix.
+  SF representors follow the same syntax::
+
    -a DBDF,representor=sf0
    -a DBDF,representor=sf[1,3,5]
    -a DBDF,representor=sf[0-1023]
    -a DBDF,representor=sf[0,2-4,7,9-11]
+
+  If there are multiple PFs associated with the same PCI device,
+  the PF ID must be used to distinguish between representors relative to different PFs::
+
    -a DBDF,representor=pf1vf0
-   -a DBDF,representor=pf[0-1]sf[0-127]
-   -a DBDF,representor=pf1
+   -a DBDF,representor=pf[0-1]vf0
+
+  The example above will attach 4 representors pf0vf0, pf1vf0, pf0 and pf1.
+  If only VF representors are required, the PF part must be enclosed with parentheses::
+
+   -a DBDF,representor=(pf[0-1])vf0
+
+  The example above will attach 2 representors pf0vf0, pf1vf0.
+
+  List of representors for the same PCI device is enclosed in square brackets::
+
    -a DBDF,representor=[pf[0-1],pf2vf[0-2],pf3[3,5-8]]
-   (Multiple representors in one device argument can be represented as a list)
 
-Note: PMDs are not required to support the standard device arguments and users
-should consult the relevant PMD documentation to see support devargs.
+  Note: PMDs may have additional extensions for the representor parameter, and users
+  should consult the relevant PMD documentation to see support devargs.
 
 Extended Statistics API
 ~~~~~~~~~~~~~~~~~~~~~~~

lib/ethdev/ethdev_driver.h +5 -0

index db0b3d2c40..1255cd6f2c 100644
@@ -2012,6 +2012,10 @@ __rte_internal
 int
 rte_eth_switch_domain_free(uint16_t domain_id);
 
+/* Flags for rte_eth_devargs::flags. */
+/* When enclosed in parentheses, the PF representor is not required. */
+#define RTE_ETH_DEVARG_REPRESENTOR_IGNORE_PF RTE_BIT32(0)
+
 /**
  * Generic Ethernet device arguments
  *

@@ -2026,6 +2030,7 @@ struct rte_eth_devargs {
 	/** port/s number to enable on a multi-port single function */
 	uint16_t nb_ports;
 	/** number of ports in ports field */
+	uint32_t flags; /* see RTE_ETH_DEVARG_* */
 	uint16_t representor_ports[RTE_MAX_ETHPORTS];
 	/** representor port/s identifier to enable on device */
 	uint16_t nb_representor_ports;

lib/ethdev/ethdev_private.c +11 -2

index a881e9c003..72a0723846 100644
@@ -152,11 +152,20 @@ rte_eth_devargs_parse_representor_ports(char *str, void *data)
 		if (str == NULL)
 			goto done;
 	}
-	if (str[0] == 'p' && str[1] == 'f') {
+	/* pfX... or (pfX)... */
+	if ((str[0] == 'p' && str[1] == 'f') ||
+	    (str[0] == '(' && str[1] == 'p' && str[2] == 'f')) {
 		eth_da->type = RTE_ETH_REPRESENTOR_PF;
-		str += 2;
+		if (str[0] == '(')
+			str++; /* advance past leading "(" */
+		str += 2; /* advance past "pf" */
 		str = rte_eth_devargs_process_list(str, eth_da->ports,
 				&eth_da->nb_ports, RTE_DIM(eth_da->ports));
+		if (str != NULL && str[0] == ')') {
+			str++; /* advance past ")" */
+			eth_da->flags =
+				RTE_ETH_DEVARG_REPRESENTOR_IGNORE_PF;
+		}
 		if (str == NULL || str[0] == '\0')
 			goto done;
 	} else if (eth_da->nb_mh_controllers > 0) {

Signature · 1 line

2.51.0

Gregory Etelson

author

2025-11-06 05:54 UTC #9 lore raw

PATCH v4 2/2 net/mlx5: support PF representor suppression in multi-port E-Switch

In multi-port E-Switch setup, the MLX5 PMD always added
PF representor port.
For example, representor=pf1vf[0,1] implicitly added PF1 representor port:

```
Port     Name
0        p0
1        p1
2        representor_c0pf1vf0
3        representor_c0pf1vf1
```

The patch adds support for the new representor format that suppresses PF representor attachment:

Example: representor=(pf1)vf[0,1]

```
Port     Name
0        p0
1        representor_c0pf1vf0
2        representor_c0pf1vf1
```

Signed-off-by Gregory Etelson <[email protected]>

---
v2: Use updated rte_eth_devargs::flags.
v3: Fix typo in comment.
v4: Use update devarg macro name.

---
 drivers/net/mlx5/linux/mlx5_os.c | 8 ++++++++
 1 file changed, 8 insertions(+)

drivers/net/mlx5/linux/mlx5_os.c +8 -0

index c742e0f282..dba3b61b68 100644
@@ -2284,6 +2284,12 @@ mlx5_device_mpesw_pci_match(struct ibv_device *ibv,
 	return -1;
 }
 
+static inline bool
+mlx5_ignore_pf_representor(const struct rte_eth_devargs *eth_da)
+{
+	return (eth_da->flags & RTE_ETH_DEVARG_REPRESENTOR_IGNORE_PF) != 0;
+}
+
 /**
  * Register a PCI device within bonding.
  *

@@ -2592,6 +2598,8 @@ mlx5_os_pci_probe_pf(struct mlx5_common_device *cdev,
 					if (list[ns].info.port_name == mpesw) {
 						list[ns].info.master = 1;
 						list[ns].info.representor = 0;
+					} else if (mlx5_ignore_pf_representor(&eth_da)) {
+						continue;
 					} else {
 						list[ns].info.master = 0;
 						list[ns].info.representor = 1;

Signature · 1 line

2.51.0

Dariusz Sosnowski

2025-11-12 10:13 UTC #10 lore raw

Re: [PATCH v4 2/2] net/mlx5: support PF representor suppression in multi-port E-Switch

Quoted 18 lines · Gregory Etelson

In multi-port E-Switch setup, the MLX5 PMD always added
PF representor port.
For example, representor=pf1vf[0,1] implicitly added PF1 representor port:
```
Port     Name
0        p0
1        p1
2        representor_c0pf1vf0
3        representor_c0pf1vf1
```
The patch adds support for the new representor format that suppresses PF representor attachment:
Example: representor=(pf1)vf[0,1]

Quoted 8 lines

```
Port     Name
0        p0
1        representor_c0pf1vf0
2        representor_c0pf1vf1
```
Signed-off-by Gregory Etelson <[email protected]>

Ackedy-by Dariusz Sosnowski <[email protected]>

Andrew Rybchenko

Acked-by on v4 1/2

2025-11-09 14:42 UTC #11 lore raw

In reply to Gregory Etelson

Quoted 6 lines · Gregory Etelson

The current format for a port representor parameter is '-a DBDF,representor=pfXvfY'.
That parameter syntax describes port representor relative to PCI device DBDF.
In that notation VF Y belongs to PF X and PF X is relative to DBDF.

Quoted 6 lines

The syntax 'pfXvfY' will probe 2 port representors: PF X and VF Y. If we want to refer only to VF Y related to PF X, the parameter must be '(pfX)vfY'.
In this case only VF Y representor will be probed.
Signed-off-by Gregory Etelson <[email protected]>

Acked-by Andrew Rybchenko <[email protected]>

Thomas Monjalon

Acked-by

2025-11-12 10:24 UTC #12 lore raw

09/11/2025 15:42, Andrew Rybchenko:

Quoted 7 lines · Gregory Etelson

Quoted 6 lines
The current format for a port representor parameter is '-a DBDF,representor=pfXvfY'.
That parameter syntax describes port representor relative to PCI device DBDF.
In that notation VF Y belongs to PF X and PF X is relative to DBDF.

Quoted 8 lines

Quoted 6 lines
The syntax 'pfXvfY' will probe 2 port representors: PF X and VF Y. If we want to refer only to VF Y related to PF X, the parameter must be '(pfX)vfY'.
In this case only VF Y representor will be probed.
Signed-off-by Gregory Etelson <[email protected]>
Acked-by Andrew Rybchenko <[email protected]>

Acked-by Thomas Monjalon <[email protected]>

Stephen Hemminger

Acked-by on v4 1/2

2025-11-12 15:02 UTC #13 lore raw

In reply to Gregory Etelson

Quoted 11 lines · On Thu, 6 Nov 2025 07:52:44 +0200 Gregory Etelson <[email protected]> wrote:

The current format for a port representor parameter is '-a DBDF,representor=pfXvfY'.
That parameter syntax describes port representor relative to PCI device DBDF.
In that notation VF Y belongs to PF X and PF X is relative to DBDF.
The syntax 'pfXvfY' will probe 2 port representors: PF X and VF Y. If we want to refer only to VF Y related to PF X, the parameter must be '(pfX)vfY'.
In this case only VF Y representor will be probed.

Quoted 5 lines

Signed-off-by Gregory Etelson <[email protected]>
---
v2: Add comments.
    In rte_eth_devargs structure rename port_flags -> flags.
v4: Rename devargs flag macro.

Acked-by Stephen Hemminger <[email protected]>

Stephen Hemminger

2025-11-13 16:41 UTC #14 lore raw

In reply to Gregory Etelson

Quoted 6 lines · On Thu, 6 Nov 2025 07:52:44 +0200 Gregory Etelson <[email protected]> wrote:

The current format for a port representor parameter is '-a DBDF,representor=pfXvfY'.
That parameter syntax describes port representor relative to PCI device DBDF.
In that notation VF Y belongs to PF X and PF X is relative to DBDF.

Quoted 7 lines

The syntax 'pfXvfY' will probe 2 port representors: PF X and VF Y. If we want to refer only to VF Y related to PF X, the parameter must be '(pfX)vfY'.
In this case only VF Y representor will be probed.
Signed-off-by Gregory Etelson <[email protected]>
---

Both patches queued in next-net