[PATCH v6 0/4] vdpa tool enhancements

[PATCH v6 0/4] vdpa tool enhancements

[Eli Cohen]

Hi,

The following four patch series enhances vdpa to show negotiated
features for a vdpa device, max features for a management device and
allows to configure max number of virtqueue pairs.


v5->v6:
1. Use macro to define number of feature bits
2. Use print_nl() to print new line in non json output.
3. Break usage message to two line so resulting output is confined to 80
   columns.


Eli Cohen (4):
  vdpa: Remove unsupported command line option
  vdpa: Allow for printing negotiated features of a device
  vdpa: Support for configuring max VQ pairs for a device
  vdpa: Support reading device features

 vdpa/vdpa.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 145 insertions(+), 6 deletions(-)

-- 
2.35.1

[PATCH v6 1/4] vdpa: Remove unsupported command line option

[Eli Cohen]

"-v[erbose]" option is not supported.
Remove it.

Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 vdpa/vdpa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
index f048e470c929..4ccb564872a0 100644
--- a/vdpa/vdpa.c
+++ b/vdpa/vdpa.c
@@ -711,7 +711,7 @@ static void help(void)
 	fprintf(stderr,
 		"Usage: vdpa [ OPTIONS ] OBJECT { COMMAND | help }\n"
 		"where  OBJECT := { mgmtdev | dev }\n"
-		"       OPTIONS := { -V[ersion] | -n[o-nice-names] | -j[son] | -p[retty] | -v[erbose] }\n");
+		"       OPTIONS := { -V[ersion] | -n[o-nice-names] | -j[son] | -p[retty] }\n");
 }
 
 static int vdpa_cmd(struct vdpa *vdpa, int argc, char **argv)
-- 
2.35.1

[PATCH v6 2/4] vdpa: Allow for printing negotiated features of a device

[Eli Cohen]

When reading the configuration of a vdpa device, check if the
VDPA_ATTR_DEV_NEGOTIATED_FEATURES is available. If it is, parse the
feature bits and print a string representation of each of the feature
bits.

We keep the strings in two different arrays. One for net device related
devices and one for generic feature bits.

In this patch we parse only net device specific features. Support for
other devices can be added later. If the device queried is not a net
device, we print its bit number only.

Examples:
1. Standard presentation
$ vdpa dev config show vdpa-a
vdpa-a: mac 00:00:00:00:88:88 link up link_announce false max_vq_pairs 2 mtu 9000
  negotiated_features CSUM GUEST_CSUM MTU MAC HOST_TSO4 HOST_TSO6 STATUS \
CTRL_VQ MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

2. json output
$ vdpa -j dev config show vdpa-a
{"config":{"vdpa-a":{"mac":"00:00:00:00:88:88","link":"up","link_announce":false,\
"max_vq_pairs":2,"mtu":9000,"negotiated_features":["CSUM","GUEST_CSUM",\
"MTU","MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ","CTRL_MAC_ADDR",\
"VERSION_1","ACCESS_PLATFORM"]}}}

3. Pretty json
$ vdpa -jp dev config show vdpa-a
{
    "config": {
        "vdpa-a": {
            "mac": "00:00:00:00:88:88",
            "link ": "up",
            "link_announce ": false,
            "max_vq_pairs": 2,
            "mtu": 9000,
            "negotiated_features": [
"CSUM","GUEST_CSUM","MTU","MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ",\
"MQ","CTRL_MAC_ADDR","VERSION_1","ACCESS_PLATFORM" ]
        }
    }
}

Reviewed-by: Si-Wei Liu<si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 vdpa/vdpa.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 2 deletions(-)

diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
index 4ccb564872a0..7cc370e34118 100644
--- a/vdpa/vdpa.c
+++ b/vdpa/vdpa.c
@@ -10,6 +10,8 @@
 #include <linux/virtio_net.h>
 #include <linux/netlink.h>
 #include <libmnl/libmnl.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_config.h>
 #include "mnl_utils.h"
 #include <rt_names.h>
 
@@ -78,6 +80,7 @@ static const enum mnl_attr_data_type vdpa_policy[VDPA_ATTR_MAX + 1] = {
 	[VDPA_ATTR_DEV_VENDOR_ID] = MNL_TYPE_U32,
 	[VDPA_ATTR_DEV_MAX_VQS] = MNL_TYPE_U32,
 	[VDPA_ATTR_DEV_MAX_VQ_SIZE] = MNL_TYPE_U16,
+	[VDPA_ATTR_DEV_NEGOTIATED_FEATURES] = MNL_TYPE_U64,
 };
 
 static int attr_cb(const struct nlattr *attr, void *data)
@@ -385,6 +388,98 @@ static const char *parse_class(int num)
 	return class ? class : "< unknown class >";
 }
 
+static const char * const net_feature_strs[64] = {
+	[VIRTIO_NET_F_CSUM] = "CSUM",
+	[VIRTIO_NET_F_GUEST_CSUM] = "GUEST_CSUM",
+	[VIRTIO_NET_F_CTRL_GUEST_OFFLOADS] = "CTRL_GUEST_OFFLOADS",
+	[VIRTIO_NET_F_MTU] = "MTU",
+	[VIRTIO_NET_F_MAC] = "MAC",
+	[VIRTIO_NET_F_GUEST_TSO4] = "GUEST_TSO4",
+	[VIRTIO_NET_F_GUEST_TSO6] = "GUEST_TSO6",
+	[VIRTIO_NET_F_GUEST_ECN] = "GUEST_ECN",
+	[VIRTIO_NET_F_GUEST_UFO] = "GUEST_UFO",
+	[VIRTIO_NET_F_HOST_TSO4] = "HOST_TSO4",
+	[VIRTIO_NET_F_HOST_TSO6] = "HOST_TSO6",
+	[VIRTIO_NET_F_HOST_ECN] = "HOST_ECN",
+	[VIRTIO_NET_F_HOST_UFO] = "HOST_UFO",
+	[VIRTIO_NET_F_MRG_RXBUF] = "MRG_RXBUF",
+	[VIRTIO_NET_F_STATUS] = "STATUS",
+	[VIRTIO_NET_F_CTRL_VQ] = "CTRL_VQ",
+	[VIRTIO_NET_F_CTRL_RX] = "CTRL_RX",
+	[VIRTIO_NET_F_CTRL_VLAN] = "CTRL_VLAN",
+	[VIRTIO_NET_F_CTRL_RX_EXTRA] = "CTRL_RX_EXTRA",
+	[VIRTIO_NET_F_GUEST_ANNOUNCE] = "GUEST_ANNOUNCE",
+	[VIRTIO_NET_F_MQ] = "MQ",
+	[VIRTIO_F_NOTIFY_ON_EMPTY] = "NOTIFY_ON_EMPTY",
+	[VIRTIO_NET_F_CTRL_MAC_ADDR] = "CTRL_MAC_ADDR",
+	[VIRTIO_F_ANY_LAYOUT] = "ANY_LAYOUT",
+	[VIRTIO_NET_F_RSC_EXT] = "RSC_EXT",
+	[VIRTIO_NET_F_HASH_REPORT] = "HASH_REPORT",
+	[VIRTIO_NET_F_RSS] = "RSS",
+	[VIRTIO_NET_F_STANDBY] = "STANDBY",
+	[VIRTIO_NET_F_SPEED_DUPLEX] = "SPEED_DUPLEX",
+};
+
+#define VIRTIO_F_IN_ORDER 35
+#define VIRTIO_F_NOTIFICATION_DATA 38
+#define VDPA_EXT_FEATURES_SZ (VIRTIO_TRANSPORT_F_END - \
+			      VIRTIO_TRANSPORT_F_START + 1)
+
+static const char * const ext_feature_strs[VDPA_EXT_FEATURES_SZ] = {
+	[VIRTIO_RING_F_INDIRECT_DESC - VIRTIO_TRANSPORT_F_START] = "RING_INDIRECT_DESC",
+	[VIRTIO_RING_F_EVENT_IDX - VIRTIO_TRANSPORT_F_START] = "RING_EVENT_IDX",
+	[VIRTIO_F_VERSION_1 - VIRTIO_TRANSPORT_F_START] = "VERSION_1",
+	[VIRTIO_F_ACCESS_PLATFORM - VIRTIO_TRANSPORT_F_START] = "ACCESS_PLATFORM",
+	[VIRTIO_F_RING_PACKED - VIRTIO_TRANSPORT_F_START] = "RING_PACKED",
+	[VIRTIO_F_IN_ORDER - VIRTIO_TRANSPORT_F_START] = "IN_ORDER",
+	[VIRTIO_F_ORDER_PLATFORM - VIRTIO_TRANSPORT_F_START] = "ORDER_PLATFORM",
+	[VIRTIO_F_SR_IOV - VIRTIO_TRANSPORT_F_START] = "SR_IOV",
+	[VIRTIO_F_NOTIFICATION_DATA - VIRTIO_TRANSPORT_F_START] = "NOTIFICATION_DATA",
+};
+
+static const char * const *dev_to_feature_str[] = {
+	[VIRTIO_ID_NET] = net_feature_strs,
+};
+
+#define NUM_FEATURE_BITS 64
+
+static void print_features(struct vdpa *vdpa, uint64_t features, bool mgmtdevf,
+			   uint16_t dev_id)
+{
+	const char * const *feature_strs = NULL;
+	const char *s;
+	int i;
+
+	if (dev_id < ARRAY_SIZE(dev_to_feature_str))
+		feature_strs = dev_to_feature_str[dev_id];
+
+	if (mgmtdevf)
+		pr_out_array_start(vdpa, "dev_features");
+	else
+		pr_out_array_start(vdpa, "negotiated_features");
+
+	for (i = 0; i < NUM_FEATURE_BITS; i++) {
+		if (!(features & (1ULL << i)))
+			continue;
+
+		if (i < VIRTIO_TRANSPORT_F_START || i > VIRTIO_TRANSPORT_F_END) {
+			if (feature_strs) {
+				s = feature_strs[i];
+			} else {
+				s = NULL;
+			}
+		} else {
+			s = ext_feature_strs[i - VIRTIO_TRANSPORT_F_START];
+		}
+		if (!s)
+			print_uint(PRINT_ANY, NULL, " bit_%d", i);
+		else
+			print_string(PRINT_ANY, NULL, " %s", s);
+	}
+
+	pr_out_array_end(vdpa);
+}
+
 static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
 				struct nlattr **tb)
 {
@@ -579,9 +674,10 @@ static int cmd_dev_del(struct vdpa *vdpa,  int argc, char **argv)
 	return mnlu_gen_socket_sndrcv(&vdpa->nlg, nlh, NULL, NULL);
 }
 
-static void pr_out_dev_net_config(struct nlattr **tb)
+static void pr_out_dev_net_config(struct vdpa *vdpa, struct nlattr **tb)
 {
 	SPRINT_BUF(macaddr);
+	uint64_t val_u64;
 	uint16_t val_u16;
 
 	if (tb[VDPA_ATTR_DEV_NET_CFG_MACADDR]) {
@@ -610,6 +706,15 @@ static void pr_out_dev_net_config(struct nlattr **tb)
 		val_u16 = mnl_attr_get_u16(tb[VDPA_ATTR_DEV_NET_CFG_MTU]);
 		print_uint(PRINT_ANY, "mtu", "mtu %d ", val_u16);
 	}
+	if (tb[VDPA_ATTR_DEV_NEGOTIATED_FEATURES]) {
+		uint16_t dev_id = 0;
+
+		if (tb[VDPA_ATTR_DEV_ID])
+			dev_id = mnl_attr_get_u32(tb[VDPA_ATTR_DEV_ID]);
+
+		val_u64 = mnl_attr_get_u64(tb[VDPA_ATTR_DEV_NEGOTIATED_FEATURES]);
+		print_features(vdpa, val_u64, false, dev_id);
+	}
 }
 
 static void pr_out_dev_config(struct vdpa *vdpa, struct nlattr **tb)
@@ -619,7 +724,7 @@ static void pr_out_dev_config(struct vdpa *vdpa, struct nlattr **tb)
 	pr_out_vdev_handle_start(vdpa, tb);
 	switch (device_id) {
 	case VIRTIO_ID_NET:
-		pr_out_dev_net_config(tb);
+		pr_out_dev_net_config(vdpa, tb);
 		break;
 	default:
 		break;
-- 
2.35.1

[PATCH v6 3/4] vdpa: Support for configuring max VQ pairs for a device

[Eli Cohen]

Use VDPA_ATTR_DEV_MGMTDEV_MAX_VQS to specify max number of virtqueue
pairs to configure for a vdpa device when adding a device.

Examples:
1. Create a device with 3 virtqueue pairs:
$ vdpa dev add name vdpa-a mgmtdev auxiliary/mlx5_core.sf.1 max_vqp 3

2. Read the configuration of a vdpa device
$ vdpa dev config show vdpa-a
  vdpa-a: mac 00:00:00:00:88:88 link up link_announce false max_vq_pairs 3 \
          mtu 1500
  negotiated_features CSUM GUEST_CSUM MTU MAC HOST_TSO4 HOST_TSO6 STATUS \
                      CTRL_VQ MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 vdpa/vdpa.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
index 7cc370e34118..1326a63e729d 100644
--- a/vdpa/vdpa.c
+++ b/vdpa/vdpa.c
@@ -25,6 +25,7 @@
 #define VDPA_OPT_VDEV_HANDLE		BIT(3)
 #define VDPA_OPT_VDEV_MAC		BIT(4)
 #define VDPA_OPT_VDEV_MTU		BIT(5)
+#define VDPA_OPT_MAX_VQP		BIT(6)
 
 struct vdpa_opts {
 	uint64_t present; /* flags of present items */
@@ -34,6 +35,7 @@ struct vdpa_opts {
 	unsigned int device_id;
 	char mac[ETH_ALEN];
 	uint16_t mtu;
+	uint16_t max_vqp;
 };
 
 struct vdpa {
@@ -81,6 +83,7 @@ static const enum mnl_attr_data_type vdpa_policy[VDPA_ATTR_MAX + 1] = {
 	[VDPA_ATTR_DEV_MAX_VQS] = MNL_TYPE_U32,
 	[VDPA_ATTR_DEV_MAX_VQ_SIZE] = MNL_TYPE_U16,
 	[VDPA_ATTR_DEV_NEGOTIATED_FEATURES] = MNL_TYPE_U64,
+	[VDPA_ATTR_DEV_MGMTDEV_MAX_VQS] = MNL_TYPE_U32,
 };
 
 static int attr_cb(const struct nlattr *attr, void *data)
@@ -222,6 +225,8 @@ static void vdpa_opts_put(struct nlmsghdr *nlh, struct vdpa *vdpa)
 			     sizeof(opts->mac), opts->mac);
 	if (opts->present & VDPA_OPT_VDEV_MTU)
 		mnl_attr_put_u16(nlh, VDPA_ATTR_DEV_NET_CFG_MTU, opts->mtu);
+	if (opts->present & VDPA_OPT_MAX_VQP)
+		mnl_attr_put_u16(nlh, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, opts->max_vqp);
 }
 
 static int vdpa_argv_parse(struct vdpa *vdpa, int argc, char **argv,
@@ -290,6 +295,14 @@ static int vdpa_argv_parse(struct vdpa *vdpa, int argc, char **argv,
 
 			NEXT_ARG_FWD();
 			o_found |= VDPA_OPT_VDEV_MTU;
+		} else if ((matches(*argv, "max_vqp")  == 0) && (o_optional & VDPA_OPT_MAX_VQP)) {
+			NEXT_ARG_FWD();
+			err = vdpa_argv_u16(vdpa, argc, argv, &opts->max_vqp);
+			if (err)
+				return err;
+
+			NEXT_ARG_FWD();
+			o_found |= VDPA_OPT_MAX_VQP;
 		} else {
 			fprintf(stderr, "Unknown option \"%s\"\n", *argv);
 			return -EINVAL;
@@ -503,6 +516,14 @@ static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
 		pr_out_array_end(vdpa);
 	}
 
+	if (tb[VDPA_ATTR_DEV_MGMTDEV_MAX_VQS]) {
+		uint32_t num_vqs;
+
+		print_nl();
+		num_vqs = mnl_attr_get_u32(tb[VDPA_ATTR_DEV_MGMTDEV_MAX_VQS]);
+		print_uint(PRINT_ANY, "max_supported_vqs", "  max_supported_vqs %d", num_vqs);
+	}
+
 	pr_out_handle_end(vdpa);
 }
 
@@ -563,6 +584,7 @@ static void cmd_dev_help(void)
 {
 	fprintf(stderr, "Usage: vdpa dev show [ DEV ]\n");
 	fprintf(stderr, "       vdpa dev add name NAME mgmtdev MANAGEMENTDEV [ mac MACADDR ] [ mtu MTU ]\n");
+	fprintf(stderr, "                                                    [ max_vqp MAX_VQ_PAIRS ]\n");
 	fprintf(stderr, "       vdpa dev del DEV\n");
 	fprintf(stderr, "Usage: vdpa dev config COMMAND [ OPTIONS ]\n");
 }
@@ -652,7 +674,8 @@ static int cmd_dev_add(struct vdpa *vdpa, int argc, char **argv)
 					  NLM_F_REQUEST | NLM_F_ACK);
 	err = vdpa_argv_parse_put(nlh, vdpa, argc, argv,
 				  VDPA_OPT_VDEV_MGMTDEV_HANDLE | VDPA_OPT_VDEV_NAME,
-				  VDPA_OPT_VDEV_MAC | VDPA_OPT_VDEV_MTU);
+				  VDPA_OPT_VDEV_MAC | VDPA_OPT_VDEV_MTU |
+				  VDPA_OPT_MAX_VQP);
 	if (err)
 		return err;
 
-- 
2.35.1

[PATCH v6 4/4] vdpa: Support reading device features

[Eli Cohen]

When showing the available management devices, check if
VDPA_ATTR_DEV_SUPPORTED_FEATURES feature is available and print the
supported features for a management device.

Examples:
$ vdpa mgmtdev show
auxiliary/mlx5_core.sf.1:
  supported_classes net
  max_supported_vqs 257
  dev_features CSUM GUEST_CSUM MTU HOST_TSO4 HOST_TSO6 STATUS CTRL_VQ MQ \
               CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

$ vdpa -jp mgmtdev show
{
    "mgmtdev": {
        "auxiliary/mlx5_core.sf.1": {
            "supported_classes": [ "net" ],
            "max_supported_vqs": 257,
            "dev_features": [
"CSUM","GUEST_CSUM","MTU","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ",\
"CTRL_MAC_ADDR","VERSION_1","ACCESS_PLATFORM" ]
        }
    }
}

Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 vdpa/vdpa.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
index 1326a63e729d..c63bf52d3c49 100644
--- a/vdpa/vdpa.c
+++ b/vdpa/vdpa.c
@@ -84,6 +84,7 @@ static const enum mnl_attr_data_type vdpa_policy[VDPA_ATTR_MAX + 1] = {
 	[VDPA_ATTR_DEV_MAX_VQ_SIZE] = MNL_TYPE_U16,
 	[VDPA_ATTR_DEV_NEGOTIATED_FEATURES] = MNL_TYPE_U64,
 	[VDPA_ATTR_DEV_MGMTDEV_MAX_VQS] = MNL_TYPE_U32,
+	[VDPA_ATTR_DEV_SUPPORTED_FEATURES] = MNL_TYPE_U64,
 };
 
 static int attr_cb(const struct nlattr *attr, void *data)
@@ -496,14 +497,14 @@ static void print_features(struct vdpa *vdpa, uint64_t features, bool mgmtdevf,
 static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
 				struct nlattr **tb)
 {
+	uint64_t classes = 0;
 	const char *class;
 	unsigned int i;
 
 	pr_out_handle_start(vdpa, tb);
 
 	if (tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]) {
-		uint64_t classes = mnl_attr_get_u64(tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]);
-
+		classes = mnl_attr_get_u64(tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]);
 		pr_out_array_start(vdpa, "supported_classes");
 
 		for (i = 1; i < 64; i++) {
@@ -524,6 +525,16 @@ static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
 		print_uint(PRINT_ANY, "max_supported_vqs", "  max_supported_vqs %d", num_vqs);
 	}
 
+	if (tb[VDPA_ATTR_DEV_SUPPORTED_FEATURES]) {
+		uint64_t features;
+
+		features  = mnl_attr_get_u64(tb[VDPA_ATTR_DEV_SUPPORTED_FEATURES]);
+		if (classes & BIT(VIRTIO_ID_NET))
+			print_features(vdpa, features, true, VIRTIO_ID_NET);
+		else
+			print_features(vdpa, features, true, 0);
+	}
+
 	pr_out_handle_end(vdpa);
 }
 
-- 
2.35.1

Re: [PATCH v6 2/4] vdpa: Allow for printing negotiated features of a device

[Stephen Hemminger]

On Sun, 13 Mar 2022 14:46:27 +0200
Eli Cohen <elic@nvidia.com> wrote:

> When reading the configuration of a vdpa device, check if the
> VDPA_ATTR_DEV_NEGOTIATED_FEATURES is available. If it is, parse the
> feature bits and print a string representation of each of the feature
> bits.
> 
> We keep the strings in two different arrays. One for net device related
> devices and one for generic feature bits.
> 
> In this patch we parse only net device specific features. Support for
> other devices can be added later. If the device queried is not a net
> device, we print its bit number only.
> 
> Examples:
> 1. Standard presentation
> $ vdpa dev config show vdpa-a
> vdpa-a: mac 00:00:00:00:88:88 link up link_announce false max_vq_pairs 2 mtu 9000
>   negotiated_features CSUM GUEST_CSUM MTU MAC HOST_TSO4 HOST_TSO6 STATUS \
> CTRL_VQ MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM
> 
> 2. json output
> $ vdpa -j dev config show vdpa-a
> {"config":{"vdpa-a":{"mac":"00:00:00:00:88:88","link":"up","link_announce":false,\
> "max_vq_pairs":2,"mtu":9000,"negotiated_features":["CSUM","GUEST_CSUM",\
> "MTU","MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ","CTRL_MAC_ADDR",\
> "VERSION_1","ACCESS_PLATFORM"]}}}
> 
> 3. Pretty json
> $ vdpa -jp dev config show vdpa-a
> {
>     "config": {
>         "vdpa-a": {
>             "mac": "00:00:00:00:88:88",
>             "link ": "up",
>             "link_announce ": false,
>             "max_vq_pairs": 2,
>             "mtu": 9000,
>             "negotiated_features": [
> "CSUM","GUEST_CSUM","MTU","MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ",\
> "MQ","CTRL_MAC_ADDR","VERSION_1","ACCESS_PLATFORM" ]
>         }
>     }
> }
> 
> Reviewed-by: Si-Wei Liu<si-wei.liu@oracle.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Eli Cohen <elic@nvidia.com>
> ---

checkpatch says:

WARNING: braces {} are not necessary for any arm of this statement
#280: FILE: vdpa/vdpa.c:466:
+			if (feature_strs) {
[...]
+			} else {
[...]

RE: [PATCH v6 2/4] vdpa: Allow for printing negotiated features of a device

[Eli Cohen]

> 
> checkpatch says:
> 
> WARNING: braces {} are not necessary for any arm of this statement
> #280: FILE: vdpa/vdpa.c:466:
> +			if (feature_strs) {
> [...]
> +			} else {
> [...]
> 

Sorry about this. 
Sending v7.