[PATCH v2 3/4] vdpa: Support for configuring max VQ pairs for a device

[Eli Cohen <elic@nvidia.com>]

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>
Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 vdpa/include/uapi/linux/vdpa.h |  1 +
 vdpa/vdpa.c                    | 27 +++++++++++++++++++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/vdpa/include/uapi/linux/vdpa.h b/vdpa/include/uapi/linux/vdpa.h
index 748c350450b2..a3ebf4d4d9b8 100644
--- a/vdpa/include/uapi/linux/vdpa.h
+++ b/vdpa/include/uapi/linux/vdpa.h
@@ -41,6 +41,7 @@ enum vdpa_attr {
 	VDPA_ATTR_DEV_NET_CFG_MTU,		/* u16 */
 
 	VDPA_ATTR_DEV_NEGOTIATED_FEATURES,	/* u64 */
+	VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,          /* u32 */
 
 	/* new attributes must be added above here */
 	VDPA_ATTR_MAX,
diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
index f60e647b8cf8..78736b1422b6 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;
@@ -500,6 +513,15 @@ 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]) {
+		uint16_t num_vqs;
+
+		if (!vdpa->json_output)
+			printf("\n");
+		num_vqs = mnl_attr_get_u16(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);
 }
 
@@ -559,7 +581,7 @@ static int cmd_mgmtdev(struct vdpa *vdpa, int argc, char **argv)
 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, "       vdpa dev add name NAME mgmtdev MANAGEMENTDEV [ mac MACADDR ] [ mtu MTU ] [max_vqp MAX_VQ_PAIRS]\n");
 	fprintf(stderr, "       vdpa dev del DEV\n");
 	fprintf(stderr, "Usage: vdpa dev config COMMAND [ OPTIONS ]\n");
 }
@@ -649,7 +671,8 @@ 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