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From:   Eli Cohen <elic@nvidia.com>
To:     <mst@redhat.com>, <jasowang@redhat.com>
CC:     <virtualization@lists.linux-foundation.org>,
        <linux-kernel@vger.kernel.org>, <si-wei.liu@oracle.com>,
        Eli Cohen <elic@nvidia.com>
Subject: [PATCH v4 3/3] vdpa/mlx5: Add support for reading descriptor statistics
Date:   Sun, 8 May 2022 19:33:17 +0300
Message-ID: <20220508163317.204673-4-elic@nvidia.com>
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Implement the get_vq_stats calback of vdpa_config_ops to return the
statistics for a virtqueue.

The statistics are provided as vendor specific statistics where the
driver provides a pair of attribute name and attribute value.

In addition to the attribute name/attribute value pair, the driver
returns the negotiated features and max virtqueue pairs for userspace
can decide for a given queue index whether it is a data or control
virtqueue.

Currently supported are received descriptors and completed descriptors.

Signed-off-by: Eli Cohen <elic@nvidia.com>

v3 -> v4:
Only return statistics if feature negotiation was complete
---
 drivers/vdpa/mlx5/core/mlx5_vdpa.h |   2 +
 drivers/vdpa/mlx5/net/mlx5_vnet.c  | 171 +++++++++++++++++++++++++++++
 include/linux/mlx5/mlx5_ifc.h      |   1 +
 include/linux/mlx5/mlx5_ifc_vdpa.h |  39 +++++++
 4 files changed, 213 insertions(+)

diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index daaf7b503677..44104093163b 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -61,6 +61,8 @@ struct mlx5_control_vq {
 	struct vringh_kiov riov;
 	struct vringh_kiov wiov;
 	unsigned short head;
+	unsigned int received_desc;
+	unsigned int completed_desc;
 };
 
 struct mlx5_vdpa_wq_ent {
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 79001301b383..5b1c4304ffc7 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -119,6 +119,7 @@ struct mlx5_vdpa_virtqueue {
 	struct mlx5_vdpa_umem umem2;
 	struct mlx5_vdpa_umem umem3;
 
+	u32 counter_set_id;
 	bool initialized;
 	int index;
 	u32 virtq_id;
@@ -164,6 +165,8 @@ struct mlx5_vdpa_net {
 	struct notifier_block nb;
 	struct vdpa_callback config_cb;
 	struct mlx5_vdpa_wq_ent cvq_ent;
+	/* sync access to virtqueues statistics */
+	struct mutex numq_lock;
 };
 
 static void free_resources(struct mlx5_vdpa_net *ndev);
@@ -822,6 +825,12 @@ static u16 get_features_12_3(u64 features)
 	       (!!(features & BIT_ULL(VIRTIO_NET_F_GUEST_CSUM)) << 6);
 }
 
+static bool counters_supported(const struct mlx5_vdpa_dev *mvdev)
+{
+	return MLX5_CAP_GEN_64(mvdev->mdev, general_obj_types) &
+	       BIT_ULL(MLX5_OBJ_TYPE_VIRTIO_Q_COUNTERS);
+}
+
 static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 {
 	int inlen = MLX5_ST_SZ_BYTES(create_virtio_net_q_in);
@@ -876,6 +885,8 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	MLX5_SET(virtio_q, vq_ctx, umem_3_id, mvq->umem3.id);
 	MLX5_SET(virtio_q, vq_ctx, umem_3_size, mvq->umem3.size);
 	MLX5_SET(virtio_q, vq_ctx, pd, ndev->mvdev.res.pdn);
+	if (counters_supported(&ndev->mvdev))
+		MLX5_SET(virtio_q, vq_ctx, counter_set_id, mvq->counter_set_id);
 
 	err = mlx5_cmd_exec(ndev->mvdev.mdev, in, inlen, out, sizeof(out));
 	if (err)
@@ -1139,6 +1150,47 @@ static int modify_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	return err;
 }
 
+static int counter_set_alloc(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+{
+	u32 in[MLX5_ST_SZ_DW(create_virtio_q_counters_in)] = {};
+	u32 out[MLX5_ST_SZ_DW(create_virtio_q_counters_out)] = {};
+	void *cmd_hdr;
+	int err;
+
+	if (!counters_supported(&ndev->mvdev))
+		return 0;
+
+	cmd_hdr = MLX5_ADDR_OF(create_virtio_q_counters_in, in, hdr);
+
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, opcode, MLX5_CMD_OP_CREATE_GENERAL_OBJECT);
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, obj_type, MLX5_OBJ_TYPE_VIRTIO_Q_COUNTERS);
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, uid, ndev->mvdev.res.uid);
+
+	err = mlx5_cmd_exec(ndev->mvdev.mdev, in, sizeof(in), out, sizeof(out));
+	if (err)
+		return err;
+
+	mvq->counter_set_id = MLX5_GET(general_obj_out_cmd_hdr, out, obj_id);
+
+	return 0;
+}
+
+static void counter_set_dealloc(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+{
+	u32 in[MLX5_ST_SZ_DW(destroy_virtio_q_counters_in)] = {};
+	u32 out[MLX5_ST_SZ_DW(destroy_virtio_q_counters_out)] = {};
+
+	if (!counters_supported(&ndev->mvdev))
+		return;
+
+	MLX5_SET(destroy_virtio_q_counters_in, in, hdr.opcode, MLX5_CMD_OP_DESTROY_GENERAL_OBJECT);
+	MLX5_SET(destroy_virtio_q_counters_in, in, hdr.obj_id, mvq->counter_set_id);
+	MLX5_SET(destroy_virtio_q_counters_in, in, hdr.uid, ndev->mvdev.res.uid);
+	MLX5_SET(destroy_virtio_q_counters_in, in, hdr.obj_type, MLX5_OBJ_TYPE_VIRTIO_Q_COUNTERS);
+	if (mlx5_cmd_exec(ndev->mvdev.mdev, in, sizeof(in), out, sizeof(out)))
+		mlx5_vdpa_warn(&ndev->mvdev, "dealloc counter set 0x%x\n", mvq->counter_set_id);
+}
+
 static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 {
 	u16 idx = mvq->index;
@@ -1166,6 +1218,10 @@ static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 	if (err)
 		goto err_connect;
 
+	err = counter_set_alloc(ndev, mvq);
+	if (err)
+		goto err_counter;
+
 	err = create_virtqueue(ndev, mvq);
 	if (err)
 		goto err_connect;
@@ -1183,6 +1239,8 @@ static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 	return 0;
 
 err_connect:
+	counter_set_dealloc(ndev, mvq);
+err_counter:
 	qp_destroy(ndev, &mvq->vqqp);
 err_vqqp:
 	qp_destroy(ndev, &mvq->fwqp);
@@ -1227,6 +1285,7 @@ static void teardown_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *
 
 	suspend_vq(ndev, mvq);
 	destroy_virtqueue(ndev, mvq);
+	counter_set_dealloc(ndev, mvq);
 	qp_destroy(ndev, &mvq->vqqp);
 	qp_destroy(ndev, &mvq->fwqp);
 	cq_destroy(ndev, mvq->index);
@@ -1633,8 +1692,10 @@ static virtio_net_ctrl_ack handle_ctrl_mq(struct mlx5_vdpa_dev *mvdev, u8 cmd)
 			break;
 		}
 
+		mutex_lock(&ndev->numq_lock);
 		if (!change_num_qps(mvdev, newqps))
 			status = VIRTIO_NET_OK;
+		mutex_unlock(&ndev->numq_lock);
 
 		break;
 	default:
@@ -1681,6 +1742,7 @@ static void mlx5_cvq_kick_handler(struct work_struct *work)
 		if (read != sizeof(ctrl))
 			break;
 
+		cvq->received_desc++;
 		switch (ctrl.class) {
 		case VIRTIO_NET_CTRL_MAC:
 			status = handle_ctrl_mac(mvdev, ctrl.cmd);
@@ -1704,6 +1766,7 @@ static void mlx5_cvq_kick_handler(struct work_struct *work)
 		if (vringh_need_notify_iotlb(&cvq->vring))
 			vringh_notify(&cvq->vring);
 
+		cvq->completed_desc++;
 		queue_work(mvdev->wq, &wqent->work);
 		break;
 	}
@@ -2323,6 +2386,8 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
 	mlx5_vdpa_destroy_mr(&ndev->mvdev);
 	ndev->mvdev.status = 0;
 	ndev->cur_num_vqs = 0;
+	ndev->mvdev.cvq.received_desc = 0;
+	ndev->mvdev.cvq.completed_desc = 0;
 	memset(ndev->event_cbs, 0, sizeof(*ndev->event_cbs) * (mvdev->max_vqs + 1));
 	ndev->mvdev.actual_features = 0;
 	++mvdev->generation;
@@ -2401,6 +2466,7 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev)
 		mlx5_mpfs_del_mac(pfmdev, ndev->config.mac);
 	}
 	mlx5_vdpa_free_resources(&ndev->mvdev);
+	mutex_destroy(&ndev->numq_lock);
 	mutex_destroy(&ndev->reslock);
 	kfree(ndev->event_cbs);
 	kfree(ndev->vqs);
@@ -2442,6 +2508,108 @@ static u64 mlx5_vdpa_get_driver_features(struct vdpa_device *vdev)
 	return mvdev->actual_features;
 }
 
+static int counter_set_query(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq,
+			     u64 *received_desc, u64 *completed_desc)
+{
+	u32 in[MLX5_ST_SZ_DW(query_virtio_q_counters_in)] = {};
+	u32 out[MLX5_ST_SZ_DW(query_virtio_q_counters_out)] = {};
+	void *cmd_hdr;
+	void *ctx;
+	int err;
+
+	if (!counters_supported(&ndev->mvdev))
+		return -EOPNOTSUPP;
+
+	if (mvq->fw_state != MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY)
+		return -EAGAIN;
+
+	cmd_hdr = MLX5_ADDR_OF(query_virtio_q_counters_in, in, hdr);
+
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, opcode, MLX5_CMD_OP_QUERY_GENERAL_OBJECT);
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, obj_type, MLX5_OBJ_TYPE_VIRTIO_Q_COUNTERS);
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, uid, ndev->mvdev.res.uid);
+	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, obj_id, mvq->counter_set_id);
+
+	err = mlx5_cmd_exec(ndev->mvdev.mdev, in, sizeof(in), out, sizeof(out));
+	if (err)
+		return err;
+
+	ctx = MLX5_ADDR_OF(query_virtio_q_counters_out, out, counters);
+	*received_desc = MLX5_GET64(virtio_q_counters, ctx, received_desc);
+	*completed_desc = MLX5_GET64(virtio_q_counters, ctx, completed_desc);
+	return 0;
+}
+
+static int mlx5_vdpa_get_vendor_vq_stats(struct vdpa_device *vdev, u16 idx,
+					 struct sk_buff *msg,
+					 struct netlink_ext_ack *extack)
+{
+	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
+	struct mlx5_vdpa_virtqueue *mvq;
+	struct mlx5_control_vq *cvq;
+	u64 received_desc;
+	u64 completed_desc;
+	int err = 0;
+	u16 max_vqp;
+
+	mutex_lock(&ndev->numq_lock);
+	if (!(ndev->mvdev.status & VIRTIO_CONFIG_S_FEATURES_OK)) {
+		NL_SET_ERR_MSG_MOD(extack, "feature negotiation not complete");
+		err = -EAGAIN;
+		goto out_err;
+	}
+
+	if (!is_index_valid(mvdev, idx)) {
+		NL_SET_ERR_MSG_MOD(extack, "virtqueue index is not valid");
+		err = -EINVAL;
+		goto out_err;
+	}
+
+	if (idx == ctrl_vq_idx(mvdev)) {
+		cvq = &mvdev->cvq;
+		received_desc = cvq->received_desc;
+		completed_desc = cvq->completed_desc;
+		goto out;
+	}
+
+	mvq = &ndev->vqs[idx];
+	err = counter_set_query(ndev, mvq, &received_desc, &completed_desc);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "failed to query hardware");
+		goto out_err;
+	}
+
+out:
+	err = -EMSGSIZE;
+	if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES,
+			      mvdev->actual_features, VDPA_ATTR_PAD))
+		goto out_err;
+
+	max_vqp = mlx5vdpa16_to_cpu(mvdev, ndev->config.max_virtqueue_pairs);
+	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, max_vqp))
+		goto out_err;
+
+	if (nla_put_string(msg, VDPA_ATTR_DEV_VENDOR_ATTR_NAME, "received_desc"))
+		goto out_err;
+
+	if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_VENDOR_ATTR_VALUE, received_desc,
+			      VDPA_ATTR_PAD))
+		goto out_err;
+
+	if (nla_put_string(msg, VDPA_ATTR_DEV_VENDOR_ATTR_NAME, "completed_desc"))
+		goto out_err;
+
+	if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_VENDOR_ATTR_VALUE, completed_desc,
+			      VDPA_ATTR_PAD))
+		goto out_err;
+
+	err = 0;
+out_err:
+	mutex_unlock(&ndev->numq_lock);
+	return err;
+}
+
 static const struct vdpa_config_ops mlx5_vdpa_ops = {
 	.set_vq_address = mlx5_vdpa_set_vq_address,
 	.set_vq_num = mlx5_vdpa_set_vq_num,
@@ -2451,6 +2619,7 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
 	.get_vq_ready = mlx5_vdpa_get_vq_ready,
 	.set_vq_state = mlx5_vdpa_set_vq_state,
 	.get_vq_state = mlx5_vdpa_get_vq_state,
+	.get_vendor_vq_stats = mlx5_vdpa_get_vendor_vq_stats,
 	.get_vq_notification = mlx5_get_vq_notification,
 	.get_vq_irq = mlx5_get_vq_irq,
 	.get_vq_align = mlx5_vdpa_get_vq_align,
@@ -2706,6 +2875,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 
 	init_mvqs(ndev);
 	mutex_init(&ndev->reslock);
+	mutex_init(&ndev->numq_lock);
 	config = &ndev->config;
 
 	if (add_config->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU)) {
@@ -2788,6 +2958,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 	if (!is_zero_ether_addr(config->mac))
 		mlx5_mpfs_del_mac(pfmdev, config->mac);
 err_mtu:
+	mutex_destroy(&ndev->numq_lock);
 	mutex_destroy(&ndev->reslock);
 err_alloc:
 	put_device(&mvdev->vdev.dev);
diff --git a/include/linux/mlx5/mlx5_ifc.h b/include/linux/mlx5/mlx5_ifc.h
index 49a48d7709ac..1d193d9b6029 100644
--- a/include/linux/mlx5/mlx5_ifc.h
+++ b/include/linux/mlx5/mlx5_ifc.h
@@ -94,6 +94,7 @@ enum {
 enum {
 	MLX5_OBJ_TYPE_GENEVE_TLV_OPT = 0x000b,
 	MLX5_OBJ_TYPE_VIRTIO_NET_Q = 0x000d,
+	MLX5_OBJ_TYPE_VIRTIO_Q_COUNTERS = 0x001c,
 	MLX5_OBJ_TYPE_MATCH_DEFINER = 0x0018,
 	MLX5_OBJ_TYPE_MKEY = 0xff01,
 	MLX5_OBJ_TYPE_QP = 0xff02,
diff --git a/include/linux/mlx5/mlx5_ifc_vdpa.h b/include/linux/mlx5/mlx5_ifc_vdpa.h
index 1a9c9d94cb59..4414ed5b6ed2 100644
--- a/include/linux/mlx5/mlx5_ifc_vdpa.h
+++ b/include/linux/mlx5/mlx5_ifc_vdpa.h
@@ -165,4 +165,43 @@ struct mlx5_ifc_modify_virtio_net_q_out_bits {
 	struct mlx5_ifc_general_obj_out_cmd_hdr_bits general_obj_out_cmd_hdr;
 };
 
+struct mlx5_ifc_virtio_q_counters_bits {
+	u8    modify_field_select[0x40];
+	u8    reserved_at_40[0x40];
+	u8    received_desc[0x40];
+	u8    completed_desc[0x40];
+	u8    error_cqes[0x20];
+	u8    bad_desc_errors[0x20];
+	u8    exceed_max_chain[0x20];
+	u8    invalid_buffer[0x20];
+	u8    reserved_at_180[0x280];
+};
+
+struct mlx5_ifc_create_virtio_q_counters_in_bits {
+	struct mlx5_ifc_general_obj_in_cmd_hdr_bits hdr;
+	struct mlx5_ifc_virtio_q_counters_bits virtio_q_counters;
+};
+
+struct mlx5_ifc_create_virtio_q_counters_out_bits {
+	struct mlx5_ifc_general_obj_in_cmd_hdr_bits hdr;
+	struct mlx5_ifc_virtio_q_counters_bits virtio_q_counters;
+};
+
+struct mlx5_ifc_destroy_virtio_q_counters_in_bits {
+	struct mlx5_ifc_general_obj_in_cmd_hdr_bits hdr;
+};
+
+struct mlx5_ifc_destroy_virtio_q_counters_out_bits {
+	struct mlx5_ifc_general_obj_out_cmd_hdr_bits hdr;
+};
+
+struct mlx5_ifc_query_virtio_q_counters_in_bits {
+	struct mlx5_ifc_general_obj_in_cmd_hdr_bits hdr;
+};
+
+struct mlx5_ifc_query_virtio_q_counters_out_bits {
+	struct mlx5_ifc_general_obj_in_cmd_hdr_bits hdr;
+	struct mlx5_ifc_virtio_q_counters_bits counters;
+};
+
 #endif /* __MLX5_IFC_VDPA_H_ */
-- 
2.35.1