vdpa/mlx5: Allow creation of blank VQs

Based on the filled flag, create VQs that are filled or blank.
Blank VQs will be filled in later through VQ modify.

Downstream patches will make use of this to pre-create blank VQs at
vdpa device creation.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-15-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -158,7 +158,7 @@ static bool is_index_valid(struct mlx5_vdpa_dev *mvdev, u16 idx)
 
 static void free_fixed_resources(struct mlx5_vdpa_net *ndev);
 static void mvqs_set_defaults(struct mlx5_vdpa_net *ndev);
-static int setup_vq_resources(struct mlx5_vdpa_net *ndev);
+static int setup_vq_resources(struct mlx5_vdpa_net *ndev, bool filled);
 static void teardown_vq_resources(struct mlx5_vdpa_net *ndev);
 
 static bool mlx5_vdpa_debug;
@@ -874,13 +874,16 @@ static bool msix_mode_supported(struct mlx5_vdpa_dev *mvdev)
 		pci_msix_can_alloc_dyn(mvdev->mdev->pdev);
 }
 
-static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+static int create_virtqueue(struct mlx5_vdpa_net *ndev,
+			    struct mlx5_vdpa_virtqueue *mvq,
+			    bool filled)
 {
 	int inlen = MLX5_ST_SZ_BYTES(create_virtio_net_q_in);
 	u32 out[MLX5_ST_SZ_DW(create_virtio_net_q_out)] = {};
 	struct mlx5_vdpa_dev *mvdev = &ndev->mvdev;
 	struct mlx5_vdpa_mr *vq_mr;
 	struct mlx5_vdpa_mr *vq_desc_mr;
+	u64 features = filled ? mvdev->actual_features : mvdev->mlx_features;
 	void *obj_context;
 	u16 mlx_features;
 	void *cmd_hdr;
@@ -898,7 +901,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 		goto err_alloc;
 	}
 
-	mlx_features = get_features(ndev->mvdev.actual_features);
+	mlx_features = get_features(features);
 	cmd_hdr = MLX5_ADDR_OF(create_virtio_net_q_in, in, general_obj_in_cmd_hdr);
 
 	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, opcode, MLX5_CMD_OP_CREATE_GENERAL_OBJECT);
@@ -906,8 +909,6 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	MLX5_SET(general_obj_in_cmd_hdr, cmd_hdr, uid, ndev->mvdev.res.uid);
 
 	obj_context = MLX5_ADDR_OF(create_virtio_net_q_in, in, obj_context);
-	MLX5_SET(virtio_net_q_object, obj_context, hw_available_index, mvq->avail_idx);
-	MLX5_SET(virtio_net_q_object, obj_context, hw_used_index, mvq->used_idx);
 	MLX5_SET(virtio_net_q_object, obj_context, queue_feature_bit_mask_12_3,
 		 mlx_features >> 3);
 	MLX5_SET(virtio_net_q_object, obj_context, queue_feature_bit_mask_2_0,
@@ -929,17 +930,36 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	MLX5_SET(virtio_q, vq_ctx, queue_index, mvq->index);
 	MLX5_SET(virtio_q, vq_ctx, queue_size, mvq->num_ent);
 	MLX5_SET(virtio_q, vq_ctx, virtio_version_1_0,
-		 !!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_F_VERSION_1)));
+		 !!(features & BIT_ULL(VIRTIO_F_VERSION_1)));
+
+	if (filled) {
+		MLX5_SET(virtio_net_q_object, obj_context, hw_available_index, mvq->avail_idx);
+		MLX5_SET(virtio_net_q_object, obj_context, hw_used_index, mvq->used_idx);
+
 		MLX5_SET64(virtio_q, vq_ctx, desc_addr, mvq->desc_addr);
 		MLX5_SET64(virtio_q, vq_ctx, used_addr, mvq->device_addr);
 		MLX5_SET64(virtio_q, vq_ctx, available_addr, mvq->driver_addr);
+
 		vq_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]];
 		if (vq_mr)
 			MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, vq_mr->mkey);
 
 		vq_desc_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_DESC_GROUP]];
-	if (vq_desc_mr && MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, desc_group_mkey_supported))
+		if (vq_desc_mr &&
+		    MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, desc_group_mkey_supported))
 			MLX5_SET(virtio_q, vq_ctx, desc_group_mkey, vq_desc_mr->mkey);
+	} else {
+		/* If there is no mr update, make sure that the existing ones are set
+		 * modify to ready.
+		 */
+		vq_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]];
+		if (vq_mr)
+			mvq->modified_fields |= MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_MKEY;
+
+		vq_desc_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_DESC_GROUP]];
+		if (vq_desc_mr)
+			mvq->modified_fields |= MLX5_VIRTQ_MODIFY_MASK_DESC_GROUP_MKEY;
+	}
 
 	MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
@@ -959,13 +979,16 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	kfree(in);
 	mvq->virtq_id = MLX5_GET(general_obj_out_cmd_hdr, out, obj_id);
 
+	if (filled) {
 		mlx5_vdpa_get_mr(mvdev, vq_mr);
 		mvq->vq_mr = vq_mr;
 
-	if (vq_desc_mr && MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, desc_group_mkey_supported)) {
+		if (vq_desc_mr &&
+		    MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, desc_group_mkey_supported)) {
 			mlx5_vdpa_get_mr(mvdev, vq_desc_mr);
 			mvq->desc_mr = vq_desc_mr;
 		}
+	}
 
 	return 0;
 
@@ -1442,7 +1465,9 @@ static void dealloc_vector(struct mlx5_vdpa_net *ndev,
 		}
 }
 
-static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+static int setup_vq(struct mlx5_vdpa_net *ndev,
+		    struct mlx5_vdpa_virtqueue *mvq,
+		    bool filled)
 {
 	u16 idx = mvq->index;
 	int err;
@@ -1471,7 +1496,7 @@ static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 		goto err_connect;
 
 	alloc_vector(ndev, mvq);
-	err = create_virtqueue(ndev, mvq);
+	err = create_virtqueue(ndev, mvq, filled);
 	if (err)
 		goto err_vq;
 
@@ -2062,7 +2087,7 @@ static int change_num_qps(struct mlx5_vdpa_dev *mvdev, int newqps)
 	} else {
 		ndev->cur_num_vqs = 2 * newqps;
 		for (i = cur_qps * 2; i < 2 * newqps; i++) {
-			err = setup_vq(ndev, &ndev->vqs[i]);
+			err = setup_vq(ndev, &ndev->vqs[i], true);
 			if (err)
 				goto clean_added;
 		}
@@ -2558,14 +2583,14 @@ static int verify_driver_features(struct mlx5_vdpa_dev *mvdev, u64 features)
 	return 0;
 }
 
-static int setup_virtqueues(struct mlx5_vdpa_dev *mvdev)
+static int setup_virtqueues(struct mlx5_vdpa_dev *mvdev, bool filled)
 {
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	int err;
 	int i;
 
 	for (i = 0; i < mvdev->max_vqs; i++) {
-		err = setup_vq(ndev, &ndev->vqs[i]);
+		err = setup_vq(ndev, &ndev->vqs[i], filled);
 		if (err)
 			goto err_vq;
 	}
@@ -2877,7 +2902,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 
 	if (teardown) {
 		restore_channels_info(ndev);
-		err = setup_vq_resources(ndev);
+		err = setup_vq_resources(ndev, true);
 		if (err)
 			return err;
 	}
@@ -2888,7 +2913,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
 }
 
 /* reslock must be held for this function */
-static int setup_vq_resources(struct mlx5_vdpa_net *ndev)
+static int setup_vq_resources(struct mlx5_vdpa_net *ndev, bool filled)
 {
 	struct mlx5_vdpa_dev *mvdev = &ndev->mvdev;
 	int err;
@@ -2906,7 +2931,7 @@ static int setup_vq_resources(struct mlx5_vdpa_net *ndev)
 	if (err)
 		goto err_setup;
 
-	err = setup_virtqueues(mvdev);
+	err = setup_virtqueues(mvdev, filled);
 	if (err) {
 		mlx5_vdpa_warn(mvdev, "setup_virtqueues\n");
 		goto err_setup;
@@ -3000,7 +3025,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
 				goto err_setup;
 			}
 			register_link_notifier(ndev);
-			err = setup_vq_resources(ndev);
+			err = setup_vq_resources(ndev, true);
 			if (err) {
 				mlx5_vdpa_warn(mvdev, "failed to setup driver\n");
 				goto err_driver;