vdpa/mlx5: Add support for modifying the virtio_version VQ field

This is done in preparation for the pre-creation of hardware virtqueues
at device add time.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-10-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1283,6 +1283,10 @@ static int modify_virtqueue(struct mlx5_vdpa_net *ndev,
 	if (mvq->modified_fields & MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_USED_IDX)
 		MLX5_SET(virtio_net_q_object, obj_context, hw_used_index, mvq->used_idx);
 
+	if (mvq->modified_fields & MLX5_VIRTQ_MODIFY_MASK_QUEUE_VIRTIO_VERSION)
+		MLX5_SET(virtio_q, vq_ctx, virtio_version_1_0,
+			!!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_F_VERSION_1)));
+
 	if (mvq->modified_fields & MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_MKEY) {
 		vq_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]];
 
@@ -2709,6 +2713,7 @@ static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
 {
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
+	u64 old_features = mvdev->actual_features;
 	int err;
 
 	print_features(mvdev, features, true);
@@ -2723,6 +2728,17 @@ static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
 	else
 		ndev->rqt_size = 1;
 
+	/* Interested in changes of vq features only. */
+	if (get_features(old_features) != get_features(mvdev->actual_features)) {
+		for (int i = 0; i < mvdev->max_vqs; ++i) {
+			struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[i];
+
+			mvq->modified_fields |= (
+				MLX5_VIRTQ_MODIFY_MASK_QUEUE_VIRTIO_VERSION
+			);
+		}
+	}
+
 	update_cvq_info(mvdev);
 	return err;
 }

include/linux/mlx5/mlx5_ifc_vdpa.h

@@ -148,6 +148,7 @@ enum {
 	MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_ADDRS           = (u64)1 << 6,
 	MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_AVAIL_IDX       = (u64)1 << 7,
 	MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_USED_IDX        = (u64)1 << 8,
+	MLX5_VIRTQ_MODIFY_MASK_QUEUE_VIRTIO_VERSION	= (u64)1 << 10,
 	MLX5_VIRTQ_MODIFY_MASK_VIRTIO_Q_MKEY            = (u64)1 << 11,
 	MLX5_VIRTQ_MODIFY_MASK_DESC_GROUP_MKEY          = (u64)1 << 14,
 };