Linux Virtualization - Sep 2020 - [PATCH v2] vdpa/mlx5: Setup driver only if VIRTIO_CONFIG_S_DRIVER_OK

----- Original Message -----
> set_map() is used by mlx5 vdpa to create a memory region based on the
> address map passed by the iotlb argument. If we get successive calls, we
> will destroy the current memory region and build another one based on
> the new address mapping. We also need to setup the hardware resources
> since they depend on the memory region.
> 
> If these calls happen before DRIVER_OK, It means that driver VQs may
> also not been setup and we may not create them yet. In this case we want
> to avoid setting up the other resources and defer this till we get
> DRIVER OK.
> 
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5
devices")
> Signed-off-by: Eli Cohen <elic at nvidia.com>
> ---
> V1->V2: Improve changelog description
> 
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 9df69d5efe8c..c89cd48a0aab 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1645,6 +1645,9 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_net
> *ndev, struct vhost_iotlb *
>  	if (err)
>  		goto err_mr;
>  
> +	if (!(ndev->mvdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
> +		return 0;
> +
Is there any reason that we still need to do vq suspending and saving before?

Thanks
>  	restore_channels_info(ndev);
>  	err = setup_driver(ndev);
>  	if (err)
> --
> 2.26.0
> 
>