[dpdk-stable] [PATCH] net/virtio: fix kernel set features for multi-queue devices

[Maxime Coquelin]

On 5/28/21 3:20 PM, Thierry Herbelot wrote:
> Restore the original code, where VHOST_SET_FEATURES is applied to
> all vhostfds of the device.
> 
> Fixes: cc0151b34dee ("net/virtio: add virtio-user features ops")
> Cc: stable at dpdk.org
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>
> Cc: Chenbo Xia <chenbo.xia at intel.com>
> 
> Signed-off-by: Thierry Herbelot <thierry.herbelot at 6wind.com>
> ---
>  drivers/net/virtio/virtio_user/vhost_kernel.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c
> index ad46f10a9300..d65f89e1fc16 100644
> --- a/drivers/net/virtio/virtio_user/vhost_kernel.c
> +++ b/drivers/net/virtio/virtio_user/vhost_kernel.c
> @@ -158,6 +158,8 @@ static int
>  vhost_kernel_set_features(struct virtio_user_dev *dev, uint64_t features)
>  {
>  	struct vhost_kernel_data *data = dev->backend_data;
> +	uint32_t i;
> +	int ret;
>  
>  	/* We don't need memory protection here */
>  	features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
> @@ -166,7 +168,16 @@ vhost_kernel_set_features(struct virtio_user_dev *dev, uint64_t features)
>  	features &= ~VHOST_KERNEL_HOST_OFFLOADS_MASK;
>  	features &= ~(1ULL << VIRTIO_NET_F_MQ);
>  
> -	return vhost_kernel_ioctl(data->vhostfds[0], VHOST_SET_FEATURES, &features);
> +	for (i = 0; i < dev->max_queue_pairs; ++i) {
> +		if (data->vhostfds[i] < 0)
> +			continue;
> +
> +		ret = vhost_kernel_ioctl(data->vhostfds[i], VHOST_SET_FEATURES, &features);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
>  }
>  
>  static int
> 

Thanks for fixing it, it should be the last one...

Except GET_FEATURES that was also queried for every queue pair, but I
don't think it makes sense to query it and just drop the value read.
What do you think?

Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>

Thanks,
Maxime