Re: [dpdk-dev] [PATCH 1/3] net/virtio: keep device and frontend features separated

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, June 8, 2021 10:14 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; amorenoz@redhat.com;
> david.marchand@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH 1/3] net/virtio: keep device and frontend features separated
> 
> This patch is preliminary rework to add support for getting
> and setting device's config space.
> 
> In order to get or set a device config such as its MAC address,
> we need to know whether the device itself support the feature,
> or if it is emulated by the frontend.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  drivers/net/virtio/virtio_user/virtio_user_dev.c | 10 ++--------
>  drivers/net/virtio/virtio_user_ethdev.c          |  5 +++--
>  2 files changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index 364f43e21c..ed55cd7524 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -573,11 +573,7 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char
> *path, int queues,
>  	if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER)
>  		dev->frontend_features |= (1ull << VIRTIO_NET_F_STATUS);
> 
> -	/*
> -	 * Device features =
> -	 *     (frontend_features | backend_features) & ~unsupported_features;
> -	 */
> -	dev->device_features |= dev->frontend_features;
> +	dev->frontend_features &= ~dev->unsupported_features;
>  	dev->device_features &= ~dev->unsupported_features;
> 
>  	if (rte_mem_event_callback_register(VIRTIO_USER_MEM_EVENT_CLB_NAME,
> @@ -980,12 +976,10 @@ virtio_user_dev_server_reconnect(struct virtio_user_dev
> *dev)
>  		return -1;
>  	}
> 
> -	dev->device_features |= dev->frontend_features;
> -
>  	/* unmask vhost-user unsupported features */
>  	dev->device_features &= ~(dev->unsupported_features);
> 
> -	dev->features &= dev->device_features;
> +	dev->features &= (dev->device_features | dev->frontend_features);
> 
>  	/* For packed ring, resetting queues is required in reconnection. */
>  	if (virtio_with_packed_queue(hw) &&
> diff --git a/drivers/net/virtio/virtio_user_ethdev.c
> b/drivers/net/virtio/virtio_user_ethdev.c
> index e85906e9eb..3ecbb4184a 100644
> --- a/drivers/net/virtio/virtio_user_ethdev.c
> +++ b/drivers/net/virtio/virtio_user_ethdev.c
> @@ -110,7 +110,8 @@ virtio_user_get_features(struct virtio_hw *hw)
>  	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
> 
>  	/* unmask feature bits defined in vhost user protocol */
> -	return dev->device_features & VIRTIO_PMD_SUPPORTED_GUEST_FEATURES;
> +	return (dev->device_features | dev->frontend_features) &
> +		VIRTIO_PMD_SUPPORTED_GUEST_FEATURES;
>  }
> 
>  static void
> @@ -118,7 +119,7 @@ virtio_user_set_features(struct virtio_hw *hw, uint64_t
> features)
>  {
>  	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
> 
> -	dev->features = features & dev->device_features;
> +	dev->features = features & (dev->device_features | dev-
> >frontend_features);
>  }
> 
>  static int
> --
> 2.31.1

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>