Re: [PATCH 3/5] net/virtio-user: support to report net status

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

On 3/29/2017 2:33 PM, Yuanhan Liu wrote:
> On Mon, Mar 27, 2017 at 07:46:32AM +0000, Tan, Jianfeng wrote:
>>>> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>>> index 9777d6b..cc6f557 100644
>>>> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>>> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>>> @@ -176,6 +176,7 @@ virtio_user_start_device(struct virtio_user_dev
>>> *dev, uint8_t portid)
>>>>   	features &= ~(1ull << VIRTIO_NET_F_MAC);
>>>>   	/* Strip VIRTIO_NET_F_CTRL_VQ, as devices do not really need to
>>> know */
>>>>   	features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
>>>> +	features &= ~(1ull << VIRTIO_NET_F_STATUS);
>>>>   	ret = dev->ops->send_request(dev, VHOST_USER_SET_FEATURES,
>>> &features);
>>>>   	if (ret < 0)
>>>>   		goto error;
>>>> diff --git a/drivers/net/virtio/virtio_user_ethdev.c
>>> b/drivers/net/virtio/virtio_user_ethdev.c
>>>> index fa79419..fbdd0a8 100644
>>>> --- a/drivers/net/virtio/virtio_user_ethdev.c
>>>> +++ b/drivers/net/virtio/virtio_user_ethdev.c
>>>> @@ -121,7 +121,8 @@ 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 | (1 << VIRTIO_NET_F_STATUS))
>>>> +		& VIRTIO_PMD_SUPPORTED_GUEST_FEATURES;
>>> Why not handle the features at virtio_user_dev_init()?
>> You mean add VIRTIO_NET_F_STATUS when get_features from device? Yes, we could do that there. But we originally add device_features to only record features supported by device.
>>
> Aren't you adding the F_STATUS features to this device?
>

For virtio driver, yes, we are adding F_STATUS feature so the it sees a 
device supporting LSC. But for backend driver, we need hide this 
feature, it happens when we set_features to the backend driver.

Thanks,
Jianfeng