Re: [PATCH V4 5/6] vDPA: answer num of queue pairs = 1 to userspace when VIRTIO_NET_F_MQ == 0

["Zhu, Lingshan" <lingshan.zhu@intel.com>]

On 7/22/2022 9:14 PM, Parav Pandit wrote:
>
>> From: Zhu Lingshan <lingshan.zhu@intel.com>
>> Sent: Friday, July 22, 2022 7:53 AM
>>
>> If VIRTIO_NET_F_MQ == 0, the virtio device should have one queue pair, so
>> when userspace querying queue pair numbers, it should return mq=1 than
>> zero.
>>
>> Function vdpa_dev_net_config_fill() fills the attributions of the vDPA
>> devices, so that it should call vdpa_dev_net_mq_config_fill() so the
>> parameter in vdpa_dev_net_mq_config_fill() should be feature_device than
>> feature_driver for the vDPA devices themselves
>>
>> Before this change, when MQ = 0, iproute2 output:
>> $vdpa dev config show vdpa0
>> vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false max_vq_pairs 0
>> mtu 1500
>>
>> After applying this commit, when MQ = 0, iproute2 output:
>> $vdpa dev config show vdpa0
>> vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false max_vq_pairs 1
>> mtu 1500
>>
> No. We do not want to diverge returning values of config space for fields which are not present as discussed in previous versions.
> Please drop this patch.
> Nack on this patch.
I believe MST has replied to you in the V3 thread, did you miss that?
>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vdpa/vdpa.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index
>> d76b22b2f7ae..846dd37f3549 100644
>> --- a/drivers/vdpa/vdpa.c
>> +++ b/drivers/vdpa/vdpa.c
>> @@ -806,9 +806,10 @@ static int vdpa_dev_net_mq_config_fill(struct
>> vdpa_device *vdev,
>>   	u16 val_u16;
>>
>>   	if ((features & BIT_ULL(VIRTIO_NET_F_MQ)) == 0)
>> -		return 0;
>> +		val_u16 = 1;
>> +	else
>> +		val_u16 = __virtio16_to_cpu(true, config-
>>> max_virtqueue_pairs);
>> -	val_u16 = le16_to_cpu(config->max_virtqueue_pairs);
>>   	return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP,
>> val_u16);  }
>>
>> @@ -842,7 +843,7 @@ static int vdpa_dev_net_config_fill(struct
>> vdpa_device *vdev, struct sk_buff *ms
>>   			      VDPA_ATTR_PAD))
>>   		return -EMSGSIZE;
>>
>> -	return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver,
>> &config);
>> +	return vdpa_dev_net_mq_config_fill(vdev, msg, features_device,
>> +&config);
>>   }
>>
>>   static int
>> --
>> 2.31.1