From: "Zhu, Lingshan" <lingshan.zhu@intel•com>
To: Parav Pandit <parav@nvidia•com>, "Michael S. Tsirkin" <mst@redhat•com>
Cc: "jasowang@redhat•com" <jasowang@redhat•com>,
"virtualization@lists•linux-foundation.org"
<virtualization@lists•linux-foundation.org>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"xieyongji@bytedance•com" <xieyongji@bytedance•com>,
"gautam.dawar@amd•com" <gautam.dawar@amd•com>
Subject: Re: [PATCH V3 5/6] vDPA: answer num of queue pairs = 1 to userspace when VIRTIO_NET_F_MQ == 0
Date: Wed, 27 Jul 2022 10:11:02 +0800 [thread overview]
Message-ID: <4cdfe0b5-2fca-0189-237c-e598d8368d33@intel.com> (raw)
In-Reply-To: <PH0PR12MB54811EB71F4D9C32DA2D6F02DC949@PH0PR12MB5481.namprd12.prod.outlook.com>
On 7/27/2022 4:53 AM, Parav Pandit wrote:
>> From: Michael S. Tsirkin<mst@redhat•com>
>> Sent: Tuesday, July 26, 2022 3:49 PM
>>
>> On Tue, Jul 26, 2022 at 03:54:06PM +0000, Parav Pandit wrote:
>>>> From: Michael S. Tsirkin<mst@redhat•com>
>>>> Sent: Wednesday, July 13, 2022 1:27 AM
>>>>
>>>> On Fri, Jul 01, 2022 at 10:07:59PM +0000, Parav Pandit wrote:
>>>>>> From: Zhu Lingshan<lingshan.zhu@intel•com>
>>>>>> Sent: Friday, July 1, 2022 9:28 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
>>>>>>
>>>>> The fix belongs to user space.
>>>>> When a feature bit _MQ is not negotiated, vdpa kernel space will
>>>>> not add
>>>> attribute VDPA_ATTR_DEV_NET_CFG_MAX_VQP.
>>>>> When such attribute is not returned by kernel, max_vq_pairs should
>>>>> not be
>>>> shown by the iproute2.
>>>>> We have many config space fields that depend on the feature bits
>>>>> and
>>>> some of them do not have any defaults.
>>>>> To keep consistency of existence of config space fields among all,
>>>>> we don't
>>>> want to show default like below.
>>>>> Please fix the iproute2 to not print max_vq_pairs when it is not
>>>>> returned by
>>>> the kernel.
>>>>
>>>> Parav I read the discussion and don't get your argument. From
>>>> driver's POV _MQ with 1 VQ pair and !_MQ are exactly functionally
>> equivalent.
>>> But we are talking from user POV here.
>> From spec POV there's just driver and device, user would be part of driver here.
> User space application still need to inspect the _MQ bit to
>>>> It's true that iproute probably needs to be fixed too, to handle old kernels.
>>>> But iproute is not the only userspace, why not make it's life easier
>>>> by fixing the kernel?
>>> Because it cannot be fixed for other config space fields which are control by
>> feature bits those do not have any defaults.
>>> So better to treat all in same way from user POV.
>> Consistency is good for sure. What are these other fields though?
>> Can you give examples so I understand please?
> speed only exists if VIRTIO_NET_F_SPEED_DUPLEX.
> rss_max_key_size exists only if VIRTIO_NET_F_RSS exists.
That's different cases from the MQ case.
There are no default values for speed and rss_max_key_size. And talking
on speed without VIRTIO_NET_F_SEPPD_DUPLEX or rss_max_key_size without
VIRTIO_NET_F_RSS are meaningless.
But for MQ, if without MQ, we know it has to be 1 queue pair to be a
functional virtio-net, and this is meaningful.
next prev parent reply other threads:[~2022-07-27 2:11 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-01 13:28 [PATCH V3 0/6] ifcvf/vDPA: support query device config space through netlink Zhu Lingshan
2022-07-01 13:28 ` [PATCH V3 1/6] vDPA/ifcvf: get_config_size should return a value no greater than dev implementation Zhu Lingshan
2022-07-04 4:39 ` Jason Wang
2022-07-08 6:44 ` Zhu, Lingshan
2022-07-13 5:44 ` Michael S. Tsirkin
2022-07-13 7:52 ` Zhu, Lingshan
2022-07-13 5:31 ` Michael S. Tsirkin
2022-07-13 7:48 ` Zhu, Lingshan
2022-07-01 13:28 ` [PATCH V3 2/6] vDPA/ifcvf: support userspace to query features and MQ of a management device Zhu Lingshan
2022-07-04 4:43 ` Jason Wang
2022-07-08 6:54 ` Zhu, Lingshan
2022-07-01 13:28 ` [PATCH V3 3/6] vDPA: allow userspace to query features of a vDPA device Zhu Lingshan
2022-07-01 22:02 ` Parav Pandit
2022-07-04 4:46 ` Jason Wang
2022-07-04 12:53 ` Parav Pandit
2022-07-05 7:59 ` Zhu, Lingshan
2022-07-05 11:56 ` Parav Pandit
2022-07-05 16:56 ` Zhu, Lingshan
2022-07-05 17:01 ` Parav Pandit
2022-07-06 2:25 ` Zhu, Lingshan
2022-07-06 2:28 ` Parav Pandit
2022-07-23 11:27 ` Zhu, Lingshan
2022-07-24 15:23 ` Parav Pandit
2022-07-27 8:15 ` Si-Wei Liu
2022-07-27 11:38 ` Zhu, Lingshan
2022-07-08 6:16 ` Zhu, Lingshan
2022-07-08 16:13 ` Parav Pandit
2022-07-11 2:18 ` Zhu, Lingshan
2022-07-01 13:28 ` [PATCH V3 4/6] vDPA: !FEATURES_OK should not block querying device config space Zhu Lingshan
2022-07-01 22:12 ` Parav Pandit
2022-07-08 6:22 ` Zhu, Lingshan
2022-07-13 5:23 ` Michael S. Tsirkin
2022-07-13 7:46 ` Zhu, Lingshan
[not found] ` <00889067-50ac-d2cd-675f-748f171e5c83@oracle.com>
[not found] ` <63242254-ba84-6810-dad8-34f900b97f2f@intel.com>
[not found] ` <8002554a-a77c-7b25-8f99-8d68248a741d@oracle.com>
2022-07-28 2:06 ` Jason Wang
2022-07-28 7:08 ` Si-Wei Liu
2022-07-28 7:36 ` Jason Wang
2022-07-28 7:44 ` Zhu, Lingshan
[not found] ` <2dfff5f3-3100-4a63-6da3-3e3d21ffb364@oracle.com>
2022-07-28 11:28 ` spec clarification (was Re: [PATCH V3 4/6] vDPA: !FEATURES_OK should not block querying device config space) Michael S. Tsirkin
2022-07-28 11:35 ` [PATCH V3 4/6] vDPA: !FEATURES_OK should not block querying device config space Michael S. Tsirkin
2022-07-28 22:12 ` Si-Wei Liu
[not found] ` <00e2e07e-1a2e-7af8-a060-cc9034e0d33f@intel.com>
[not found] ` <b58dba25-3258-d600-ea06-879094639852@oracle.com>
[not found] ` <c143e2da-208e-b046-9b8f-1780f75ed3e6@intel.com>
2022-07-29 20:55 ` Si-Wei Liu
2022-08-01 4:44 ` Jason Wang
2022-08-01 22:53 ` Si-Wei Liu
2022-08-01 22:58 ` Si-Wei Liu
2022-08-02 6:33 ` Jason Wang
2022-08-03 1:26 ` Si-Wei Liu
2022-08-03 2:30 ` Zhu, Lingshan
2022-08-03 23:09 ` Si-Wei Liu
2022-08-04 1:41 ` Zhu, Lingshan
2022-08-04 1:41 ` Zhu, Lingshan
2022-07-01 13:28 ` [PATCH V3 5/6] vDPA: answer num of queue pairs = 1 to userspace when VIRTIO_NET_F_MQ == 0 Zhu Lingshan
2022-07-01 22:07 ` Parav Pandit
2022-07-08 6:21 ` Zhu, Lingshan
2022-07-08 16:23 ` Parav Pandit
2022-07-11 2:29 ` Zhu, Lingshan
2022-07-12 16:48 ` Parav Pandit
2022-07-13 3:03 ` Zhu, Lingshan
2022-07-13 3:06 ` Parav Pandit
2022-07-13 3:45 ` Zhu, Lingshan
2022-07-26 15:56 ` Parav Pandit
2022-07-26 19:52 ` Michael S. Tsirkin
2022-07-26 20:49 ` Parav Pandit
2022-07-27 2:14 ` Zhu, Lingshan
2022-07-27 2:17 ` Parav Pandit
2022-07-27 2:53 ` Zhu, Lingshan
2022-07-27 3:47 ` Parav Pandit
2022-07-27 4:24 ` Zhu, Lingshan
2022-07-27 6:01 ` Michael S. Tsirkin
2022-07-27 6:25 ` Zhu, Lingshan
2022-07-27 6:56 ` Jason Wang
2022-07-27 9:05 ` Michael S. Tsirkin
2022-07-27 6:54 ` Jason Wang
2022-07-27 9:02 ` Michael S. Tsirkin
2022-07-27 9:50 ` Jason Wang
2022-07-27 15:45 ` Michael S. Tsirkin
2022-07-28 1:21 ` Jason Wang
2022-07-28 3:46 ` Zhu, Lingshan
2022-07-28 5:53 ` Jason Wang
2022-07-28 6:02 ` Zhu, Lingshan
2022-07-28 6:41 ` Michael S. Tsirkin
2022-08-01 4:50 ` Jason Wang
2022-07-27 7:50 ` Si-Wei Liu
2022-07-27 9:01 ` Michael S. Tsirkin
2022-07-27 10:09 ` Si-Wei Liu
2022-07-27 11:54 ` Zhu, Lingshan
2022-07-28 1:41 ` Si-Wei Liu
2022-07-28 2:44 ` Zhu, Lingshan
2022-07-28 21:54 ` Si-Wei Liu
2022-07-29 2:07 ` Zhu, Lingshan
2022-07-27 15:48 ` Michael S. Tsirkin
2022-07-13 5:26 ` Michael S. Tsirkin
2022-07-13 7:47 ` Zhu, Lingshan
2022-07-26 15:54 ` Parav Pandit
2022-07-26 19:48 ` Michael S. Tsirkin
2022-07-26 20:53 ` Parav Pandit
2022-07-27 1:56 ` Zhu, Lingshan
2022-07-27 2:11 ` Zhu, Lingshan [this message]
2022-07-01 13:28 ` [PATCH V3 6/6] vDPA: fix 'cast to restricted le16' warnings in vdpa.c Zhu Lingshan
2022-07-01 22:18 ` Parav Pandit
2022-07-08 6:25 ` Zhu, Lingshan
2022-07-08 16:08 ` Parav Pandit
2022-07-29 8:53 ` Michael S. Tsirkin
2022-07-29 9:07 ` Zhu, Lingshan
2022-07-29 9:17 ` Michael S. Tsirkin
2022-07-29 9:20 ` Zhu, Lingshan
2022-07-29 9:23 ` Michael S. Tsirkin
2022-07-29 9:35 ` Zhu, Lingshan
2022-07-29 9:39 ` Michael S. Tsirkin
2022-07-29 10:01 ` Zhu, Lingshan
2022-07-29 10:16 ` Michael S. Tsirkin
2022-07-29 10:18 ` Zhu, Lingshan
2022-08-01 4:33 ` Jason Wang
2022-08-01 6:25 ` Michael S. Tsirkin
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