From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Parav Pandit <parav@nvidia.com>,
"Zhu, Lingshan" <lingshan.zhu@intel.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 14:54:13 +0800 [thread overview]
Message-ID: <CACGkMEv62tuOP3ra0GBhjCH=syFWxP+GVfGL_i0Ce0iD4uMY=Q@mail.gmail.com> (raw)
In-Reply-To: <20220727015626-mutt-send-email-mst@kernel.org>
On Wed, Jul 27, 2022 at 2:01 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Wed, Jul 27, 2022 at 03:47:35AM +0000, Parav Pandit wrote:
> >
> > > From: Zhu, Lingshan <lingshan.zhu@intel.com>
> > > Sent: Tuesday, July 26, 2022 10:53 PM
> > >
> > > On 7/27/2022 10:17 AM, Parav Pandit wrote:
> > > >> From: Zhu, Lingshan <lingshan.zhu@intel.com>
> > > >> Sent: Tuesday, July 26, 2022 10:15 PM
> > > >>
> > > >> On 7/26/2022 11:56 PM, Parav Pandit wrote:
> > > >>>> From: Zhu, Lingshan <lingshan.zhu@intel.com>
> > > >>>> Sent: Tuesday, July 12, 2022 11:46 PM
> > > >>>>> When the user space which invokes netlink commands, detects that
> > > >> _MQ
> > > >>>> is not supported, hence it takes max_queue_pair = 1 by itself.
> > > >>>> I think the kernel module have all necessary information and it is
> > > >>>> the only one which have precise information of a device, so it
> > > >>>> should answer precisely than let the user space guess. The kernel
> > > >>>> module should be reliable than stay silent, leave the question to
> > > >>>> the user space
> > > >> tool.
> > > >>> Kernel is reliable. It doesn’t expose a config space field if the
> > > >>> field doesn’t
> > > >> exist regardless of field should have default or no default.
> > > >> so when you know it is one queue pair, you should answer one, not try
> > > >> to guess.
> > > >>> User space should not guess either. User space gets to see if _MQ
> > > >> present/not present. If _MQ present than get reliable data from kernel.
> > > >>> If _MQ not present, it means this device has one VQ pair.
> > > >> it is still a guess, right? And all user space tools implemented this
> > > >> feature need to guess
> > > > No. it is not a guess.
> > > > It is explicitly checking the _MQ feature and deriving the value.
> > > > The code you proposed will be present in the user space.
> > > > It will be uniform for _MQ and 10 other features that are present now and
> > > in the future.
> > > MQ and other features like RSS are different. If there is no _RSS_XX, there
> > > are no attributes like max_rss_key_size, and there is not a default value.
> > > But for MQ, we know it has to be 1 wihtout _MQ.
> > "we" = user space.
> > To keep the consistency among all the config space fields.
>
> Actually I looked and the code some more and I'm puzzled:
>
>
> struct virtio_net_config config = {};
> u64 features;
> u16 val_u16;
>
> vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config));
>
> if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac),
> config.mac))
> return -EMSGSIZE;
>
>
> Mac returned even without VIRTIO_NET_F_MAC
>
>
> val_u16 = le16_to_cpu(config.status);
> if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16))
> return -EMSGSIZE;
>
>
> status returned even without VIRTIO_NET_F_STATUS
>
> val_u16 = le16_to_cpu(config.mtu);
> if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
> return -EMSGSIZE;
>
>
> MTU returned even without VIRTIO_NET_F_MTU
>
>
> What's going on here?
Probably too late to fix, but this should be fine as long as all
parents support STATUS/MTU/MAC.
I wonder if we can add a check in the core and fail the device
registration in this case.
Thanks
>
>
> --
> MST
>
next prev parent reply other threads:[~2022-07-27 6:54 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 [this message]
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
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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