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From: Jason Wang <jasowang@redhat.com>
To: Parav Pandit <parav@nvidia.com>,
	virtualization@lists.linux-foundation.org
Cc: mst@redhat.com, elic@nvidia.com, netdev@vger.kernel.org,
	谢永吉 <xieyongji@bytedance.com>
Subject: Re: [PATCH 0/7] Introduce vdpa management tool
Date: Fri, 27 Nov 2020 11:53:09 +0800
Message-ID: <5b2235f6-513b-dbc9-3670-e4c9589b4d1f@redhat.com> (raw)
In-Reply-To: <20201112064005.349268-1-parav@nvidia.com>


On 2020/11/12 下午2:39, Parav Pandit wrote:
> This patchset covers user requirements for managing existing vdpa devices,
> using a tool and its internal design notes for kernel drivers.
>
> Background and user requirements:
> ----------------------------------
> (1) Currently VDPA device is created by driver when driver is loaded.
> However, user should have a choice when to create or not create a vdpa device
> for the underlying parent device.
>
> For example, mlx5 PCI VF and subfunction device supports multiple classes of
> device such netdev, vdpa, rdma. Howevever it is not required to always created
> vdpa device for such device.
>
> (2) In another use case, a device may support creating one or multiple vdpa
> device of same or different class such as net and block.
> Creating vdpa devices at driver load time further limits this use case.
>
> (3) A user should be able to monitor and query vdpa queue level or device level
> statistics for a given vdpa device.
>
> (4) A user should be able to query what class of vdpa devices are supported
> by its parent device.
>
> (5) A user should be able to view supported features and negotiated features
> of the vdpa device.
>
> (6) A user should be able to create a vdpa device in vendor agnostic manner
> using single tool.
>
> Hence, it is required to have a tool through which user can create one or more
> vdpa devices from a parent device which addresses above user requirements.
>
> Example devices:
> ----------------
>   +-----------+ +-----------+ +---------+ +--------+ +-----------+
>   |vdpa dev 0 | |vdpa dev 1 | |rdma dev | |netdev  | |vdpa dev 3 |
>   |type=net   | |type=block | |mlx5_0   | |ens3f0  | |type=net   |
>   +----+------+ +-----+-----+ +----+----+ +-----+--+ +----+------+
>        |              |            |            |         |
>        |              |            |            |         |
>   +----+-----+        |       +----+----+       |    +----+----+
>   |  mlx5    +--------+       |mlx5     +-------+    |mlx5     |
>   |pci vf 2  |                |pci vf 4 |            |pci sf 8 |
>   |03:00:2   |                |03:00.4  |            |mlx5_sf.8|
>   +----+-----+                +----+----+            +----+----+
>        |                           |                      |
>        |                      +----+-----+                |
>        +----------------------+mlx5      +----------------+
>                               |pci pf 0  |
>                               |03:00.0   |
>                               +----------+
>
> vdpa tool:
> ----------
> vdpa tool is a tool to create, delete vdpa devices from a parent device. It is a
> tool that enables user to query statistics, features and may be more attributes
> in future.
>
> vdpa tool command draft:
> ------------------------
> (a) List parent devices which supports creating vdpa devices.
> It also shows which class types supported by this parent device.
> In below command example two parent devices support vdpa device creation.
> First is PCI VF whose bdf is 03.00:2.
> Second is PCI VF whose name is 03:00.4.
> Third is PCI SF whose name is mlx5_core.sf.8
>
> $ vdpa parentdev list
> vdpasim
>    supported_classes
>      net
> pci/0000:03.00:3
>    supported_classes
>      net block
> pci/0000:03.00:4
>    supported_classes
>      net block
> auxiliary/mlx5_core.sf.8
>    supported_classes
>      net
>
> (b) Now add a vdpa device of networking class and show the device.
> $ vdpa dev add parentdev pci/0000:03.00:2 type net name foo0 $ vdpa dev show foo0
> foo0: parentdev pci/0000:03.00:2 type network parentdev vdpasim vendor_id 0 max_vqs 2 max_vq_size 256
>
> (c) Show features of a vdpa device
> $ vdpa dev features show foo0
> supported
>    iommu platform
>    version 1
>
> (d) Dump vdpa device statistics
> $ vdpa dev stats show foo0
> kickdoorbells 10
> wqes 100
>
> (e) Now delete a vdpa device previously created.
> $ vdpa dev del foo0
>
> vdpa tool support in this patchset:
> -----------------------------------
> vdpa tool is created to create, delete and query vdpa devices.
> examples:
> Show vdpa parent device that supports creating, deleting vdpa devices.
>
> $ vdpa parentdev show
> vdpasim:
>    supported_classes
>      net
>
> $ vdpa parentdev show -jp
> {
>      "show": {
>         "vdpasim": {
>            "supported_classes": {
>               "net"
>          }
>      }
> }
>
> Create a vdpa device of type networking named as "foo2" from the parent device vdpasim:
>
> $ vdpa dev add parentdev vdpasim type net name foo2
>
> Show the newly created vdpa device by its name:
> $ vdpa dev show foo2
> foo2: type network parentdev vdpasim vendor_id 0 max_vqs 2 max_vq_size 256
>
> $ vdpa dev show foo2 -jp
> {
>      "dev": {
>          "foo2": {
>              "type": "network",
>              "parentdev": "vdpasim",
>              "vendor_id": 0,
>              "max_vqs": 2,
>              "max_vq_size": 256
>          }
>      }
> }
>
> Delete the vdpa device after its use:
> $ vdpa dev del foo2
>
> vdpa tool support by kernel:
> ----------------------------
> vdpa tool user interface will be supported by existing vdpa kernel framework,
> i.e. drivers/vdpa/vdpa.c It services user command through a netlink interface.
>
> Each parent device registers supported callback operations with vdpa subsystem
> through which vdpa device(s) can be managed.
>
> FAQs:
> -----
> 1. Where does userspace vdpa tool reside which users can use?
> Ans: vdpa tool can possibly reside in iproute2 [1] as it enables user to
> create vdpa net devices.
>
> 2. Why not create and delete vdpa device using sysfs/configfs?
> Ans:
> (a) A device creation may involve passing one or more attributes.
> Passing multiple attributes and returning error code and more verbose
> information for invalid attributes cannot be handled by sysfs/configfs.
>
> (b) netlink framework is rich that enables user space and kernel driver to
> provide nested attributes.
>
> (c) Exposing device specific file under sysfs without net namespace
> awareness exposes details to multiple containers. Instead exposing
> attributes via a netlink socket secures the communication channel with kernel.
>
> (d) netlink socket interface enables to run syscaller kernel tests.
>
> 3. Why not use ioctl() interface?
> Ans: ioctl() interface replicates the necessary plumbing which already
> exists through netlink socket.
>
> 4. What happens when one or more user created vdpa devices exist for a
> parent PCI VF or SF and such parent device is removed?
> Ans: All user created vdpa devices are removed that belong to a parent.
>
> [1] git://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git
>
> Next steps:
> -----------
> (a) Post this patchset and iproute2/vdpa inclusion, remaining two drivers
> will be coverted to support vdpa tool instead of creating unmanaged default
> device on driver load.
> (b) More net specific parameters such as mac, mtu will be added.
> (c) Features bits get and set interface will be added.


Adding Yong Ji for sharing some thoughts from the view of userspace vDPA 
device.

Thanks



  parent reply index

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12  6:39 Parav Pandit
2020-11-12  6:39 ` [PATCH 1/7] vdpa: Add missing comment for virtqueue count Parav Pandit
2020-11-12  6:40 ` [PATCH 2/7] vdpa: Use simpler version of ida allocation Parav Pandit
2020-11-12  6:40 ` [PATCH 3/7] vdpa: Extend routine to accept vdpa device name Parav Pandit
2020-11-12  6:40 ` [PATCH 4/7] vdpa: Define vdpa parent device, ops and a netlink interface Parav Pandit
2020-11-12  6:40 ` [PATCH 5/7] vdpa: Enable a user to add and delete a vdpa device Parav Pandit
2020-11-12  6:40 ` [PATCH 6/7] vdpa: Enable user to query vdpa device info Parav Pandit
2020-11-12  6:40 ` [PATCH 7/7] vdpa/vdpa_sim: Enable user to create vdpasim net devices Parav Pandit
2020-11-16  9:41 ` [PATCH 0/7] Introduce vdpa management tool Stefan Hajnoczi
2020-11-17 19:41   ` Parav Pandit
2020-11-16 22:23 ` Jakub Kicinski
2020-11-17 19:51   ` Parav Pandit
2020-12-16  9:13     ` Michael S. Tsirkin
     [not found]       ` <20201216080610.08541f44@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
2020-12-16 16:54         ` Parav Pandit
2020-12-16 19:57           ` Michael S. Tsirkin
2020-12-17 12:13             ` Parav Pandit
2020-11-27  3:53 ` Jason Wang [this message]
     [not found]   ` <CACycT3sYScObb9nN3g7L3cesjE7sCZWxZ5_5R1usGU9ePZEeqA@mail.gmail.com>
2020-11-30  3:36     ` [External] " Jason Wang
2020-11-30  7:07       ` Yongji Xie
2020-12-01  6:25         ` Jason Wang
2020-12-01  9:55           ` Yongji Xie
2020-12-01 11:32             ` Parav Pandit
2020-12-01 14:18               ` Yongji Xie
2020-12-01 15:58                 ` Parav Pandit
2020-12-02  3:29                   ` Yongji Xie
2020-12-02  4:53                     ` Parav Pandit
2020-12-02  5:51                       ` Jason Wang
2020-12-02  6:24                         ` Parav Pandit
2020-12-02  7:55                           ` Jason Wang
2020-12-02  9:27                         ` Yongji Xie
2020-12-02  9:21                       ` Yongji Xie
2020-12-02 11:13                         ` Parav Pandit
2020-12-02 13:18                           ` Yongji Xie
2020-12-02  5:48             ` Jason Wang
2020-12-08 22:47   ` David Ahern
2021-01-19  4:21     ` Parav Pandit
2020-12-16  9:16 ` Michael S. Tsirkin
2021-01-04  3:31 ` [PATCH linux-next v2 " Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 1/7] vdpa_sim_net: Make mac address array static Parav Pandit
2021-01-04  7:00     ` Jason Wang
2021-01-04  3:31   ` [PATCH linux-next v2 2/7] vdpa_sim_net: Add module param to disable default vdpa net device Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 3/7] vdpa: Extend routine to accept vdpa device name Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 4/7] vdpa: Define vdpa mgmt device, ops and a netlink interface Parav Pandit
2021-01-04  7:03     ` Jason Wang
2021-01-04  7:24       ` Parav Pandit
2021-01-05  4:10         ` Jason Wang
2021-01-05  6:33           ` Parav Pandit
2021-01-05  8:36             ` Jason Wang
2021-01-04  3:31   ` [PATCH linux-next v2 5/7] vdpa: Enable a user to add and delete a vdpa device Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 6/7] vdpa: Enable user to query vdpa device info Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 7/7] vdpa_sim_net: Add support for user supported devices Parav Pandit
2021-01-04  7:05     ` Jason Wang
2021-01-04  7:21       ` Parav Pandit
2021-01-05  4:06         ` Jason Wang
2021-01-05  6:22           ` Parav Pandit
2021-01-05 10:31 ` [PATCH linux-next v3 0/6] Introduce vdpa management tool Parav Pandit
2021-01-05 10:31   ` [PATCH linux-next v3 1/6] vdpa_sim_net: Make mac address array static Parav Pandit
2021-01-07 13:45     ` Stefano Garzarella
2021-01-05 10:31   ` [PATCH linux-next v3 2/6] vdpa: Extend routine to accept vdpa device name Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 3/6] vdpa: Define vdpa mgmt device, ops and a netlink interface Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 4/6] vdpa: Enable a user to add and delete a vdpa device Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 5/6] vdpa: Enable user to query vdpa device info Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 6/6] vdpa_sim_net: Add support for user supported devices Parav Pandit
2021-01-05 11:48     ` Michael S. Tsirkin
2021-01-05 12:02       ` Parav Pandit
2021-01-05 12:14         ` Michael S. Tsirkin
2021-01-05 12:30           ` Parav Pandit
2021-01-05 13:23             ` Michael S. Tsirkin
2021-01-07  3:48               ` Parav Pandit
2021-01-12  4:14                 ` Parav Pandit
2021-01-14  4:17                 ` Jason Wang
2021-01-14  7:58                   ` Parav Pandit
2021-01-15  5:38                     ` Jason Wang
2021-01-15  6:27                       ` Parav Pandit
2021-01-19 11:09                         ` Jason Wang
2021-01-20  3:21                           ` Parav Pandit
2021-01-20  3:46                             ` Parav Pandit
2021-01-18 18:03                       ` Parav Pandit
2021-01-20  7:53                         ` Michael S. Tsirkin

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