| Message ID | 20210104033141.105876-1-parav@nvidia.com |
|---|---|
| Headers | show |
| Series | Introduce vdpa management tool | expand |
On 2021/1/4 下午3:21, Parav Pandit wrote: > >> From: Jason Wang <jasowang@redhat.com> >> Sent: Monday, January 4, 2021 12:35 PM >> >> On 2021/1/4 上午11:31, Parav Pandit wrote: >>> static int __init vdpasim_net_init(void) >>> { >>> int ret = 0; >>> @@ -176,6 +264,8 @@ static int __init vdpasim_net_init(void) >>> >>> if (default_device) >>> ret = vdpasim_net_default_dev_register(); >>> + else >>> + ret = vdpasim_net_mgmtdev_init(); >>> return ret; >>> } >>> >>> @@ -183,6 +273,8 @@ static void __exit vdpasim_net_exit(void) >>> { >>> if (default_device) >>> vdpasim_net_default_dev_unregister(); >>> + else >>> + vdpasim_net_mgmtdev_cleanup(); >>> } >>> >>> module_init(vdpasim_net_init); >>> -- 2.26.2 >> >> I wonder what's the value of keeping the default device that is out of the >> control of management API. > I think we can remove it like how I did in the v1 version. And actual vendor drivers like mlx5_vdpa will likely should do only user created devices. > I added only for backward compatibility purpose, but we can remove the default simulated vdpa net device. > What do you recommend? I think we'd better mandate this management API. This can avoid vendor specific configuration that may complex management layer. Thanks
> From: Jason Wang <jasowang@redhat.com> > Sent: Tuesday, January 5, 2021 9:36 AM > > > On 2021/1/4 下午3:21, Parav Pandit wrote: > > > >> From: Jason Wang <jasowang@redhat.com> > >> Sent: Monday, January 4, 2021 12:35 PM > >> > >> On 2021/1/4 上午11:31, Parav Pandit wrote: > >>> static int __init vdpasim_net_init(void) > >>> { > >>> int ret = 0; > >>> @@ -176,6 +264,8 @@ static int __init vdpasim_net_init(void) > >>> > >>> if (default_device) > >>> ret = vdpasim_net_default_dev_register(); > >>> + else > >>> + ret = vdpasim_net_mgmtdev_init(); > >>> return ret; > >>> } > >>> > >>> @@ -183,6 +273,8 @@ static void __exit vdpasim_net_exit(void) > >>> { > >>> if (default_device) > >>> vdpasim_net_default_dev_unregister(); > >>> + else > >>> + vdpasim_net_mgmtdev_cleanup(); > >>> } > >>> > >>> module_init(vdpasim_net_init); > >>> -- 2.26.2 > >> > >> I wonder what's the value of keeping the default device that is out > >> of the control of management API. > > I think we can remove it like how I did in the v1 version. And actual vendor > drivers like mlx5_vdpa will likely should do only user created devices. > > I added only for backward compatibility purpose, but we can remove the > default simulated vdpa net device. > > What do you recommend? > > > I think we'd better mandate this management API. This can avoid vendor > specific configuration that may complex management layer. > Sounds good. I will drop the patch that allows vdpasim_net default device via module parameter. Will post v3 with that removal.
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 management 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 management 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 management device which addresses above user requirements. Example devices: ---------------- +-----------+ +-----------+ +---------+ +--------+ +-----------+ |vdpa dev 0 | |vdpa dev 1 | |rdma dev | |netdev | |vdpa dev 3 | |type=net | |type=net | |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 management 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 management devices which support creating vdpa devices. It also shows which class types supported by this management device. In below command example four management 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 mgmtdev list vdpasim_net supported_classes net pci/0000:03.00:0 supported_classes net pci/0000:03.00:4 supported_classes net auxiliary/mlx5_core.sf.8 supported_classes net (b) Now add a vdpa device of networking class and show the device. $ vdpa dev add mgmtdev pci/0000:03.00:0 name foo0 $ vdpa dev show foo0 foo0: mgmtdev pci/0000:03.00:2 type network 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 management device that supports creating, deleting vdpa devices. $ vdpa mgmtdev show vdpasim_net: supported_classes net $ vdpa mgmtdev show -jp { "show": { "vdpasim_net": { "supported_classes": { "net" } } } Create a vdpa device of type networking named as "foo2" from the management device vdpasim: $ vdpa dev add mgmtdev vdpasim type net name foo2 Show the newly created vdpa device by its name: $ vdpa dev show foo2 foo2: type network mgmtdev vdpasim vendor_id 0 max_vqs 2 max_vq_size 256 $ vdpa dev show foo2 -jp { "dev": { "foo2": { "type": "network", "mgmtdev": "vdpasim_net", "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 management device registers supported callback operations with vdpa subsystem through which vdpa device(s) can be managed. Patch summary: -------------- Patch-1 Makes mac address array static Patch-2 adds module parameter to avoid breaking backward compatibility for default device Patch-3 Extends API to accept vdpa device name Patch-4 Defines management device interface Patch-5 Extends netlink interface to add, delete vdpa devices Patch-6 Extends netlink interface to query vdpa device attributes Patch-7 Extends vdpa_sim_net driver to add/delete simulated vdpa devices 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 handler vdpa network 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 management PCI VF or SF and such management device is removed? Ans: All user created vdpa devices are removed that belong to a management device. [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. Parav Pandit (7): vdpa_sim_net: Make mac address array static vdpa_sim_net: Add module param to disable default vdpa net device vdpa: Extend routine to accept vdpa device name vdpa: Define vdpa mgmt device, ops and a netlink interface vdpa: Enable a user to add and delete a vdpa device vdpa: Enable user to query vdpa device info vdpa_sim_net: Add support for user supported devices drivers/vdpa/Kconfig | 1 + drivers/vdpa/ifcvf/ifcvf_main.c | 2 +- drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +- drivers/vdpa/vdpa.c | 503 ++++++++++++++++++++++++++- drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 +- drivers/vdpa/vdpa_sim/vdpa_sim.h | 2 + drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 135 ++++++- include/linux/vdpa.h | 44 ++- include/uapi/linux/vdpa.h | 40 +++ 9 files changed, 707 insertions(+), 25 deletions(-) create mode 100644 include/uapi/linux/vdpa.h