Re: Re: [PATCH RESEND iproute2-next] devlink: Add optional controller user input

On 2021/6/8 16:47, Parav Pandit wrote:

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From: Yunsheng Lin <redacted>
Sent: Tuesday, June 8, 2021 1:06 PM

On 2021/6/8 13:26, Parav Pandit wrote:

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From: Yunsheng Lin <redacted>
Sent: Tuesday, June 8, 2021 8:58 AM

On 2021/6/7 19:12, Parav Pandit wrote:

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From: Yunsheng Lin <redacted>
Sent: Monday, June 7, 2021 4:27 PM

[..]

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2. each PF's devlink instance has three types of port, which is
   FLAVOUR_PHYSICAL, FLAVOUR_PCI_PF and

FLAVOUR_PCI_VF(supposing I

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understand
   port flavour correctly).

FLAVOUR_PCI_{PF,VF,SF} belongs to eswitch (representor) side on

switchdev device.

If devlink instance or eswitch is in DEVLINK_ESWITCH_MODE_LEGACY
mode, the FLAVOUR_PCI_{PF,VF,SF} port instance does not need to

created?

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No. in eswitch legacy, there are no representor netdevice or devlink

ports.

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It seems each devlink port instance corresponds to a netdevice.
More specificly, the devlink instance is created in the struct
pci_driver' probe function of a pci function, a devlink port instance
is created and registered to that devlink instance when a netdev of that

pci function is created?

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Yes.

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As in diagram [1], the devlink port instance(flavour
FLAVOUR_PHYSICAL) for
ctrl-0-pf0 is created when the netdev of ctrl-0-pf0 is created in the
host of smartNIC, the devlink port instance(flavour FLAVOUR_VIRTUAL)
for ctrl-0- pf0vfN is created when the netdev of ctrl-0-pf0vfN is
created in the host of smartNIC, right?

Ctrl-0-pf0vfN, ctrl-0-pf0 ports are eswitch ports. They are created where

there is eswitch.

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Usually in smartnic where eswitch is located.

Does diagram in [1] corresponds to the multi-host (two) host setup as
memtioned previously?
H1.pf0.phyical_port = p0.
H1.pf1.phyical_port = p1.
H2.pf0.phyical_port = p0.
H2.pf1.phyical_port = p1.

Yes.

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Let's say H1 = server and H2 = smartNIC as the pci rc connected to below:
                 ---------------------------------------------------------
                 |                                                       |
                 |           --------- ---------         ------- ------- |
    -----------  |           | vf(s) | | sf(s) |         |vf(s)| |sf(s)| |
    | server  |  | -------   ----/---- ---/----- ------- ---/--- ---/--- |
    | pci rc  |=== | pf0 |______/________/       | pf1 |___/_______/     |
    | connect |  | -------                       -------                 |
    -----------  |     | controller_num=1 (no eswitch)                   |
                 ------|--------------------------------------------------
                 (internal wire)
                       |
                 ---------------------------------------------------------
                 | devlink eswitch ports and reps                        |
                 | ----------------------------------------------------- |
                 | |ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 |ctrl-0 | |
                 | |pf0    | pf0vfN | pf0sfN | pf1    | pf1vfN |pf1sfN | |
                 | ----------------------------------------------------- |
                 | |ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 |ctrl-1 | |
                 | |pf0    | pf0vfN | pf0sfN | pf1    | pf1vfN |pf1sfN | |
                 | ----------------------------------------------------- |
                 |                                                       |
                 |                                                       |
    -----------  |           --------- ---------         ------- ------- |
    | smartNIC|  |           | vf(s) | | sf(s) |         |vf(s)| |sf(s)| |
    | pci rc  |==| -------   ----/---- ---/----- ------- ---/--- ---/--- |
    | connect |  | | pf0 |______/________/       | pf1 |___/_______/     |
    -----------  | -------                       -------                 |
                 |                                                       |
                 |  local controller_num=0 (eswitch)                     |
                 ---------------------------------------------------------

A vanilla kernel can run on the smartNIC host, right?

Right.

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what the smartNIC host see is two PF corresponding to ctrl-0-pf0 and
ctrl-0-pf1 When the kernel is boot up first and mlx driver is not loaded yet,
right?

I am not sure it is ok to leave out the VF and SF, but let's leave them out for
simplicity now.
When mlx driver is loaded, two devlink instances are created, which
corresponds to ctrl-0-pf0 and ctrl-0-pf1, and two devlink port instances
(flavour FLAVOUR_PHYSICAL) is created and registered to corresponding
devlink instances just created, right?

As the eswitch mode is based on devlink instance, Let's only set the mode of
ctrl-0-pf0' devlink instance to DEVLINK_ESWITCH_MODE_SWITCHDEV, the
representor netdev of ctrl-1-pf0 is created and devlink port instance of that
representor netdev is created and registered to devlink instances
corresponding to ctrl-0-pf0?

I think I miss something here, the above does not seems right, because：
1. For single host case：the PF is not passed through to the VM, devlink port
   instance of VF's representor netdev can be registered to the devlink
instance
   corresponding to it's PF, right?

Yes, if I understand your question right.

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2. But for two-host case as above, do we need to create a devlink instances
   for the PF corresponding to ctrl-1-pf0 in smartNIC host?

You can choose not to create a devlink instance in external controller PF. It may not be even a Linux OS running there.

I read questions few more times, but I find it hard to understand what you really want to ask.
Not sure I understood you.

Trying again,

The model is really very straight forward as visible in the diagram.

There is one PF that has the eswitch. Eswitch contains representor ports.

I thought the representor ports of a PF'eswitch is decided by the function
under a specific PF(For example, the PF itself and the VF under this PF)?

Each representor port represent either PF, VF or SF.
This PF, VF or SF can be of local controller residing on the eswitch device or it can be of an external controller(s).
Here external controller = 1.

If I understood above correctly:
The fw/hw decide which PF has the eswitch, and how many devlink/representor
port does this eswitch has?
Suppose PF0 of controller_num=0 in have the eswitch, and the eswitch may has
devlink/representor port representing other PF, like PF1 in controller_num=0,
and even PF0/PF1 in controller_num=1?

Every single PF, VF, SF has devlink instance including the eswitch PF and PF of external controller (often called as external host).
Why such devlink instance exists? -> I explained you before in [1].

[1] https://lore.kernel.org/netdev/PH0PR12MB5481FB8528A90E34FA3578C1DC389@PH0PR12MB5481.namprd12.prod.outlook.com/ (local)