netdev - Re: [PATCH 07/22] RDMA/irdma: Register an auxiliary driver and implement private channel OPs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <236bd48f-ad16-1502-3194-b3e48ca2de97@intel.com>
Date:   Tue, 26 Jan 2021 14:07:40 -0800
From:   Jacob Keller <jacob.e.keller@...el.com>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     "Saleem, Shiraz" <shiraz.saleem@...el.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        "dledford@...hat.com" <dledford@...hat.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "linux-rdma@...r.kernel.org" <linux-rdma@...r.kernel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "Ertman, David M" <david.m.ertman@...el.com>,
        "Nguyen, Anthony L" <anthony.l.nguyen@...el.com>,
        "Ismail, Mustafa" <mustafa.ismail@...el.com>,
        "jiri@...dia.com" <jiri@...dia.com>,
        "Samudrala, Sridhar" <sridhar.samudrala@...el.com>,
        "Williams, Dan J" <dan.j.williams@...el.com>
Subject: Re: [PATCH 07/22] RDMA/irdma: Register an auxiliary driver and
 implement private channel OPs



On 1/25/2021 9:29 PM, Leon Romanovsky wrote:
> On Mon, Jan 25, 2021 at 05:01:40PM -0800, Jacob Keller wrote:
>>
>>
>> On 1/25/2021 4:39 PM, Saleem, Shiraz wrote:
>>>> Subject: Re: [PATCH 07/22] RDMA/irdma: Register an auxiliary driver and
>>>> implement private channel OPs
>>>>
>>>> On Sun, Jan 24, 2021 at 03:45:51PM +0200, Leon Romanovsky wrote:
>>>>> On Fri, Jan 22, 2021 at 05:48:12PM -0600, Shiraz Saleem wrote:
>>>>>> From: Mustafa Ismail <mustafa.ismail@...el.com>
>>>>>>
>>>>>> Register irdma as an auxiliary driver which can attach to auxiliary
>>>>>> RDMA devices from Intel PCI netdev drivers i40e and ice. Implement
>>>>>> the private channel ops, add basic devlink support in the driver and
>>>>>> register net notifiers.
>>>>>
>>>>> Devlink part in "the RDMA client" is interesting thing.
>>>>>
>>>>> The idea behind auxiliary bus was that PCI logic will stay at one
>>>>> place and devlink considered as the tool to manage that.
>>>>
>>>> Yes, this doesn't seem right, I don't think these auxiliary bus objects should have
>>>> devlink instances, or at least someone from devlink land should approve of the
>>>> idea.
>>>>
>>>
>>> In our model, we have one auxdev (for RDMA) per PCI device function owned by netdev driver
>>> and one devlink instance per auxdev. Plus there is an Intel netdev driver for each HW generation.
>>> Moving the devlink logic to the PCI netdev driver would mean duplicating the same set of RDMA
>>> params in each Intel netdev driver. Additionally, plumbing RDMA specific params in the netdev
>>> driver sort of seems misplaced to me.
>>>
>>
>> I agree that plumbing these parameters at the PCI side in the devlink of
>> the parent device is weird. They don't seem to be parameters that the
>> parent driver cares about.
>>
>> Maybe there is another mechanism that makes more sense? To me it is a
>> bit like if we were plumbing netdev specific paramters into devlink
>> instead of trying to expose them through netdevice specific interfaces
>> like iproute2 or ethtool.
> 
> I'm far from being expert in devlink, but for me separation is following:
> 1. devlink - operates on physical device level, when PCI device already initialized.
> 2. ethtool - changes needed to be done on netdev layer.
> 3. ip - upper layer of the netdev
> 4. rdmatool - RDMA specific when IB device already exists.
> 
> And the ENABLE_ROCE/ENABLE_RDMA thing shouldn't be in the RDMA driver at
> all, because it is physical device property which once toggled will
> prohibit creation of respective aux device.
> 

Ok. I guess I hadn't looked quite as close at the specifics here. I
agree that ENABLE_RDMA should go in the PF devlink.

If there's any other sort of RDMA-specific configuration that ties to
the IB device, that should go somehow into rdmatool, rather than
devlink. And thus: I think I agree, we don't want the IB device or the
aux device to create a devlink instance.

> Thanks
>