Date:   Wed, 20 May 2020 10:15:33 -0600
From:   Jeffrey Hugo <jhugo@...eaurora.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Daniel Vetter <daniel@...ll.ch>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Olof Johansson <olof.johansson@...il.com>,
        Jason Gunthorpe <jgg@...lanox.com>,
        Dave Airlie <airlied@...il.com>, Arnd Bergmann <arnd@...db.de>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        wufan@...eaurora.org, pratanan@...eaurora.org,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 0/8] Qualcomm Cloud AI 100 driver

On 5/20/2020 9:59 AM, Greg Kroah-Hartman wrote:
> On Wed, May 20, 2020 at 08:48:13AM -0600, Jeffrey Hugo wrote:
>> On 5/20/2020 2:34 AM, Daniel Vetter wrote:
>>> On Wed, May 20, 2020 at 7:15 AM Greg Kroah-Hartman
>>> <gregkh@...uxfoundation.org> wrote:
>>>>
>>>> On Tue, May 19, 2020 at 10:41:15PM +0200, Daniel Vetter wrote:
>>>>> On Tue, May 19, 2020 at 07:41:20PM +0200, Greg Kroah-Hartman wrote:
>>>>>> On Tue, May 19, 2020 at 08:57:38AM -0600, Jeffrey Hugo wrote:
>>>>>>> On 5/18/2020 11:08 PM, Dave Airlie wrote:
>>>>>>>> On Fri, 15 May 2020 at 00:12, Jeffrey Hugo <jhugo@...eaurora.org> wrote:
>>>>>>>>>
>>>>>>>>> Introduction:
>>>>>>>>> Qualcomm Cloud AI 100 is a PCIe adapter card which contains a dedicated
>>>>>>>>> SoC ASIC for the purpose of efficently running Deep Learning inference
>>>>>>>>> workloads in a data center environment.
>>>>>>>>>
>>>>>>>>> The offical press release can be found at -
>>>>>>>>> https://www.qualcomm.com/news/releases/2019/04/09/qualcomm-brings-power-efficient-artificial-intelligence-inference
>>>>>>>>>
>>>>>>>>> The offical product website is -
>>>>>>>>> https://www.qualcomm.com/products/datacenter-artificial-intelligence
>>>>>>>>>
>>>>>>>>> At the time of the offical press release, numerious technology news sites
>>>>>>>>> also covered the product.  Doing a search of your favorite site is likely
>>>>>>>>> to find their coverage of it.
>>>>>>>>>
>>>>>>>>> It is our goal to have the kernel driver for the product fully upstream.
>>>>>>>>> The purpose of this RFC is to start that process.  We are still doing
>>>>>>>>> development (see below), and thus not quite looking to gain acceptance quite
>>>>>>>>> yet, but now that we have a working driver we beleive we are at the stage
>>>>>>>>> where meaningful conversation with the community can occur.
>>>>>>>>
>>>>>>>>
>>>>>>>> Hi Jeffery,
>>>>>>>>
>>>>>>>> Just wondering what the userspace/testing plans for this driver.
>>>>>>>>
>>>>>>>> This introduces a new user facing API for a device without pointers to
>>>>>>>> users or tests for that API.
>>>>>>>
>>>>>>> We have daily internal testing, although I don't expect you to take my word
>>>>>>> for that.
>>>>>>>
>>>>>>> I would like to get one of these devices into the hands of Linaro, so that
>>>>>>> it can be put into KernelCI.  Similar to other Qualcomm products. I'm trying
>>>>>>> to convince the powers that be to make this happen.
>>>>>>>
>>>>>>> Regarding what the community could do on its own, everything but the Linux
>>>>>>> driver is considered proprietary - that includes the on device firmware and
>>>>>>> the entire userspace stack.  This is a decision above my pay grade.
>>>>>>
>>>>>> Ok, that's a decision you are going to have to push upward on, as we
>>>>>> really can't take this without a working, open, userspace.
>>>>>
>>>>> Uh wut.
>>>>>
>>>>> So the merge criteria for drivers/accel (atm still drivers/misc but I
>>>>> thought that was interim until more drivers showed up) isn't actually
>>>>> "totally-not-a-gpu accel driver without open source userspace".
>>>>>
>>>>> Instead it's "totally-not-a-gpu accel driver without open source
>>>>> userspace" _and_ you have to be best buddies with Greg. Or at least
>>>>> not be on the naughty company list. Since for habanalabs all you
>>>>> wanted is a few test cases to exercise the ioctls. Not the entire
>>>>> userspace.
>>>>
>>>> Also, to be fair, I have changed my mind after seeing the mess of
>>>> complexity that these "ioctls for everyone!" type of pass-through
>>>> these kinds of drivers are creating.  You were right, we need open
>>>> userspace code in order to be able to properly evaluate and figure out
>>>> what they are doing is right or not and be able to maintain things over
>>>> time correctly.
>>>>
>>>> So I was wrong, and you were right, my apologies for my previous
>>>> stubbornness.
>>>
>>> Awesome and don't worry, I'm pretty sure we've all been stubborn
>>> occasionally :-)
>>>
>>>   From a drivers/gpu pov I think still not quite there since we also
>>> want to see the compiler for these programmable accelerator thingies.
>>> But just having a fairly good consensus that "userspace library with
>>> all the runtime stuff excluding compiler must be open" is a huge step
>>> forward. Next step may be that we (kernel overall, drivers/gpu will
>>> still ask for the full thing) have ISA docs for these programmable
>>> things, so that we can also evaluate that aspect and gauge how many
>>> security issues there might be. Plus have a fighting chance to fix up
>>> the security leaks when (post smeltdown I don't really want to
>>> consider this an if) someone finds a hole in the hw security wall. At
>>> least in drivers/gpu we historically have a ton of drivers with
>>> command checkers to validate what userspace wants to run on the
>>> accelerator thingie. Both in cases where the hw was accidentally too
>>> strict, and not strict enough.
>>
>> I think this provides a pretty clear guidance on what you/the community are
>> looking for, both now and possibly in the future.
>>
>> Thank you.
>>
>>  From my perspective, it would be really nice if there was something like
>> Mesa that was a/the standard for these sorts of accelerators.  Its somewhat
>> the wild west, and we've struggled with it.
> 
> Put a first cut at such a thing out there and see how it goes!  Nothing
> is preventing you from starting such a project, and it would be most
> welcome as you have seen.

I wish.  I'll float the idea, but don't hold your breath.

-- 
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

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