Re: [PATCH] crypto: qce - Replace with stub driver

[Krzysztof Kozlowski <krzk@kernel.org>]

On 01/08/2026 18:29, Eric Biggers wrote:
> On Sat, Aug 01, 2026 at 11:18:46AM +0200, Krzysztof Kozlowski wrote:
>> On 31/07/2026 20:31, Demi Marie Obenour wrote:
>>> On 7/31/26 05:06, Krzysztof Kozlowski wrote:
>>>> On 31/07/2026 07:08, Eric Biggers wrote:
>>>>> None of the algorithms the QCE driver registers with the crypto API are
>>>>> even close to being useful.  They're massively outperformed by the
>>>>
>>>> The amount of patches you send towards removal of QCE is really
>>>> stunning. Or rather worrying. This is like third approach or so.
>>>>
>>>> Your previous approaches received valid feedback, including even fixes
>>>> and committment of new maintainer.
>>>>
>>>> But you even complained that it does receive fixes! [1]
>>>>
>>>> We removed the driver temporarily from typical configurations, so no one
>>>> will be affected, by whatever is found now and not yet fixed. Still not
>>>> enough! For you this was reason to remove the driver (AGAIN!) [2]
>>>
>>> A stub driver needs to be added for power management reasons.  It turns
>>> out that if there is no driver, power consumption is very high.
>>>
>>>> This is beyond comprehension and very unpleasant, because you actively
>>>> work against the community with this approach.
>>>
>>> I trust that Bartosz can fix the driver with enough work.  However,
>>> even if the QCE driver had never had a single bug, it would still not
>>> be worth using.  Its performance is so poor that one should always
>>> use CPU-based crypto instead.  In the default configuration, that is
>>> in fact what happens.
>>>
>>> The QCE's algorithm implementations only provide a way people can
>>> misconfigure their systems and ruin their performance.  There are
>>> debug options that also severely harm performance, but they have
>>> legitimate uses during development.  The current QCE driver doesn't.
>>>
>>> I have no problem with a driver for the QCE that does something actually
>>> useful.  While there are disagreements about whether restricted media
>>> processing is a feature or an anti-feature, my view is that it is
>>> better for it to be implemented upstream than in an out-of-tree driver.
>>> However, the driver as it currently exists does not implement this.
>>>
>>> I expect that such a driver would not use the crypto API at all.
>>> Instead, I suspect it would use dmabufs for source and destination
>>> buffers and integrate with the secure world firmware in some way.
>>> That means that the driver doesn't belong under drivers/crypto.
>>>
>>> These are the reasons I submitted a patch to mark the driver as BROKEN,
>>> which Herbert Xu has since accepted.
>>
>> And Bartosz and other people committed to work on this by improving,
>> fixing and in the long term providing you with the actual important user
>> of this. All this was already said.
>>
>> And then after having all these discussions Eric sends AGAIN patch to
>> remove the driver. How many times this will have to be discussed the
>> same way? If we now reach agreement the driver stays, next month again
>> there will be a patch to remove it? And then one more month again?
>>
>> The driver is marked as BROKEN, thus absolutely NO ONE is affected by
>> any issues the driver has.
>>
>> It's some personal vendetta to keep coming after that - unimportant now
>> - driver.
> 
> Well, there was also feedback that BROKEN drivers should not stay in the
> tree and instead just be removed.  So I was considering that feedback
> too, as well as the results of additional testing and review of this
> driver, including evidence that the driver performs even worse than
> thought and is actually getting even worse; the performance seems
> irredeemable.  As for proposing the stub driver, that is addressing the
> power management issue that was mentioned on the other thread.
> 
> Anyway, it sounds like you support it being BROKEN.  Okay, but again, as
> Greg mentioned
> (https://lore.kernel.org/linux-crypto/2026071312-uncover-refining-8cac@gregkh/)
> it is awkward to have BROKEN stuff in the tree since it cannot even be
> built.  I'm not sure we can have it both ways!

Which was I think pointed already a few times that it will not stay
BROKEN but will get fixed and get proper useful use cases.

Best regards,
Krzysztof