Re: [PATCH v2] drivers/crypto: Mark QCE as BROKEN

[Demi Marie Obenour]

On 7/13/26 09:07, Eric Biggers wrote:
> On Mon, Jul 13, 2026 at 06:47:07AM +0200, Greg KH wrote:
>> On Sun, Jul 12, 2026 at 05:31:31PM -0400, Demi Marie Obenour via B4 Relay wrote:
>>> From: Demi Marie Obenour <demiobenour@xxxxxxxxx>
>>>
>>> This driver is harmful:
>>>
>>> - It is much slower than the CPU [1] [2].
>>> - It Has a history of bugs [2] [3].
>>> - It does not have exclusive access to the hardware [4], causing races
>>>   with the secure world.
>>> - It register its implementations with too low a cra_priority for them
>>>   to be actually used [5].
>>>
>>> Therefore, disable it to ensure that nobody builds it into kernels they
>>> intend to ship.
>>>
>>> In the future, the driver will be used for processing restricted media
>>> content.  However, the kernel does not currently support this.  Since
>>> the driver will have future uses, allow building it if COMPILE_TEST is
>>> enabled.
>>
>> Why not just delete it now, and then bring it back when it is needed in
>> the future?  Otherwise this will just trip up the static code checkers
>> who will attempt to "fix" things in it.
> 
> That makes sense to me, but Qualcomm pushed back on deletion:
> https://lore.kernel.org/linux-crypto/20260602-qcom-qce-broken-v1-1-a4ef756089e0@xxxxxxxxxxxxxxxx/
> 
> But I've still not seen any evidence that this driver is useful for
> anything or has any users.  Even Qualcomm seems to be unwilling to make
> such claims; they only claim that the IP is used (i.e., not in Linux)
> and that new features are planned.
> 
> - Eric

Here is my reading of Qualcomm's statements:

QCE is currently used by the Arm secure world.  In the future, QCE
will be used by the kernel as part of restricted content playback.
Qualcomm wants to add the needed features to the existing driver.
This will not use the crypto API.

I would be fine with the driver being removed, but not if it means
another out-of-tree Android driver.
-- 
Sincerely,
Demi Marie Obenour (she/her/hers)

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