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

[Greg KH]

On Mon, Jul 13, 2026 at 10:42:04AM -0400, Demi Marie Obenour wrote:
> 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.

Why is a crypto driver not going to use the crypto API?

> I would be fine with the driver being removed, but not if it means
> another out-of-tree Android driver.

It's not another out-of-tree Android driver if nothing in Android
actually uses it :)

thanks,

greg k-h