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

On Fri, 31 Jul 2026 07:08:38 +0200, Eric Biggers <[email protected]> said:
> None of the algorithms the QCE driver registers with the crypto API are
> even close to being useful.  They're massively outperformed by the
> CPU-based crypto (even actually using far more CPU cycles than the
> CPU-based crypto, due to the massive driver overhead), don't provide any
> security benefits over the CPU-based crypto, and have various other
> issues.  They're also unrelated to the Inline Crypto Engine which works
> far better and is what is actually being used these days.
>
> Due to the major performance problems people experienced when
> accidentally using this driver, the algorithms were already demoted to
> below the priority of ARMv8 CE in the crypto API several years ago.
> Regardless of priority, these algorithms also aren't compatible with the
> most common uses of in-kernel crypto; for example, they don't support
> dm-crypt because they allocate memory, and they don't support IPsec
> since they take a mutex which isn't compatible with softirq context.
>
> It's time to move on and just drop this obsolete functionality entirely.
>
> However, the driver does serve one purpose which is to bind to the
> devicetree node and allow the interconnects to scale down (though even
> that part is broken, as it holds static interconnect bandwidth votes).
>
> Thus, clear out the crypto functionality, leaving just a stub driver
> that drops the interconnection bandwidth votes to zero.
>
> Tested on the SM8650 HDK.
>
> Signed-off-by: Eric Biggers <[email protected]>
> ---

I'll be on vacation for most of August so my lack of responses won't mean I
no longer care, only that I'm disconnected. Let me just leave this here for
completness:

Nacked-by: Bartosz Golaszewski <[email protected]>

I don't understand why the push to fast track the removal of this driver now,
when there's clearly an effort to get it fixed from the vendor itself. I've
also never seen a driver for an IP on a supported platform being removed from
mainline linux.

Thanks,
Bartosz