Re: [PATCH] crypto: qce - Remove driver

[Eric Biggers <ebiggers@kernel.org>]

On Fri, Jul 24, 2026 at 03:26:41PM +0530, Sumit Garg wrote:
> Hi Eric,
> 
> On Thu, Jul 23, 2026 at 10:06:45PM -0700, Eric Biggers wrote:
> > This obsolete driver was already marked as BROKEN.  However, keeping
> > BROKEN code around in the tree is unnecessary and causes problems.  It's
> > much better to just remove it entirely.  Let's do that.
> > 
> > Crypto acceleration remains well-supported on Qualcomm SoCs via the
> > Qualcomm Inline Crypto Engine and the ARMv8 Crypto Extensions, which are
> > what Linux actually uses in practice.  The obsolete QCE driver is a
> > dead-end approach.  It's extremely slow and just doesn't work well.
> 
> Not sure why only performance is seen as the major driver to drop crypto
> accelerators from kernel

Maybe you missed all the other reasons I gave too.

> while neglecting the security use-cases they support as well like:
> 
> - Support for hardware backed keys
> - Support for secure media playback use-cases

The QCE driver doesn't support these features.  So they aren't relevant
to this patch.

> I know it's not good to add functionality based on a prospective
> future use-cases but at the same time dropping functionality for it to be
> added again is just too much unnecessary churn.

This conflates current functionality, which doesn't meet upstream kernel
inclusion standards, with mostly-unrelated speculative future
functionality.  Anything new should just start from a clean slate with
just what is actually needed.

> I am sure you are aware about support for hardware backed key use-cases
> for many of those crypto accelerators. NXP CAAM engine is one such
> example.

The CAAM driver does register a "cbc(paes)" algorithm with the crypto
API (i.e., CBC-AES with a hardware backed key).  However, there's no
upstream user of that algorithm as far as I can tell.

But this is unrelated to this patch, which is for the QCE driver.

- Eric