Re: [PATCH 9/9] crypto: qce - switch to using a mutex

[Eric Biggers <ebiggers@kernel.org>]

On Sat, Jan 18, 2025 at 10:28:26AM +0100, Bartosz Golaszewski wrote:
> I was testing with kcapi-speed and cryptsetup benchmark. I've never
> seen any errors.
> 
> Is this after my changes only or did it exist before? You're testing
> with the tcrypt module? How are you inserting it exactly? What params?

Those are all benchmarks, not tests.  The tests run at registration time if you
just enable the kconfig options for them:

    # CONFIG_CRYPTO_MANAGER_DISABLE_TESTS is not set
    CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y

The test failures and KASAN error occur on mainline too, so yes they occur
before your patchset too.

> >
> > I personally still struggle to understand how this driver could plausibly be
> > useful when the software crypto has no issues, is much faster, and is much
> > better tested.  What is motivating having this driver in the kernel?
> 
> We want to use it in conjunction with the upcoming scminvoke (for
> loading TAs and invoking objects - used to program the keys into the
> QCE) to support the DRM use-case for decrypting streaming data inside
> secure buffers upstream.

Notably lacking is any claim that any of the current features of the driver are
actually useful.

- Eric