Re: [PATCH] gitlab: enable afalg tests in fedora system test

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Oct 22, 2024 at 07:31:49AM +0200, Thomas Huth wrote:
> On 21/10/2024 19.02, Daniel P. Berrangé wrote:
> > The AF_ALG crypto integration for Linux is not being tested in
> > any CI scenario. It always requires an explicit configure time
> > flag to be passed to turn it on. The Fedora system test is
> > arbitrarily picked as the place to test it.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >   .gitlab-ci.d/buildtest.yml | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > This is to detect the situation Markus found here:
> > 
> >    https://lists.nongnu.org/archive/html/qemu-devel/2024-10/msg03040.html
> > 
> > diff --git a/.gitlab-ci.d/buildtest.yml b/.gitlab-ci.d/buildtest.yml
> > index 01e8470a69..f0cbdf1992 100644
> > --- a/.gitlab-ci.d/buildtest.yml
> > +++ b/.gitlab-ci.d/buildtest.yml
> > @@ -115,7 +115,7 @@ build-system-fedora:
> >       job: amd64-fedora-container
> >     variables:
> >       IMAGE: fedora
> > -    CONFIGURE_ARGS: --disable-gcrypt --enable-nettle --enable-docs
> > +    CONFIGURE_ARGS: --disable-gcrypt --enable-nettle --enable-docs --enable-crypto-afalg
> >       TARGETS: microblaze-softmmu mips-softmmu
> >         xtensa-softmmu m68k-softmmu riscv32-softmmu ppc-softmmu sparc64-softmmu
> >       MAKE_CHECK_ARGS: check-build
> 
> Is there a reason for this feature being disabled by default? Who is using
> it if it is disabled by default? Should we maybe rather enable it by default
> instead?

afalg isn't something you want to use in general. It performs worse than
the userspace crypto in many cases, especially for small buffers where the
context switch overhead kills.

It is potentially interesting if you have hardware crypto accelerator and
your guest workload also wants virtio-crypto.

Having it as a compile time option is not ideal, but it was the least
effort tradeoff.

With regards,
Daniel
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