Re: [PATCH v2 3/3] arm64: entry: Convert to generic entry

From: Kees Cook
Date: Thu Jun 27 2024 - 14:25:05 EST


On Thu, Jun 27, 2024 at 06:15:36PM +0100, Mark Brown wrote:
> On Thu, Jun 27, 2024 at 10:01:11AM -0700, Kees Cook wrote:
>
> > I've really struggled to get MTE working with qemu, so likely real
> > hardware would be needed for that... I'm hoping the ARM folks have
> > access to something that would work well for this. :)
>
> What issues have you been running into?

It was so slow to emulate that I couldn't finish booting.

However, looking at my qemu scripts, it seems I may have solved this at
some point. I remembered wrong! I can test MTE. :P

This is what I'm using currently:

-cpu max,pauth-impdef=on \
-machine virtualization=true \
-machine virt,gic-version=max,mte=on \

It seems PAC was the issue. Using "pauth-impdef=on" solved it. "The
architected QARMA5 and QARMA3 algorithms have good cryptographic
properties, but can be quite slow to emulate."
https://qemu-project.gitlab.io/qemu/system/arm/cpu-features.html

I will go test MTE with this series...

--
Kees Cook