Re: [PATCH 0/5] target/arm: Fixes for RME

[Peter Maydell]

On Wed, 19 Jul 2023 at 16:56, Jean-Philippe Brucker
<jean-philippe@linaro.org> wrote:
>
> With these patches I'm able to boot a Realm guest under
> "-cpu max,x-rme=on". They are based on Peter's series which fixes
> handling of NSTable:
> 20230714154648.327466-1-peter.maydell@linaro.org/">https://lore.kernel.org/qemu-devel/20230714154648.327466-1-peter.maydell@linaro.org/

Thanks for testing this -- this is a lot closer to
working out of the box than I thought we might be :-)
I'm tempted to try to put these fixes (and my ptw patchset)
into 8.1, but OTOH I suspect work on Realm guests will probably
still want to use a bleeding-edge QEMU for other bugs we're
going to discover over the next few months, so IDK. We'll
see how code review goes on those, I guess.

> Running a Realm guest requires components at EL3 and R-EL2. Some rough
> support for TF-A and RMM is available here:
> https://jpbrucker.net/git/tf-a/log/?h=qemu-rme
> https://jpbrucker.net/git/rmm/log/?h=qemu-rme
> I'll clean this up before sending it out.
>
> I also need to manually disable FEAT_SME in QEMU in order to boot this,

Do you mean you needed to do something more invasive than
'-cpu max,x-rme=on,sme=off' ?

> otherwise the Linux host fails to boot because hyp-stub accesses to SME
> regs are trapped to EL3, which doesn't support RME+SME at the moment.
> The right fix is probably in TF-A but I haven't investigated yet.

thanks
-- PMM