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

[Jean-Philippe Brucker]

On Thu, Jul 20, 2023 at 01:05:58PM +0100, Peter Maydell wrote:
> 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' ?

Ah no, I hadn't noticed there was a sme=off switch, that's much better

Thanks,
Jean

> 
> > 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