Hi Ross, following changes were merged which help building on Arm and integrating to Yocto. Let us know how it goes. Thanks.

I found the bug causing both worlds scenario to randomly fail: is wrong handling of telnet connection with the model causing some message loss; a fix in on-going.
I'm also having a look to get the right telnet port number from the model.
Will update the ticket with the new developments.

Merged https://review.trustedfirmware.org/c/hafnium/hafnium/+/10759

Copying response on mailing list.

ACS can be updated to skip checks for this. But spec isn't specific about whether this way of retrieving memory is optional.

Hi Olivier,

Raghu as you are originator for this ask; can you state more about the requirements as to the why we'd really need to do so?

That's not currently supported.

I think it would be reasonable if Hafnium implements this feature when there is an explicit request for it from a Trusted OS or SP vendor. In the meantime, Hafnium returning INVALID_PARAMETERS sounds like a reasonable approach to me. It implies that the ACK test can be ignored. What do you reckon?

FWIW, agree with Olivier's analysis.

That's a very interesting definition of reproducible.

Yes, we include a prebuilt toolchain so that the builds are reproducible. It's a copy of the Android prebuilt toolchain (from https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/), which I'm afraid doesn't seem to include aarch64 binaries at the moment.

In particular this is about specifying the offset field in the endpoint memory access descriptor.

The possible envisioned scenario is related to booting TF-A+UEFI and support for authenticated variables.

https://review.trustedfirmware.org/c/hafnium/hafnium/+/8243

I haven't looked at in much detail but I think the shareability attributes would need to be exposed by the mm module, and then converted by ffa_memory_permissions_to_mode.

SMMUv3.2 supports secure Stage-2 translations and that's the feature we intend to enable as a first step.
The IP also supports "nested translations" aka S-EL1 SMMU paravirtualization although we're not looking at this option immediately.

Thanks for your reply, so there is Stage-2 SMMU support, right? And i think we can support passthrough io support in Secure-EL1 with Stage-2 SMMU

We're considering the SMMUv3.2 support which covers the Secure Stage-2 mappings (https://developer.arm.com/documentation/ihi0070/latest).
This is still in initial investigation phases, but we hope to share design details and early patches by end of Q4'20.

@odeprez / Arm might be able to comment on this.

what about SMMUV3.x ?