Hello Jaehyeon,
We are still working on providing support for FEAT_MEC on RMM. More patches are coming in the next few weeks.
In order to run the current patches with MEC enabled, you have to set some more parameters for the FVP:
-C bp.mpe.enable=1 \
-C bp.mpe.block_size_in_bytes=4096 \
-C bp.mpe.corruption_strategy=0 \
-C bp.mpe.ignore_mecid=0 \
-C bp.mpe.output_attributes_parameter_of_core=ExtendedID[62:55]=MPAM_PMG \
-C bp.mpe.output_attributes_parameter_of_core=ExtendedID[38]=MPAM_SP[0] \
-C bp.mpe.output_attributes_parameter_of_core=ExtendedID[37]=MPAM_SP[1] \
-C bp.mpe.output_attributes_parameter_of_core=UserFlags[31:16]=MECID \
-C bp.mpe.non_secure_pas_enc_key=34 \
-C bp.mpe.realm_pas_enc_key=136 \
-C bp.mpe.root_pas_enc_key=68 \
-C bp.mpe.secure_pas_enc_key=17 \
-C cluster0.mec_support_level=2 \
-C cluster0.rme_mecid_width=16 \
-C cluster1.mec_support_level=2 \
-C cluster1.rme_mecid_width=16 \
I have attached a Shrinkwrap overlay in case you want to use it instead.
Let me know if you have any questions.
All the best,
Juan Pablo
--
From: Jaehyeon Lee
Sent: 23 Jun 2025 6:07 a.m
To: tf-rmm(a)lists.trustedfirmware.org<https://lists.trustedfirmware.org/archives/list/tf-rmm@lists.trustedfirmwar…>
Subject: [tf-rmm] Questions regarding ARM CCA MEC feature
Hello tf-rmm group,
I'm currently conducting research on the MEC (Memory Encryption Context) feature for sharing memory pages across multiple realms, and I'm interested in testing and potentially extending this functionality w/ new use-cases.
I noticed that there are mec-proto branches available across the TF-A repositories, including rmm, linux, kvmtool, and tf-a, specifically for the CCA memory encryption context. However, I've been unable to successfully launch a system using these branches on the FVP models.
Is there a reference setup or guidance available for bringing up a MEC-enabled Realm environment, similar to the DA branches discussed here<https://lists.trustedfirmware.org/archives/list/tf-rmm@lists.trustedfirmwar…>?
Also, extending MEC feature to allow sharing pages across multiple realms are feasible w/ current hardware (RME w/ MPE) spec? w/ utilizing MEC_STATE_SHARED state in RMM 1.1 alp14 spec.
Thank you,
Jaehyeon Lee
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
Hello tf-rmm group,
I'm currently conducting research on the MEC (Memory Encryption Context) feature for sharing memory pages across multiple realms, and I'm interested in testing and potentially extending this functionality w/ new use-cases.
I noticed that there are mec-proto branches available across the TF-A repositories, including rmm, linux, kvmtool, and tf-a, specifically for the CCA memory encryption context. However, I've been unable to successfully launch a system using these branches on the FVP models.
Is there a reference setup or guidance available for bringing up a MEC-enabled Realm environment, similar to the DA branches discussed here<https://lists.trustedfirmware.org/archives/list/tf-rmm@lists.trustedfirmwar…>?
Also, extending MEC feature to allow sharing pages across multiple realms are feasible w/ current hardware (RME w/ MPE) spec? w/ utilizing MEC_STATE_SHARED state in RMM 1.1 alp14 spec.
Thank you,
Jaehyeon Lee
Hi, On June 12th 2025, the TF-A Tech forum will take place at 4.00pm UK
with the following topic: TF-RMM live activation design discussion
Presenters: Andre Przywara Soby Mathew Manish Badarkhe In this meeting, we
aim to discuss the details of live firmware activation for TF-RMM. The key
topics will include: * Design details of TF-RMM live activation * Rationale
for EL3-RMM communication changes: We will explain the motivation behind
the proposed changes to the communication mechanism between EL3 and RMM
which simplifies internal state migration for LFA, enables sharing of the
state across RMM instances that are live-activated, supports localized
per-CPU allocations for NUMA and multi-chip configurations, decouples the
RMM binary from platform-specifics. * LFA SMC Implementation in EL3: We
will also provide an overview of the LFA SMC implementation at EL3.
Regards, Olivier.
TF-A Tech Forum
Thursday Jun 12, 2025 ⋅ 5pm – 6pm
Central European Time - Paris
Location
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tf-a(a)lists.trustedfirmware.org
Hi Manoj,
Hi, Yes, your understanding is correct, according to the reference manual, if HaveEL(EL3) and MPAM3_EL3.TRAPLOWER == 1,
then any EL2 access to MPAMIDR_EL1 is trapped to EL3 (AArch64.SystemAccessTrap(EL3, 0x18)).
The upstream TF-A master disables this bit :
https://review.trustedfirmware.org/plugins/gitiles/TF-A/trusted-firmware-a/…
Currently there is a strong dependency between feature enablement in EL3 and RMM accessing the registers.
We have some patches in progress for RMM to discover feature enablement status in EL3 and only proceed with register access (like MPAM) when explicitly permitted.
Link to the patches for your reference:
https://review.trustedfirmware.org/q/topic:%22sm/revlock%22
Thanks
-Sona
Manoj Ekbote wrote:
> Hi,
> I am trying to run TF-RMM and there's an exception while reading the MPAMIDR_EL1 register in rmm_arch_init().
> if (is_feat_mpam_present()) {
> unsigned long mpamidr_el1 = read_mpamidr_el1();
> ..
> }
> The condition to access MPAMIDR_EL1 is:
> elsif PSTATE.EL == EL2 then
> if HaveEL(EL3) && EL3SDDUndefPriority() && MPAM3_EL3.TRAPLOWER == '1' then
> UNDEFINED;
> elsif HaveEL(EL3) && MPAM3_EL3.TRAPLOWER == '1' then
> if EL3SDDUndef() then
> UNDEFINED;
> else
> AArch64.SystemAccessTrap(EL3, 0x18);
> else
> X[t, 64] = MPAMIDR_EL1;
> I am running TF-A before TF-RMM, so the default value of 1 in MPAM3_EL3.TRAPLOWER forces all accesses to MPAMIDR_EL1 to be trapped to EL3.
> And the read in TF-RMM then causes an exception.
> But there's no handler for the trap in TF-RMM that can forward the read to EL3.
> Is my understanding right that the code to handle the trap is missing in RMM?
> Thanks,
> Manoj
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
Hi,
I am trying to run TF-RMM and there's an exception while reading the MPAMIDR_EL1 register in rmm_arch_init().
if (is_feat_mpam_present()) {
unsigned long mpamidr_el1 = read_mpamidr_el1();
..
}
The condition to access MPAMIDR_EL1 is:
elsif PSTATE.EL == EL2 then
if HaveEL(EL3) && EL3SDDUndefPriority() && MPAM3_EL3.TRAPLOWER == '1' then
UNDEFINED;
elsif HaveEL(EL3) && MPAM3_EL3.TRAPLOWER == '1' then
if EL3SDDUndef() then
UNDEFINED;
else
AArch64.SystemAccessTrap(EL3, 0x18);
else
X[t, 64] = MPAMIDR_EL1;
I am running TF-A before TF-RMM, so the default value of 1 in MPAM3_EL3.TRAPLOWER forces all accesses to MPAMIDR_EL1 to be trapped to EL3.
And the read in TF-RMM then causes an exception.
But there's no handler for the trap in TF-RMM that can forward the read to EL3.
Is my understanding right that the code to handle the trap is missing in RMM?
Thanks,
Manoj
Hello tf-rmm group,
I think i found several vulnerabilities in tf-rmm code, where should i report it. I don't see ways to report vulnerabilities in your github repositories security page or docs. After the vulnerability is confirmed, can you assign a CVE-ID for it?
--
Best Regards
Haiwang Wang
