On 02/03/2023 16:46, Dr. David Alan Gilbert wrote:
* Suzuki K Poulose (suzuki.poulose@xxxxxxx) wrote:
Hi Dave
Thanks for your response, and apologies for the delay. Response, in line.
On 14/02/2023 17:13, Dr. David Alan Gilbert wrote:
* Suzuki K Poulose (suzuki.poulose@xxxxxxx) wrote:
We are happy to announce the early RFC version of the Arm
Confidential Compute Architecture (CCA) support for the Linux
stack. The intention is to seek early feedback in the following areas:
* KVM integration of the Arm CCA
* KVM UABI for managing the Realms, seeking to generalise the operations
wherever possible with other Confidential Compute solutions.
Note: This version doesn't support Guest Private memory, which will be added
later (see below).
* Linux Guest support for Realms
Arm CCA Introduction
=====================
The Arm CCA is a reference software architecture and implementation that builds
on the Realm Management Extension (RME), enabling the execution of Virtual
machines, while preventing access by more privileged software, such as hypervisor.
The Arm CCA allows the hypervisor to control the VM, but removes the right for
access to the code, register state or data that is used by VM.
More information on the architecture is available here[0].
Arm CCA Reference Software Architecture
Realm World || Normal World || Secure World ||
|| | || ||
EL0 x-------x || x----x | x------x || ||
| Realm | || | | | | | || ||
| | || | VM | | | | || ||
----| VM* |---------||-| |---| |-||----------------||
| | || | | | | H | || ||
EL1 x-------x || x----x | | | || ||
^ || | | o | || ||
| || | | | || ||
------- R*------------------------| s -|---------------------
S || | | || ||
I || | t | || ||
| || | | || ||
v || x------x || ||
EL2 RMM* || ^ || ||
^ || | || ||
========|=============================|========================
| | SMC
x--------- *RMI* -------------x
EL3 Root World
EL3 Firmware
===============================================================
Where :
RMM - Realm Management Monitor
RMI - Realm Management Interface
RSI - Realm Service Interface
SMC - Secure Monitor Call
Hi,
It's nice to see this full stack posted - thanks!
Are there any pointers to information on attestation and similar
measurement things? In particular, are there any plans for a vTPM
The RMM v1.0 provides attestation and measurement services to the Realm,
via Realm Service Interface (RSI) calls.
Can you point me at some docs for that?
It is part of the RMM specification [1], linked below.
Please see "Chapter A7. Realm Measurement and Attestation"
[1] https://developer.arm.com/documentation/den0137/latest
However, there is no support
for partitioning the Realm VM with v1.0. This is currently under
development and should be available in the near future.
With that in place, a vTPM could reside in a partition of the Realm VM along
side the OS in another. Does that answer your question ?
Possibly; it would be great to be able to use a standard vTPM interface
here rather than have to do anything special. People already have this
working on AMD SEV-SNP.
Ok.
Dave
...
[1] RMM Specification Latest
https://developer.arm.com/documentation/den0137/latest
Suzuki
[2] RMM v1.0-Beta0 specification
https://developer.arm.com/documentation/den0137/1-0bet0/
[3] Trusted Firmware RMM - TF-RMM
https://www.trustedfirmware.org/projects/tf-rmm/
GIT: https://git.trustedfirmware.org/TF-RMM/tf-rmm.git
[4] FVP Base RevC AEM Model (available on x86_64 / Arm64 Linux)
https://developer.arm.com/Tools%20and%20Software/Fixed%20Virtual%20Platforms
[5] Trusted Firmware for A class
https://www.trustedfirmware.org/projects/tf-a/
[6] Linux kernel support for Arm-CCA
https://gitlab.arm.com/linux-arm/linux-cca
Host Support branch: cca-host/rfc-v1
Guest Support branch: cca-guest/rfc-v1
[7] kvmtool support for Arm CCA
https://gitlab.arm.com/linux-arm/kvmtool-cca cca/rfc-v1
[8] kvm-unit-tests support for Arm CCA
https://gitlab.arm.com/linux-arm/kvm-unit-tests-cca cca/rfc-v1
[9] Instructions for Building Firmware components and running the model, see
section 4.19.2 "Building and running TF-A with RME"
https://trustedfirmware-a.readthedocs.io/en/latest/components/realm-management-extension.html#building-and-running-tf-a-with-rme
[10] fd based Guest Private memory for KVM
https://lkml.kernel.org/r/20221202061347.1070246-1-chao.p.peng@xxxxxxxxxxxxxxx
Cc: Alexandru Elisei <alexandru.elisei@xxxxxxx>
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