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CMakeLists.txt A D22-Nov-20221.2 KiB3326

conf.py A D22-Nov-20223.4 KiB10741

global_substitutions.txt A D22-Nov-2022225 87

glossary.rst A D22-Nov-2022643 3724

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readme.rst A D22-Nov-20224.7 KiB11892

requirements.txt A D22-Nov-2022195 1110

readme.rst

1.. SPDX-License-Identifier: BSD-3-Clause
2.. SPDX-FileCopyrightText: Copyright TF-RMM Contributors.
3
4######
5TF-RMM
6######
7
8TF-RMM (or simply RMM) is the Trusted Firmware Implementation of the `Realm
9Management Monitor (RMM) Specification`_. The RMM
10is a software component that runs at Realm EL2 and forms part of a system
11which implements the Arm Confidential Compute Architecture (Arm CCA).
12`Arm CCA`_ is an architecture which provides Protected Execution Environments
13called Realms.
14
15Prior to Arm CCA, virtual machines have to trust hypervisors that manage them
16and a resource that is managed by the hypervisor is also accessible by it.
17Exploits against the hypervisors can leak confidential data held in the virtual
18machines.  `Arm CCA`_ introduces a new confidential compute environment called
19a `Realm`. Any code or data belonging to a `Realm`, whether in memory or in
20registers, cannot be accessed or modified by the hypervisor. This means that
21the Realm owner does not need to trust the hypervisor that manages the
22resources used by the Realm.
23
24The Realm VM is initiated and controlled by the Normal world Hypervisor.
25To allow the isolated execution of the Realm VM, a new component called the
26Realm Management Monitor (RMM) is introduced, executing at R_EL2. The
27hypervisor interacts with the RMM via Realm Management Interface (RMI) to
28manage the Realm VM. Policy decisions, such as which Realm to run or what
29memory to be delegated to the Realm are made by the hypervisor and communicated
30via the RMI. The RMM also provides services to the Realm via the Realm Service
31Interface (RSI). These services include cryptographic services and
32attestation. The Realm initial state can be measured and an attestation
33report, which also includes platform attestation, can be requested via RSI.
34The RSI is also the channel for memory management requests from the
35Realm VM to the RMM.
36
37The following diagram shows the complete Arm CCA software stack running a
38confidential Realm VM :
39
40|Realm VM|
41
42Figure 1. Realm VM execution
43
44The TF-RMM interacts with the Root EL3 Firmware via the
45`RMM-EL3 Communication Interface`_ and this is implemented by the reference
46EL3 Firmware implementation `TF-A`_.
47
48More details about the RMM and how it fits in the Software Stack can be
49found in `Arm CCA Software Stack Guide`_.
50
51The :ref:`Change-log and Release notes` has the details of features implemented
52by this version of TF-RMM and lists any known issues.
53
54*******
55License
56*******
57
58Unless specifically indicated otherwise in a file, TF-RMM files are provided
59under the :ref:`BSD-3-Clause License <License>`. For contributions, please
60see :ref:`License and Copyright for Contributions <copyright-license-guidance>`.
61
62Third Party Projects
63====================
64
65The TF-RMM project requires to be linked with certain other 3rd party projects
66and they are to be cloned from their repositories into ``ext`` folder before
67building. The projects are `MbedTLS`_, `t_cose`_, and `QCBOR`_.
68
69The project also contains files which are imported from other projects
70into the source tree and may have a different license. Such files with
71different licenses are listed in the table below. This table is used by the
72``checkspdx`` tool in the project to verify license headers.
73
74.. list-table:: **List of files with different license**
75
76      * - File
77	- License
78      * - lib/libc/src/printf.c
79	- MIT
80      * - lib/libc/include/stdio.h
81	- MIT
82      * - lib/libc/src/strlcpy.c
83	- ISC
84      * - lib/libc/src/strnlen.c
85	- BSD-2-Clause
86      * - lib/allocator/src/memory_alloc.c
87	- Apache-2.0
88
89
90************
91Contributing
92************
93
94We gratefully accept bug reports and contributions from the community.
95Please see the :ref:`Contributor's Guide` for details on how to do this.
96
97********************
98Feedback and support
99********************
100
101Feedback is requested via email to:
102`tf-rmm@lists.trustedfirmware.org <tf-rmm@lists.trustedfirmware.org>`__.
103
104To report a bug, please file an `issue on Github`_
105
106-----------------
107
108.. |Realm VM| image:: ./about/diagrams/cca_software_arch.png
109.. _Realm Management Monitor (RMM) Specification: https://developer.arm.com/documentation/den0137/1-0bet0/?lang=en
110.. _Arm CCA: https://www.arm.com/architecture/security-features/arm-confidential-compute-architecture
111.. _Arm CCA Software Stack Guide: https://developer.arm.com/documentation/den0127/0100/Overview
112.. _TF-A: https://www.trustedfirmware.org/projects/tf-a/
113.. _RMM-EL3 Communication Interface: https://trustedfirmware-a.readthedocs.io/en/latest/components/rmm-el3-comms-spec.html
114.. _issue on Github: https://github.com/TF-RMM/tf-rmm/issues
115.. _MbedTLS: https://github.com/ARMmbed/mbedtls.git
116.. _t_cose: https://github.com/laurencelundblade/t_cose
117.. _QCBOR: https://github.com/laurencelundblade/QCBOR.git
118