| |
| Realm Management Extension (RME) |
| ==================================== |
| |
| FEAT_RME (or RME for short) is an Armv9-A extension and is one component of the |
| `Arm Confidential Compute Architecture (Arm CCA)`_. TF-A supports RME starting |
| from version 2.6. This chapter discusses the changes to TF-A to support RME and |
| provides instructions on how to build and run TF-A with RME. |
| |
| RME support in TF-A |
| --------------------- |
| |
| The following diagram shows an Arm CCA software architecture with TF-A as the |
| EL3 firmware. In the Arm CCA architecture there are two additional security |
| states and address spaces: ``Root`` and ``Realm``. TF-A firmware runs in the |
| Root world. In the realm world, a Realm Management Monitor firmware (RMM) |
| manages the execution of Realm VMs and their interaction with the hypervisor. |
| |
| .. image:: ../resources/diagrams/arm-cca-software-arch.png |
| |
| RME is the hardware extension to support Arm CCA. To support RME, various |
| changes have been introduced to TF-A. We discuss those changes below. |
| |
| Changes to translation tables library |
| *************************************** |
| RME adds Root and Realm Physical address spaces. To support this, two new |
| memory type macros, ``MT_ROOT`` and ``MT_REALM``, have been added to the |
| :ref:`Translation (XLAT) Tables Library`. These macros are used to configure |
| memory regions as Root or Realm respectively. |
| |
| .. note:: |
| |
| Only version 2 of the translation tables library supports the new memory |
| types. |
| |
| Changes to context management |
| ******************************* |
| A new CPU context for the Realm world has been added. The existing |
| :ref:`CPU context management API<PSCI Library Integration guide for Armv8-A |
| AArch32 systems>` can be used to manage Realm context. |
| |
| Boot flow changes |
| ******************* |
| In a typical TF-A boot flow, BL2 runs at Secure-EL1. However when RME is |
| enabled, TF-A runs in the Root world at EL3. Therefore, the boot flow is |
| modified to run BL2 at EL3 when RME is enabled. In addition to this, a |
| Realm-world firmware (RMM) is loaded by BL2 in the Realm physical address |
| space. |
| |
| The boot flow when RME is enabled looks like the following: |
| |
| 1. BL1 loads and executes BL2 at EL3 |
| 2. BL2 loads images including RMM |
| 3. BL2 transfers control to BL31 |
| 4. BL31 initializes SPM (if SPM is enabled) |
| 5. BL31 initializes RMM |
| 6. BL31 transfers control to Normal-world software |
| |
| Granule Protection Tables (GPT) library |
| ***************************************** |
| Isolation between the four physical address spaces is enforced by a process |
| called Granule Protection Check (GPC) performed by the MMU downstream any |
| address translation. GPC makes use of Granule Protection Table (GPT) in the |
| Root world that describes the physical address space assignment of every |
| page (granule). A GPT library that provides APIs to initialize GPTs and to |
| transition granules between different physical address spaces has been added. |
| More information about the GPT library can be found in the |
| :ref:`Granule Protection Tables Library` chapter. |
| |
| RMM Dispatcher (RMMD) |
| ************************ |
| RMMD is a new standard runtime service that handles the switch to the Realm |
| world. It initializes the RMM and handles Realm Management Interface (RMI) |
| SMC calls from Non-secure and Realm worlds. |
| |
| Test Realm Payload (TRP) |
| ************************* |
| TRP is a small test payload that runs at R-EL2 and implements a subset of |
| the Realm Management Interface (RMI) commands to primarily test EL3 firmware |
| and the interface between R-EL2 and EL3. When building TF-A with RME enabled, |
| if a path to an RMM image is not provided, TF-A builds the TRP by default |
| and uses it as RMM image. |
| |
| Building and running TF-A with RME |
| ------------------------------------ |
| |
| This section describes how you can build and run TF-A with RME enabled. |
| We assume you have all the :ref:`Prerequisites` to build TF-A. |
| |
| To enable RME, you need to set the ENABLE_RME build flag when building |
| TF-A. Currently, this feature is only supported for the FVP platform. |
| |
| The following instructions show you how to build and run TF-A with RME |
| for two scenarios: TF-A with TF-A Tests, and four-world execution with |
| Hafnium and TF-A Tests. The instructions assume you have already obtained |
| TF-A. You can use the following command to clone TF-A. |
| |
| .. code:: shell |
| |
| git clone https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git |
| |
| To run the tests, you need an FVP model. Please use the :ref:`latest version |
| <Arm Fixed Virtual Platforms (FVP)>` of *FVP_Base_RevC-2xAEMvA* model. |
| |
| .. note:: |
| |
| ENABLE_RME build option is currently experimental. |
| |
| Building TF-A with TF-A Tests |
| ******************************************** |
| Use the following instructions to build TF-A with `TF-A Tests`_ as the |
| non-secure payload (BL33). |
| |
| **1. Obtain and build TF-A Tests** |
| |
| .. code:: shell |
| |
| git clone https://git.trustedfirmware.org/TF-A/tf-a-tests.git |
| cd tf-a-tests |
| make CROSS_COMPILE=aarch64-none-elf- PLAT=fvp DEBUG=1 |
| |
| This produces a TF-A Tests binary (*tftf.bin*) in the *build/fvp/debug* directory. |
| |
| **2. Build TF-A** |
| |
| .. code:: shell |
| |
| cd trusted-firmware-a |
| make CROSS_COMPILE=aarch64-none-elf- \ |
| PLAT=fvp \ |
| ENABLE_RME=1 \ |
| FVP_HW_CONFIG_DTS=fdts/fvp-base-gicv3-psci-1t.dts \ |
| DEBUG=1 \ |
| BL33=<path/to/tftf.bin> \ |
| all fip |
| |
| This produces *bl1.bin* and *fip.bin* binaries in the *build/fvp/debug* directory. |
| The above command also builds TRP. The TRP binary is packaged in *fip.bin*. |
| |
| Four-world execution with Hafnium and TF-A Tests |
| **************************************************** |
| Four-world execution involves software components at each security state: root, |
| secure, realm and non-secure. This section describes how to build TF-A |
| with four-world support. We use TF-A as the root firmware, `Hafnium`_ as the |
| secure component, TRP as the realm-world firmware and TF-A Tests as the |
| non-secure payload. |
| |
| Before building TF-A, you first need to build the other software components. |
| You can find instructions on how to get and build TF-A Tests above. |
| |
| **1. Obtain and build Hafnium** |
| |
| .. code:: shell |
| |
| git clone --recurse-submodules https://git.trustedfirmware.org/hafnium/hafnium.git |
| cd hafnium |
| # Use the default prebuilt LLVM/clang toolchain |
| PATH=$PWD/prebuilts/linux-x64/clang/bin:$PWD/prebuilts/linux-x64/dtc:$PATH |
| make PROJECT=reference |
| |
| The Hafnium binary should be located at |
| *out/reference/secure_aem_v8a_fvp_clang/hafnium.bin* |
| |
| **2. Build TF-A** |
| |
| Build TF-A with RME as well as SPM enabled. |
| |
| .. code:: shell |
| |
| make CROSS_COMPILE=aarch64-none-elf- \ |
| PLAT=fvp \ |
| ENABLE_RME=1 \ |
| FVP_HW_CONFIG_DTS=fdts/fvp-base-gicv3-psci-1t.dts \ |
| SPD=spmd \ |
| SPMD_SPM_AT_SEL2=1 \ |
| BRANCH_PROTECTION=1 \ |
| CTX_INCLUDE_PAUTH_REGS=1 \ |
| DEBUG=1 \ |
| SP_LAYOUT_FILE=<path/to/tf-a-tests>/build/fvp/debug/sp_layout.json> \ |
| BL32=<path/to/hafnium.bin> \ |
| BL33=<path/to/tftf.bin> \ |
| all fip |
| |
| Running the tests |
| ********************* |
| Use the following command to run the tests on FVP. TF-A Tests should boot |
| and run the default tests including RME tests. |
| |
| .. code:: shell |
| |
| FVP_Base_RevC-2xAEMvA \ |
| -C bp.flashloader0.fname=<path/to/fip.bin> \ |
| -C bp.secureflashloader.fname=<path/to/bl1.bin> \ |
| -C bp.refcounter.non_arch_start_at_default=1 \ |
| -C bp.refcounter.use_real_time=0 \ |
| -C bp.ve_sysregs.exit_on_shutdown=1 \ |
| -C cache_state_modelled=1 \ |
| -C cluster0.NUM_CORES=4 \ |
| -C cluster0.PA_SIZE=48 \ |
| -C cluster0.ecv_support_level=2 \ |
| -C cluster0.gicv3.cpuintf-mmap-access-level=2 \ |
| -C cluster0.gicv3.without-DS-support=1 \ |
| -C cluster0.gicv4.mask-virtual-interrupt=1 \ |
| -C cluster0.has_arm_v8-6=1 \ |
| -C cluster0.has_branch_target_exception=1 \ |
| -C cluster0.has_rme=1 \ |
| -C cluster0.has_rndr=1 \ |
| -C cluster0.has_amu=1 \ |
| -C cluster0.has_v8_7_pmu_extension=2 \ |
| -C cluster0.max_32bit_el=-1 \ |
| -C cluster0.restriction_on_speculative_execution=2 \ |
| -C cluster0.restriction_on_speculative_execution_aarch32=2 \ |
| -C cluster1.NUM_CORES=4 \ |
| -C cluster1.PA_SIZE=48 \ |
| -C cluster1.ecv_support_level=2 \ |
| -C cluster1.gicv3.cpuintf-mmap-access-level=2 \ |
| -C cluster1.gicv3.without-DS-support=1 \ |
| -C cluster1.gicv4.mask-virtual-interrupt=1 \ |
| -C cluster1.has_arm_v8-6=1 \ |
| -C cluster1.has_branch_target_exception=1 \ |
| -C cluster1.has_rme=1 \ |
| -C cluster1.has_rndr=1 \ |
| -C cluster1.has_amu=1 \ |
| -C cluster1.has_v8_7_pmu_extension=2 \ |
| -C cluster1.max_32bit_el=-1 \ |
| -C cluster1.restriction_on_speculative_execution=2 \ |
| -C cluster1.restriction_on_speculative_execution_aarch32=2 \ |
| -C pci.pci_smmuv3.mmu.SMMU_AIDR=2 \ |
| -C pci.pci_smmuv3.mmu.SMMU_IDR0=0x0046123B \ |
| -C pci.pci_smmuv3.mmu.SMMU_IDR1=0x00600002 \ |
| -C pci.pci_smmuv3.mmu.SMMU_IDR3=0x1714 \ |
| -C pci.pci_smmuv3.mmu.SMMU_IDR5=0xFFFF0475 \ |
| -C pci.pci_smmuv3.mmu.SMMU_S_IDR1=0xA0000002 \ |
| -C pci.pci_smmuv3.mmu.SMMU_S_IDR2=0 \ |
| -C pci.pci_smmuv3.mmu.SMMU_S_IDR3=0 \ |
| -C bp.pl011_uart0.out_file=uart0.log \ |
| -C bp.pl011_uart1.out_file=uart1.log \ |
| -C bp.pl011_uart2.out_file=uart2.log \ |
| -C pctl.startup=0.0.0.0 \ |
| -Q 1000 \ |
| "$@" |
| |
| The bottom of the output from *uart0* should look something like the following. |
| |
| .. code-block:: shell |
| |
| ... |
| |
| > Test suite 'FF-A Interrupt' |
| Passed |
| > Test suite 'SMMUv3 tests' |
| Passed |
| > Test suite 'PMU Leakage' |
| Passed |
| > Test suite 'DebugFS' |
| Passed |
| > Test suite 'Realm payload tests' |
| Passed |
| > Test suite 'Invalid memory access' |
| Passed |
| ... |
| |
| |
| .. _Arm Confidential Compute Architecture (Arm CCA): https://www.arm.com/why-arm/architecture/security-features/arm-confidential-compute-architecture |
| .. _Arm Architecture Models website: https://developer.arm.com/tools-and-software/simulation-models/fixed-virtual-platforms/arm-ecosystem-models |
| .. _TF-A Tests: https://trustedfirmware-a-tests.readthedocs.io/en/latest |
| .. _Hafnium: https://www.trustedfirmware.org/projects/hafnium |