Fixed Virtual Platforms (FVP) are complete simulations of an Arm system, including processor, memory and peripherals. These are set out in a "programmer's view", which gives you a comprehensive model on which to build and test your software.
The Armv8-R AEM FVP is a free of charge Armv8-R Fixed Virtual Platform. It supports the latest Armv8-R feature set.
This BSP implements a reference stack for the AArch64 support in the R-class first announced with the Cortex-R82 processor: https://developer.arm.com/ip-products/processors/cortex-r/cortex-r82
Fast Models Fixed Virtual Platforms (FVP) Reference Guide: https://developer.arm.com/docs/100966/latest
The fvp-baser-aemv8r64 Yocto MACHINE supports the following BSP components, where either a standard or Real-Time Linux kernel (PREEMPT_RT) can be built and run:
Note that the Real-Time Linux kernel (PREEMPT_RT) does not use the real-time architectural extensions of the Armv8-R feature set.
The diagram below shows the current boot flow:
+---------------------------------------------------------------+
| Linux kernel |
+---------------------------------------------------------------+
/|\ /|\
| |
| UEFI services |
| PSCI services |
\|/ |
+----------------+ | S-EL1
----| U-Boot |------------------------------|-----------
+----------------+ | S-EL2
/|\ |
| |
| |
| |
+--------------------------------------------------\|/----------+
| +----------------+ +----------------+ |
| boot-wrapper-aarch64 | Device tree | | PSCI handler | |
| +----------------+ +----------------+ |
+---------------------------------------------------------------+
The firmware binary (generated as linux-system.axf) includes boot-wrapper-aarch64, the flattened device tree and U-Boot. U-Boot is configured to automatically detect a virtio block device and boot the UEFI payload at the path /efi/boot/bootaa64.efi. Using the standard build, the first partition contains a Grub image at this path, which boots the Linux kernel at /Image on the same partition. The second partition of the image contains the Linux root file system.
There is no EL3 or non-secure world in the Armv8-R AArch64 architecture, so the reset vector starts boot-wrapper-aarch64 at S-EL2. Boot-wrapper-aarch64 is compiled with the --enable-keep-el flag, which causes it to boot U-Boot at S-EL2 too. U-Boot is compiled with the CONFIG_ARMV8_SWITCH_TO_EL1 flag, which causes it to switch to S-EL1 before booting Linux.
The bundled device tree is passed to U-Boot via register x0. U-Boot passes the same device tree to Linux via the UEFI system table.
Power state management is provided by PSCI services in boot-wrapper-aarch64. Linux accesses the PSCI handler via HVC calls to S-EL2. U-Boot has been patched to prevent it from overriding the exception vector at S-EL2. The PSCI handler memory region is added to a /memreserve/ node in the device tree.
Please note that the final firmware architecture for the fvp-baser-aemv8r64 is not yet stabilized. The patches in this layer are provided for development and evaluation purposes only, and should not be used in production firmware.
The following instructions have been tested on hosts running Ubuntu 18.04 and Ubuntu 20.04. Install the required packages for the build host: https://docs.yoctoproject.org/singleindex.html#required-packages-for-the-build-host
Kas is a setup tool for bitbake based projects. The minimal supported version is 3.0, install it like so:
pip3 install --user --upgrade kas
For more details on kas, see https://kas.readthedocs.io/.
To build the images for the fvp-baser-aemv8r64 machine, you also need to accept the EULA at https://developer.arm.com/downloads/-/arm-ecosystem-fvps/eula by setting the following environment variable:
FVP_BASE_R_ARM_EULA_ACCEPT="True"
Note: The host machine should have at least 50 GBytes of free disk space for the next steps to work correctly.
To fetch and build the ongoing development of the software stack follow the instructions on this document.
To fetch and build the version 1 (single core) find instructions at https://community.arm.com/developer/tools-software/oss-platforms/w/docs/633/release-1-single-core
To fetch and build the version 2 (linux smp) find instructions at https://community.arm.com/developer/tools-software/oss-platforms/w/docs/634/release-2---smp
Fetch the meta-arm repository into a build directory:
mkdir -p ~/fvp-baser-aemv8r64-build cd ~/fvp-baser-aemv8r64-build git clone https://git.yoctoproject.org/git/meta-arm
Building with the standard Linux kernel:
cd ~/fvp-baser-aemv8r64-build export FVP_BASE_R_ARM_EULA_ACCEPT="True" kas build meta-arm/kas/fvp-baser-aemv8r64-bsp.yml
Building with the Real-Time Linux kernel (PREEMPT_RT):
cd ~/fvp-baser-aemv8r64-build export FVP_BASE_R_ARM_EULA_ACCEPT="True" kas build meta-arm/kas/fvp-baser-aemv8r64-rt-bsp.yml
To run an image after the build is done with the standard Linux kernel:
kas shell --keep-config-unchanged \
meta-arm/kas/fvp-baser-aemv8r64-bsp.yml \
--command "../layers/meta-arm/scripts/runfvp \
--console "
To run an image after the build is done with the Real-Time Linux kernel (PREEMPT_RT):
kas shell --keep-config-unchanged \
meta-arm/kas/fvp-baser-aemv8r64-rt-bsp.yml \
--command "../layers/meta-arm/scripts/runfvp \
--console "
Note: The terminal console login is root without password.
To finish the fvp emulation, you need to close the telnet session:
ctrl+].quit to close the session.The FVP is configured by default to use "user-mode networking", which simulates an IP router and DHCP server to avoid additional host dependencies and networking configuration. Outbound connections work automatically, e.g. by running:
wget www.arm.com
Inbound connections require an explicit port mapping from the host. By default, port 8022 on the host is mapped to port 22 on the FVP, so that the following command will connect to an ssh server running on the FVP:
ssh root@localhost -p 8022
Note that user-mode networking does not support ICMP, so ping will not work. For more information about user-mode networking, please see https://developer.arm.com/documentation/100964/1117/Introduction-to-Fast-Models/User-mode-networking?lang=en
It is possible to share a directory between the host machine and the fvp using the virtio P9 device component included in the kernel. To do so, create a directory to be mounted from the host machine:
mkdir /path/to/host-mount-dir
Then, add the following parameter containing the path to the directory when launching the model:
--parameter 'bp.virtiop9device.root_path=/path/to/host-mount-dir'
e.g. for the standard Linux kernel:
kas shell --keep-config-unchanged \
meta-arm/kas/fvp-baser-aemv8r64-bsp.yml \
--command "../layers/meta-arm/scripts/runfvp \
--console -- --parameter \
'bp.virtiop9device.root_path=/path/to/host-mount-dir'"
Once you are logged into the fvp, the host directory can be mounted in a directory on the model using the following command:
mount -t 9p -o trans=virtio,version=9p2000.L FM /path/to/fvp-mount-dir
cache_state_modelled parameter will affect the cache coherence behavior of peripherals’ DMA. When users set cache_state_modelled=1, they also have to set cci400.force_on_from_start=1 to force the FVP to enable snooping on upstream ports.memory node in the device tree to be ignored./memreserve/ region.