7.23. QEMU virt Armv8-A
Trusted Firmware-A (TF-A) implements the EL3 firmware layer for QEMU virt Armv8-A. BL1 is used as the BootROM, supplied with the -bios argument. When QEMU starts all CPUs are released simultaneously, BL1 selects a primary CPU to handle the boot and the secondaries are placed in a polling loop to be released by normal world via PSCI.
BL2 edits the Flattened Device Tree, FDT, generated by QEMU at run-time to add a node describing PSCI and also enable methods for the CPUs.
ARM_LINUX_KERNEL_AS_BL33 is set to 1 then this FDT will be passed to BL33
via register x0, as expected by a Linux kernel. This allows a Linux kernel image
to be booted directly as BL33 rather than using a bootloader.
An ARM64 defconfig v5.5 Linux kernel is known to boot, FDT doesn’t need to be provided as it’s generated by QEMU.
Only cold boot is supported
7.23.1. Getting non-TF images
QEMU_EFI.fd can be downloaded from
or, can be built as follows:
git clone https://github.com/tianocore/edk2.git cd edk2 git submodule update --init make -C BaseTools source edksetup.sh export GCC5_AARCH64_PREFIX=aarch64-linux-gnu- build -a AARCH64 -t GCC5 -p ArmVirtPkg/ArmVirtQemuKernel.dsc
Then, you will get
Please note you do not need to use GCC 5 in spite of the environment variable
The rootfs can be built by using Buildroot as follows:
git clone git://git.buildroot.net/buildroot.git cd buildroot make qemu_aarch64_virt_defconfig utils/config -e BR2_TARGET_ROOTFS_CPIO utils/config -e BR2_TARGET_ROOTFS_CPIO_GZIP make olddefconfig make
Then, you will get
7.23.2. Booting via semi-hosting option
Boot binaries, except BL1, are primarily loaded via semi-hosting so all binaries has to reside in the same directory as QEMU is started from. This is conveniently achieved with symlinks the local names as:
bl33.bin-> BL33 (
make CROSS_COMPILE=aarch64-none-elf- PLAT=qemu
To start (QEMU v5.0.0):
qemu-system-aarch64 -nographic -machine virt,secure=on -cpu cortex-a57 \ -kernel Image \ -append "console=ttyAMA0,38400 keep_bootcon" \ -initrd rootfs.cpio.gz -smp 2 -m 1024 -bios bl1.bin \ -d unimp -semihosting-config enable,target=native
7.23.3. Booting via flash based firmware
An alternate approach to deploy a full system stack on QEMU is to load the
firmware via a secure flash device. This involves concatenating
fip.bin to create a boot ROM that is flashed onto secure FLASH0 with the
For example, to test the following firmware stack:
BL32 Extra1 -
BL32 Extra2 -
make CROSS_COMPILE=aarch64-linux-gnu- PLAT=qemu BL32=bl32.bin \ BL32_EXTRA1=bl32_extra1.bin BL32_EXTRA2=bl32_extra2.bin \ BL33=bl33.bin BL32_RAM_LOCATION=tdram SPD=opteed all fip
Or, alternatively, to build with TBBR enabled, as well as, BL31 and BL32 encrypted with test key:make CROSS_COMPILE=aarch64-linux-gnu- PLAT=qemu BL32=bl32.bin \ BL32_EXTRA1=bl32_extra1.bin BL32_EXTRA2=bl32_extra2.bin \ BL33=bl33.bin BL32_RAM_LOCATION=tdram SPD=opteed all fip \ MBEDTLS_DIR=<path-to-mbedtls-repo> TRUSTED_BOARD_BOOT=1 \ GENERATE_COT=1 DECRYPTION_SUPPORT=aes_gcm FW_ENC_STATUS=0 \ ENCRYPT_BL31=1 ENCRYPT_BL32=1
fip.binto create the boot ROM
dd if=build/qemu/release/bl1.bin of=flash.bin bs=4096 conv=notrunc dd if=build/qemu/release/fip.bin of=flash.bin seek=64 bs=4096 conv=notrunc
qemu-system-aarch64 -nographic -machine virt,secure=on -cpu cortex-a57 -kernel Image \ -append 'console=ttyAMA0,38400 keep_bootcon' \ -initrd rootfs.cpio.gz -smp 2 -m 1024 -bios flash.bin \ -d unimp
-bios option abstracts the loading of raw bare metal binaries into flash
or ROM memory. QEMU loads the binary into the region corresponding to
the hardware’s entrypoint, from which the binary is executed upon a platform
“reset”. In addition to this, it places the information about the kernel
provided with option
-kernel, and the RamDisk provided with
into the firmware configuration
fw_cfg. In this setup, EDK II is responsible
for extracting and launching these from
QEMU may be launched with or without ACPI (
either case, ensure that the kernel build options are aligned with the
parameters passed to QEMU.
7.23.4. Running QEMU in OpenCI
Linaro’s continuous integration platform OpenCI supports running emulated tests on QEMU. The tests are kicked off on Jenkins and deployed through the Linaro Automation and Validation Architecture LAVA.
There are a set of Linux boot tests provided in OpenCI. They rely on prebuilt
binaries for UEFI, the kernel, root file system, as well as, any other TF-A
dependencies, and are run as part of the OpenCI TF-A daily job. To run them
manually, a builder job may be triggered with the test configuration
You may see the following warning repeated several times in the boot logs:
pflash_write: Write to buffer emulation is flawed
Please ignore this as it is an unresolved issue in QEMU, it is an internal QEMU warning that logs flawed use of “write to buffer”.
For more information on how to trigger jobs in OpenCI, please refer to Linaro’s CI documentation, which explains how to trigger a manual job.