4.4 KiB
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.
If 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.
Current limitations:
- Only cold boot is supported
Getting non-TF images
QEMU_EFI.fd can be downloaded from http://snapshots.linaro.org/components/kernel/leg-virt-tianocore-edk2-upstream/latest/QEMU-KERNEL-AARCH64/RELEASE_GCC5/QEMU_EFI.fd
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 Build/ArmVirtQemuKernel-AARCH64/DEBUG_GCC5/FV/QEMU_EFI.fd
Please note you do not need to use GCC 5 in spite of the environment variable GCC5_AARCH64_PREFIX
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 output/images/rootfs.cpio.gz.
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:
- bl2.bin -> BL2
- bl31.bin -> BL31
- bl33.bin -> BL33 (QEMU_EFI.fd)
- Image -> linux/arch/arm64/boot/Image
To build:
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
Booting via flash based firmwares
Boot firmwares are loaded via secure FLASH0 device so bl1.bin and fip.bin should be concatenated to create a flash.bin that is flashed onto secure FLASH0.
- bl32.bin -> BL32 (tee-header_v2.bin)
- bl32_extra1.bin -> BL32 Extra1 (tee-pager_v2.bin)
- bl32_extra2.bin -> BL32 Extra2 (tee-pageable_v2.bin)
- bl33.bin -> BL33 (QEMU_EFI.fd)
- Image -> linux/arch/arm64/boot/Image
To build:
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
To build with TBBR enabled, 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
To build flash.bin:
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
To start (QEMU v5.0.0):
qemu-system-aarch64 -nographic -machine virt,secure=on -cpu cortex-a57 \ -kernel Image -no-acpi \ -append 'console=ttyAMA0,38400 keep_bootcon' \ -initrd rootfs.cpio.gz -smp 2 -m 1024 -bios flash.bin \ -d unimp