# QEMU AArch64 emulator This page describes how to build and run coreboot for QEMU/AArch64. You can use LinuxBoot via `make menuconfig` or an arbitrary FIT image as a payload for QEMU/AArch64. ## Running coreboot in QEMU ```bash qemu-system-aarch64 -bios ./build/coreboot.rom \ -M virt,secure=on,virtualization=on -cpu cortex-a53 \ -nographic -m 8192M ``` - The default CPU in QEMU for AArch64 is a cortex-a15 which is 32-bit ARM CPU. You need to specify 64-bit ARM CPU via `-cpu cortex-a53`. - The default privilege level in QEMU for AArch64 is EL1 that we can't have the right to access EL3/EL2 registers. You need to enable EL3/EL2 via `-machine secure=on,virtualization=on`. - You need to specify the size of memory more than 544 MiB because 512 MiB is reserved for the kernel. - The maximum size of memory is 255GiB (-m 261120). ## Building coreboot with an arbitrary FIT payload There are 3 steps to make coreboot.rom for QEMU/AArch64. If you select LinuxBoot, step 2 and 3 have done by LinuxBoot. 1. Get a DTB (Device Tree Blob) 2. Build a FIT image with a DTB 3. Add a FIT image to coreboot.rom ### 1. Get a DTB You can get the DTB from QEMU with the following command. ``` $ qemu-system-aarch64 \ -M virt,dumpdtb=virt.dtb,secure=on,virtualization=on \ -cpu cortex-a53 -nographic -m 8192M ``` ### 2. Build a FIT image with a DTB You need to write an image source file that has an `.its` extension to configure kernels, ramdisks, and DTBs. See [Flattened uImage Tree documentation](../../lib/payloads/fit.md) for more details. ### 3. Add a FIT image to coreboot.rom You can use cbfstool to add the payload you created in step 2 to the coreboot.rom. ``` $ ./build/cbfstool ./build/coreboot.rom add -f <path-to-a-payload>/uImage \ -n fallback/payload -t fit -c lzma ```