1# qemu i440fx mainboard 2 3## Running coreboot in qemu 4Emulators like qemu don't need a firmware to do hardware init. 5The hardware starts in the configured state already. 6 7The coreboot port allows to test non mainboard specific code. 8As you can easily attach a debugger, it's a good target for 9experimental code. 10 11## coreboot x86_64 support 12coreboot historically runs in 32-bit protected mode, even though the 13processor supports x86_64 instructions (long mode). 14 15The qemu-i440fx mainboard has been ported to x86_64 and will serve as 16reference platform to enable additional platforms. 17 18To enable the support set the Kconfig option ``CONFIG_USE_EXP_X86_64_SUPPORT=y``. 19 20## Installing qemu 21 22On debian you can install qemu by running: 23```bash 24$ sudo apt-get install qemu 25``` 26 27On redhat you can install qemu by running: 28```bash 29$ sudo dnf install qemu 30``` 31 32## Running coreboot 33 34### To run the i386 version of coreboot (default) 35Running on qemu-system-i386 will require a 32 bit operating system. 36 37```bash 38qemu-system-i386 -bios build/coreboot.rom -serial stdio -M pc 39``` 40 41### To run the experimental x86_64 version of coreboot 42Running on qemu-system-x86_64 allows to run a 32 bit or 64 bit operating system, 43as well as firmware. 44 45```bash 46qemu-system-x86_64 -bios build/coreboot.rom -serial stdio -M pc 47``` 48 49## Finding bugs 50To test coreboot's x86 code it's recommended to run on a x86 host and enable KVM. 51It will not only run faster, but is closer to real hardware. If you see the 52following message: 53 54 KVM internal error. Suberror: 1 55 emulation failure 56 57something went wrong. The same bug will likely cause a FAULT on real hardware, 58too. 59 60To enable KVM run: 61 62```bash 63qemu-system-x86_64 -bios build/coreboot.rom -serial stdio -M pc -accel kvm -cpu host 64``` 65