1 # SPDX-License-Identifier: GPL-2.0+
3 # Copyright (C) 2017, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
5 U-Boot on QEMU's 'virt' machine on ARM & AArch64
6 ================================================
8 QEMU for ARM supports a special 'virt' machine designed for emulation and
9 virtualization purposes. This document describes how to run U-Boot under it.
10 Both 32-bit ARM and AArch64 are supported.
12 The 'virt' platform provides the following as the basic functionality:
14 - A freely configurable amount of CPU cores
15 - U-Boot loaded and executing in the emulated flash at address 0x0
16 - A generated device tree blob placed at the start of RAM
17 - A freely configurable amount of RAM, described by the DTB
18 - A PL011 serial port, discoverable via the DTB
19 - An ARMv7/ARMv8 architected timer
20 - PSCI for rebooting the system
21 - A generic ECAM-based PCI host controller, discoverable via the DTB
23 Additionally, a number of optional peripherals can be added to the PCI bus.
27 Set the CROSS_COMPILE environment variable as usual, and run:
30 make qemu_arm_defconfig
34 make qemu_arm64_defconfig
39 The minimal QEMU command line to get U-Boot up and running is:
42 qemu-system-arm -machine virt -bios u-boot.bin
45 qemu-system-aarch64 -machine virt -cpu cortex-a57 -bios u-boot.bin
47 Note that for some odd reason qemu-system-aarch64 needs to be explicitly
48 told to use a 64-bit CPU or it will boot in 32-bit mode.
50 Additional persistent U-boot environment support can be added as follows:
51 - Create envstore.img using qemu-img:
52 qemu-img create -f raw envstore.img 64M
53 - Add a pflash drive parameter to the command line:
54 -drive if=pflash,format=raw,index=1,file=envstore.img
56 Additional peripherals that have been tested to work in both U-Boot and Linux
57 can be enabled with the following command line parameters:
59 - To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.:
60 -drive if=none,file=disk.img,id=mydisk -device ich9-ahci,id=ahci -device ide-drive,drive=mydisk,bus=ahci.0
61 - To add an Intel E1000 network adapter, pass e.g.:
62 -netdev user,id=net0 -device e1000,netdev=net0
63 - To add an EHCI-compliant USB host controller, pass e.g.:
64 -device usb-ehci,id=ehci
65 - To add a NVMe disk, pass e.g.:
66 -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
68 These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.