mirror of
https://source.denx.de/u-boot/u-boot.git
synced 2025-08-18 21:21:26 +02:00
cdd20e3f66
As reported by Jonas Karlman this series breaks booting on some AArch64 platforms with common use cases. For now the best path forward is to revert the series. This reverts commit 777c28460947371ada40868dc994dfe8537d7115, reversing changes made to ab3453e7b12daef47b9e91da2a2a3d48615dc6fc. Link: https://lore.kernel.org/u-boot/50dfa3d6-a1ca-4492-a3fc-8d8c56b40b43@kwiboo.se/ Signed-off-by: Tom Rini <trini@konsulko.com>
203 lines
7.8 KiB
ReStructuredText
203 lines
7.8 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
.. sectionauthor:: Bin Meng <bmeng.cn@gmail.com>
|
|
|
|
QEMU x86
|
|
========
|
|
|
|
Build instructions for bare mode
|
|
--------------------------------
|
|
|
|
To build u-boot.rom for QEMU x86 targets, just simply run::
|
|
|
|
$ make qemu-x86_defconfig (for 32-bit)
|
|
$ make qemu-x86_64_defconfig (for 64-bit)
|
|
$ make all
|
|
|
|
Note this default configuration will build a U-Boot for the QEMU x86 i440FX
|
|
board. To build a U-Boot against QEMU x86 Q35 board, you can change the build
|
|
configuration during the 'make menuconfig' process like below::
|
|
|
|
Device Tree Control --->
|
|
...
|
|
(qemu-x86_q35) Default Device Tree for DT control
|
|
|
|
Test with QEMU for bare mode
|
|
----------------------------
|
|
|
|
QEMU is a fancy emulator that can enable us to test U-Boot without access to
|
|
a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
|
|
U-Boot. To launch QEMU with u-boot.rom, call QEMU as follows::
|
|
|
|
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom
|
|
|
|
This will instantiate an emulated x86 board with i440FX and PIIX chipset. QEMU
|
|
also supports emulating an x86 board with Q35 and ICH9 based chipset, which is
|
|
also supported by U-Boot. To instantiate such a machine, call QEMU with::
|
|
|
|
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -M q35
|
|
|
|
Note by default QEMU instantiated boards only have 128 MiB system memory. But
|
|
it is enough to have U-Boot boot and function correctly. You can increase the
|
|
system memory by pass '-m' parameter to QEMU if you want more memory::
|
|
|
|
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024
|
|
|
|
This creates a board with 1 GiB system memory. Currently U-Boot for QEMU only
|
|
supports 3 GiB maximum system memory and reserves the last 1 GiB address space
|
|
for PCI device memory-mapped I/O and other stuff, so the maximum value of '-m'
|
|
would be 3072.
|
|
|
|
QEMU emulates a graphic card which U-Boot supports. Removing '-nographic' will
|
|
show QEMU's VGA console window. Note this will disable QEMU's serial output.
|
|
If you want to check both consoles, use '-serial stdio'.
|
|
|
|
Multicore is also supported by QEMU via '-smp n' where n is the number of cores
|
|
to instantiate. Note, the maximum supported CPU number in QEMU is 255.
|
|
|
|
U-Boot uses 'distro_bootcmd' by default when booting on x86 QEMU. This tries to
|
|
load a boot script, kernel, and ramdisk from several different interfaces. For
|
|
the default boot order, see 'qemu-x86.h'. For more information, see
|
|
'doc/develop/distro.rst'. Most Linux distros can be booted by writing a uboot
|
|
script.
|
|
For example, Debian (stretch) can be booted by creating a script file named
|
|
'boot.txt' with the contents::
|
|
|
|
setenv bootargs root=/dev/sda1 ro
|
|
load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} /vmlinuz
|
|
load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} /initrd.img
|
|
zboot ${kernel_addr_r} - ${ramdisk_addr_r} ${filesize}
|
|
|
|
Then compile and install it with::
|
|
|
|
$ apt install u-boot-tools && \
|
|
mkimage -T script -C none -n "Boot script" -d boot.txt /boot/boot.scr
|
|
|
|
The fw_cfg interface in QEMU also provides information about kernel data,
|
|
initrd, command-line arguments and more. U-Boot supports directly accessing
|
|
these informtion from fw_cfg interface, which saves the time of loading them
|
|
from hard disk or network again, through emulated devices. To use it , simply
|
|
providing them in QEMU command line::
|
|
|
|
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024 \
|
|
-kernel /path/to/bzImage -append 'root=/dev/ram console=ttyS0' \
|
|
-initrd /path/to/initrd -smp 8
|
|
|
|
Note: -initrd and -smp are both optional
|
|
|
|
Then start QEMU, in U-Boot command line use the following U-Boot command to
|
|
setup kernel::
|
|
|
|
=> qfw
|
|
qfw - QEMU firmware interface
|
|
|
|
Usage:
|
|
qfw <command>
|
|
- list : print firmware(s) currently loaded
|
|
- cpus : print online cpu number
|
|
- load <kernel addr> <initrd addr> : load kernel and initrd (if any) and setup for zboot
|
|
|
|
=> qfw load
|
|
loading kernel to address 01000000 size 5d9d30 initrd 04000000 size 1b1ab50
|
|
|
|
Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then,
|
|
'zboot' can be used to boot the kernel::
|
|
|
|
=> zboot 01000000 - 04000000 1b1ab50
|
|
|
|
To run 64-bit U-Boot, qemu-system-x86_64 should be used instead, e.g.::
|
|
|
|
$ qemu-system-x86_64 -nographic -bios path/to/u-boot.rom
|
|
|
|
A specific CPU can be specified via the '-cpu' parameter but please make
|
|
sure the specified CPU supports 64-bit like '-cpu core2duo'. Conversely
|
|
'-cpu pentium' won't work for obvious reasons that the processor only
|
|
supports 32-bit.
|
|
|
|
Booting distros
|
|
---------------
|
|
|
|
It is possible to install and boot a standard Linux distribution using
|
|
qemu-x86_64 by setting up a root disk::
|
|
|
|
qemu-img create root.img 10G
|
|
|
|
then using the installer to install. For example, with Ubuntu 2023.04::
|
|
|
|
qemu-system-x86_64 -m 8G -smp 4 -bios /tmp/b/qemu-x86_64/u-boot.rom \
|
|
-drive file=root.img,if=virtio,driver=raw \
|
|
-drive file=ubuntu-23.04-desktop-amd64.iso,if=virtio,driver=raw
|
|
|
|
You can also add `-serial mon:stdio` if you want the serial console to show as
|
|
well as the video.
|
|
|
|
The output will be something like this::
|
|
|
|
U-Boot SPL 2023.07 (Jul 23 2023 - 08:00:12 -0600)
|
|
Trying to boot from SPI
|
|
Jumping to 64-bit U-Boot: Note many features are missing
|
|
|
|
|
|
U-Boot 2023.07 (Jul 23 2023 - 08:00:12 -0600)
|
|
|
|
CPU: QEMU Virtual CPU version 2.5+
|
|
DRAM: 8 GiB
|
|
Core: 20 devices, 13 uclasses, devicetree: separate
|
|
Loading Environment from nowhere... OK
|
|
Model: QEMU x86 (I440FX)
|
|
Net: e1000: 52:54:00:12:34:56
|
|
eth0: e1000#0
|
|
Hit any key to stop autoboot: 0
|
|
Scanning for bootflows in all bootdevs
|
|
Seq Method State Uclass Part Name Filename
|
|
--- ----------- ------ -------- ---- ------------------------ ----------------
|
|
Scanning global bootmeth 'efi_mgr':
|
|
Hunting with: nvme
|
|
Hunting with: qfw
|
|
Hunting with: scsi
|
|
scanning bus for devices...
|
|
Hunting with: virtio
|
|
Scanning bootdev 'qfw_pio.bootdev':
|
|
fatal: no kernel available
|
|
Scanning bootdev 'virtio-blk#0.bootdev':
|
|
Scanning bootdev 'virtio-blk#1.bootdev':
|
|
0 efi ready virtio 2 virtio-blk#1.bootdev.part efi/boot/bootx64.efi
|
|
** Booting bootflow 'virtio-blk#1.bootdev.part_2' with efi
|
|
EFI using ACPI tables at f0060
|
|
efi_install_fdt() WARNING: Can't have ACPI table and device tree - ignoring DT.
|
|
efi_run_image() Booting /efi\boot\bootx64.efi
|
|
error: file `/boot/' not found.
|
|
|
|
Standard boot looks through various available devices and finds the virtio
|
|
disks, then boots from the first one. After a second or so the grub menu appears
|
|
and you can work through the installer flow normally.
|
|
|
|
Note that standard boot will not find 32-bit distros, since it looks for a
|
|
different filename.
|
|
|
|
Current limitations
|
|
-------------------
|
|
|
|
Only qemu-x86-64 can be used for booting distros, since qemu-x86 (the 32-bit
|
|
version of U-Boot) seems to have an EFI bug leading to the boot handing after
|
|
Linux is selected from grub, e.g. with `debian-12.1.0-i386-netinst.iso`::
|
|
|
|
** Booting bootflow 'virtio-blk#1.bootdev.part_2' with efi
|
|
EFI using ACPI tables at f0180
|
|
efi_install_fdt() WARNING: Can't have ACPI table and device tree - ignoring DT.
|
|
efi_run_image() Booting /efi\boot\bootia32.efi
|
|
Failed to open efi\boot\root=/dev/sdb3 - Not Found
|
|
Failed to load image 큀緃: Not Found
|
|
start_image() returned Not Found, falling back to default loader
|
|
Welcome to GRUB!
|
|
|
|
The bochs video driver also seems to cause problems before the OS is able to
|
|
show a display.
|
|
|
|
The QEMU `-cdrom` option is intended to work with the original ISO-format
|
|
images, not the recently invented ISOHybrid image.
|
|
|
|
Finally, the use of `-M accel=kvm` is intended to use the native CPU's
|
|
virtual-machine features to accelerate operation, but this causes U-Boot to hang
|
|
when jumping 64-bit mode, at least on AMD machines. This may be a bug in U-Boot
|
|
or something else.
|