Hi Soeren,
On Sun, 30 Jul 2023 at 11:38, Soeren Moch smoch@web.de wrote:
On 30.07.23 19:16, Simon Glass wrote:
Add some hints and observations related to booting distros on QEMU on x86.
Signed-off-by: Simon Glass sjg@chromium.org
Simon,
you cc'd me on this patch (both versions), but I never used u-boot on x86. What do you expect from my side here?
This is automatic with get_maintainers.pl but I am not sure why it added you.
Regards, Simon
(no changes since v1)
doc/board/emulation/qemu-x86.rst | 88 ++++++++++++++++++++++++++++++-- 1 file changed, 84 insertions(+), 4 deletions(-)
diff --git a/doc/board/emulation/qemu-x86.rst b/doc/board/emulation/qemu-x86.rst index e7dd4e994d38..15f56b6bc706 100644 --- a/doc/board/emulation/qemu-x86.rst +++ b/doc/board/emulation/qemu-x86.rst @@ -113,7 +113,87 @@ 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.
-Note 64-bit support is very preliminary at this point. Lots of features -are missing in the 64-bit world. One notable feature is the VGA console -support which is currently missing, so that you must specify '-nographic' -to get 64-bit U-Boot up and running. +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.
+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.