qemu: add/update examples #80
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Partially addresses #71 |
content/qemu/index.md
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| ### Black / blank screen | ||
| In all examples below you can add `-nographic` to get the first serial console on your terminal. | ||
| This might work better on arm64, where most software defaults to supporting serial console, and less good on amd64. |
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Hmm, what do you mean with "most software defaults to supporting serial console" on arm64? Why is that so?
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EDK2, grub, linux kernel appear to default-enable serial console support. This is probably because there is no native "VGA" like on x86.
ISTR on x86 most of these things don't bother enabling serial.
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Ah, ok...
I haven't tested Grml/arm64 with -nographic on my system, but Grml/amd64 does not give me the serial console. It would be nice to let Grub detect that somehow... is that even possible?
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grub: good question! it does somehow work on arm64, so i guess it should be possible on x86?
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I've done my tests on arm64 with the arm64 ISO, and -nographic just works ootb.
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Ah... with qemu-system-x86_64 -M q35 -m 2048 -cpu host -enable-kvm -nographic -cdrom /srv/isos/grml-full-2024.12-amd64.iso I get:
SeaBIOS (version 1.16.2-debian-1.16.2-1)
iPXE (http://ipxe.org) 00:02.0 CA00 PCI2.10 PnP PMM+7EFCEDF0+7EF0EDF0 CA00
Booting from Hard Disk...
Boot failed: could not read the boot disk
Booting from DVD/CD...
ISOLINUX 6.04 20200816 ETCD Copyright (C) 1994-2015 H. Peter Anvin et al
If I hit ESC within the timeout of 30s I get the boot prompt where I can enter serial. If not I am stuck...
Can you confirm that behavior? (Maybe worth to be documented somehow?)
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ISTR on x86 most of these things don't bother enabling serial.
Looks like at least grub enables serial, if I remove VGA. Kernel doesn't automatically enable serial though. Might be worth investigating if that can be if-ed in grub.
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Can you confirm that behavior? (Maybe worth to be documented somehow?)
Yes, I can. The trick appears to add this to the qemu command line: -vga none
Then ISOLINUX presents this menu:
content/qemu/index.md
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| ### Black / blank screen | ||
| In all examples below you can add `-nographic` to get the first serial console on your terminal. | ||
| This might work better on arm64, where most software defaults to supporting serial console, and less good on amd64. |
There was a problem hiding this comment.
Ah, ok...
I haven't tested Grml/arm64 with -nographic on my system, but Grml/amd64 does not give me the serial console. It would be nice to let Grub detect that somehow... is that even possible?
content/qemu/index.md
Outdated
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|
||
| ### Black / blank screen | ||
| In all examples below you can add `-nographic` to get the first serial console on your terminal. | ||
| This might work better on arm64, where most software defaults to supporting serial console, and less good on amd64. |
There was a problem hiding this comment.
Ah... with qemu-system-x86_64 -M q35 -m 2048 -cpu host -enable-kvm -nographic -cdrom /srv/isos/grml-full-2024.12-amd64.iso I get:
SeaBIOS (version 1.16.2-debian-1.16.2-1)
iPXE (http://ipxe.org) 00:02.0 CA00 PCI2.10 PnP PMM+7EFCEDF0+7EF0EDF0 CA00
Booting from Hard Disk...
Boot failed: could not read the boot disk
Booting from DVD/CD...
ISOLINUX 6.04 20200816 ETCD Copyright (C) 1994-2015 H. Peter Anvin et al
If I hit ESC within the timeout of 30s I get the boot prompt where I can enter serial. If not I am stuck...
Can you confirm that behavior? (Maybe worth to be documented somehow?)
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These examples come from my notes. I cannot verify the amd64 examples right now, so if someone else can that'd be nice.