add grub_run_no_partition option to generate correct grub.conf

[biancalana]

Its common cloud images provide unpartitioned disks.
This add an option that generate grub.conf that allow boot using unpartitioned disks.

[metalefty]

@biancalana Could you let me know an example of unpartitioned cloud images? I'll test it with it.

[biancalana]

@metalefty alpine nocloud images (https://www.alpinelinux.org/cloud/)

https://dl-cdn.alpinelinux.org/alpine/v3.23/releases/cloud/nocloud_alpine-3.23.3-x86_64-bios-tiny-r0.qcow2

You need to convert from qcow2 to raw using qemu-img

[metalefty]

The Alpine image successfully booted with the following additional configuration.

grub_run_no_partition="yes"
grub_run0="linux /boot/vmlinuz-virt root=/dev/vda rootfstype=ext4 rw"
grub_run1="initrd /boot/initramfs-virt"

[metalefty]

Please also reflect changes on man pages, edit vm.8.

[metalefty]

Suggested change

	if [ -n "${_grub_opt}" ]; then
	if [ config::yesno "grub_run_no_partition" ]; then

[metalefty]

config:yesno might be better because it can handle on/true/yes/1|off/false/no/0.
The current code interprets grun_run_no_partition=no as "yes". It could mislead.

[metalefty]

Suggested change

config::get "_grub_opt" "grub_run_no_partition"

[metalefty]

@michael-o Do you have any opinions?

[michael-o]

@michael-o Do you have any opinions?

No opinion, but would to know whether these images can also boot via UEFI?

[metalefty]

It actually doesn't boot with UEFI, but images for UEFI are also available. BIOS versions seem to support only BIOS+GRUB.

[michael-o]

It actually doesn't boot with UEFI, but images for UEFI are also available. BIOS versions seem to support only BIOS+GRUB.

I see, ok. Then this makes sense, I guess.

[metalefty]

@biancalana This one can be merged once the comments are addressed.