Expose Linux kernel command line

[LaszloGombos]

Description

Expose the linux kernel command line in limactl start.

qemu

-append cmdline
Use cmdline as kernel command line

VZLinuxBootLoader

[AkihiroSuda]

For QEMU, we already have this: https://github.com/lima-vm/lima/blob/a21b5f3bbcb63a37987a328e63d8a1a9f1c2e098/pkg/limayaml/limayaml.go#L80-L83

[ericdbishop]

First time contributor but I'd like to work on a PR for this issue, could it be assigned to me?

[jandubois]

First time contributor but I'd like to work on a PR for this issue, could it be assigned to me?

Sure, thank you!

[ericdbishop]

For QEMU, we already have this:

https://github.com/lima-vm/lima/blob/a21b5f3bbcb63a37987a328e63d8a1a9f1c2e098/pkg/limayaml/limayaml.go#L80-L83

Shouldn't you be able to specify kernel cmdline options without including the File struct parameters? It seems like this is only used in a very specific instance to run u-boot:

https://github.com/lima-vm/lima/blob/b453dedb757e5fc1e249f352d0812d008e66fa3f/examples/experimental/riscv64.yaml#L14-L19

Could I move cmdline to the top-level of the config? Or is there another way you'd suggest making it possible to add cmdline to the config without the file location?

[AkihiroSuda]

Shouldn't you be able to specify kernel cmdline options without including the File struct parameters?

How to specify vmlinuz then?

[ericdbishop]

So in an instance where you specify kernel cmdline options, you want it to be a requirement to specify a file for the kernel? Just want to make sure that is the intended behavior. It seemed to me like those things shouldn't necessarily be dependent on each other.

[AkihiroSuda]

So in an instance where you specify kernel cmdline options, you want it to be a requirement to specify a file for the kernel? Just want to make sure that is the intended behavior.

Yes

It seemed to me like those things shouldn't necessarily be dependent on each other.

• How to specify cmdline without vmlinuz? Theoretically you could parse VFAT/ext4/XFS and grub.cfg to extract vmlinuz from qcow2, but its implementation cost is extremely high.

• How to boot vmlinuz without cmdline?

[ncopa]

I missed this option today when I had to rescue an Alpine VM. The kernel in the VM was broken, and I needed to boot a different kernel/initrd. I looked for how to pass -kernel <file> -initrd <file> -append <cmdline> to lima, but I didn't find anythign about it. I ended up limactl start .. (which didnt work ofc) , and pasted output of ps xa|grep qemu to a file, and twaek the qemu args manually.