Re: How to solve: 'Please append a correct "root=" boot option' ?

[Frantisek Rysanek]

On 19 Apr 2023 at 23:40, Freitas GDH wrote:

> [    1.579213] VFS: Cannot open root device "vda" or
> unknown-block(0,0): error -6
> [    1.579566] Please append a correct "root=" boot option; here are
> the available partitions:
> [    1.580137] Kernel panic - not syncing: VFS: Unable to mount root
> fs on unknown-block(0,0)

Regardless of platform and kernel version, this generally means that
the device desired has not "emerged" before the "time to mount the
root fs" - typically because your monolithic kernel is missing the
driver module(s) that cater for the hardware and that should
nominally advertise the block device desired.

In your case, I believe you need virtio-blk .
Your log should then contain something like:

# dmesg | grep vda
[    9.549329] virtio_blk virtio0: [vda] 20971520 512-byte logical blocks (10.7 
GB/10.0 GiB)
...and further notes about the FS getting recognized on the block
device, perhaps only upon a successful mount attempt.

Perhaps you should use the initrd, load the driver from there, and
"pivot the root" ?

Another thought: on the host side, how about
-drive ... if=virtio ?

Frank