Re: Invalid accelerator kvm / error: kvm run failed Function not implemented ERRORS trying to virtualize a guest OS on the ARM Chromebook running with a relatively recent kernel version and KVM enabled

[Peter Maydell]

On Thu, 10 Aug 2023 at 17:52, Mario Marietto <marietto2008@gmail.com> wrote:

> I conducted some further experiments :
>
> In this example I've used qemu 5.2.0 installed by default by the devuan 4 :
>
>
> qemu-system-arm \
>     -enable-kvm -serial stdio -kernel zImage \
>     -m 512 -M vexpress-a15 -cpu cortex-a15 \
>     -drive 
> file=/mnt/fisso/bhyve/img/Linux/ubuntu2210.img,id=virtio-blk,if=none \
>     -device virtio-blk,drive=virtio-blk,transport=virtio-mmio.0 \
>     -device 
> virtio-net,transport=virtio-mmio.1,netdev=net0,mac="52:54:00:12:34:55" \
>     -netdev type=user,id=net0 \
>     -append "earlyprintk=ttyAMA0 console=ttyAMA0 mem=512M \
>              virtio_mmio.device=1M@0x4e000000:74:0 \
>              virtio_mmio.device=1M@0x4e100000:75:1 \
>              root=/dev/vda rw ip=dhcp --no-log"
>
> qemu-system-arm: invalid accelerator kvm.

You can't use KVM with the vexpress-a15 board. The only
Arm guest machine that will work with KVM is the "virt"
board.

Further, it looks like your host CPU is 32-bit. QEMU 5.2
dropped support for running KVM on 32-bit hosts, because this
support was dropped from host kernels in kernel version 5.7.

Basically, 32-bit hosts are just too small to do anything
sensible with virtual machines, which is why the kernel
(and in turn QEMU) dropped that support. If you want
to play around with Arm virtualization, use a 64-bit host.
(64-bit hosts can still use KVM to virtualize 32-bit
guests if you want 32-bit guests.)

thanks
-- PMM