Re: [QUESTION] qemu: how to control the switch of floppy drive

[Xu, Yanfei]

On 4/9/21 3:10 PM, Philippe Mathieu-Daudé wrote:
> [Please note: This e-mail is from an EXTERNAL e-mail address]
>
> Hi,
>
> On 4/9/21 8:48 AM, Xu, Yanfei wrote:
> > How can I disable the floppy controller drive when I boot a VM by qemu-
> > system-x86_64? I did not specify any arguments about floppy, but after
> > the qemu boots up, linux always can detect floppy drive and then
> > modprobe the matched floppy.ko.
> >
> > qemu version: v5.2
> >
> > command line:
> >
> > qemu-system-x86_64 -device virtio-net-
> > pci,netdev=net0,mac=52:54:00:12:34:02 -netdev
> > tap,id=net0,ifname=tap0,script=no,downscript=no -object rng-
> > random,filename=/dev/urandom,id=rng0 -device virtio-rng-pci,rng=rng0
> > -drive file=/path/to/images/qemux86-64
> > /qemux86-64.ext4,if=virtio,format=raw -usb -device usb-tablet   -cpu
> > core2duo -enable-kvm -m 512  -pidfile /path/to/pidfile_4167420 -m 512
> > -snapshot -serial mon:vc -serial null  -kernel /path/to/qemux86-64
> > /bzImage.bin -append 'root=/dev/vda rw  mem=512M
> > ip=192.168.7.2::192.168.7.1:255.255.255.0 oprofile.timer=1
> > printk.time=1'
> >
> > As I konw BIOS can control the switch of floppy controller on a real
> > hardware, But how can I do it on qemu? And does the qemu enable that by
> > default?
>
> See
> https://gitlab.com/qemu-project/qemu/-/blob/master/docs/qdev-device-use.txt#L105
>
> * if=floppy
>
>    -device floppy,unit=UNIT,drive=DRIVE-ID
>
>    Without any -device floppy,... you get an empty unit 0 and no unit
>    1.  You can use -nodefaults to suppress the default unit 0, see
>    "Default Devices".

I see. Thanks for your link and detailed explanation. :)

Thanks,
Yanfei

> Regards,
>
> Phil.