Re: QEMU, Windows 11, and Raspios

[Jakob Bohm]

Hi list,

On 2024-10-19 14:09, G.W. Haywood wrote:
> Hi there,
>
> On Fri, 18 Oct 2024, Ignacio wrote:
>
> > I am currently using a laptop that is running Windows 11 and I have
> > downloaded QEMU. However, I cannot figure out how to use QEMU to emulate
> > Raspios. Raspios does not use a .iso, but instead a .img. I was 
> > wondering
> > if there is a way around this or if I am complicating this process.
>
> There surely is a way.  The two data formats you mention are different
> because they are used for different purposes.
>
> [Snipped Long ranty description of everything but how to use the files 
> with qemu ]
The rant got a lot of details wrong, so don't use it.

Here's the short version as I understand it:

For the .img file (if it is truly a bootable SD card image):

1. Create a Qemu copy-on-write (version 2) virtual SD card image which
uses the .img file as the base butkeeps all changes written by the
virtual RPi in the qcow2 file (this command specifies a 64G SD Card).

$ qemu-img create -f qcow2 \
 -o 
backing_file=rpiosNNN.img,backing_fmt=raw,lazy_refcounts=on,preallocation=metadata 
\
 raspiSD1.qcow2 64G

2. Pass the new sdcard raspiSD1.qcow2 as a disk to the
 qemu-system-aarch64 virtual machine emulator, also specify other
 relevant hardware such as the virtual RPi GPU, the virtual ethernet
 card, virtual keyboard/mouse etc.  Such qemu command lines can
 become quite long and thus you should put the arguments in a .BAT
 file for Windows (or .sh file for Linux etc.)

For .iso files with an OS for more normal hardware:

1. Create a blank thin provisioned virtual hard drive in qcow2 format
 (this command specifies a 0.5 TB HDD):

$ qemu-img crate -f qcow2 -o lazy_refcounts=on,preallocation=metadata \
  qemuPC1.qcow2 512G

2. Pass the new HDD qemuPC1.qcow2 as a disk to the qemu-system-x86_64
virtual machineemulator.  Pass the someosNNN.iso file as a read only
CD-ROM, also specify other hardware such as a virtual UEFI BIOS ROM,
a virtual GPU etc.  Such qemucommand lines can become quite long and
thus you should put the argumentsin a .BAT file for Windows (or .sh
file for Linux etc.).


Hint: On Windows 10 original (1507), Notepad was the obvious program
for editing .BAT files, later releases and Windows 11 may have Fouled
things Up Beyond All Repair (FUBAR).

P.S.: I am not sure if current qemu builds for Windows have a working
audio driver, a few years ago it didn't .

Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
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