Using accelorator tcg is very inefficient. But using hvf can cause bugs.
hvf is hyper visor technology built into mac. You can install it and if you can get qemu to boot with hvf instead. It is supposedly supposed to run much faster.

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addtional resources:

• (Official Github Repo) https://github.com/qemu/qemu
• (Other Useful Resource) https://github.com/macbian-admin/macos-subsystem-for-linux

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Mac OS QEMU Virtualization

A simple guide for running Ubuntu (or other Linux distributions) on macOS using QEMU.

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1. Install QEMU via Homebrew

brew update
brew install qemu

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2. Create a Local Directory

Create and navigate into a folder (e.g., ~/ubuntu):

mkdir ~/ubuntu
cd ~/ubuntu

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3. Create the Disk Image

Inside ~/ubuntu/, run:

qemu-img create -f qcow2 msl.qcow2 40G

This creates a 40 GB disk named msl.qcow2.

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4. Check Available Accelerators

To see which accelerators your system supports (e.g., hvf or tcg):

qemu-system-x86_64 -accel help

• Intel Macs often support hvf.
• Apple Silicon or unsupported setups may need tcg (software emulation).

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5. Start the VM Installer

Example command (adjust ISO file name and memory as needed):

qemu-system-x86_64 -accel tcg \
  -m 4096 \
  -hda msl.qcow2 \
  -cdrom ubuntu-24.04.1-desktop-amd64.iso \
  -boot d \
  -smp 2 \
  -net nic \
  -net user,hostfwd=tcp::4022-:22

Tip: Replace -accel tcg with -accel hvf if hvf is supported. Increase -m to allocate more memory (e.g., 8192 for 8 GB) but leave enough RAM for macOS.

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6. Installing Ubuntu / Debian

Proceed with the installer. If prompted:

• Root Password: Leave blank (allows sudo access).
• Username: Match your macOS username if desired.
• Installation Options: For a minimal setup, uncheck desktop environments and include the SSH server.

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7. Boot from the Installed OS

After installation completes, remove the -cdrom and switch -boot d to -boot c:

qemu-system-x86_64 -accel tcg \
  -m 4096 \
  -hda msl.qcow2 \
  -boot c \
  -smp 2 \
  -net nic \
  -net user,hostfwd=tcp::4022-:22

This boots from the installed disk rather than the ISO.

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8. Basic QEMU Commands

View Created VMs
QEMU doesn’t manage VMs like VirtualBox. You manually track disk files:

ls *.qcow2

Remove a VM
Delete the .qcow2 file:

rm msl.qcow2

Create a New VM
Create another disk image (e.g., 20 GB):

qemu-img create -f qcow2 newvm.qcow2 20G

Start an Existing VM

qemu-system-x86_64 -accel tcg \
  -m 4096 \
  -hda newvm.qcow2 \
  -boot c \
  -smp 2

Stop a Running VM

• Shutdown from inside the guest, or

killall qemu-system-x86_64

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9. Improving Performance

1. Hardware Acceleration: Use -accel hvf if on an Intel Mac with HVF support.
2. Increase CPU Cores: -smp 4 or more if available.
3. Optimize Disk I/O: Try virtio drivers:

   -drive file=msl.qcow2,if=virtio

4. Allocate Adequate Memory: -m 8192 (8 GB) or more, but leave enough for macOS.

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Notes & Tips

• On Apple Silicon, x86_64 guests must often use -accel tcg, making performance slower. Tools like UTM may perform better by using Apple’s Virtualization.framework under the hood.
• Always keep your QEMU and macOS updated to ensure the latest hardware-acceleration support.

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Happy Virtualizing!

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Extra

QEMU does not have a centralized location to "store installations" like WSL or VirtualBox. Instead, QEMU stores everything in the disk image file(s) you create (e.g., .qcow2), which you specify in the command when starting a VM.

Here’s a breakdown of where files are stored:

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1. Disk Images

• When you create a disk image with qemu-img, it is stored wherever you specify.
• Example: If you run:

  qemu-img create -f qcow2 ~/ubuntu/msl.qcow2 40G

  The disk image (msl.qcow2) is saved in the ~/ubuntu directory.
  This file contains the entire OS installation, including all its data.

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2. Configuration and Metadata

QEMU doesn’t store configurations or metadata globally. Instead,
all configurations (e.g., RAM, CPU, accelerators) are provided as command-line arguments each time you run the VM.
To persist settings:

• Save your QEMU command to a script for reuse.

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3. ISO Files

• The OS installation ISO is usually stored where you downloaded it. QEMU doesn’t copy the ISO;
  it only references the file during installation.
• Example: If your ISO is in ~/ubuntu, QEMU will read it directly from there.

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4. Temporary and Log Files

• Snapshots: If you take snapshots, these may be stored alongside the .qcow2 file.
• Temporary Files: QEMU may store temporary files in /tmp or similar system directories, but these are cleared after shutdown.

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Summary

• OS and data: Stored in the .qcow2 disk file you specify.
• ISOs: Stored where you download them (not moved by QEMU).
• Configurations: Provided via commands/scripts (no centralized config).
• Temporary files: Stored in system temp directories during runtime.

If you’d like to explore the contents of your .qcow2 files, you can use QEMU tools like qemu-img to manage them.