Unlocking the Power of QEMU

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Unlocking the Power of QEMU

Advanced Command-Line Options Demystified


3 min read

QEMU is a versatile and powerful emulator that allows you to run various operating systems and architectures on your host system. In this article, we will dive into advanced QEMU options, with a specific focus on acceleration techniques, using qemu-system-aarch64 as our base command. This command is used for emulating the ARM64 architecture and is a popular choice for working with ARM-based systems.

This tutorial is intended for macOS with Apple Silicon chips.


Before we explore advanced QEMU options, ensure you have the following prerequisites in place:

  1. A working installation of QEMU.

  2. Basic knowledge of QEMU commands and usage.

  3. A compatible ARM64 guest image (e.g., an ARM64 Linux distribution).

  4. A bootable Alpine Linux image for use as the guest operating system in QEMU.

  5. A VARSTORE image (varstore.img) for persistent storage.

  6. QEMU's EFI image for UEFI-based virtual machines.

If you lack any of these prerequisites, you can obtain them by following the instructions in the provided link: "Creating a Lightweight Alpine Linux Virtual Machine on macOS with QEMU."

Navigating Advanced QEMU Options:

The following QEMU command is a powerful and feature-rich example that can be used to create and run a virtual machine with specific configurations. Let's break down each part of the command to understand its purpose:

qemu-system-aarch64 \
-cpu max \
-smp 4 \
-accel hvf \
-M virt \
-m 4G \
-nographic \
-drive if=pflash,format=raw,file=QEMU_EFI.img \
-drive if=pflash,file=varstore.img \
-drive if=virtio,file=alpine.img \
-netdev user,id=eth0,hostfwd=tcp::2222-:22 \
-device virtio-net-pci,netdev=eth0

Explanation of Command Parts:

  1. qemu-system-aarch64:

    • Specifies the QEMU binary for the aarch64 (ARM64) architecture.
  2. -cpu max:

    • Sets the CPU model to 'max,' which makes use of the host's maximum available CPU features.
  3. -smp 4:

    • Configures the number of virtual processors to 4, allowing for multi-threaded execution.
  4. -accel hvf:

    • Specifies the acceleration mode 'hvf' (Hardware Virtualization Framework), suitable for macOS host systems.
  5. -M virt:

    • Sets the machine type to 'virt,' which is a versatile platform used for virtualization.
  6. -m 4G:

    • Allocates 4 GB of RAM for the virtual machine.
  7. -nographic:

    • Disables graphical output, making it suitable for text-based or headless operation.
  8. -drive if=pflash,format=raw,file=QEMU_EFI.img:

    • Configures the first drive as a flash memory device with the provided QEMU EFI firmware image.
  9. -drive if=pflash,file=varstore.img:

    • Adds another drive for persistent storage using the specified VARSTORE image.
  10. -drive if=virtio,file=alpine.img:

    • Attaches a virtual drive using the VirtIO interface, with 'alpine.img' as its content. Please note that 'alpine.img' refers to the previously prepared Alpine Linux image.
  11. -netdev user,id=eth0,hostfwd=tcp::2222-:22:

    • Sets up a virtual network device ('eth0') and forwards host port 2222 to port 22 within the virtual machine, facilitating SSH access.
  12. -device virtio-net-pci,netdev=eth0:

    • Defines a VirtIO-based network device and associates it with the 'eth0' network device.


Unlocking the advanced concepts in QEMU empowers you to create and manage highly customizable virtual machines, tailored to your specific requirements. By understanding and manipulating these command-line options, you can harness the full potential of QEMU for your development, testing, or legacy system emulation projects. Experiment and explore, and see how QEMU can elevate your virtualization endeavors to new heights.

About me

I'm Tanmay Jaiswal, a Software Engineer at GeekyAnts. I'm passionate about coding, complex problem-solving, and open source. Let's connect and innovate in the world of software development. ๐Ÿš€

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