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Comment by daxfohl | Hacker News Reader

I thought QEMU was supposed to be quite inferior in performance to KVM (though more flexible). Is that not the case? The link in the article just directed to the QEMU homepage.

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KVM is the kernel virtualization module on Linux, QEMU handles the userland side support, all device emulation. The kvm binary on Linux is equivalent to running qemu-system-* with -enable-kvm. Newer versions of QEMU also support the '-accel kvm' argument but also adds other acceleration backends, such as '-accel tcg' (slower), '-accel haxm' (Intel/Windows), and finally '-accel hvf' for Apple's Hypervisor.Framework. This work here is extending that existing support from only Intel VT-x to also cover ARM Silicon, factoring out common code and API differences made by Apple.

By default, QEMU uses emulation which will be slow. Qemu can also use an "accelerator" such as KVM. See https://www.qemu.org/docs/master/system/invocation.html#hxto...

e.g. I can do this on my Raspberry Pi 4 running 64-bit Raspberry Pi OS.

  qemu-system-aarch64 \
      -M virt,accel=kvm -cpu host -m 2G -smp 2 -nographic \
      -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
      -cdrom alpine-virt-3.12.0-aarch64.iso

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