A macOS VM on an Apple silicon Mac

On an Apple silicon Mac, a VM runs arm64 macOS on QEMU's vmapple machine, under Hypervisor.framework, with its GPU on Metal. macOS installs from Apple's IPSW, the same restore image a Mac uses, through Virtualization.framework, which is the only thing that restores one. There's no OpenCore and nothing to set up in the guest.

You need reims-ctl installed with its installer, which signs it with the virtualization entitlement an IPSW install needs. reims-ctl doctor says whether it has it.

Create it from an IPSW

$ reims-ctl create mac --ipsw latest

latest asks Apple for the newest macOS this Mac supports and downloads it into ~/.local/share/reims-ctl/ipsw, where the next VM finds it. An interrupted download picks up where it stopped. The install itself took 3 min 17 s on an M3 Max:

zsh — M3 Max, macOS 27

$ reims-ctl create mac --ipsw latest
mac: asking Apple for the newest macOS this Mac supports
mac: using the IPSW downloaded before, ~/.local/share/reims-ctl/ipsw/UniversalMac_27.0.1_26A434_Restore.ipsw
mac: loading the IPSW
mac: creating the auxiliary storage
mac: installing macOS
mac: installing macOS: 0%
mac: installing macOS: 9%
mac: installing macOS: 16%
…
mac: installing macOS: 90%
mac: done
created mac in ~/.local/share/reims-ctl/vms/mac

Real output, with the IPSW already downloaded; … marks progress lines left out.

On a Mac running macOS 27, latest is macOS 27. The project has tested arm64 macOS 13, 14, 15 and 26 guests; for one of those, give --ipsw its IPSW file instead:

$ reims-ctl create tahoe --ipsw ~/Downloads/UniversalMac.ipsw

The new VM gets a 64G disk, half the Mac's cores (2 to 8) and half its memory (4 to 16 GiB), and one 1920×1080 display. Each of these is an option of create, or a setting you can change later:

$ reims-ctl create mac --ipsw latest --cpus 6 --memory 12G --disk-size 128G --borderless --resolution host

Or run reims-ctl, press n, fill in the form and press Ctrl-S: the same create, with each field explained as you reach it.

Or bring a VM you already have

A VM that macosvm or tart made is a Virtualization.framework VM, which vmapple boots as it is. --bundle imports its directory as an APFS clone, which takes no extra space until either copy changes:

$ reims-ctl create mac --bundle ~/VMs/macos13
$ reims-ctl create mac --bundle ~/VMs/macos13 --bundle-mode in-place  # use its files where they are

The VM keeps its machine identifier. If the bundle doesn't hold the identifier's ECID, give it with --ecid.

Start it

$ reims-ctl start mac

zsh — M3 Max, macOS 27

$ reims-ctl start macos-26
macos-26: running, pid 49388

A window opens for each display. A fresh install starts in Setup Assistant; a VM you imported starts where it left off. Click into the window to give the guest your keyboard and mouse, and press ⌃⌥⌘ to take them back. Running a VM covers the window, settings and everything after.

reims-ctl create … --start starts the VM as soon as it's made.

What a VM looks like

zsh — M3 Max, macOS 27

$ reims-ctl show macos-26
macos-26
  state         running (pid 49388)
  kind          arm64 macOS guest (vmapple, HVF)
  directory     ~/.local/share/reims-ctl/vms/macos-26
  cpus          4
  memory        8G
  disk          disk.img (raw)
  displays      1 x 1920x1080
  ecid          11400282047089759542
  audio         on
  network       user, mac 52:54:00:b7:2b:36
  logs          on (info)
  stop timeout  90 s

disk.img and aux.img are the files Virtualization.framework makes; the ECID is the machine identifier vmapple boots with.

Without reims-ctl

reims-ctl command mac prints the QEMU command a VM runs as a shell script, to run or change yourself. Working on the project itself, make vm VM=path/to/macosvm-vm boots a macosvm VM on the checkout's own QEMU build; the QEMU notes cover it.