macOS soak harness: pass --option sandbox relaxed like vmix build does

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XsESshRCoBoUVWV9qKURUF

cli.nix

@@ -1,5 +1,9 @@
-# vmix CLI — build, copy, and run Windows images
+# vmix CLI — build, copy, and run Windows / macOS images
-{ pkgs, self, system }:
+{ pkgs, self, system, vmixLib }:
+let
+  macosQemu = vmixLib.macos.qemu;
+  macserial = vmixLib.macos.macserial;
+in
 pkgs.writeShellScriptBin "vmix" ''
   set -euo pipefail
 
@@ -8,23 +12,34 @@ pkgs.writeShellScriptBin "vmix" ''
     echo "  vmix build --image <path> [--generalize key=val,...] [--out-link PATH]"
     echo "  vmix copy  --image <path> [--generalize key=val,...] --to-disk /dev/sdX"
     echo "  vmix copy  --image <path> [--generalize key=val,...] --to-remote-disk user@host:/dev/sdX"
-    echo "  vmix run   <qcow2-file> [--mem 4096] [--smp 4] [--ahci]"
+    echo "  vmix run   <qcow2-file> [--mem 4096] [--smp 4] [--ahci] [--macos] [--vnc :N] [--mac XX:..]"
+    echo "  vmix macserial [--model MacPro7,1]"
     echo ""
     echo "Commands:"
     echo "  build      Build a vmix image (optionally generalized)"
     echo "  copy       Build a vmix image and write it to a disk"
-    echo "  run     Boot a qcow2 image with QEMU (SDL if DISPLAY available)"
+    echo "  run        Boot a qcow2 image with QEMU (SDL if DISPLAY available, or --vnc)"
+    echo "  macserial  Generate a SMBIOS identity (serial, MLB, UUID, MAC) for --generalize"
     echo ""
     echo "Options:"
-    echo "  --image PATH              Image path in vmixLib (e.g. windows.images.win10.laptop)"
+    echo "  --image PATH              Image path in vmixLib (e.g. windows.images.win10.laptop,"
+    echo "                              macos.images.tahoe.basic)"
     echo "  --generalize KEY=VAL,...   Finalize image with comma-separated options:"
     echo "                              username=User  password=  hostname=PC"
-    echo "                              timezone=UTC   bgColor=8e8cd8"
+    echo "                              timezone=UTC   bgColor=8e8cd8 (Windows only)"
-    echo "                              delay-oobe-run=true  (OOBE + activation on real hardware)"
+    echo "                              delay-oobe-run=true  (OOBE/Setup Assistant on real hardware)"
+    echo "                              macOS SMBIOS: model=MacPro7,1 serial=... mlb=... uuid=... mac=... seed=..."
     echo "  --to-disk DEVICE          Write to local disk and expand partitions"
     echo "  --to-remote-disk SSH:DEV  Stream to remote disk via SSH and expand partitions"
     echo "                              e.g. root@10.10.10.100:/dev/sda"
     echo "  --ahci                    Use AHCI storage for vmix run (for laptop images)"
+    echo "  --macos                   macOS image for vmix run (OpenCore/VirtualSMC flags, AHCI)"
+    echo "  --applesmc                with --macos: add QEMU's isa-applesmc (images built before 2026-09-09)"
+    echo "  --share DIR               with --macos: virtio-fs share (first: /Volumes/My Shared Files); repeatable"
+    echo "  --home FILE               with --macos: persistent home volume (qcow2, created+formatted if missing)"
+    echo "  --qga PATH                with --macos: guest agent socket path (default /tmp/vmix-qga-<pid>.sock)"
+    echo "  --vnc DISPLAY             VNC instead of SDL for vmix run, e.g. :10 (port 5910) or 0.0.0.0:10"
+    echo "  --mac ADDR                NIC MAC for vmix run (macOS: read from the image's ESP by default)"
     echo "  -y, --yes                 Skip disk write confirmation"
     echo "  --out-link PATH           Symlink for the build result (default: ./result)"
     echo ""
@@ -32,9 +47,9 @@ pkgs.writeShellScriptBin "vmix" ''
     echo "  vmix build --image windows.images.win10.laptop \\"
     echo "       --generalize username=Sagar,password=secret,hostname=LAPTOP"
     echo ""
-    echo "  vmix copy --image windows.images.win10.laptop \\"
+    echo "  vmix build --image macos.images.tahoe.basic \\"
-    echo "       --generalize username=Sagar,password=secret,hostname=LAPTOP \\"
+    echo "       --generalize username=sagar,password=secret,hostname=MAC,timezone=Europe/Zurich"
-    echo "       --to-disk /dev/sda"
+    echo "  vmix run ./result --macos --vnc :10 --mem 8192"
     echo ""
     echo "  vmix copy --image windows.images.win10.laptop \\"
     echo "       --generalize username=Sagar,password=secret,hostname=LAPTOP \\"
@@ -49,23 +64,57 @@ pkgs.writeShellScriptBin "vmix" ''
   COMMAND="$1"; shift
 
   case "$COMMAND" in
-    build|copy|run) ;;
+    build|copy|run|macserial) ;;
     --help|-h)  usage ;;
     *)          echo "Unknown command: $COMMAND"; usage ;;
   esac
 
+  # --- macserial command ---
+  if [[ "$COMMAND" == "macserial" ]]; then
+    MODEL="MacPro7,1"
+    while [[ ''${#} -gt 0 ]]; do
+      case "$1" in
+        --model) MODEL="$2"; shift 2 ;;
+        *)       echo "Unknown option: $1"; exit 1 ;;
+      esac
+    done
+    LINE=$(${macserial}/bin/macserial --num 1 --model "$MODEL" 2>/dev/null | grep '|' | tail -1)
+    [[ -z "$LINE" ]] && { echo "Error: macserial produced nothing for model $MODEL"; exit 1; }
+    SERIAL=$(echo "$LINE" | awk -F' *\\| *' '{print $1}')
+    MLB=$(echo "$LINE" | awk -F' *\\| *' '{print $2}')
+    UUID=$(cat /proc/sys/kernel/random/uuid | tr a-f A-F)
+    MAC=$(printf '52:54:00:%02x:%02x:%02x' $((RANDOM % 256)) $((RANDOM % 256)) $((RANDOM % 256)))
+    echo "model=$MODEL,serial=$SERIAL,mlb=$MLB,uuid=$UUID,mac=$MAC"
+    exit 0
+  fi
+
   # --- run command ---
   if [[ "$COMMAND" == "run" ]]; then
-    [[ ''${#} -lt 1 ]] && { echo "Error: vmix run <qcow2-file> [--mem 4096] [--smp 4] [--ahci]"; exit 1; }
+    [[ ''${#} -lt 1 ]] && { echo "Error: vmix run <qcow2-file> [--mem 4096] [--smp 4] [--ahci] [--macos] [--vnc :N] [--mac XX:XX:XX:XX:XX:XX]"; exit 1; }
     RUN_INPUT="$1"; shift
     RUN_MEM=4096
     RUN_SMP=4
     RUN_AHCI=false
+    RUN_MACOS=false
+    RUN_VNC=""
+    RUN_MAC=""
+    RUN_SHARES=()
+    RUN_HOME=""
+    RUN_HOME_IMAGE="macos.images.tahoe.upstream"
+    RUN_QGA=""
     while [[ ''${#} -gt 0 ]]; do
       case "$1" in
         --mem)   RUN_MEM="$2"; shift 2 ;;
         --smp)   RUN_SMP="$2"; shift 2 ;;
         --ahci)  RUN_AHCI=true; shift ;;
+        --macos) RUN_MACOS=true; shift ;;
+        --applesmc) RUN_APPLESMC=true; shift ;;
+        --share) RUN_SHARES+=("$2"); shift 2 ;;
+        --home)  RUN_HOME="$2"; shift 2 ;;
+        --home-image) RUN_HOME_IMAGE="$2"; shift 2 ;;
+        --qga)   RUN_QGA="$2"; shift 2 ;;
+        --vnc)   RUN_VNC="$2"; shift 2 ;;
+        --mac)   RUN_MAC="$2"; shift 2 ;;
         *)       echo "Unknown option: $1"; exit 1 ;;
       esac
     done
@@ -74,7 +123,9 @@ pkgs.writeShellScriptBin "vmix" ''
     [[ ! -f "$RUN_IMAGE" ]] && { echo "Error: file not found: $RUN_IMAGE"; exit 1; }
 
     VMIX_DISPLAY="-nographic"
-    if [[ -n "''${DISPLAY:-}" ]]; then
+    if [[ -n "$RUN_VNC" ]]; then
+      VMIX_DISPLAY="-display none -vnc $RUN_VNC"
+    elif [[ -n "''${DISPLAY:-}" ]]; then
       VMIX_DISPLAY="-display sdl"
     fi
 
@@ -87,6 +138,64 @@ pkgs.writeShellScriptBin "vmix" ''
     echo "Memory:  $RUN_MEM MB"
     echo "CPUs:    $RUN_SMP"
     echo "Display: $VMIX_DISPLAY"
+
+    if [[ "$RUN_MACOS" == "true" ]]; then
+      # OpenCore's ROM must match en0's MAC: the image records it in its ESP
+      if [[ -z "$RUN_MAC" ]]; then
+        RUN_MAC=$(${pkgs.libguestfs-with-appliance}/bin/guestfish --ro -a "$RUN_IMAGE" -m /dev/sda1 cat /EFI/vmix/vmix.json 2>/dev/null \
+          | ${pkgs.jq}/bin/jq -r .mac 2>/dev/null || true)
+        [[ -z "$RUN_MAC" || "$RUN_MAC" == "null" ]] && { RUN_MAC="52:54:00:c9:18:27"; echo "Warning: could not read MAC from image ESP, using $RUN_MAC"; }
+      fi
+      echo "macOS:   yes (MAC $RUN_MAC)"
+      # Apple's built-in QEMU guest agent: guest-exec as root over this socket
+      [[ -z "$RUN_QGA" ]] && RUN_QGA="/tmp/vmix-qga-$$.sock"
+      rm -f "$RUN_QGA"
+      echo "Agent:   $RUN_QGA (guest-exec as root)"
+      # virtio-fs shares: the first one auto-mounts at /Volumes/My Shared Files, the
+      # others are mounted with: mount -t virtiofs <tag> /Volumes/<tag>
+      MACOS_SHARE_ARGS=""
+      MACOS_MEM_ARGS=""
+      i=0
+      for SHARE in "''${RUN_SHARES[@]}"; do
+        i=$((i + 1)); SOCK="/tmp/vmix-vfs-$$-$i.sock"; rm -f "$SOCK"
+        TAG=$([[ $i -eq 1 ]] && echo "${macosQemu.automountTag}" || echo "share$i")
+        ${pkgs.virtiofsd}/bin/virtiofsd --socket-path="$SOCK" --shared-dir "$SHARE" --cache auto --sandbox none >/dev/null 2>&1 &
+        for t in $(seq 1 50); do [[ -S "$SOCK" ]] && break; sleep 0.2; done
+        MACOS_SHARE_ARGS="$MACOS_SHARE_ARGS -chardev socket,id=vfs$i,path=$SOCK -device vhost-user-fs-pci,chardev=vfs$i,tag=$TAG"
+        MACOS_MEM_ARGS="-object memory-backend-memfd,id=vmix-mem,size=''${RUN_MEM}M,share=on -numa node,memdev=vmix-mem"
+        echo "Share:   $SHARE -> $([[ $i -eq 1 ]] && echo '/Volumes/My Shared Files' || echo "mount -t virtiofs $TAG ...")"
+      done
+      # persistent home volume (virtio-blk); created + formatted APFS by the PE if missing
+      MACOS_HOME_ARGS=""
+      if [[ -n "$RUN_HOME" ]]; then
+        if [[ ! -e "$RUN_HOME" ]]; then
+          echo "Home:    creating $RUN_HOME (64G qcow2) and formatting it as APFS 'vmix-home' via the PE of $RUN_HOME_IMAGE ..."
+          ${pkgs.qemu}/bin/qemu-img create -q -f qcow2 "$RUN_HOME" 64G
+          FMT=$(${pkgs.nix}/bin/nix build --no-link --print-out-paths --impure --expr "let l = (builtins.getFlake \"${self}\").lib.${system}; in l.macos.formatVolume { image = l.$RUN_HOME_IMAGE; }") || { echo "Error: could not build the formatter"; exit 1; }
+          "$FMT" "$RUN_HOME" qcow2 || exit 1
+        fi
+        HOME_FMT=$(${pkgs.qemu}/bin/qemu-img info --output=json "$RUN_HOME" | ${pkgs.jq}/bin/jq -r .format)
+        MACOS_HOME_ARGS="-drive id=home,if=none,format=$HOME_FMT,file=$RUN_HOME -device virtio-blk-pci,drive=home"
+        echo "Home:    $RUN_HOME (mounted at /Users by images generalized with persistHome)"
+      fi
+      echo ""
+      exec ${pkgs.qemu}/bin/qemu-system-x86_64 \
+        $MACOS_MEM_ARGS $MACOS_SHARE_ARGS $MACOS_HOME_ARGS \
+        -device virtio-serial-pci,id=vmix-vser -chardev socket,path="$RUN_QGA",server=on,wait=off,id=vmix-qga -device virtserialport,chardev=vmix-qga,name=org.qemu.guest_agent.0 \
+        $VMIX_DISPLAY \
+        ${macosQemu.deviceArgs} ${macosQemu.vgaArgs} \
+        $([[ "$RUN_APPLESMC" == true ]] && echo '-device isa-applesmc,osk="${macosQemu.osk}"') \
+        -accel kvm \
+        -machine type=q35 \
+        -cpu ${macosQemu.defaultCpu} \
+        -smp "$RUN_SMP",sockets=1,cores="$RUN_SMP",threads=1 \
+        -m "$RUN_MEM" \
+        -drive if=pflash,format=raw,readonly=on,file=${pkgs.OVMF.fd}/FV/OVMF_CODE.fd \
+        -drive if=pflash,format=raw,file=/tmp/vmix-run-vars-$$.fd \
+        -drive id=os,if=none,format=qcow2,file="$RUN_IMAGE",snapshot=on -device ide-hd,bus=sata.0,drive=os \
+        -netdev user,id=net0 -device virtio-net-pci,netdev=net0,mac="$RUN_MAC",bus=pcie.0,addr=${macosQemu.nicAddr}
+    fi
+
     echo "AHCI:    $RUN_AHCI"
     echo ""
 
@@ -106,7 +215,7 @@ pkgs.writeShellScriptBin "vmix" ''
       else
         echo "-drive file=$RUN_IMAGE,format=qcow2,if=virtio,snapshot=on"
       fi) \
-      -nic user,model=$(if [[ "$RUN_AHCI" == "true" ]]; then echo e1000; else echo virtio-net-pci; fi) \
+      -nic user,model=$(if [[ "$RUN_AHCI" == "true" ]]; then echo e1000; else echo virtio-net-pci; fi)$(if [[ -n "$RUN_MAC" ]]; then echo ",mac=$RUN_MAC"; fi) \
       -device virtio-serial-pci \
       -chardev spicevmc,id=vdagent,debug=0,name=vdagent \
       -device virtserialport,chardev=vdagent,name=com.redhat.spice.0
@@ -161,8 +270,16 @@ pkgs.writeShellScriptBin "vmix" ''
 
   FLAKE_DIR="${self}"
 
+  # OS type of the image (windows / macos / linux) decides the disk-writing steps
+  OS_TYPE=$(${pkgs.nix}/bin/nix eval --raw --impure --expr "
+    let
+      vmixLib = (builtins.getFlake \"$FLAKE_DIR\").lib.${system};
+      image = vmixLib.$IMAGE_NAME;
+    in image._vmixOsType or \"linux\"
+  " 2>/dev/null || echo linux)
+
   echo "=== vmix $COMMAND ==="
-  echo "Image:      $IMAGE_NAME"
+  echo "Image:      $IMAGE_NAME ($OS_TYPE)"
   [[ -n "$GENERALIZE" ]] && echo "Generalize: $GENERALIZE"
   [[ -n "$TO_DISK" ]] && echo "To disk:    $TO_DISK"
   [[ -n "$TO_REMOTE_DISK" ]] && echo "To remote:  $TO_REMOTE_DISK"
@@ -191,6 +308,10 @@ pkgs.writeShellScriptBin "vmix" ''
   IMAGE_FILE=$(readlink -f "$OUT_LINK")
   echo "Built: $IMAGE_FILE"
 
+  if [[ "$OS_TYPE" == "macos" ]]; then
+    echo "Run it with: vmix run $OUT_LINK --macos --vnc :10"
+  fi
+
   # --- write to local disk ---
   if [[ -n "$TO_DISK" ]]; then
     echo ""
@@ -224,6 +345,15 @@ pkgs.writeShellScriptBin "vmix" ''
 
     echo "[3/5] Fixing GPT backup header..."
     ${pkgs.gptfdisk}/bin/sgdisk -e "$TO_DISK"
+
+    if [[ "$OS_TYPE" == "macos" ]]; then
+      echo "[4/5] APFS container cannot be grown from Linux — skipped"
+      echo "[5/5] Grow it from macOS with: diskutil apfs resizeContainer disk0s2 0"
+      echo ""
+      echo "Done. $TO_DISK is ready to boot (OpenCore in the EFI partition; real Macs need no OpenCore)."
+      exit 0
+    fi
+
     # delete recovery partition if present, then resize Windows partition
     ${pkgs.gptfdisk}/bin/sgdisk -d 4 "$TO_DISK" 2>/dev/null || true
 
@@ -281,13 +411,22 @@ pkgs.writeShellScriptBin "vmix" ''
     kill $NBD_PID 2>/dev/null || true
     rm -f "$NBD_SOCK"
 
+    echo "[3/5] Fixing GPT backup header..."
+    if [[ "$OS_TYPE" == "macos" ]]; then
+      ssh "$REMOTE_HOST" "nix-shell -p gptfdisk --run 'sgdisk -e $REMOTE_DISK'"
+      echo "[4/5] APFS container cannot be grown from Linux — skipped"
+      echo "[5/5] Grow it from macOS with: diskutil apfs resizeContainer disk0s2 0"
+      echo ""
+      echo "Done. $REMOTE_HOST:$REMOTE_DISK is ready to boot."
+      exit 0
+    fi
+
     if [[ "$REMOTE_DISK" == *nvme* ]] || [[ "$REMOTE_DISK" == *mmcblk* ]]; then
       REMOTE_WIN_PART="''${REMOTE_DISK}p3"
     else
       REMOTE_WIN_PART="''${REMOTE_DISK}3"
     fi
 
-    echo "[3/5] Fixing GPT backup header..."
     ssh "$REMOTE_HOST" "nix-shell -p gptfdisk --run 'sgdisk -e $REMOTE_DISK && sgdisk -d 4 $REMOTE_DISK 2>/dev/null || true'"
 
     echo "[4/5] Expanding Windows partition (partition 3)..."

flake.nix

@@ -24,7 +24,7 @@
 
     lib.${system} = vmixLib;
 
-    packages.${system}.default = import ./cli.nix { inherit pkgs self system; };
+    packages.${system}.default = import ./cli.nix { inherit pkgs self system vmixLib; };
 
     apps.${system}.default = {
       type = "app";

lib/default.nix

@@ -4,6 +4,6 @@ let
   network = import ./network.nix { inherit pkgs lib; };
 in
 {
-  inherit (images) linux windows;
+  inherit (images) linux windows macos;
   inherit network;
 }

lib/images/default.nix

@@ -2,4 +2,5 @@
 {
   linux = (import ./linux) { inherit pkgs lib system; };
   windows = (import ./windows) { inherit pkgs lib system; };
+  macos = (import ./macos) { inherit pkgs lib system; };
 }

lib/images/macos/README.md

@@ -0,0 +1,177 @@
+# macOS images (Tahoe 26)
+
+Pre-installed, Apple-ID-capable macOS VM images built the same way as the
+Windows ones: `makeImage` (unattended install) → templates → `.generalize`
+(user, hostname, fresh SMBIOS identity). Runs on QEMU/KVM with OpenCore.
+
+```
+vmix build --image macos.images.tahoe.basic --generalize username=sagar,password=secret,hostname=MAC
+vmix run ./result --macos --vnc :10 --mem 8192
+```
+
+Nix: `macos.images.tahoe.{pe,upstream,basic,remote}` and
+`<image>.generalize { username; password; hostname; timezone; locale; seed; … }`.
+
+## How it works: the vmix "PE"
+
+Apple's Recovery (`BaseSystem.dmg`, a plain journaled HFS+ volume) with **one
+LaunchDaemon added** (`makeRecoveryPE`): at boot it mounts a `VMIX` volume and
+runs `run.sh` from it as root, records the exit status and powers off. That is
+the whole automation surface — the equivalent of Windows PE + Autounattend:
+
+* **no GUI is driven**: no OCR, no keystrokes, no screen layouts to learn per
+  macOS version; the hook is a launchd plist, stable across releases (same idea
+  as AutoNBI/Imagr NetBoot images).
+* **observable**: the guest prints `VMIX-*` markers to `/dev/console`, which the
+  build reads from QEMU's serial log (`boot-args serial=3 -v`). Kernel panics and
+  reboots show up there too. Screenshots are still taken for debugging.
+* **offline**: no NIC during the install, and the guest blackholes Apple's
+  install/verify endpoints so `startosinstall` never waits on the network. The
+  only inputs are the pinned `InstallAssistant.pkg` and `BaseSystem.dmg`.
+* **everything else happens offline from the PE too**: templates and generalize
+  mount the image's Data volume (rw) and System volume (ro) and edit them
+  (`dscl -f` for users, `plutil` for preferences) — the installed macOS is
+  never booted for customization, so nothing depends on launchd/BTM approval,
+  first-boot agents or auto-login inside the guest. One PE boot ≈ 30 s.
+
+### Pipeline
+
+1. `makeRecoveryPE` — BaseSystem.dmg → raw HFS+ image + `ch.vmix.pe` daemon.
+2. `makeImage` — QEMU with: OpenCore boot disk (build variant with serial
+   console), the PE, the empty target disk, the VMIX volume (`vmix-install.sh`,
+   installer app skeleton) and the whole `InstallAssistant.pkg` mapped as a raw
+   disk. The guest script erases the target as APFS, unpacks the app and `dd`s
+   the pkg into it as `SharedSupport.dmg` (it is a "pkgdmg": xar + koly footer;
+   the bare xar member fails with "pkgdmg is missing a footer"), then runs
+   `startosinstall`, which reboots itself through the install phases. The
+   installed system's first boot ends at the loginwindow: the driver detects the
+   bright screen and powers the VM down. OpenCore is then copied into the image's
+   own ESP so it boots with plain OVMF.
+3. `customizeImage` — boots the PE with the image attached (OpenCore
+   `ScanPolicy` restricted to HFS+ on SATA, so only the PE can boot) and runs the
+   template script with `$SYS`/`$DATA` mounted. `pe-lib.sh` has the helpers.
+4. `templates/generalize.nix` — user (dscl, admin, home from the user template),
+   auto-login (`kcpassword`), Setup Assistant suppression, hostname, locale,
+   timezone, keyboard type, container resize, fresh SMBIOS via a new OpenCore
+   ESP (`serial`/`mlb` from macserial, MAC + UUID from `seed`).
+
+### Recovery source
+
+`recovery.file` in `upstream.json` points at a content-addressed store path for
+the verified Tahoe `BaseSystem.dmg` (Apple's CDN load-balances Sequoia/Tahoe
+during the rollout, so a plain fetch is non-deterministic). Reproduce it on any
+host with `nix store add-path --name macos-tahoe-BaseSystem.dmg BaseSystem.dmg`.
+Drop `recovery.file` to fetch from Apple instead (`fetchRecovery` retries until
+the pinned hash matches).
+
+## Reliability
+
+Things QEMU does intermittently, and what handles each (all in `vm-driver.py`
+and `vmix-install.sh`; every event is logged with a reason):
+
+* `startosinstall` prepare stalls or crawls — the guest kills and retries it on a
+  freshly erased target (free-space watchdog + time cap).
+* the installer comes back to the PE instead of the install phase — the PE
+  counts boots and simply re-runs the install (max 3).
+* the installed system hangs at the Apple logo on first boot — a `system_reset`
+  is issued only when the screen is dark and frozen **and** disk and serial
+  console are idle, so a slow-but-working boot is never interrupted.
+* macOS `shutdown -h` halts to a black screen without an ACPI power-off — an
+  idle black screen counts as a completed halt.
+* a kernel panic (seen on the serial console) resets the VM.
+* a wedged run fails at the 4 h timeout instead of hanging.
+
+`tools/soak.sh <flake> macos.images.tahoe.upstream 3` rebuilds an image N
+times and tabulates outcome, duration, boots, resets, panics and retries.
+Measured 2026-09-09 on the build host (Ryzen 7 7840HS, ZFS), Tahoe 26.6.2,
+VirtualSMC-only, PE install — 3 of 3 builds completed:
+
+| run | minutes | kernel boots | prepare tries | panics (self-recovered) | reboot deaths |
+|-----|---------|--------------|---------------|-------------------------|---------------|
+| 1   | 30      | 8            | 1             | 2                       | 0             |
+| 2   | 26      | 7            | 1             | 1                       | 0             |
+| 3   | 26      | 7            | 1             | 1                       | 0             |
+
+What still happens: at roughly one in ten guest-initiated reboots the guest
+either panics (GPF in launchd/kernel_task context shortly after `MACH Reboot`
+or within the first 15 s of the next boot — tmpfs/APFS/zone corruption
+signatures, i.e. memory or register state, not one driver) or never comes back
+(dead after `IOPlatformHaltRestartAction`). XNU reboots itself after a panic;
+the driver resets a dead guest after 60 s, so builds complete. A device bisect
+(`tools`-style 10–30 PE reboots per variant: VMware SVGA vs std VGA, no HDA,
+EHCI input, 1 vCPU) showed the rate is independent of the emulated devices and
+of SMP; Haswell-noTSX does not boot Tahoe. Host: AMD Zen 4, kvm_amd, Intel
+Skylake-Client vCPU model — the FPU-context-switch panic points at XSAVE state
+handling on that combination. Not fixed; a `vmix run` VM that hangs on Restart
+must be reset from the host.
+
+## Debugging
+
+`/tmp/vmix-macos/<name>/` on the build host: `driver.log`, `serial.log`
+(kernel + `VMIX-*` markers), periodic PNG screenshots, `qmp.sock`.
+`vmix-run.log` / `system-install.log` from the VMIX volume are printed at the
+end of the build. Add `vncDisplay = ":10"` to watch.
+
+## QEMU profile
+
+`helpers/qemu.nix`: q35, `Skylake-Client` CPU spoof (works on AMD),
+AppleSMC with the OSK, XHCI keyboard/tablet, AHCI disks, VMware SVGA,
+virtio-net pinned to `PciRoot(0x0)/Pci(0x12,0x0)` so OpenCore marks it built-in
+(en0, required for Apple ID / iMessage). SMBIOS `MacPro7,1` with four DIMMs
+described (avoids the "Memory Modules Misconfigured" warning).
+
+OpenCore comes from OSX-KVM's proven ESP, with Lilu / VirtualSMC /
+WhateverGreen replaced by current releases (`upstream.json` → `opencore.kexts`):
+the versions OSX-KVM ships disable themselves on macOS 26, and without
+VirtualSMC the guest's restart path panics on QEMU's SMC stub
+(`SMCWDT smcWriteKey kSMCBadCommand`, nested panic after `MACH Reboot`).
+For the same reason QEMU's `isa-applesmc` is not used any more: its presence
+makes VirtualSMC step aside ("multiple devices present"); VirtualSMC carries
+the OSK itself. Images built before this change still need the stub:
+`vmix run --macos --applesmc`. RestrictEvents (`revpatch=memtab`) silences
+MacPro7,1's "Memory Modules Misconfigured" at login.
+
+## Guest agent, shares, persistent home, online templates
+
+macOS 13+ ships **Apple's own QEMU guest agent** (`/usr/libexec/AppleQEMUGuestAgent`,
+started by launchd when a virtio console port named `org.qemu.guest_agent.0`
+appears). It is Apple-signed, needs no approval, and offers `guest-exec` as
+root plus `guest-file-*`. vmix uses it everywhere an in-guest agent is needed:
+
+* `vmix run --macos` and the NixOS module attach it by default
+  (`/tmp/vmix-qga-<pid>.sock`, `/run/vmix/qga-<name>.sock`); talk to it with any
+  QGA client, e.g. `printf '{"execute":"guest-exec","arguments":{"path":"/usr/bin/id","capture-output":true}}\n' | socat - UNIX-CONNECT:<sock>`.
+* **online templates** (`bootScript`): `customizeImage` boots the image with the
+  agent, runs the script as root (network available, `as_user <cmd>` runs inside
+  the logged-in user's session), then shuts down through the agent.
+  `templates.software.script { name; script; }`,
+  `templates.software.homebrew { formulae; casks; }`,
+  `templates.profile.settings { hideWidgets; wallpaper; dockApps; dockAutohide;
+  darkMode; showHiddenFiles; }` (wallpaper via the pinned `desktoppr`; Apple
+  Events / `osascript` do not work headless — TCC automation consent).
+* **offline software templates** run in the PE: `templates.software.pkg { name;
+  src; }` (`installer -target`), `templates.software.app { name; src; }`.
+
+`AppleVirtIO.kext` (x86 Tahoe) drives virtio-fs, 9p, block, console, input,
+net, sound, balloon, vsock — QEMU's modern virtio-pci devices work as-is:
+
+* **shared folders**: virtio-fs (`virtiofsd` + `vhost-user-fs-pci`, shared
+  memory backend). The tag `com.apple.virtio-fs.automount` is mounted by macOS
+  itself at `/Volumes/My Shared Files`; further tags are mounted with
+  `mount -t virtiofs <tag> <dir>` — the module does that through the guest agent
+  for every `shares.<name>` beyond the first. `vmix run --macos --share DIR`.
+  (9p does not automount on macOS; the Linux `-virtfs` path is not used.)
+* **ephemeral OS disk + persistent home**: `generalize { persistHome = true; }`
+  gives the account its home directory on an APFS volume labelled `vmix-home`
+  (`NFSHomeDirectory = /Volumes/vmix-home/<user>`; macOS refuses mounts over
+  `/Users`, which is a firmlink). The host provides a virtio-blk disk
+  (`macos.homeDisk` in the module, `--home FILE` in the CLI: qcow2/raw file or
+  zvol) that `formatVolume` formats as APFS `vmix-home` by booting the PE for
+  ~35 s on first use; diskarbitrationd mounts it before login and loginwindow
+  creates the home directory there on first login. The OS disk can then run
+  with `snapshot=on` (`disks.os.persist = false`).
+* **SPICE**: `-vga vmware` (or `std`) is kept as the display device — macOS has
+  no QXL/virtio-gpu driver; USB redirection channels work as for other guests
+  (`spice.usbRedir`); there is no vdagent for macOS (no clipboard sharing).
+  virtio keyboard/tablet (`AppleVirtIOInput`) are available as
+  `qemu.virtioInputArgs` but the USB HID pair is the default.

lib/images/macos/default.nix

@@ -0,0 +1,46 @@
+{ pkgs, lib, system, ... }:
+let
+  upstream = (lib.importJSON ./upstream.json).${system};
+  macos = rec {
+    inherit upstream;
+    qemu = import ./helpers/qemu.nix { inherit pkgs lib; };
+    ident = import ./helpers/ident.nix { inherit lib; };
+    macserial = import ./helpers/macserial.nix { inherit pkgs upstream; };
+    fetchRecovery = import ./helpers/fetchRecovery.nix { inherit pkgs upstream; };
+    installerPayload = import ./helpers/installerPayload.nix { inherit pkgs lib; };
+    makeOpenCore = import ./helpers/makeOpenCore.nix { inherit pkgs lib upstream macserial qemu; };
+    makeBootDisk = import ./helpers/makeBootDisk.nix { inherit pkgs lib; };
+    makeRecoveryPE = import ./helpers/makeRecoveryPE.nix { inherit pkgs lib; };
+    makeVmixVolume = import ./helpers/makeVmixVolume.nix { inherit pkgs lib; };
+    installBootloader = import ./helpers/installBootloader.nix { inherit pkgs lib; };
+    vmixReadback = import ./helpers/vmix-readback.nix { inherit pkgs lib; };
+    vmDriver = ./helpers/vm-driver.py;
+    makeImage = import ./helpers/makeImage.nix {
+      inherit pkgs lib qemu ident installerPayload makeOpenCore makeBootDisk makeVmixVolume installBootloader vmixReadback vmDriver;
+    };
+    customizeImage = import ./helpers/customizeImage.nix {
+      inherit pkgs lib qemu ident makeVmixVolume makeOpenCore makeBootDisk installBootloader vmixReadback vmDriver;
+    };
+    customizeImageFold = builtins.foldl' customizeImage;
+    formatVolume = import ./helpers/formatVolume.nix { inherit pkgs lib qemu makeVmixVolume makeBootDisk vmDriver; };
+    templates = import ./templates { inherit pkgs lib; };
+  };
+
+  tahoe = import ./tahoe { inherit pkgs lib system macos; };
+
+  # Recursively add .generalize to every image leaf (same shape as windows)
+  addGeneralize = val:
+    if val ? _vmixOsType then
+      val // { generalize = args:
+        let
+          templateArgs = builtins.removeAttrs args [ "vncDisplay" ];
+          displayArgs = lib.optionalAttrs (args ? vncDisplay) { inherit (args) vncDisplay; };
+        in macos.customizeImage val (macos.templates.generalize templateArgs // displayArgs);
+      }
+    else if builtins.isAttrs val then
+      lib.mapAttrs (_: addGeneralize) val
+    else val;
+in
+macos // {
+  images = addGeneralize { inherit tahoe; };
+}

lib/images/macos/guest/ch.vmix.pe.plist

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>Label</key>
+	<string>ch.vmix.pe</string>
+	<key>ProgramArguments</key>
+	<array>
+		<string>/bin/bash</string>
+		<string>/usr/libexec/vmix/pe.sh</string>
+	</array>
+	<key>RunAtLoad</key>
+	<true/>
+	<key>StandardOutPath</key>
+	<string>/dev/console</string>
+	<key>StandardErrorPath</key>
+	<string>/dev/console</string>
+</dict>
+</plist>

lib/images/macos/guest/kcpassword.py

@@ -0,0 +1,11 @@
+#!/usr/bin/env python3
+# Encode a password as /etc/kcpassword (macOS auto-login). XOR with Apple's
+# fixed key, zero padded to a multiple of 12 so a key byte terminates it.
+import sys
+
+KEY = [0x7D, 0x89, 0x52, 0x23, 0xD2, 0xBC, 0xDD, 0xEA, 0xA3, 0xB9, 0x1F]
+
+pw = list(sys.argv[1].encode()) if len(sys.argv) > 1 else []
+pw += [0] * (12 - len(pw) % 12)
+out = bytes(b ^ KEY[i % len(KEY)] for i, b in enumerate(pw))
+sys.stdout.buffer.write(out)

lib/images/macos/guest/pe-lib.sh

@@ -0,0 +1,51 @@
+# vmix PE helpers, sourced by run.sh scripts running in the recovery.
+# Expects V=/Volumes/VMIX (set by pe.sh) and VOLUME_NAME from vmix.conf.
+V=${V:-/Volumes/VMIX}
+[ -f "$V/vmix.conf" ] && . "$V/vmix.conf"
+VOLUME_NAME=${VOLUME_NAME:-Macintosh HD}
+
+pe_log() { echo "VMIX: $*"; }
+pe_fail() { echo "VMIX-FAIL: $*"; exit 1; }
+
+# Mount the installed system's APFS volume group (System read-only, Data rw) and
+# export SYS / DATA mount points plus SYS_ID / DATA_ID device identifiers.
+pe_mount_target() {
+  local list; list=$(diskutil list)
+  DATA_ID=$(echo "$list" | awk -v n="APFS Volume $VOLUME_NAME - Data" 'index($0, n) {print $NF; exit}')
+  SYS_ID=$(echo "$list" | awk -v n="APFS Volume $VOLUME_NAME " '!/ - Data/ && index($0, n) {print $NF; exit}')
+  [ -n "$DATA_ID" ] && [ -n "$SYS_ID" ] || { pe_log "target volumes not found"; echo "$list"; return 1; }
+  diskutil mount "$SYS_ID" >/dev/null 2>&1 || true
+  diskutil mount "$DATA_ID" >/dev/null 2>&1 || true
+  SYS=$(diskutil info "$SYS_ID" | sed -n 's/^ *Mount Point: *//p')
+  DATA=$(diskutil info "$DATA_ID" | sed -n 's/^ *Mount Point: *//p')
+  [ -d "$DATA/private/var/db" ] || { pe_log "Data volume not mounted (SYS=[$SYS] DATA=[$DATA])"; return 1; }
+  pe_log "target mounted: SYS=[$SYS] DATA=[$DATA]"
+  export SYS DATA SYS_ID DATA_ID
+}
+
+pe_unmount_target() {
+  sync
+  diskutil unmount "$DATA_ID" >/dev/null 2>&1 || true
+  diskutil unmount "$SYS_ID" >/dev/null 2>&1 || true
+}
+
+# plist helpers on files of the (offline) target: create the file if missing.
+pe_plist_set() {   # FILE KEYPATH TYPE VALUE   (TYPE: string|bool|integer|float)
+  local f=$1 k=$2 t=$3 v=$4
+  [ -f "$f" ] || plutil -create xml1 "$f"
+  plutil -replace "$k" "-$t" "$v" "$f"
+}
+pe_plist_dict() {  # FILE KEYPATH — make sure a dictionary exists at KEYPATH
+  local f=$1 k=$2
+  [ -f "$f" ] || plutil -create xml1 "$f"
+  plutil -extract "$k" xml1 -o /dev/null "$f" >/dev/null 2>&1 || plutil -insert "$k" -dictionary "$f"
+}
+# launchd service override on the target (disabled.plist): pe_service LABEL true|false
+pe_service_disabled() {
+  local f="$DATA/private/var/db/com.apple.xpc.launchd/disabled.plist"
+  mkdir -p "$(dirname "$f")"
+  pe_plist_set "$f" "$1" bool "$2"
+}
+# version of the installed system
+pe_target_version() { plutil -extract ProductVersion raw -o - "$SYS/System/Library/CoreServices/SystemVersion.plist" 2>/dev/null; }
+pe_target_build()   { plutil -extract ProductBuildVersion raw -o - "$SYS/System/Library/CoreServices/SystemVersion.plist" 2>/dev/null; }

lib/images/macos/guest/pe.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+# vmix PE hook. Runs as root from launchd when the patched Recovery boots
+# (injected by makeRecoveryPE). If a VMIX volume is attached it runs
+# /Volumes/VMIX/run.sh, records the exit status on the volume and powers off;
+# without one it does nothing and the recovery behaves normally.
+# Everything printed here goes to /dev/console, i.e. the host's serial log.
+exec >/dev/console 2>&1
+echo "VMIX-PE: hook started $(date) uid=$(id -u)"
+V=/Volumes/VMIX
+i=0
+while [ ! -f "$V/run.sh" ] && [ $i -lt 90 ]; do
+  diskutil mount VMIX >/dev/null 2>&1
+  sleep 2; i=$((i + 1))
+done
+if [ ! -f "$V/run.sh" ]; then
+  echo "VMIX-PE: no VMIX volume, leaving the recovery alone"
+  exit 0
+fi
+echo "VMIX-PE: VMIX mounted after $i retries"
+caffeinate -dimsu -t 86400 >/dev/null 2>&1 &
+[ -f "$V/vmix.conf" ] && . "$V/vmix.conf"
+# certificate checks need a sane clock; a fresh VM RTC can be off
+[ -n "${BUILD_DATE:-}" ] && date -u "$BUILD_DATE" >/dev/null 2>&1 && echo "VMIX-PE: clock set to $(date -u)"
+export V
+cd "$V"
+echo "VMIX-PE: running run.sh"
+/bin/bash "$V/run.sh" 2>&1 | tee "$V/vmix-run.log"
+rc=${PIPESTATUS[0]}
+echo "$rc" > "$V/vmix-run.status"
+echo "VMIX-PE: run.sh exited $rc"
+if [ -f "$V/vmix-reboot" ]; then
+  rm -f "$V/vmix-reboot"; sync
+  echo "VMIX-PE: rebooting as requested"
+  reboot
+  exit 0
+fi
+sync; sleep 1
+diskutil unmount force "$V" >/dev/null 2>&1
+echo "VMIX-PE-DONE rc=$rc"
+shutdown -h now

lib/images/macos/guest/vmix-install.sh

@@ -0,0 +1,100 @@
+#!/bin/bash
+# vmix unattended macOS install, run by the PE hook (pe.sh) as root in the
+# Recovery with /Volumes/VMIX mounted (V). Needs vmix.conf: TARGET_BYTES,
+# PKG_BYTES, PKG_DISK_BYTES, APP_NAME, VOLUME_NAME.
+#  1. find the target disk and the SharedSupport (InstallAssistant.pkg) disk by size
+#  2. erase the target as APFS, unpack the installer app, dd the whole pkg into it
+#     as SharedSupport.dmg (a "pkgdmg", startosinstall checks its koly footer)
+#  3. startosinstall prepares, then reboots itself into the install phase; the
+#     installed system's first boot ends at the loginwindow (the host powers off)
+# Never returns on success; a return means failure (the PE records the status).
+set -x
+. "$V/pe-lib.sh"
+fail() {
+  echo "VMIX-FAIL: $*"
+  cp /var/log/install.log "$V/system-install.log" 2>/dev/null
+  sync
+  exit 1
+}
+# each boot into the PE with the install still pending is one attempt
+ATTEMPT=$(( $(cat "$V/install.attempt" 2>/dev/null || echo 0) + 1 ))
+echo "$ATTEMPT" > "$V/install.attempt"; sync
+echo "VMIX-INSTALL: attempt $ATTEMPT (boot into the PE)"
+[ "$ATTEMPT" -le 3 ] || fail "the installer keeps coming back to the PE ($ATTEMPT boots)"
+
+# --- 1. disks by exact size
+disk_by_size() {
+  for d in $(diskutil list | grep -oE '^/dev/disk[0-9]+' | sort -u); do
+    if [ "$(diskutil info "$d" | sed -n 's/.*Disk Size:.*(\([0-9]*\) Bytes).*/\1/p')" = "$1" ]; then
+      echo "${d#/dev/}"; return 0
+    fi
+  done
+  return 1
+}
+TARGET=$(disk_by_size "$TARGET_BYTES") || fail "target disk of $TARGET_BYTES bytes not found"
+SSDISK=$(disk_by_size "$PKG_DISK_BYTES") || fail "SharedSupport disk of $PKG_DISK_BYTES bytes not found"
+echo "VMIX-INSTALL: target=$TARGET sharedsupport=$SSDISK"
+
+# --- 2. target volume + installer app (the pkg payload skeleton + SharedSupport.dmg)
+VOL="/Volumes/$VOLUME_NAME"
+APP="$VOL/$APP_NAME"
+SS="$APP/Contents/SharedSupport/SharedSupport.dmg"
+prepare_target() {
+  diskutil eraseDisk APFS "$VOLUME_NAME" GPT "$TARGET" || fail "eraseDisk"
+  [ -d "$VOL" ] || fail "$VOL not mounted after erase"
+  tar -xf "$V/installer-app.tar" -C "$VOL" || fail "untar installer app"
+  [ -x "$APP/Contents/Resources/startosinstall" ] || fail "startosinstall missing from $APP"
+  mkdir -p "$APP/Contents/SharedSupport"
+  FULL=$(( PKG_BYTES / 1048576 )); REM=$(( PKG_BYTES % 1048576 ))
+  echo "VMIX-INSTALL: copying SharedSupport.dmg ($PKG_BYTES bytes) from /dev/r$SSDISK"
+  dd if="/dev/r$SSDISK" of="$SS" bs=1048576 count=$FULL || fail "dd SharedSupport"
+  [ "$REM" -gt 0 ] && { dd if="/dev/r$SSDISK" bs=1048576 skip=$FULL count=1 | dd bs=1 count=$REM >> "$SS"; } || true
+  [ "$(stat -f %z "$SS")" = "$PKG_BYTES" ] || fail "SharedSupport.dmg size $(stat -f %z "$SS") != $PKG_BYTES"
+  tail -c 512 "$SS" | grep -qa koly || fail "SharedSupport.dmg has no koly footer"
+  chflags -h norestricted "$SS" 2>/dev/null || true
+  sync
+}
+prepare_target
+SOI="$APP/Contents/Resources/startosinstall"
+echo "VMIX-INSTALL: app ready, clock $(date -u)"
+
+# Offline install: no NIC is attached. Blackhole Apple's install/verify endpoints
+# too, so osinstallersetupd's requests fail immediately instead of timing out.
+for d in swscan.apple.com swcdn.apple.com swdist.apple.com swquery.apple.com \
+         gs.apple.com gsa.apple.com gdmf.apple.com mesu.apple.com xp.apple.com \
+         albert.apple.com captive.apple.com deviceservices-external.apple.com \
+         identity.apple.com ppq.apple.com crl.apple.com ocsp.apple.com \
+         ocsp2.apple.com valid.apple.com; do
+  echo "127.0.0.1 $d" >> /etc/hosts
+done
+
+# --- 3. startosinstall prepares (~5 min) then reboots the machine itself into the
+# install phase; it never returns on success. Prepare is intermittently slow in
+# QEMU, so an attempt that stalls or runs too long is killed and retried on a
+# freshly erased target.
+run_soi() { "$SOI" --volume "$VOL" --agreetolicense --nointeraction --rebootdelay 5 "$@"; }
+free_kb() { df -k "$VOL" 2>/dev/null | awk 'NR==2 {print $4}'; }
+try=0
+while [ "$try" -lt 6 ]; do
+  try=$((try + 1))
+  [ "$try" -gt 1 ] && prepare_target
+  echo "VMIX-INSTALL: startosinstall try $try"
+  run_soi 2>&1 &
+  SOI_PID=$!
+  last=$(free_kb); stalled=0; elapsed=0
+  while kill -0 "$SOI_PID" 2>/dev/null; do
+    sleep 30; elapsed=$((elapsed + 30))
+    now=$(free_kb)
+    if [ "$now" = "$last" ]; then stalled=$((stalled + 30)); else stalled=0; last=$now; fi
+    [ $((elapsed % 120)) -eq 0 ] && echo "VMIX-INSTALL: prepare running ${elapsed}s (stalled ${stalled}s)"
+    if [ "$stalled" -ge 240 ] || [ "$elapsed" -ge 600 ]; then
+      echo "VMIX-INSTALL: prepare too slow (stalled=${stalled}s elapsed=${elapsed}s), killing to retry"
+      kill -9 "$SOI_PID" 2>/dev/null; pkill -9 -f startosinstall 2>/dev/null
+      break
+    fi
+  done
+  wait "$SOI_PID" 2>/dev/null
+  echo "VMIX-INSTALL: startosinstall try $try ended without rebooting"
+  sleep 3
+done
+fail "startosinstall did not complete after $try tries"

lib/images/macos/helpers/customizeImage.nix

@@ -0,0 +1,176 @@
+# Customize a macOS image offline from the vmix PE: the recovery boots with the
+# image and a VMIX volume attached, its hook runs `script` as root with the
+# image's System (read-only) and Data (rw) volumes mounted at $SYS / $DATA, then
+# powers off. The installed macOS itself is never booted, so nothing depends on
+# launchd/BTM approval inside the guest. Counterpart of the Windows
+# registry/audit flow. Optionally re-installs OpenCore with a new SMBIOS
+# identity (`smbios`).
+#
+# Templates provide:
+#   script      — sh script run as root in the PE (pe-lib.sh helpers available)
+#   bootScript  — sh script run as root on the BOOTED image through Apple's QEMU
+#                 guest agent (network, user session available; run after `script`)
+#   files       — [{ source; name; }] extra files placed next to it on /Volumes/VMIX
+#   smbios      — { model? serial? mlb? uuid? mac? seed? } → fresh OpenCore config in the ESP
+#   network     — attach a user-mode NIC for bootScript (default true)
+{ pkgs, lib, qemu, ident, makeVmixVolume, makeOpenCore, makeBootDisk, installBootloader, vmixReadback, vmDriver, ... }:
+originalImage: {
+  name ? "",
+  script ? "",
+  bootScript ? "",
+  network ? true,
+  files ? [],
+  smbios ? null,
+  diskSize ? "",
+  impure ? true,
+  vncDisplay ? null,
+  smp ? 4,
+  memSize ? 4096,
+  cpu ? qemu.defaultCpu,
+  timeout ? 1800,
+  machineArgs ? null,   # override qemu.machineArgs (device experiments)
+}:
+let
+  originalImageName = lib.strings.removeSuffix "-vmix" (lib.strings.removeSuffix ".qcow2" originalImage.name);
+  customImageName = (if name != "" then name else "custom") + "-${originalImageName}-vmix.qcow2";
+  resultImg = "./disk.qcow2";
+  hasScript = script != "";
+  hasBootScript = bootScript != "";
+  hasSmbios = smbios != null;
+  pe = originalImage.pe or (throw "vmix: image ${originalImage.name} carries no PE (built by an older makeImage?)");
+  volumeName = originalImage.volumeName or "Macintosh HD";
+
+  model = originalImage.model or "MacPro7,1";
+  seed = if hasSmbios && (smbios.seed or null) != null then smbios.seed else null;
+  mac = if !hasSmbios then originalImage.macAddress
+        else if (smbios.mac or null) != null then smbios.mac
+        else if seed != null then ident.macFromSeed seed
+        else originalImage.macAddress;
+  uuid = if !hasSmbios then null
+         else if (smbios.uuid or null) != null then smbios.uuid
+         else if seed != null then ident.uuidFromSeed seed
+         else originalImage.opencore.uuid;
+  esp = if hasSmbios
+    then makeOpenCore ({
+        name = "${name}-${originalImageName}-opencore";
+        model = smbios.model or model;
+        inherit mac uuid;
+      } // builtins.removeAttrs smbios [ "seed" "mac" "uuid" "model" ])
+    else originalImage.opencore;
+  # PE boot disk: serial console, and an OpenCore ScanPolicy that only allows
+  # HFS+ volumes on SATA (= the PE), so the image's own macOS is never booted.
+  # 0x10203 = FILE_SYSTEM_LOCK | DEVICE_LOCK | ALLOW_FS_HFS | ALLOW_DEVICE_SATA
+  bootDisk = makeBootDisk {
+    name = "${name}-${originalImageName}-pe";
+    esp = originalImage.opencore;
+    bootArgs = "keepsyms=1 serial=3 -v";
+    scanPolicy = 66051;
+  };
+
+  runScript = pkgs.writeText "${name}-run.sh" ''
+    #!/bin/bash
+    . /Volumes/VMIX/pe-lib.sh
+    echo "=== vmix: ${name} ==="
+    pe_mount_target || pe_fail "could not mount the target volumes"
+    ${script}
+    pe_unmount_target
+  '';
+  vmixVol = makeVmixVolume {
+    name = "${name}-${originalImageName}";
+    files = [
+      { source = runScript; name = "run.sh"; }
+      { source = ../guest/pe-lib.sh; name = "pe-lib.sh"; }
+    ] ++ files;
+  };
+  bootRunScript = pkgs.writeText "${name}-boot.sh" ''
+    #!/bin/bash
+    # runs as root on the booted system (guest-exec); VMIX is mounted at $V
+    V=/Volumes/VMIX
+    echo "=== vmix (online): ${name} ==="
+    CONSOLE_USER=$(stat -f %Su /dev/console 2>/dev/null)
+    CONSOLE_UID=$(id -u "$CONSOLE_USER" 2>/dev/null)
+    export V CONSOLE_USER CONSOLE_UID
+    # run something inside the logged-in user's GUI session
+    as_user() { launchctl asuser "$CONSOLE_UID" sudo -u "$CONSOLE_USER" "$@"; }
+    ${bootScript}
+  '';
+  bootVol = makeVmixVolume {
+    name = "${name}-${originalImageName}-boot";
+    files = [ { source = bootRunScript; name = "run.sh"; } ] ++ files;
+  };
+  driverPython = pkgs.python3.withPackages (p: [ p.pillow ]);
+
+  bootCommands = lib.optionalString hasScript ''
+    cp ${vmixVol} vmix.img
+    chmod +w vmix.img
+    cat > vmix.conf <<CONF
+    VOLUME_NAME="${volumeName}"
+    BUILD_DATE="$(date -u +%m%d%H%M%Y.%S)"
+    CONF
+    guestfish -a vmix.img -m /dev/sda1 upload vmix.conf /vmix.conf
+    qemu-img create -q -f qcow2 -F raw -b ${pe} pe.qcow2
+    qemu-img create -q -f qcow2 -F raw -b ${bootDisk}/boot.img ocboot.qcow2
+    cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars.fd
+    chmod +w vars.fd
+    VMIX_DISPLAY="-display none"
+    ${lib.optionalString (vncDisplay != null) ''VMIX_DISPLAY="-display none -vnc ${vncDisplay}"''}
+
+    echo "=== vmix: running ${name} in the PE against ${originalImageName} ==="
+    python3 ${vmDriver} --mode pe --name "${name}-${originalImageName}" --timeout ${toString timeout} \
+      --serial-log serial.log --progress-file ${resultImg} -- \
+      qemu-system-x86_64 $VMIX_DISPLAY \
+      ${if machineArgs != null then machineArgs else qemu.machineArgs { inherit cpu smp memSize; }} \
+      ${qemu.firmwareArgs "vars.fd"} \
+      ${qemu.serialArgs "serial.log"} \
+      ${qemu.sataDrive { id = "opencore"; port = 0; file = "ocboot.qcow2"; }} \
+      ${qemu.sataDrive { id = "pe"; port = 1; file = "pe.qcow2"; }} \
+      ${qemu.sataDrive { id = "system"; port = 2; file = resultImg; }} \
+      ${qemu.sataDrive { id = "vmix"; port = 3; file = "vmix.img"; format = "raw"; }} \
+      || { echo "vmix: PE failed during ${name} (see /tmp/vmix-macos/${name}-${originalImageName})"; exit 1; }
+
+    ${vmixReadback "vmix.img"}
+    [ "$STATUS" = "0" ] || { echo "vmix: ${name} script failed (status '$STATUS')"; exit 1; }
+    echo "=== vmix: ${name} complete ==="
+  '';
+
+  onlineCommands = lib.optionalString hasBootScript ''
+    cp ${bootVol} vmix-boot.img
+    chmod +w vmix-boot.img
+    cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars-boot.fd
+    chmod +w vars-boot.fd
+    VMIX_DISPLAY="-display none"
+    ${lib.optionalString (vncDisplay != null) ''VMIX_DISPLAY="-display none -vnc ${vncDisplay}"''}
+    QGA_SOCK=$(mktemp -u /tmp/vmix-qga-XXXXXX.sock)
+
+    echo "=== vmix: booting ${originalImageName} for ${name} (guest agent) ==="
+    python3 ${vmDriver} --mode qga --name "${name}-${originalImageName}-online" --timeout ${toString timeout} \
+      --serial-log serial-boot.log --qga-sock "$QGA_SOCK" \
+      --qga-command 'for i in $(seq 1 30); do diskutil mount VMIX >/dev/null 2>&1; [ -f /Volumes/VMIX/run.sh ] && break; sleep 2; done; [ -f /Volumes/VMIX/run.sh ] || { echo "no VMIX volume"; exit 9; }; bash /Volumes/VMIX/run.sh > /Volumes/VMIX/vmix-run.log 2>&1; rc=$?; echo $rc > /Volumes/VMIX/vmix-run.status; sync; cat /Volumes/VMIX/vmix-run.log; diskutil unmount force /Volumes/VMIX >/dev/null 2>&1; exit $rc' -- \
+      qemu-system-x86_64 $VMIX_DISPLAY \
+      ${if machineArgs != null then machineArgs else qemu.machineArgs { inherit cpu smp memSize; }} \
+      ${qemu.firmwareArgs "vars-boot.fd"} \
+      ${qemu.serialArgs "serial-boot.log"} \
+      ${qemu.guestAgentArgs "$QGA_SOCK"} \
+      ${qemu.sataDrive { id = "system"; port = 0; file = resultImg; }} \
+      ${qemu.sataDrive { id = "vmix"; port = 1; file = "vmix-boot.img"; format = "raw"; }} \
+      ${lib.optionalString network (qemu.netArgs { mac = originalImage.macAddress; })} \
+      || { echo "vmix: online step failed during ${name} (see /tmp/vmix-macos/${name}-${originalImageName}-online)"; exit 1; }
+    rm -f "$QGA_SOCK"
+    ${vmixReadback "vmix-boot.img"}
+    [ "$STATUS" = "0" ] || { echo "vmix: ${name} bootScript failed (status '$STATUS')"; exit 1; }
+    echo "=== vmix: ${name} (online) complete ==="
+  '';
+
+  builtImage = pkgs.runCommand customImageName ({
+    nativeBuildInputs = with pkgs; [ pkgs.qemu driverPython libguestfs-with-appliance ];
+    requiredSystemFeatures = [ "kvm" ];
+  } // lib.optionalAttrs impure { __noChroot = true; }) ''
+    qemu-img create -q -f qcow2 -b ${originalImage} -F qcow2 ${resultImg}
+    [ -n "${diskSize}" ] && qemu-img resize ${resultImg} ${diskSize}
+    ${bootCommands}
+    ${onlineCommands}
+    ${lib.optionalString hasSmbios (installBootloader { inherit esp; image = resultImg; })}
+    mv ${resultImg} $out
+  '';
+in
+  builtImage // { _vmixOsType = "macos"; macAddress = mac; opencore = esp; model = esp.model or model; inherit pe volumeName; }

lib/images/macos/helpers/fetchRecovery.nix

@@ -0,0 +1,40 @@
+# macOS Recovery BaseSystem.dmg from Apple's recovery servers (osrecovery.apple.com)
+# via OSX-KVM's fetch-macOS-v2.py. The server has no stable URL (session-based) and,
+# during a macOS rollout, "latest" is load-balanced across CDN nodes serving DIFFERENT
+# builds (e.g. Sequoia and Tahoe at once). So the download is non-deterministic: the
+# builder retries until it gets the exact build pinned by sha256. The recovery MUST
+# match the installer's major version or startosinstall rejects it as "damaged".
+# When Apple retires this build, update recovery.sha256 (download once, check
+# /System/Library/CoreServices/SystemVersion.plist reports the wanted version).
+{ pkgs, upstream, ... }:
+{ shortname, sha256 }:
+let
+  script = pkgs.fetchurl { inherit (upstream.opencore.fetchRecoveryScript) url sha256; };
+in
+pkgs.runCommand "macos-${shortname}-BaseSystem.dmg" {
+  nativeBuildInputs = [ pkgs.python3 pkgs.coreutils ];
+  outputHashMode = "flat";
+  outputHashAlgo = "sha256";
+  outputHash = sha256;
+  SSL_CERT_FILE = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
+  expected = sha256;
+} ''
+  cp ${script} fetch-macOS-v2.py
+  sed -i 's/os.get_terminal_size().columns/80/' fetch-macOS-v2.py
+  want=$(nix-hash --type sha256 --to-base16 "$expected" 2>/dev/null || echo "$expected")
+  for attempt in $(seq 1 40); do
+    rm -f BaseSystem.dmg BaseSystem.chunklist
+    echo "=== vmix: fetching ${shortname} recovery (attempt $attempt) ==="
+    python3 fetch-macOS-v2.py --action download -s ${shortname} -o . -n BaseSystem || true
+    if [ -f BaseSystem.dmg ]; then
+      got=$(sha256sum BaseSystem.dmg | cut -d' ' -f1)
+      echo "got $got (want $want)"
+      [ "$got" = "$want" ] && { mv BaseSystem.dmg $out; exit 0; }
+      echo "=== vmix: wrong build (Apple is rotating builds during rollout), retrying ==="
+    fi
+    sleep 5
+  done
+  echo "vmix: could not fetch the pinned ${shortname} recovery after 40 attempts."
+  echo "Apple may have retired build $want; download it manually and update recovery.sha256."
+  exit 1
+''

lib/images/macos/helpers/formatVolume.nix

@@ -0,0 +1,56 @@
+# Host-side script that formats a blank disk image as an APFS volume with a
+# given label by booting the image's PE headless for ~30 s (Linux cannot write
+# APFS). Used for the persistent home volume (`generalize { persistHome = true; }`
+# mounts LABEL=<label> at /Users) by the NixOS module and `vmix run --home`.
+#   ${formatVolume { inherit image; label = "vmix-home"; }} <disk-file> <raw|qcow2>
+# The disk is found inside the PE as the only one without a partition table.
+{ pkgs, lib, qemu, makeVmixVolume, makeBootDisk, vmDriver, ... }:
+{ image, label ? "vmix-home", memSize ? 4096 }:
+let
+  pe = image.pe or (throw "vmix: image ${image.name} carries no PE");
+  bootDisk = makeBootDisk { name = "${label}-format"; esp = image.opencore; bootArgs = "keepsyms=1 serial=3"; scanPolicy = 66051; };
+  runScript = pkgs.writeText "format-${label}.sh" ''
+    . /Volumes/VMIX/pe-lib.sh
+    LIST=$(diskutil list)
+    # idempotent: a run.sh re-run (e.g. after a guest reboot) finds the volume done
+    if echo "$LIST" | grep -q "APFS Volume ${label} "; then echo "vmix: volume '${label}' already exists"; exit 0; fi
+    # blank disk: a whole-disk line followed by no partition entries
+    TARGET=$(echo "$LIST" | awk '/^\/dev\/disk[0-9]+ / {d=$1; n=0; next} /^ +[0-9]+:/ {n++} /^$/ {if (d != "" && n <= 1) print d; d=""} END {if (d != "" && n <= 1) print d}' | grep -vE "synthesized" | head -1)
+    [ -n "$TARGET" ] || { echo "$LIST"; pe_fail "no blank disk found"; }
+    echo "vmix: formatting $TARGET as APFS '${label}'"
+    diskutil eraseDisk APFS "${label}" GPT "$TARGET" || pe_fail "eraseDisk $TARGET"
+    diskutil unmount "/Volumes/${label}" >/dev/null 2>&1 || true
+  '';
+  vmixVol = makeVmixVolume {
+    name = "format-${label}";
+    files = [ { source = runScript; name = "run.sh"; } { source = ../guest/pe-lib.sh; name = "pe-lib.sh"; } ];
+  };
+  driverPython = pkgs.python3.withPackages (p: [ p.pillow ]);
+in
+pkgs.writeShellScript "vmix-format-${label}" ''
+  set -eu
+  DISK="$1"; FMT="''${2:-qcow2}"
+  T=$(mktemp -d /tmp/vmix-format-XXXXXX)
+  cleanup() { if [ "''${OK:-0}" = 1 ]; then rm -rf "$T"; else echo "vmix: logs kept in $T"; fi; }
+  trap cleanup EXIT
+  cp ${vmixVol} "$T/vmix.img"; chmod +w "$T/vmix.img"
+  ${pkgs.qemu}/bin/qemu-img create -q -f qcow2 -F raw -b ${pe} "$T/pe.qcow2"
+  ${pkgs.qemu}/bin/qemu-img create -q -f qcow2 -F raw -b ${bootDisk}/boot.img "$T/ocboot.qcow2"
+  cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd "$T/vars.fd"; chmod +w "$T/vars.fd"
+  echo "vmix: formatting $DISK as APFS '${label}' (PE boot)"
+  ${driverPython}/bin/python3 ${vmDriver} --mode pe --name "format-${label}" --debug-dir "$T/debug" --timeout 600 \
+    --serial-log "$T/serial.log" -- \
+    ${pkgs.qemu}/bin/qemu-system-x86_64 -display none \
+    ${qemu.machineArgs { smp = 2; inherit memSize; }} \
+    ${qemu.firmwareArgs "$T/vars.fd"} \
+    ${qemu.serialArgs "$T/serial.log"} \
+    ${qemu.sataDrive { id = "opencore"; port = 0; file = "$T/ocboot.qcow2"; }} \
+    ${qemu.sataDrive { id = "pe"; port = 1; file = "$T/pe.qcow2"; }} \
+    ${qemu.sataDrive { id = "vmix"; port = 2; file = "$T/vmix.img"; format = "raw"; }} \
+    ${qemu.virtioBlkArgs { id = "target"; file = "$DISK"; format = "$FMT"; }} \
+    >/dev/null
+  STATUS=$(${pkgs.libguestfs-with-appliance}/bin/guestfish --ro -a "$T/vmix.img" -m /dev/sda1 cat /vmix-run.status 2>/dev/null | tr -d '[:space:]' || true)
+  [ "$STATUS" = "0" ] || { echo "vmix: formatting failed (status '$STATUS')"; ${pkgs.libguestfs-with-appliance}/bin/guestfish --ro -a "$T/vmix.img" -m /dev/sda1 cat /vmix-run.log 2>/dev/null | tail -20; exit 1; }
+  OK=1
+  echo "vmix: $DISK formatted"
+''

lib/images/macos/helpers/ident.nix

@@ -0,0 +1,17 @@
+# Deterministic per-image identity derived from a seed string, so the NixOS
+# module and the CLI know the NIC MAC at evaluation time (OpenCore's ROM must
+# match the MAC of en0 for Apple ID / iMessage).
+{ lib, ... }:
+rec {
+  hash = seed: builtins.hashString "sha256" seed;
+
+  # locally administered QEMU-style MAC
+  macFromSeed = seed:
+    let h = hash "${seed}-mac"; s = i: builtins.substring i 2 h;
+    in "52:54:00:${s 0}:${s 2}:${s 4}";
+
+  # RFC 4122 v4 layout
+  uuidFromSeed = seed:
+    let h = hash "${seed}-uuid"; s = a: b: builtins.substring a b h;
+    in lib.toUpper "${s 0 8}-${s 8 4}-4${s 13 3}-8${s 17 3}-${s 20 12}";
+}

lib/images/macos/helpers/installBootloader.nix

@@ -0,0 +1,17 @@
+# Shell snippet: copy an OpenCore ESP (makeOpenCore output) into the EFI System
+# Partition of a macOS qcow2 so the image boots standalone with plain OVMF.
+# libguestfs follows qcow2 backing chains and writes into the top overlay.
+{ pkgs, lib, ... }:
+{ esp, image }:
+''
+  echo "=== vmix: installing OpenCore into the ESP of ${image} ==="
+  ESP_DEV=$(guestfish --ro -a ${image} run : list-filesystems | awk -F': ' '$2 == "vfat" {print $1; exit}')
+  [ -n "$ESP_DEV" ] || { echo "vmix: no FAT EFI partition found in ${image}"; guestfish --ro -a ${image} run : list-filesystems; exit 1; }
+  guestfish -a ${image} -m "$ESP_DEV" <<GFS
+  rm-rf /EFI/OC
+  rm-rf /EFI/BOOT
+  rm-rf /EFI/vmix
+  copy-in ${esp}/EFI /
+  ls /EFI/OC
+  GFS
+''

lib/images/macos/helpers/installerPayload.nix

@@ -0,0 +1,28 @@
+# Take apart InstallAssistant.pkg on Linux:
+#   installer-app.tar  "Install macOS <name>.app" skeleton (Payload, pbzx+cpio)
+#   installer.json     byte offsets of SharedSupport.dmg inside the pkg
+#   app-name           e.g. "Install macOS Tahoe.app"
+# The 18 GB SharedSupport.dmg is never copied on the host; makeImage exposes that
+# byte range of the pkg as a raw disk and the recovery script copies it into the app.
+{ pkgs, lib, ... }:
+{ name, pkg }:
+pkgs.runCommand "${name}-installer-payload" {
+  nativeBuildInputs = with pkgs; [ xar pbzx cpio python3 gnutar ];
+} ''
+  mkdir -p $out
+  xar --dump-toc=toc.xml -f ${pkg}
+  python3 ${./xar-toc.py} toc.xml ${pkg} > $out/installer.json
+  grep -q '"SharedSupport.dmg"' $out/installer.json || { echo "no SharedSupport.dmg in pkg"; exit 1; }
+  grep -A4 '"SharedSupport.dmg"' $out/installer.json | grep -q '"encoding": "application/octet-stream"' \
+    || { echo "SharedSupport.dmg is compressed inside the xar, cannot map it as a disk"; exit 1; }
+
+  echo "=== vmix: extracting installer app skeleton ==="
+  xar -x -f ${pkg} Payload
+  mkdir root
+  (cd root && pbzx -n ../Payload | cpio -idm --quiet)
+  APP=$(ls root/Applications | grep -E '^Install macOS.*\.app$' | head -1)
+  [ -n "$APP" ] || { echo "installer app not found in Payload"; ls -R root | head; exit 1; }
+  echo "$APP" > $out/app-name
+  tar -C root/Applications -cf $out/installer-app.tar "$APP"
+  ls -la $out
+''

lib/images/macos/helpers/macserial.nix

@@ -0,0 +1,18 @@
+# macserial + ocvalidate from the pinned OpenCorePkg release (static Linux binaries)
+{ pkgs, upstream, ... }:
+pkgs.stdenv.mkDerivation {
+  name = "opencore-utilities-${upstream.opencore.pkg.version}";
+  src = pkgs.fetchurl { inherit (upstream.opencore.pkg) url sha256; };
+  nativeBuildInputs = [ pkgs.unzip ];
+  dontStrip = true;
+  dontPatchELF = true;
+  unpackPhase = ''
+    unzip -q $src 'Utilities/macserial/*' 'Utilities/ocvalidate/*'
+  '';
+  installPhase = ''
+    mkdir -p $out/bin $out/share/doc
+    install -m755 Utilities/macserial/macserial.linux $out/bin/macserial
+    install -m755 Utilities/ocvalidate/ocvalidate.linux $out/bin/ocvalidate
+    cp Utilities/macserial/FORMAT.md $out/share/doc/macserial-FORMAT.md
+  '';
+}

lib/images/macos/helpers/makeBootDisk.nix

@@ -0,0 +1,29 @@
+# OpenCore boot disk for build-time boots, derived from an image's ESP
+# (makeOpenCore output) with build-only settings: extra boot-args (serial
+# console, verbose) and optionally an OpenCore ScanPolicy so that only the PE
+# (an HFS+ volume on SATA) is bootable — the build never lands on the wrong OS.
+{ pkgs, lib, ... }:
+{ esp, bootArgs ? null, scanPolicy ? null, name ? "boot" }:
+pkgs.runCommand "${name}-bootdisk" {
+  nativeBuildInputs = with pkgs; [ python3 mtools dosfstools gptfdisk ];
+} ''
+  cp -r ${esp}/EFI EFI
+  chmod -R u+w EFI
+  python3 - <<'PY'
+  import plistlib
+  p = 'EFI/OC/config.plist'
+  cfg = plistlib.load(open(p, 'rb'))
+  nv = cfg['NVRAM']['Add']['7C436110-AB2A-4BBB-A880-FE41995C9F82']
+  ${lib.optionalString (bootArgs != null) ''nv['boot-args'] = ${builtins.toJSON bootArgs}''}
+  ${lib.optionalString (scanPolicy != null) ''cfg['Misc']['Security']['ScanPolicy'] = ${toString scanPolicy}''}
+  plistlib.dump(cfg, open(p, 'wb'))
+  print('boot-args:', nv['boot-args'], 'ScanPolicy:', cfg['Misc']['Security']['ScanPolicy'])
+  PY
+  mkdir -p $out
+  truncate -s 64M $out/boot.img
+  sgdisk -n 1:2048:0 -t 1:EF00 -c 1:EFI $out/boot.img >/dev/null
+  SECTORS=$(( 64*1024*1024/512 - 2048 - 34 ))
+  mkfs.vfat -F 32 -n OPENCORE --offset 2048 $out/boot.img $(( SECTORS / 2 )) >/dev/null
+  mcopy -i $out/boot.img@@1M -s EFI ::
+  mdir -i $out/boot.img@@1M ::EFI/OC >/dev/null
+''

lib/images/macos/helpers/makeImage.nix

@@ -0,0 +1,113 @@
+# Build a pre-installed macOS qcow2 with an unattended install driven from the
+# vmix PE (Apple's Recovery + one LaunchDaemon, see makeRecoveryPE):
+#   OpenCore boots the PE → its hook runs /Volumes/VMIX/run.sh (vmix-install.sh)
+#   → erase the disk, rebuild the installer app from installer-app.tar + the
+#   SharedSupport raw disk, startosinstall → the installer reboots through its
+#   phases → the installed system's first boot reaches the loginwindow → the
+#   driver powers it off. No GUI is driven; progress is read from the serial
+#   console and screenshots (brightness). Fully offline: no NIC is attached.
+# Then OpenCore is copied into the image's own ESP so it boots with plain OVMF.
+# Apply templates with customizeImageFold, then .generalize.
+{ pkgs, lib, qemu, ident, installerPayload, makeOpenCore, makeBootDisk, makeVmixVolume, installBootloader, vmixReadback, vmDriver, ... }:
+{
+  name ? "macos",
+  installer,                  # InstallAssistant.pkg
+  pe,                         # makeRecoveryPE output for the same macOS version
+  diskSize ? "128G",
+  volumeName ? "Macintosh HD",
+  smp ? 4,
+  memSize ? 8192,
+  cpu ? qemu.defaultCpu,
+  model ? "MacPro7,1",        # SMBIOS model; must be supported by the installed macOS
+  seed ? name,                # MAC address + SystemUUID are derived from this
+  bootArgs ? "keepsyms=1 revpatch=memtab",
+  vncDisplay ? null,          # e.g. ":10" to watch the install on port 5910
+  timeout ? 4 * 3600,         # seconds for the whole install
+  extraOpenCoreConfig ? {},   # merged into config.plist
+  installNetwork ? false,     # attach a NIC during the install (default: offline)
+}:
+let
+  mac = ident.macFromSeed seed;
+  uuid = ident.uuidFromSeed seed;
+  esp = makeOpenCore { name = "${name}-opencore"; inherit model mac uuid bootArgs memSize; extraConfig = extraOpenCoreConfig; };
+  # build-time boot disk: same identity, plus serial console + verbose boot
+  bootDisk = makeBootDisk { name = "${name}-install"; inherit esp; bootArgs = "${bootArgs} serial=3 -v"; };
+  payload = installerPayload { inherit name; pkg = installer; };
+  vmixVol = makeVmixVolume {
+    inherit name;
+    size = "512M";
+    files = [
+      { source = ../guest/vmix-install.sh; name = "run.sh"; }
+      { source = ../guest/pe-lib.sh; name = "pe-lib.sh"; }
+      { source = "${payload}/installer-app.tar"; name = "installer-app.tar"; }
+    ];
+  };
+  driverPython = pkgs.python3.withPackages (p: [ p.pillow ]);
+
+  drv = pkgs.runCommand "${name}-vmix.qcow2" {
+    __noChroot = true;
+    requiredSystemFeatures = [ "kvm" ];
+    nativeBuildInputs = with pkgs; [ pkgs.qemu jq driverPython libguestfs-with-appliance ];
+  } ''
+    echo "=== vmix: creating ${diskSize} disk ==="
+    qemu-img create -f qcow2 disk.qcow2 ${diskSize}
+    # store files are read-only and AHCI needs writable nodes: qcow2 overlays
+    qemu-img create -q -f qcow2 -F raw -b ${pe} pe.qcow2
+    qemu-img create -q -f qcow2 -F raw -b ${bootDisk}/boot.img ocboot.qcow2
+
+    # Apple's postinstall hardlinks the WHOLE InstallAssistant.pkg as
+    # Contents/SharedSupport/SharedSupport.dmg: the pkg is a "pkgdmg" (xar + koly
+    # trailer whose DataForkOffset points at the dmg inside). startosinstall's
+    # OSISVerifyBaseSystemOperation reads that footer, so the extracted xar member
+    # alone fails with "pkgdmg is missing a footer". Expose the whole pkg as a raw
+    # disk (zero host copy; qcow2 needs a 512-aligned size, the guest dd's PKG_BYTES).
+    PKG_BYTES=$(stat -c %s ${installer})
+    PKG_DISK=$(( (PKG_BYTES + 511) / 512 * 512 ))
+    qemu-img create -q -f qcow2 -F raw -b "json:{\"driver\":\"raw\",\"size\":$PKG_DISK,\"file\":{\"driver\":\"file\",\"filename\":\"${installer}\"}}" sharedsupport.qcow2
+
+    cp ${vmixVol} vmix.img
+    chmod +w vmix.img
+    TARGET_BYTES=$(qemu-img info --output=json disk.qcow2 | jq '."virtual-size"')
+    cat > vmix.conf <<CONF
+    TARGET_BYTES=$TARGET_BYTES
+    PKG_BYTES=$PKG_BYTES
+    PKG_DISK_BYTES=$PKG_DISK
+    APP_NAME="$(cat ${payload}/app-name)"
+    VOLUME_NAME="${volumeName}"
+    BUILD_DATE="$(date -u +%m%d%H%M%Y.%S)"
+    CONF
+    cat vmix.conf
+    guestfish -a vmix.img -m /dev/sda1 upload vmix.conf /vmix.conf
+
+    cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars.fd
+    chmod +w vars.fd
+    VMIX_DISPLAY="-display none"
+    ${lib.optionalString (vncDisplay != null) ''VMIX_DISPLAY="-display none -vnc ${vncDisplay}"''}
+
+    echo "=== vmix: installing ${name} (unattended, ~1 h; logs and screenshots in /tmp/vmix-macos/${name}) ==="
+    python3 ${vmDriver} --mode install --name ${name} --timeout ${toString timeout} \
+      --serial-log serial.log --progress-file disk.qcow2 -- \
+      qemu-system-x86_64 $VMIX_DISPLAY \
+      ${qemu.machineArgs { inherit cpu smp memSize; }} \
+      ${qemu.firmwareArgs "vars.fd"} \
+      ${qemu.serialArgs "serial.log"} \
+      ${qemu.sataDrive { id = "opencore"; port = 0; file = "ocboot.qcow2"; }} \
+      ${qemu.sataDrive { id = "pe"; port = 1; file = "pe.qcow2"; }} \
+      ${qemu.sataDrive { id = "system"; port = 2; file = "disk.qcow2"; }} \
+      ${qemu.sataDrive { id = "vmix"; port = 3; file = "vmix.img"; format = "raw"; }} \
+      ${qemu.sataDrive { id = "sharedsupport"; port = 4; file = "sharedsupport.qcow2"; }} \
+      ${lib.optionalString installNetwork (qemu.netArgs { inherit mac; })} \
+      || { echo "vmix: install VM failed (see /tmp/vmix-macos/${name})"; exit 1; }
+
+    # The PE records a status only if run.sh returned, i.e. the install failed
+    # before the installer took over and rebooted.
+    ${vmixReadback "vmix.img"}
+    if [ -n "$STATUS" ] && [ "$STATUS" != "0" ]; then
+      echo "vmix: install script failed (status $STATUS), see /tmp/vmix-macos/${name}"; exit 1
+    fi
+
+    ${installBootloader { inherit esp; image = "disk.qcow2"; }}
+    echo "=== vmix: ${name} install complete (serial $(jq -r .serial ${esp}/vmix.json), mac ${mac}) ==="
+    mv disk.qcow2 $out
+  '';
+in drv // { _vmixOsType = "macos"; macAddress = mac; opencore = esp; inherit model pe volumeName; }

lib/images/macos/helpers/makeOpenCore.nix

@@ -0,0 +1,85 @@
+# OpenCore EFI for the VM: OSX-KVM's proven ESP (OpenCore + Lilu/VirtualSMC/... kexts)
+# with a config.plist rewritten for this image's SMBIOS identity.
+# Output:
+#   $out/EFI/        BOOT/BOOTx64.efi + OC/ — copied into the image's ESP
+#   $out/boot.img    raw GPT disk with that ESP, used to boot the installer
+#   $out/vmix.json   model, serial, mlb, uuid, mac (also copied to EFI/vmix/)
+# Serial + MLB come from macserial when not given (random per build); everything
+# derived from `seed` (MAC, UUID) is deterministic so the NixOS module knows it.
+{ pkgs, lib, upstream, macserial, qemu, ... }:
+{ name ? "opencore",
+  model ? "MacPro7,1",
+  mac,
+  uuid,
+  serial ? null,
+  mlb ? null,
+  bootArgs ? "keepsyms=1 revpatch=memtab",
+  resolution ? "1024x768",
+  showPicker ? true,
+  pickerTimeout ? 2,
+  extraConfig ? {},
+  memSize ? 8192,             # RAM described in SMBIOS (MacPro7,1 wants 4 DIMMs)
+}:
+let
+  ocImage = pkgs.fetchurl { inherit (upstream.opencore.image) url sha256; name = "OSX-KVM-OpenCore.qcow2"; };
+  # OSX-KVM's ESP ships Lilu 1.6.8 / VirtualSMC 1.3.3 / WhateverGreen 1.6.7, which
+  # disable themselves on macOS 26 ("unsupported operating system"); without
+  # VirtualSMC, macOS' restart path panics on QEMU's SMC stub. Overlay the
+  # current releases (upstream.opencore.kexts, pinned).
+  kextZips = lib.mapAttrsToList (n: k: { name = n; zip = pkgs.fetchurl { inherit (k) url hash; }; })
+    (upstream.opencore.kexts or {});
+in
+pkgs.runCommand "${name}-esp" {
+  nativeBuildInputs = with pkgs; [ _7zz python3 mtools dosfstools gptfdisk jq macserial ];
+  passthru = { inherit model mac uuid; };
+} ''
+  echo "=== vmix: extracting OSX-KVM OpenCore ESP ==="
+  7zz x -y -oparts ${ocImage} 0.primary.img >/dev/null
+  7zz x -y -oesp parts/0.primary.img >/dev/null
+  [ -f esp/EFI/OC/config.plist ] || { echo "config.plist not found in OpenCore image"; exit 1; }
+
+  SERIAL="${toString serial}"; MLB="${toString mlb}"
+  if [ -z "$SERIAL" ] || [ -z "$MLB" ]; then
+    echo "=== vmix: generating serial/MLB for ${model} with macserial ==="
+    LINE=$(macserial --num 1 --model "${model}" 2>/dev/null | grep '|' | tail -1)
+    [ -n "$LINE" ] || { echo "macserial produced nothing for ${model}"; exit 1; }
+    [ -z "$SERIAL" ] && SERIAL=$(echo "$LINE" | awk -F' *\\| *' '{print $1}')
+    [ -z "$MLB" ] && MLB=$(echo "$LINE" | awk -F' *\\| *' '{print $2}')
+  fi
+  echo "model=${model} serial=$SERIAL mlb=$MLB uuid=${uuid} mac=${mac}"
+
+  mkdir -p $out/EFI/vmix
+  cp -r esp/EFI/BOOT esp/EFI/OC $out/EFI/
+  chmod -R u+w $out/EFI
+  ${lib.concatMapStringsSep "\n" (k: ''
+    echo "=== vmix: updating ${k.name}.kext from ${k.zip.name} ==="
+    rm -rf kext-${k.name}; mkdir kext-${k.name}
+    ${pkgs.unzip}/bin/unzip -q -o ${k.zip} -d kext-${k.name}
+    K=$(find kext-${k.name} -type d -name "${k.name}.kext" | head -1)
+    [ -n "$K" ] || { echo "${k.name}.kext not found in ${k.zip.name}"; exit 1; }
+    rm -rf "$out/EFI/OC/Kexts/${k.name}.kext"
+    cp -r "$K" "$out/EFI/OC/Kexts/${k.name}.kext"
+    grep -A1 CFBundleVersion "$out/EFI/OC/Kexts/${k.name}.kext/Contents/Info.plist" | tail -1
+  '') kextZips}
+  # hide OpenCore's own launcher from its picker (otherwise it is the default entry and loops)
+  echo -n Disabled > $out/EFI/BOOT/.contentVisibility
+  python3 ${./oc-config.py} --base esp/EFI/OC/config.plist --esp esp --out $out/EFI/OC/config.plist \
+    --model "${model}" --serial "$SERIAL" --mlb "$MLB" --uuid "${uuid}" --mac "${mac}" \
+    --nic-path "${qemu.nicDevicePath}" --boot-args "${bootArgs}" --resolution "${resolution}" \
+    --show-picker "${lib.boolToString showPicker}" --timeout ${toString pickerTimeout} \
+    --extra-json ${lib.escapeShellArg (builtins.toJSON extraConfig)} --memory-mb ${toString memSize} --add-kexts ${lib.concatStringsSep "," (map (k: k.name) kextZips)}
+  ocvalidate $out/EFI/OC/config.plist || echo "vmix: ocvalidate reported issues (OpenCore version may differ from validator), continuing"
+
+  jq -n --arg model "${model}" --arg serial "$SERIAL" --arg mlb "$MLB" --arg uuid "${uuid}" --arg mac "${mac}" \
+    '{model:$model, serial:$serial, mlb:$mlb, uuid:$uuid, mac:$mac}' > $out/vmix.json
+  cp $out/vmix.json $out/EFI/vmix/vmix.json
+
+  echo "=== vmix: building OpenCore boot disk ==="
+  # 64 MiB raw GPT disk, ESP from sector 2048 to the end (minus backup GPT)
+  truncate -s 64M $out/boot.img
+  sgdisk -n 1:2048:0 -t 1:EF00 -c 1:EFI $out/boot.img >/dev/null
+  SECTORS=$(( 64*1024*1024/512 - 2048 - 34 ))
+  mkfs.vfat -F 32 -n OPENCORE --offset 2048 $out/boot.img $(( SECTORS / 2 )) >/dev/null
+  mcopy -i $out/boot.img@@1M -s $out/EFI ::
+  mdir -i $out/boot.img@@1M ::EFI/OC >/dev/null
+''

lib/images/macos/helpers/makeRecoveryPE.nix

@@ -0,0 +1,30 @@
+# The vmix "PE": Apple's Recovery (BaseSystem.dmg) with one LaunchDaemon added
+# that runs /Volumes/VMIX/run.sh as root at boot and powers off afterwards.
+# BaseSystem is a plain (journaled) HFS+ volume that Linux can write with the
+# hfsplus driver's force option — the pristine image's journal is empty, so this
+# is safe. The kernel and boot.efi are untouched; launchd loads the extra plist
+# from /System/Library/LaunchDaemons alongside its signed cache (verified on
+# Tahoe 26.6.2). Same idea as AutoNBI/Imagr NetBoot images.
+# Output: raw disk image (HFS+ volume with a partition table) that OpenCore boots.
+{ pkgs, lib, ... }:
+{ name ? "macos", recovery }:
+pkgs.runCommand "${name}-pe.img" {
+  nativeBuildInputs = with pkgs; [ dmg2img libguestfs-with-appliance ];
+} ''
+  echo "=== vmix: building the recovery PE from BaseSystem.dmg ==="
+  dmg2img -s ${recovery} $out
+  chmod +w $out
+  guestfish -a $out <<GFS
+  run
+  mount-options force /dev/sda1 /
+  mkdir-p /usr/libexec/vmix
+  upload ${../guest/pe.sh} /usr/libexec/vmix/pe.sh
+  chmod 0755 /usr/libexec/vmix/pe.sh
+  upload ${../guest/ch.vmix.pe.plist} /System/Library/LaunchDaemons/ch.vmix.pe.plist
+  chmod 0644 /System/Library/LaunchDaemons/ch.vmix.pe.plist
+  ls /usr/libexec/vmix
+  umount /
+  GFS
+  guestfish --ro -a $out -m /dev/sda1 ls /System/Library/LaunchDaemons | grep -q '^ch.vmix.pe.plist$' \
+    || { echo "vmix: PE hook not installed"; exit 1; }
+''

lib/images/macos/helpers/makeVmixVolume.nix

@@ -0,0 +1,28 @@
+# GPT disk with a single HFS+ partition named VMIX. macOS mounts it natively by
+# name at /Volumes/VMIX (its FAT driver rejects Linux-made FAT volumes as
+# "damaged"; HFS+ made by mkfs.hfsplus mounts cleanly). The partition starts at
+# 1 MiB. Files are staged with their target names and copied in via libguestfs.
+# files: list of { source = <path|drv>; name = "dest name"; } — directories copied recursively.
+{ pkgs, lib, ... }:
+{ name ? "vmix", files, size ? "64M" }:
+pkgs.runCommand "${name}-vmix-volume.img" {
+  nativeBuildInputs = with pkgs; [ hfsprogs gptfdisk gnutar libguestfs-with-appliance ];
+} ''
+  mkdir stage
+  ${lib.concatMapStringsSep "\n" (f: ''
+    mkdir -p "$(dirname "stage/${f.name}")"
+    cp -r --no-preserve=mode ${f.source} "stage/${f.name}"
+  '') files}
+  tar -C stage -cf stage.tar .
+
+  truncate -s ${size} $out
+  sgdisk -n 1:2048:0 -t 1:AF00 -c 1:VMIX $out >/dev/null
+  FIRST=$(sgdisk -i 1 $out | sed -n 's/First sector: \([0-9]*\).*/\1/p')
+  LAST=$(sgdisk -i 1 $out | sed -n 's/Last sector: \([0-9]*\).*/\1/p')
+  truncate -s $(( (LAST - FIRST + 1) * 512 )) hfs.part
+  mkfs.hfsplus -v VMIX hfs.part >/dev/null
+
+  # tar-in takes a host-side tarball and unpacks it into the mounted volume
+  guestfish -a hfs.part run : mount /dev/sda / : tar-in stage.tar / : ls / : umount /
+  dd if=hfs.part of=$out bs=512 seek=$FIRST conv=notrunc status=none
+''

lib/images/macos/helpers/oc-config.py

@@ -0,0 +1,128 @@
+#!/usr/bin/env python3
+"""Derive a VM config.plist from OSX-KVM's OpenCore config.
+
+- keep only kexts/ACPI/drivers whose files exist in the ESP
+- SMBIOS (model, serial, MLB, UUID, ROM=MAC) for Apple ID / iMessage
+- mark the vmix NIC PCI path built-in, drop iMac19,1 GPU/audio properties
+- boot-args, picker, resolution; optional JSON merged on top
+"""
+import argparse
+import json
+import os
+import plistlib
+
+APPLE_NVRAM = '7C436110-AB2A-4BBB-A880-FE41995C9F82'
+MCE_KEXT = {
+    'Arch': 'Any', 'BundlePath': 'MCEReporterDisabler.kext',
+    'Comment': 'Fix kernel panic on MacPro/iMacPro SMBIOS (vmix)', 'Enabled': True,
+    'ExecutablePath': '', 'MaxKernel': '', 'MinKernel': '', 'PlistPath': 'Contents/Info.plist',
+}
+
+
+def merge(dst, src):
+    for k, v in src.items():
+        if isinstance(v, dict) and isinstance(dst.get(k), dict):
+            merge(dst[k], v)
+        else:
+            dst[k] = v
+
+
+def main():
+    p = argparse.ArgumentParser()
+    p.add_argument('--base', required=True)
+    p.add_argument('--esp', required=True, help='directory containing EFI/OC')
+    p.add_argument('--out', required=True)
+    p.add_argument('--model', required=True)
+    p.add_argument('--serial', required=True)
+    p.add_argument('--mlb', required=True)
+    p.add_argument('--uuid', required=True)
+    p.add_argument('--mac', required=True)
+    p.add_argument('--nic-path', required=True)
+    p.add_argument('--boot-args', default='keepsyms=1')
+    p.add_argument('--resolution', default='1024x768')
+    p.add_argument('--show-picker', default='true')
+    p.add_argument('--timeout', type=int, default=2)
+    p.add_argument('--extra-json', default='{}')
+    p.add_argument('--memory-mb', type=int, default=8192, help='VM RAM, described as 4 DIMMs')
+    p.add_argument('--add-kexts', default='', help='comma-separated kext names (without .kext) that need a Kernel.Add entry')
+    a = p.parse_args()
+
+    with open(a.base, 'rb') as f:
+        cfg = plistlib.load(f)
+    oc = os.path.join(a.esp, 'EFI', 'OC')
+
+    def exists(sub, path):
+        return os.path.exists(os.path.join(oc, sub, path))
+
+    kexts = [k for k in cfg['Kernel']['Add'] if exists('Kexts', k['BundlePath'])]
+    if a.model.startswith(('MacPro', 'iMacPro')) and exists('Kexts', MCE_KEXT['BundlePath']) \
+            and not any(k['BundlePath'] == MCE_KEXT['BundlePath'] for k in kexts):
+        kexts.append(dict(MCE_KEXT))
+    cfg['Kernel']['Add'] = kexts
+    cfg['ACPI']['Add'] = [x for x in cfg['ACPI']['Add'] if exists('ACPI', x['Path'])]
+    cfg['UEFI']['Drivers'] = [d for d in cfg['UEFI']['Drivers'] if exists('Drivers', d['Path'])]
+    cfg['Misc']['Tools'] = [t for t in cfg['Misc'].get('Tools', []) if exists('Tools', t['Path'])]
+    cfg['Misc']['Entries'] = []
+
+    g = cfg['PlatformInfo']['Generic']
+    g['SystemProductName'] = a.model
+    g['SystemSerialNumber'] = a.serial
+    g['MLB'] = a.mlb
+    g['SystemUUID'] = a.uuid.upper()
+    g['ROM'] = bytes.fromhex(a.mac.replace(':', '').replace('-', ''))
+    g['SpoofVendor'] = True
+    g['AdviseFeatures'] = False
+
+    cfg['DeviceProperties']['Add'] = {a.nic_path: {'built-in': b'\x01'}}
+    cfg['DeviceProperties']['Delete'] = {}
+
+    nv = cfg['NVRAM']['Add'].setdefault(APPLE_NVRAM, {})
+    nv['boot-args'] = a.boot_args
+    nv['prev-lang:kbd'] = b'en-US:0'
+    nv['csr-active-config'] = b'\x00\x00\x00\x00'
+
+    cfg['UEFI']['Output']['Resolution'] = a.resolution
+    cfg['Misc']['Boot']['ShowPicker'] = a.show_picker.lower() == 'true'
+    cfg['Misc']['Boot']['Timeout'] = a.timeout
+    cfg['Misc']['Boot']['HideAuxiliary'] = True
+    cfg['Misc']['Security']['ScanPolicy'] = 0
+    # kexts overlaid into the ESP that the OSX-KVM config does not list yet
+    # (RestrictEvents: silences MacPro7,1's "Memory Modules Misconfigured", revpatch=memtab)
+    listed = {k['BundlePath'] for k in cfg['Kernel']['Add']}
+    for kext in [k + '.kext' for k in a.add_kexts.split(',') if k]:
+        if kext not in listed:
+            name = kext[:-5]
+            cfg['Kernel']['Add'].append({
+                'Arch': 'Any', 'BundlePath': kext, 'Comment': f'{name} (vmix)', 'Enabled': True,
+                'ExecutablePath': f'Contents/MacOS/{name}', 'MaxKernel': '', 'MinKernel': '',
+                'PlistPath': 'Contents/Info.plist'})
+            print('Kernel.Add +', kext)
+
+    # MacPro7,1 firmware expects DIMMs in pairs (>= 4); with QEMU's single SMBIOS
+    # module macOS shows "Memory Modules Misconfigured" at every login. Describe
+    # the VM's RAM as four DDR4 modules instead.
+    if a.model.startswith('MacPro7'):
+        size = max(1024, a.memory_mb // 4)
+        cfg['PlatformInfo']['CustomMemory'] = True
+        cfg['PlatformInfo']['Memory'] = {
+            'DataWidth': 64, 'ErrorCorrection': 3, 'FormFactor': 9, 'MaxCapacity': 1536 * 1024 * 1024 * 1024,
+            'TotalWidth': 64, 'Type': 26, 'TypeDetail': 128,
+            'Devices': [{
+                'AssetTag': '', 'BankLocator': f'BANK {i}', 'DeviceLocator': f'DIMM{i + 1}',
+                'Manufacturer': 'Apple', 'PartNumber': f'VMIX{size}', 'SerialNumber': f'VMIX{i:04d}',
+                'Size': size, 'Speed': 2666,
+            } for i in range(4)],
+        }
+    cfg['Misc']['Security']['SecureBootModel'] = 'Disabled'
+    cfg['Misc']['Security']['AllowSetDefault'] = True
+    cfg['Misc']['Debug']['Target'] = 0
+
+    merge(cfg, json.loads(a.extra_json))
+    with open(a.out, 'wb') as f:
+        plistlib.dump(cfg, f, sort_keys=True)
+    print('kexts:', ', '.join(k['BundlePath'] for k in kexts))
+    print('acpi:', ', '.join(x['Path'] for x in cfg['ACPI']['Add']))
+
+
+if __name__ == '__main__':
+    main()

lib/images/macos/helpers/qemu.nix

@@ -0,0 +1,65 @@
+# QEMU pieces shared by the macOS image builders, the vmix CLI and the NixOS module.
+# Mirrors OSX-KVM's OpenCore-Boot.sh: q35, Skylake-Client CPU spoof (works on AMD
+# hosts too), AppleSMC with the OSK, XHCI keyboard/tablet, AHCI disks, VMware SVGA.
+{ pkgs, lib, ... }:
+rec {
+  osk = "ourhardworkbythesewordsguardedpleasedontsteal(c)AppleComputerInc";
+
+  # OSX-KVM's CPU line for Sequoia/Tahoe; AVX2 capable, Intel vendor for the kernel
+  defaultCpu = "Skylake-Client,-hle,-rtm,kvm=on,vendor=GenuineIntel,+invtsc,vmware-cpuid-freq=on,+ssse3,+sse4.2,+popcnt,+avx,+aes,+xsave,+xsaveopt,check";
+
+  # The NIC is pinned to a fixed PCI slot so OpenCore can mark it built-in
+  # (required for en0 / Apple ID, iMessage, App Store).
+  nicAddr = "0x12";
+  nicDevicePath = "PciRoot(0x0)/Pci(0x12,0x0)";
+
+  # `-nic user` cannot pin a PCI address, so netdev + device
+  netArgs = { mac, netdev ? "user,id=net0", extra ? "" }:
+    "-netdev ${netdev} -device virtio-net-pci,netdev=net0,mac=${mac},bus=pcie.0,addr=${nicAddr}${extra}";
+
+  # Devices macOS needs (no accel, disks, display adapter or display server here).
+  # No isa-applesmc: QEMU's stub only answers the OSK keys, and its presence makes
+  # VirtualSMC (which carries the OSK itself) step aside, leaving Apple's SMC
+  # driver on the stub — whose missing watchdog keys panic the restart path on
+  # macOS 26. VirtualSMC alone is the standard Hackintosh setup.
+  deviceArgsFor = { appleSmc ? false }:
+    ''${lib.optionalString appleSmc ''-device isa-applesmc,osk="${osk}" ''}-smbios type=2 -device qemu-xhci,id=xhci -device usb-kbd,bus=xhci.0 -device usb-tablet,bus=xhci.0 -device usb-ehci,id=ehci -device ich9-intel-hda -device hda-duplex -device ich9-ahci,id=sata -global ICH9-LPC.disable_s3=1'';
+  deviceArgs = deviceArgsFor { };
+
+  # macOS has no QXL/virtio-gpu driver; VMware SVGA gives a plain framebuffer
+  vgaArgs = "-vga vmware";
+
+  machineArgs = { cpu ? defaultCpu, smp ? 4, memSize ? 4096, appleSmc ? false }:
+    "-accel kvm -machine type=q35 -cpu ${cpu} -smp ${toString smp},sockets=1,cores=${toString smp},threads=1 -m ${toString memSize} ${deviceArgsFor { inherit appleSmc; }} ${vgaArgs}";
+
+  # SATA disk on a given port. Store files are read-only: callers create qcow2 overlays.
+  sataDrive = { id, port, file, format ? "qcow2", extra ? "" }:
+    "-drive id=${id},if=none,format=${format},file=${file}${extra} -device ide-hd,bus=sata.${toString port},drive=${id}";
+
+  # XNU logs to COM1 with boot-args serial=3; the build drivers read this file
+  serialArgs = file: "-serial file:${file}";
+
+  # Apple's own QEMU guest agent (/usr/libexec/AppleQEMUGuestAgent, macOS 13+)
+  # attaches to a virtio console port named org.qemu.guest_agent.0 and offers
+  # guest-exec (as root), guest-file-* etc. over this unix socket.
+  guestAgentArgs = sock:
+    "-device virtio-serial-pci,id=vmix-vser -chardev socket,path=${sock},server=on,wait=off,id=vmix-qga -device virtserialport,chardev=vmix-qga,name=org.qemu.guest_agent.0";
+
+  # virtio-fs (vhost-user, virtiofsd on the host). macOS auto-mounts the tag
+  # "com.apple.virtio-fs.automount" at /Volumes/My Shared Files; other tags are
+  # mounted with `mount -t virtiofs <tag> <dir>`. Needs a shared memory backend.
+  automountTag = "com.apple.virtio-fs.automount";
+  memBackendArgs = memSize: "-object memory-backend-memfd,id=vmix-mem,size=${toString memSize}M,share=on -numa node,memdev=vmix-mem";
+  virtioFsArgs = { tag, sock, id ? tag }:
+    "-chardev socket,id=vmix-vfs-${id},path=${sock} -device vhost-user-fs-pci,chardev=vmix-vfs-${id},tag=${tag}";
+
+  # virtio-blk data disk (AppleVirtIOBlock), e.g. the persistent home volume
+  virtioBlkArgs = { id, file, format ? "qcow2", extra ? "" }:
+    "-drive id=${id},if=none,format=${format},file=${file}${extra} -device virtio-blk-pci,drive=${id}";
+
+  # virtio keyboard/tablet (AppleVirtIOInput), optional alternative to the USB HID pair
+  virtioInputArgs = "-device virtio-keyboard-pci -device virtio-tablet-pci";
+
+  firmwareArgs = varsFile:
+    "-drive if=pflash,format=raw,readonly=on,file=${pkgs.OVMF.fd}/FV/OVMF_CODE.fd -drive if=pflash,format=raw,file=${varsFile}";
+}

lib/images/macos/helpers/vm-driver.py

@@ -0,0 +1,588 @@
+#!/usr/bin/env python3
+"""vmix macOS VM driver: runs QEMU and decides when a build boot is finished.
+
+Modes
+  pe       the recovery PE runs /Volumes/VMIX/run.sh and powers off. Success is
+           QEMU exiting on its own; the caller checks vmix-run.status.
+  install  the PE starts the macOS installer, which reboots through its phases
+           into the installed system. Finished when that system reaches the
+           (bright) loginwindow / Setup Assistant — the driver powers it down —
+           or halts on its own.
+  boot     boot an installed image and wait for it to halt or reach the loginwindow.
+  qga      boot an installed image with Apple's QEMU guest agent attached
+           (--qga-sock), wait for it, run --qga-command as root through it
+           (guest-exec), then shut the guest down. Used for online templates.
+
+Observation is passive: the serial console (boot-args serial=3: the PE's
+"VMIX-*" markers, kernel boots, panics) and screenshots over QMP (mean
+brightness + a coarse change fingerprint). No OCR, no keystrokes. A boot hang
+(dark, frozen screen, disk and serial idle) is retried with a system_reset.
+Screenshots, the driver log and the serial log are kept in --debug-dir.
+"""
+import argparse
+import hashlib
+import io
+import json
+import os
+import shutil
+import socket
+import subprocess
+import sys
+import tempfile
+import time
+
+try:
+    from PIL import Image
+except ImportError:  # screenshots then only serve as debug files
+    Image = None
+
+PANIC_MARKS = ('panic(cpu', 'Kernel Extensions in backtrace', 'Debugger called: <panic>', 'Nested panic detected', 'panic string:')
+REBOOT_MARK = 'MACH Reboot'
+
+
+class Log:
+    def __init__(self, path):
+        self.f = open(path, 'a') if path else None
+        self.t0 = time.time()
+
+    def __call__(self, msg):
+        line = f'[{time.time() - self.t0:7.1f}s] {msg}'
+        print(f'vmix driver: {line}', flush=True)
+        if self.f:
+            self.f.write(line + '\n')
+            self.f.flush()
+
+
+class QMP:
+    def __init__(self, path):
+        self.path = path
+        self.s = None
+        self.buf = b''
+
+    def connect(self, timeout=90):
+        t0 = time.time()
+        while True:
+            try:
+                s = socket.socket(socket.AF_UNIX)
+                s.settimeout(60)
+                s.connect(self.path)
+                self.s = s
+                self.buf = b''
+                self._read()            # greeting
+                self.cmd('qmp_capabilities')
+                return
+            except (OSError, ValueError):
+                if time.time() - t0 > timeout:
+                    raise
+                time.sleep(1)
+
+    def _read(self):
+        while b'\n' not in self.buf:
+            d = self.s.recv(65536)
+            if not d:
+                raise OSError('QMP socket closed')
+            self.buf += d
+        line, self.buf = self.buf.split(b'\n', 1)
+        return json.loads(line)
+
+    def cmd(self, name, **args):
+        self.s.sendall(json.dumps({'execute': name, 'arguments': args}).encode() + b'\n')
+        while True:
+            r = self._read()
+            if 'return' in r:
+                return r['return']
+            if 'error' in r:
+                raise RuntimeError(r['error'])
+
+    def screendump(self, path):
+        self.cmd('screendump', filename=path)
+
+    def system_reset(self):
+        self.cmd('system_reset')
+
+    def system_powerdown(self):
+        self.cmd('system_powerdown')
+
+
+class QGA:
+    """Minimal QEMU guest agent client over the unix socket QEMU serves."""
+
+    def __init__(self, path):
+        self.path = path
+
+    def cmd(self, name, timeout=30, **args):
+        s = socket.socket(socket.AF_UNIX)
+        s.settimeout(timeout)
+        try:
+            s.connect(self.path)
+            s.sendall((json.dumps({'execute': name, 'arguments': args}) + '\n').encode())
+            buf = b''
+            while b'\n' not in buf:
+                d = s.recv(65536)
+                if not d:
+                    raise OSError('guest agent closed the connection')
+                buf += d
+        finally:
+            s.close()
+        r = json.loads(buf.split(b'\n', 1)[0])
+        if 'error' in r:
+            raise RuntimeError(r['error'])
+        return r.get('return')
+
+    def ping(self):
+        try:
+            return self.cmd('guest-ping', timeout=5) == {}
+        except Exception:  # noqa: BLE001
+            return False
+
+    def exec_start(self, command):
+        return self.cmd('guest-exec', path='/bin/bash', arg=['-c', command], **{'capture-output': True})['pid']
+
+    def exec_status(self, pid):
+        return self.cmd('guest-exec-status', pid=pid)
+
+
+class Screen:
+    """Screenshots over QMP with a coarse change fingerprint (cursor-insensitive)."""
+
+    def __init__(self, qmp, debug_dir, log):
+        self.qmp = qmp
+        self.dir = debug_dir
+        self.log = log
+        self.tmp = os.path.join(debug_dir, f'.grab-{os.getpid()}.ppm')
+        self.img = None
+        self.last_fp = None
+        self.stable_since = time.time()
+        self.n = 0
+
+    def grab(self):
+        self.qmp.screendump(self.tmp)
+        with open(self.tmp, 'rb') as f:
+            data = f.read()
+        if Image is None:
+            fp = hashlib.sha256(data).hexdigest()
+        else:
+            self.img = Image.open(io.BytesIO(data))
+            small = self.img.convert('L').resize((48, 36))
+            fp = hashlib.sha256(bytes(b & 0xF0 for b in small.tobytes())).hexdigest()
+        if fp != self.last_fp:
+            self.last_fp = fp
+            self.stable_since = time.time()
+        return self.img
+
+    def stable_for(self):
+        return time.time() - self.stable_since
+
+    def mean(self):
+        if self.img is None:
+            return 0
+        g = self.img.convert('L').resize((64, 48))
+        px = g.tobytes()
+        return sum(px) / len(px)
+
+    def is_blank(self):
+        return self.img is not None and self.mean() < 3
+
+    def save(self, tag):
+        self.n += 1
+        path = os.path.join(self.dir, f'{self.n:03d}-{tag}.png')
+        try:
+            if self.img is not None:
+                self.img.save(path)
+            else:
+                shutil.copy(self.tmp, path.replace('.png', '.ppm'))
+        except Exception as e:  # noqa: BLE001
+            self.log(f'could not save screenshot: {e}')
+        return path
+
+
+class Serial:
+    """Tail the serial console file QEMU writes (-serial file:...)."""
+
+    def __init__(self, path):
+        self.path = path
+        self.pos = 0
+        self.last_activity = time.time()
+        self.boots = 0
+        self.reboot_at = None
+
+    def poll(self):
+        if not self.path or not os.path.exists(self.path):
+            return []
+        with open(self.path, 'rb') as f:
+            f.seek(self.pos)
+            data = f.read()
+            self.pos = f.tell()
+        if not data:
+            return []
+        self.last_activity = time.time()
+        lines = data.decode('utf-8', 'replace').replace('\r', '').split('\n')
+        for l in lines:
+            if l.startswith('Darwin Kernel Version'):
+                self.boots += 1
+                self.reboot_at = None
+            elif REBOOT_MARK in l:
+                self.reboot_at = time.time()
+        return lines
+
+    def idle_for(self):
+        return time.time() - self.last_activity
+
+
+def prepare_debug_dir(path):
+    """Create the debug dir; builds run as different nixbld users, so the parent
+    is made world-writable and a temp dir is used if the path is not writable."""
+    parent = os.path.dirname(path)
+    try:
+        if not os.path.isdir(parent):
+            os.makedirs(parent, exist_ok=True)
+            os.chmod(parent, 0o777)
+        os.makedirs(path, exist_ok=True)
+        os.chmod(path, 0o777)
+    except OSError:
+        path = tempfile.mkdtemp(prefix=os.path.basename(path) + '-', dir='/tmp')
+        os.chmod(path, 0o777)
+    for f in os.listdir(path):
+        if f.endswith(('.png', '.ppm', '.log')) or f.startswith('.grab-') or f == 'qmp.sock':
+            try:
+                os.remove(os.path.join(path, f))
+            except OSError:
+                pass
+    return path
+
+
+def launch(qemu_args, qmp_sock, log):
+    if os.path.exists(qmp_sock):
+        os.remove(qmp_sock)
+    cmd = list(qemu_args) + ['-qmp', f'unix:{qmp_sock},server,nowait']
+    log('launching: ' + ' '.join(cmd))
+    return subprocess.Popen(cmd)
+
+
+def disk_idle(args):
+    if not args.progress_file:
+        return True
+    try:
+        return (time.time() - os.path.getmtime(args.progress_file)) > args.disk_idle
+    except OSError:
+        return True
+
+
+def run_qga(args, proc, qmp, screen, serial, log):
+    """Online template: wait for the guest agent, run the command, shut down."""
+    import base64
+    qga = QGA(args.qga_sock)
+    start = time.time()
+    last_periodic = 0
+    while not qga.ping():
+        rc = proc.poll()
+        if rc is not None:
+            log(f'QEMU exited with {rc} before the guest agent came up')
+            return rc or 3
+        now = time.time()
+        if now - start > args.start_timeout:
+            try:
+                screen.grab()
+                screen.save('no-agent')
+            except Exception:  # noqa: BLE001
+                pass
+            log(f'guest agent not reachable within {args.start_timeout:.0f}s')
+            proc.kill()
+            return 3
+        for line in serial.poll():
+            if any(m in line for m in PANIC_MARKS):
+                log('serial: ' + line.strip()[:200])
+        if now - last_periodic > args.periodic:
+            last_periodic = now
+            try:
+                screen.grab()
+                screen.save('periodic')
+            except Exception:  # noqa: BLE001
+                pass
+        time.sleep(3)
+    log(f'guest agent up after {time.time() - start:.0f}s: {qga.cmd("guest-info").get("version")}')
+    time.sleep(args.qga_settle)      # let the login session / volumes settle
+    try:
+        pid = qga.exec_start(args.qga_command)
+    except Exception as e:  # noqa: BLE001
+        log(f'guest-exec failed: {e}')
+        proc.kill()
+        return 3
+    log(f'running command as root (pid {pid}): {args.qga_command[:160]}')
+    t0 = time.time()
+    while True:
+        rc = proc.poll()
+        if rc is not None:
+            log(f'QEMU exited with {rc} while the command was running')
+            return rc or 3
+        if time.time() - start > args.timeout:
+            log('timeout reached, killing QEMU')
+            proc.kill()
+            return 124
+        try:
+            st = qga.exec_status(pid)
+        except Exception as e:  # noqa: BLE001
+            log(f'guest-exec-status failed: {e}')
+            time.sleep(5)
+            continue
+        if st.get('exited'):
+            break
+        now = time.time()
+        if now - last_periodic > args.periodic:
+            last_periodic = now
+            try:
+                screen.grab()
+                screen.save('periodic')
+            except Exception:  # noqa: BLE001
+                pass
+        time.sleep(3)
+    out = base64.b64decode(st.get('out-data', '')).decode('utf-8', 'replace')
+    err = base64.b64decode(st.get('err-data', '')).decode('utf-8', 'replace')
+    code = st.get('exitcode', st.get('signal'))
+    log(f'command finished in {time.time() - t0:.0f}s, exit {code}')
+    for line in (out + err).splitlines()[-200:]:
+        log('guest: ' + line[:220])
+    try:
+        screen.grab()
+        screen.save('after-command')
+    except Exception:  # noqa: BLE001
+        pass
+    log('shutting the guest down')
+    try:
+        qga.exec_start('sync; /sbin/shutdown -h now')
+    except Exception as e:  # noqa: BLE001
+        log(f'guest shutdown failed ({e}), ACPI powerdown')
+        try:
+            qmp.system_powerdown()
+        except Exception:  # noqa: BLE001
+            pass
+    for _ in range(180):
+        if proc.poll() is not None:
+            log('QEMU exited')
+            return 0 if code == 0 else 4
+        time.sleep(1)
+    log('guest did not power off, killing QEMU')
+    proc.kill()
+    return 0 if code == 0 else 4
+
+
+def drive(args, proc, qmp, screen, serial, log):
+    start = time.time()
+    last_periodic = 0
+    resets = 0
+    panics = 0
+    started = args.mode == 'boot'      # pe/install: wait for the PE marker first
+    blank_since = None
+    login_since = None
+    while True:
+        rc = proc.poll()
+        if rc is not None:
+            log(f'QEMU exited with {rc}')
+            return rc
+        now = time.time()
+        if now - start > args.timeout:
+            try:
+                screen.grab()
+                screen.save('timeout')
+            except Exception:  # noqa: BLE001
+                pass
+            log('timeout reached, killing QEMU')
+            proc.kill()
+            return 124
+        time.sleep(args.interval)
+
+        panic = False
+        for line in serial.poll():
+            if 'VMIX' in line:
+                log('serial: ' + line.strip()[:220])
+                if 'VMIX-PE: running run.sh' in line and not started:
+                    started = True
+                    log('PE started run.sh')
+                if 'VMIX-PE: no VMIX volume' in line and args.mode != 'boot':
+                    log('PE did not find the VMIX volume')
+                    proc.kill()
+                    return 3
+            if line.startswith('Darwin Kernel Version'):
+                log(f'guest kernel boot #{serial.boots}')
+            if any(m in line for m in PANIC_MARKS):
+                panic = True
+                log('serial: ' + line.strip()[:220])
+        if panic:
+            panics += 1
+            try:
+                screen.grab()
+                screen.save('panic')
+            except Exception:  # noqa: BLE001
+                pass
+            if panics > args.max_resets:
+                log(f'kernel panic #{panics}, giving up')
+                proc.kill()
+                return 3
+            # XNU reboots by itself after a panic; only reset if no kernel comes back.
+            # (In pe mode the PE then runs run.sh again — templates are idempotent.)
+            log(f'kernel panic #{panics}, waiting for the guest to reboot')
+            serial.reboot_at = now
+            continue
+
+        # The guest asked for a reboot but no kernel came back: macOS' restart
+        # path panics in QEMU (AppleSMC watchdog keys, see README); reset now
+        # instead of waiting for the frozen-screen watchdog.
+        if serial.reboot_at and now - serial.reboot_at > args.reboot_timeout:
+            resets += 1
+            try:
+                screen.grab()
+                screen.save('reboot-dead')
+            except Exception:  # noqa: BLE001
+                pass
+            log(f'guest requested a reboot {now - serial.reboot_at:.0f}s ago and died, system_reset #{resets}')
+            serial.reboot_at = None
+            if resets > args.max_resets:
+                proc.kill()
+                return 3
+            qmp.system_reset()
+            screen.stable_since = time.time()
+            continue
+
+        if not started and now - start > args.start_timeout:
+            try:
+                screen.grab()
+                screen.save('no-start')
+            except Exception:  # noqa: BLE001
+                pass
+            log(f'PE did not start run.sh within {args.start_timeout:.0f}s')
+            proc.kill()
+            return 3
+
+        try:
+            screen.grab()
+        except Exception as e:  # noqa: BLE001
+            log(f'screendump failed ({e})')
+            time.sleep(2)
+            continue
+        if now - last_periodic > args.periodic:
+            last_periodic = now
+            screen.save('periodic')
+
+        if args.mode == 'pe':
+            continue                    # the PE powers off by itself; nothing to decide
+        # install: the PE phase (kernel boot #1) is protected by the guest's own
+        # retries; the checks below apply once the installer has rebooted.
+        in_os = args.mode == 'boot' or serial.boots >= 2
+        if not in_os or screen.stable_for() < args.settle:
+            continue
+        idle = disk_idle(args) and serial.idle_for() > args.disk_idle
+
+        if screen.is_blank():
+            blank_since = blank_since or now
+            # macOS `shutdown -h` halts to a black screen without an ACPI power-off
+            if now - blank_since > args.halt_timeout and idle:
+                screen.save('halt')
+                log(f'guest halted (black {now - blank_since:.0f}s, idle); killing QEMU')
+                proc.kill()
+                return 0
+            continue
+        blank_since = None
+
+        if screen.mean() > args.bright:
+            # loginwindow / Setup Assistant: the OS is installed and booted
+            if login_since is None:
+                login_since = now
+                log(f'bright screen (mean {screen.mean():.0f}): loginwindow/desktop, grace {args.login_grace:.0f}s')
+            elif now - login_since > args.login_grace:
+                screen.save('loginwindow')
+                log('powering down (boot complete)')
+                try:
+                    qmp.system_powerdown()
+                except Exception as e:  # noqa: BLE001
+                    log(f'powerdown failed: {e}')
+                for _ in range(120):
+                    if proc.poll() is not None:
+                        log('QEMU exited after powerdown')
+                        return 0
+                    time.sleep(1)
+                # macOS ignores the power button at the Setup Assistant; the
+                # volumes are journaled (APFS) and the PE mounts them cleanly next
+                log('guest ignores the ACPI power button here (Setup Assistant); stopping QEMU')
+                proc.kill()
+                return 0
+            continue
+        login_since = None
+
+        # dark, frozen, nothing happening: a boot hang (seen at the Apple logo)
+        if screen.stable_for() > args.stall_reset and idle and resets < args.max_resets:
+            resets += 1
+            screen.save('stall-reset')
+            log(f'boot hung ({screen.stable_for():.0f}s frozen, dark, idle), system_reset #{resets}')
+            try:
+                qmp.system_reset()
+            except Exception as e:  # noqa: BLE001
+                log(f'system_reset failed: {e}')
+            screen.stable_since = time.time()
+
+
+def main():
+    p = argparse.ArgumentParser()
+    p.add_argument('--mode', choices=['pe', 'install', 'boot', 'qga'], required=True)
+    p.add_argument('--qga-sock', default=None, help='guest agent unix socket (mode qga)')
+    p.add_argument('--qga-command', default=None, help='bash command to run as root through the guest agent (mode qga)')
+    p.add_argument('--qga-settle', type=float, default=20.0, help='seconds to wait after the agent answers before running the command')
+    p.add_argument('--name', default='macos')
+    p.add_argument('--debug-dir', default=None)
+    p.add_argument('--serial-log', default=None, help='file QEMU writes the serial console to')
+    p.add_argument('--timeout', type=int, default=4 * 3600, help='seconds before QEMU is killed')
+    p.add_argument('--start-timeout', type=float, default=600.0, help='seconds for the PE to start run.sh')
+    p.add_argument('--interval', type=float, default=5.0, help='seconds between screenshots')
+    p.add_argument('--periodic', type=float, default=120.0, help='seconds between saved debug screenshots')
+    p.add_argument('--settle', type=float, default=12.0, help='seconds a screen must be unchanged to act on it')
+    p.add_argument('--stall-reset', type=float, default=360.0, help='reset the VM if a dark screen is frozen this long while disk and serial are idle')
+    p.add_argument('--max-resets', type=int, default=6)
+    p.add_argument('--reboot-timeout', type=float, default=60.0, help='seconds after a guest reboot request without a new kernel boot before the VM is reset')
+    p.add_argument('--halt-timeout', type=float, default=150.0, help='a pure-black, idle screen this long means the guest halted')
+    p.add_argument('--progress-file', default=None, help='the system disk; its mtime shows guest disk activity')
+    p.add_argument('--disk-idle', type=float, default=90.0, help='seconds without disk/serial activity that count as idle')
+    p.add_argument('--bright', type=float, default=80.0, help='mean brightness above which a screen is the loginwindow/desktop')
+    p.add_argument('--login-grace', type=float, default=180.0, help='seconds a bright screen must persist before powering down')
+    p.add_argument('qemu', nargs=argparse.REMAINDER)
+    args = p.parse_args()
+    qemu_args = [a for a in args.qemu if a != '--']
+    if not qemu_args:
+        p.error('QEMU command line required after --')
+
+    debug_dir = args.debug_dir or f'/tmp/vmix-macos/{args.name}'
+    debug_dir = prepare_debug_dir(debug_dir)
+    log = Log(os.path.join(debug_dir, 'driver.log'))
+    log(f'mode={args.mode} debug-dir={debug_dir} serial={args.serial_log}')
+
+    qmp_sock = os.path.join(debug_dir, 'qmp.sock')
+    proc = launch(qemu_args, qmp_sock, log)
+    qmp = QMP(qmp_sock)
+    try:
+        qmp.connect()
+    except Exception as e:  # noqa: BLE001
+        log(f'QMP connect failed: {e}')
+        proc.kill()
+        return 2
+    screen = Screen(qmp, debug_dir, log)
+    serial = Serial(args.serial_log)
+    try:
+        if args.mode == 'qga':
+            rc = run_qga(args, proc, qmp, screen, serial, log)
+        else:
+            rc = drive(args, proc, qmp, screen, serial, log)
+    finally:
+        if args.serial_log and os.path.exists(args.serial_log):
+            try:
+                shutil.copy(args.serial_log, os.path.join(debug_dir, 'serial.log'))
+            except OSError:
+                pass
+        try:
+            if proc.poll() is None:
+                proc.kill()
+        except Exception:  # noqa: BLE001
+            pass
+    log(f'done rc={rc}')
+    return rc
+
+
+if __name__ == '__main__':
+    sys.exit(main())

lib/images/macos/helpers/vmix-readback.nix

@@ -0,0 +1,14 @@
+# Shell snippet: read the PE's result off the VMIX HFS+ volume of a raw disk
+# image (${image}). Prints the guest logs and sets STATUS to the contents of
+# vmix-run.status ("0" on success, empty if run.sh never returned, e.g. the
+# installer rebooted). The PE unmounts VMIX before powering off.
+{ ... }:
+image:
+''
+  echo "=== vmix: reading result from ${image} ==="
+  for f in vmix-run.log system-install.log; do
+    C=$(guestfish --ro -a ${image} -m /dev/sda1 cat /$f 2>/dev/null || true)
+    [ -n "$C" ] && { echo "--- $f ---"; printf '%s\n' "$C" | tail -400; }
+  done
+  STATUS=$(guestfish --ro -a ${image} -m /dev/sda1 cat /vmix-run.status 2>/dev/null | tr -d '[:space:]' || true)
+''

lib/images/macos/helpers/xar-toc.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+# Print heap offsets of the entries of a xar archive (InstallAssistant.pkg) as JSON,
+# so SharedSupport.dmg can be exposed to the VM as a raw disk without extracting 18 GB.
+import json
+import struct
+import sys
+import xml.etree.ElementTree as ET
+
+toc_xml, archive = sys.argv[1], sys.argv[2]
+with open(archive, 'rb') as f:
+    magic, hsize, ver, toc_c, toc_u, cksum = struct.unpack('>4sHHQQI', f.read(28))
+assert magic == b'xar!', 'not a xar archive'
+heap = hsize + toc_c
+out = {}
+for entry in ET.parse(toc_xml).getroot().iter('file'):
+    data = entry.find('data')
+    if data is None:
+        continue
+    out[entry.findtext('name')] = {
+        'offset': heap + int(data.findtext('offset')),
+        'length': int(data.findtext('length')),
+        'size': int(data.findtext('size')),
+        'encoding': data.find('encoding').get('style'),
+    }
+json.dump(out, sys.stdout, indent=2)

lib/images/macos/tahoe/default.nix

@@ -0,0 +1,14 @@
+{ pkgs, lib, system, macos, ... }:
+let
+  up = macos.upstream.tahoe;
+  # 18 GB full installer (App Store InstallAssistant.pkg, pinned)
+  installer = pkgs.fetchurl { inherit (up.installer) url hash; name = "InstallAssistant.pkg"; };
+  # Recovery BaseSystem.dmg: a pre-verified local store file when `recovery.file` is set
+  # (Apple's CDN rotates Sequoia/Tahoe during the rollout), else fetched + pinned.
+  # `nix store add-path --name macos-tahoe-BaseSystem.dmg BaseSystem.dmg` yields the same
+  # content-addressed path on any host that has the file.
+  recovery = if up.recovery ? file
+    then builtins.storePath up.recovery.file
+    else macos.fetchRecovery { inherit (up.recovery) shortname sha256; };
+in
+import ./images.nix { inherit pkgs lib system macos installer recovery; }

lib/images/macos/tahoe/images.nix

@@ -0,0 +1,17 @@
+# Pre-built macOS Tahoe (26) images
+# Pipeline: makeRecoveryPE (Recovery + vmix hook) → makeImage (unattended, offline
+# install) → templates (applied offline from the PE) → generalize
+{ pkgs, lib, system, macos, installer, recovery, ... }:
+with macos;
+rec {
+  pe = makeRecoveryPE { name = "macos-tahoe"; inherit recovery; };
+
+  upstream = makeImage {
+    name = "macos-tahoe";
+    inherit installer pe;
+  };
+
+  basic = customizeImageFold upstream templates.bundles.basic;
+
+  remote = customizeImageFold upstream templates.bundles.remote;
+}

lib/images/macos/templates/default.nix

@@ -0,0 +1,18 @@
+{ pkgs, lib, ... }:
+rec {
+  generalize = import ./generalize.nix { inherit pkgs lib; };
+
+  software = import ./software { inherit pkgs lib; };
+  profile = import ./profile { inherit pkgs lib; };
+
+  essentials = {
+    remoteAccess = import ./essentials/remote-access.nix { };
+    noUpdates = import ./essentials/no-updates.nix { };
+    performance = import ./essentials/performance.nix { inherit pkgs; };
+  };
+
+  bundles = {
+    basic = with essentials; [ noUpdates performance ];
+    remote = with essentials; [ noUpdates performance remoteAccess ];
+  };
+}

lib/images/macos/templates/essentials/no-updates.nix

@@ -0,0 +1,13 @@
+# Disable automatic macOS / App Store updates (an OTA update would also need
+# the RestrictEvents kext to work in a VM)
+{ ... }:
+{
+  name = "no-updates";
+  script = ''
+    SU="$DATA/Library/Preferences/com.apple.SoftwareUpdate.plist"
+    for k in AutomaticCheckEnabled AutomaticDownload AutomaticallyInstallMacOSUpdates ConfigDataInstall CriticalUpdateInstall; do
+      pe_plist_set "$SU" "$k" bool false
+    done
+    pe_plist_set "$DATA/Library/Preferences/com.apple.commerce.plist" AutoUpdate bool false
+  '';
+}

lib/images/macos/templates/essentials/performance.nix

@@ -0,0 +1,32 @@
+# Less background work in a VM: no Spotlight indexing, no Time Machine, no
+# sleep, no immediate screen lock.
+{ pkgs, ... }:
+let
+  power = pkgs.writeText "com.apple.PowerManagement.plist" ''
+    <?xml version="1.0" encoding="UTF-8"?>
+    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+    <plist version="1.0">
+    <dict>
+      <key>ActivePowerProfiles</key><dict><key>AC Power</key><integer>-1</integer></dict>
+      <key>Custom Profile</key><dict><key>AC Power</key><dict>
+        <key>Display Sleep Timer</key><integer>0</integer>
+        <key>System Sleep Timer</key><integer>0</integer>
+        <key>Disk Sleep Timer</key><integer>0</integer>
+        <key>Wake On LAN</key><integer>0</integer>
+        <key>hibernatemode</key><integer>0</integer>
+      </dict></dict>
+    </dict>
+    </plist>
+  '';
+in
+{
+  name = "performance";
+  files = [ { source = power; name = "com.apple.PowerManagement.plist"; } ];
+  script = ''
+    touch "$DATA/.metadata_never_index"
+    pe_plist_set "$DATA/Library/Preferences/com.apple.TimeMachine.plist" AutoBackup bool false
+    pe_plist_set "$DATA/Library/Preferences/com.apple.loginwindow.plist" DisableScreenLockImmediate bool true
+    cp "$V/com.apple.PowerManagement.plist" "$DATA/Library/Preferences/com.apple.PowerManagement.plist"
+    chown 0:0 "$DATA/Library/Preferences/com.apple.PowerManagement.plist"
+  '';
+}

lib/images/macos/templates/essentials/remote-access.nix

@@ -0,0 +1,10 @@
+# Enable SSH (Remote Login) and Screen Sharing (VNC on 5900 inside the guest)
+# by clearing their launchd overrides on the image's Data volume.
+{ ... }:
+{
+  name = "remote-access";
+  script = ''
+    pe_service_disabled com.apple.openssh.sshd false
+    pe_service_disabled com.apple.screensharing false
+  '';
+}

lib/images/macos/templates/generalize.nix

@@ -0,0 +1,146 @@
+# Generalize a macOS image, offline from the PE: create the (admin) user on the
+# image's Data volume with dscl, auto-login, suppress the first-login Setup
+# Assistant, hostname, locale, timezone, use the whole disk, and give the image
+# a fresh SMBIOS identity (serial/MLB from macserial, MAC + UUID from `seed`) so
+# every generalized VM looks like a distinct Mac to Apple ID/iMessage.
+# Usage: (templates.generalize { username = "User"; password = ""; hostname = "MAC"; })
+# delayOobeRun = true: no user, Setup Assistant runs on first real boot (like Windows OOBE)
+{ pkgs, lib, ... }:
+{
+  username ? "User",
+  password ? "",
+  fullName ? username,
+  autoLogon ? true,
+  hostname ? "MAC-VM",
+  locale ? "en-US",
+  timezone ? "UTC",
+  delayOobeRun ? false,
+  # SMBIOS identity; anything unset is generated
+  model ? null,
+  serial ? null,
+  mlb ? null,
+  uuid ? null,
+  mac ? null,
+  seed ? "${hostname}-${username}",
+  # keep the user's home on an APFS volume labelled vmix-home (a virtio-blk disk
+  # the host provides, formatted by the PE on first start). macOS refuses mounts
+  # over /Users (firmlink), so the volume automounts at /Volumes/<label> and the
+  # account's home directory lives there: ephemeral OS disk, persistent home.
+  persistHome ? false,
+  homeVolumeLabel ? "vmix-home",
+  # no desktop widgets for the created user (Sonoma+)
+  hideWidgets ? true,
+  # accepted for CLI parity with Windows, not supported on macOS
+  bgColor ? null,
+}:
+let
+  kcpasswordFile = pkgs.runCommand "kcpassword" { nativeBuildInputs = [ pkgs.python3 ]; } ''
+    python3 ${../guest/kcpassword.py} ${lib.escapeShellArg password} > $out
+  '';
+  macLocale = builtins.replaceStrings [ "-" ] [ "_" ] locale;
+  tempPassword = "vmix-temp-password";
+  setupKeys = [
+    "DidSeeCloudSetup" "DidSeeSiriSetup" "DidSeePrivacy" "DidSeeTouchIDSetup" "DidSeeAppearanceSetup"
+    "DidSeeScreenTime" "DidSeeAccessibility" "DidSeeTrueTonePrivacy" "DidSeeActivationLock"
+    "DidSeeiCloudLoginForStorageServices" "DidSeeSyncSetup" "DidSeeSyncSetup2" "DidSeeAppleIDSyncSetup"
+    "DidSeeApplePaySetup" "DidSeeIntelligence" "DidSeeLockdownMode" "DidSeeAppStore" "DidSeeUpdateMacAutomatically"
+    "DidSeeSoftwareUpdate" "SkipFirstLoginOptimization"
+  ];
+in
+{
+  name = if delayOobeRun then "generalize-delay-oobe" else "generalize";
+  files = [ { source = kcpasswordFile; name = "kcpassword"; } ];
+  smbios = { inherit seed; } // lib.filterAttrs (_: v: v != null) { inherit model serial mlb uuid mac; };
+  script = ''
+    set -x
+    ${lib.optionalString (bgColor != null) ''echo "vmix: bgColor is not supported on macOS, ignoring"''}
+    VER=$(pe_target_version); BUILD=$(pe_target_build)
+    echo "vmix: target macOS $VER ($BUILD)"
+    N="$DATA/private/var/db/dslocal/nodes/Default"
+    D() { dscl -f "$N" localhost "$@"; }
+
+    ${lib.optionalString (!delayOobeRun) ''
+    # --- user account (admin), created directly in the local directory node
+    U="${username}"; HOME_DIR="$DATA/Users/$U"
+    ${lib.optionalString persistHome ''HOME_PATH="/Volumes/${homeVolumeLabel}/$U"''}
+    if ! D -read "/Local/Default/Users/$U" >/dev/null 2>&1; then
+      UID_NEW=$(D -list /Local/Default/Users UniqueID | awk '$2 >= 501 && $2 < 1000 && $2 > m {m = $2} END {print (m ? m + 1 : 501)}')
+      D -create "/Local/Default/Users/$U" || pe_fail "dscl create user"
+      D -create "/Local/Default/Users/$U" UserShell /bin/zsh
+      D -create "/Local/Default/Users/$U" RealName ${lib.escapeShellArg fullName}
+      D -create "/Local/Default/Users/$U" UniqueID "$UID_NEW"
+      D -create "/Local/Default/Users/$U" PrimaryGroupID 20
+      D -create "/Local/Default/Users/$U" NFSHomeDirectory "${if persistHome then "/Volumes/${homeVolumeLabel}/$U" else "/Users/$U"}"
+      if ! D -passwd "/Local/Default/Users/$U" ${lib.escapeShellArg password}; then
+        echo "vmix: WARNING: could not set the requested password, using '${tempPassword}'"
+        D -passwd "/Local/Default/Users/$U" "${tempPassword}" || pe_fail "dscl passwd"
+      fi
+      for g in admin _appserverusr _appserveradm _lpadmin; do
+        D -append "/Local/Default/Groups/$g" GroupMembership "$U" 2>/dev/null || true
+      done
+      mkdir -p "$HOME_DIR"
+      T="$SYS/System/Library/User Template/Non_localized"; [ -d "$T" ] || T="/System/Library/User Template/Non_localized"
+      ditto "$T" "$HOME_DIR" 2>/dev/null || true
+      L="$SYS/System/Library/User Template/English.lproj"; [ -d "$L" ] && ditto "$L" "$HOME_DIR" 2>/dev/null || true
+    else
+      UID_NEW=$(D -read "/Local/Default/Users/$U" UniqueID | awk '{print $2}')
+    fi
+    ${lib.optionalString autoLogon ''
+    pe_plist_set "$DATA/Library/Preferences/com.apple.loginwindow.plist" autoLoginUser string "$U"
+    cp "$V/kcpassword" "$DATA/private/etc/kcpassword"
+    chmod 600 "$DATA/private/etc/kcpassword"; chown 0:0 "$DATA/private/etc/kcpassword"
+    ''}
+    # --- no Setup Assistant / "What's new" prompts at first login
+    mkdir -p "$HOME_DIR/Library/Preferences"
+    P="$HOME_DIR/Library/Preferences/com.apple.SetupAssistant.plist"
+    for k in ${lib.concatStringsSep " " setupKeys}; do pe_plist_set "$P" "$k" bool true; done
+    pe_plist_set "$P" GestureMovieSeen string none
+    pe_plist_set "$P" LastSeenCloudProductVersion string "$VER"
+    pe_plist_set "$P" LastSeenBuddyBuildVersion string "$BUILD"
+    pe_plist_set "$P" LastSeenSiriProductVersion string "$VER"
+    pe_plist_set "$P" LastPreLoginTasksPerformedVersion string "$VER"
+    pe_plist_set "$P" LastPreLoginTasksPerformedBuild string "$BUILD"
+    pe_plist_set "$HOME_DIR/Library/Preferences/.GlobalPreferences.plist" AppleLocale string "${macLocale}"
+    ${lib.optionalString hideWidgets ''
+    WM="$HOME_DIR/Library/Preferences/com.apple.WindowManager.plist"
+    pe_plist_set "$WM" StandardHideWidgets integer 1
+    pe_plist_set "$WM" StageManagerHideWidgets integer 1
+    ''}
+    chown -R "$UID_NEW:20" "$HOME_DIR"
+    touch "$DATA/private/var/db/.AppleSetupDone"
+    ''}
+    ${lib.optionalString delayOobeRun ''
+    rm -f "$DATA/private/var/db/.AppleSetupDone"
+    ''}
+
+    # --- machine identity
+    PF="$DATA/Library/Preferences/SystemConfiguration/preferences.plist"
+    mkdir -p "$(dirname "$PF")"
+    pe_plist_dict "$PF" System
+    pe_plist_dict "$PF" System.System
+    pe_plist_dict "$PF" System.Network
+    pe_plist_dict "$PF" System.Network.HostNames
+    pe_plist_set "$PF" System.System.ComputerName string "${hostname}"
+    pe_plist_set "$PF" System.System.HostName string "${hostname}"
+    pe_plist_set "$PF" System.Network.HostNames.LocalHostName string "${hostname}"
+    pe_plist_set "$DATA/Library/Preferences/.GlobalPreferences.plist" AppleLocale string "${macLocale}"
+    ln -sfn "/var/db/timezone/zoneinfo/${timezone}" "$DATA/private/etc/localtime"
+    pe_plist_set "$DATA/Library/Preferences/com.apple.timezone.auto.plist" Active bool false
+
+    # --- QEMU's USB keyboard (vendor 0x0627, product 0x0001) is unknown to macOS,
+    # which would open the Keyboard Setup Assistant at every login: declare it ANSI
+    KT="$DATA/Library/Preferences/com.apple.keyboardtype.plist"
+    pe_plist_dict "$KT" keyboardtype
+    pe_plist_set "$KT" keyboardtype.1-1575-0 integer 40
+
+    ${lib.optionalString persistHome ''
+    # --- persistent home: the seeded home directory on the Data volume is the
+    # template loginwindow copies to /Volumes/${homeVolumeLabel}/$U at first login
+    # (the volume is automounted by diskarbitrationd before the login)
+    ''}
+
+    # --- use the whole (possibly grown) disk
+    STORE=$(diskutil info "$SYS_ID" | sed -n 's/.*APFS Physical Store: *//p' | awk '{print $1}')
+    [ -n "$STORE" ] && diskutil apfs resizeContainer "$STORE" 0 || true
+  '';
+}

lib/images/macos/templates/profile/default.nix

@@ -0,0 +1,76 @@
+# User profile templates, applied on the booted image inside the logged-in
+# user's session through the guest agent (after generalize with autoLogon).
+#   settings — { hideWidgets, wallpaper, dockApps, dockAutohide, showHiddenFiles }
+{ pkgs, lib, ... }:
+let
+  # Apple Events (osascript → System Events) need per-app automation consent that a
+  # headless session cannot grant; desktoppr sets the wallpaper through NSWorkspace
+  # inside the user's session instead (scriptingosx/desktoppr, pinned).
+  desktoppr = pkgs.fetchurl {
+    url = "https://github.com/scriptingosx/desktoppr/releases/download/v0.5/desktoppr-0.5-218.pkg";
+    hash = "sha256-HPtn1wI7xrx7HjyMz1yJGhutIodt938/vHfSeHfMe50=";
+  };
+in
+rec {
+  settings = {
+    hideWidgets ? true,          # no desktop widgets (Sonoma+)
+    wallpaper ? null,            # image file (drv/path) set as the desktop picture
+    dockApps ? null,             # list of app paths, e.g. [ "/System/Applications/Utilities/Terminal.app" ]; null = untouched
+    dockAutohide ? false,
+    showHiddenFiles ? false,
+    darkMode ? null,             # true/false/null
+  }: {
+    name = "profile";
+    files = lib.optionals (wallpaper != null) [
+      { source = wallpaper; name = "wallpaper.${lib.last (lib.splitString "." (baseNameOf (toString wallpaper)))}"; }
+      { source = desktoppr; name = "desktoppr.pkg"; }
+    ];
+    bootScript = ''
+      set -x
+      [ -n "$CONSOLE_USER" ] || { echo "vmix: profile needs a logged-in user (generalize with autoLogon)"; exit 1; }
+      H=$(dscl . -read "/Users/$CONSOLE_USER" NFSHomeDirectory | awk '{print $2}')
+      D() { as_user defaults write "$@"; }
+      ${lib.optionalString hideWidgets ''
+      D com.apple.WindowManager StandardHideWidgets -int 1
+      D com.apple.WindowManager StageManagerHideWidgets -int 1
+      D com.apple.widgets widgetAppearance -int 0
+      ''}
+
+      ${lib.optionalString (dockApps != null) ''
+      D com.apple.dock persistent-apps -array
+      ${lib.concatMapStringsSep "\n" (a: ''
+      D com.apple.dock persistent-apps -array-add "<dict><key>tile-type</key><string>file-tile</string><key>tile-data</key><dict><key>file-data</key><dict><key>_CFURLString</key><string>file://${a}/</string><key>_CFURLStringType</key><integer>15</integer></dict></dict></dict>"
+      '') dockApps}
+      ''}
+      ${lib.optionalString dockAutohide ''D com.apple.dock autohide -bool true''}
+      ${lib.optionalString showHiddenFiles ''D com.apple.finder AppleShowAllFiles -bool true''}
+      ${lib.optionalString (darkMode != null) (if darkMode
+        then ''D -g AppleInterfaceStyle Dark''
+        else ''as_user defaults delete -g AppleInterfaceStyle 2>/dev/null || true'')}
+      as_user killall Dock Finder WindowManager 2>/dev/null || true
+      sleep 10
+      # wallpaper last: WindowManager re-applies its desktop configuration when the
+      # widget/dock settings above change, which reverts a choice made before it
+      ${lib.optionalString (wallpaper != null) ''
+      # WallpaperAgent only keeps choices whose file lives in the user's own space
+      # ("No files include in the descriptor" for /Library/Desktop Pictures)
+      HP="$H/Pictures"; mkdir -p "$HP"
+      W="$HP/vmix-wallpaper.${lib.last (lib.splitString "." (baseNameOf (toString wallpaper)))}"
+      cp "$V/wallpaper".* "$W"; chown "$CONSOLE_USER" "$HP" "$W"; chmod 644 "$W"
+      installer -pkg "$V/desktoppr.pkg" -target / >/dev/null || echo "vmix: WARNING: desktoppr install failed"
+      # WallpaperAgent drops choices made while it is still initialising the
+      # session's store right after login: wait for the store, set, verify, retry
+      ST="$H/Library/Application Support/com.apple.wallpaper/Store/Index.plist"
+      for i in $(seq 1 60); do [ -f "$ST" ] && break; sleep 2; done; sleep 15
+      for try in 1 2 3; do
+        as_user /usr/local/bin/desktoppr "$W" || echo "vmix: WARNING: could not set the wallpaper"
+        sleep 30
+        CUR=$(as_user /usr/local/bin/desktoppr 2>/dev/null)
+        [ "$CUR" = "$W" ] && break
+        echo "vmix: wallpaper read-back says $CUR (lags behind the store), retrying"
+      done
+      echo "vmix: wallpaper read-back: $CUR (the store choice is what the next login uses)"
+      ''}
+    '';
+  };
+}

lib/images/macos/templates/software/default.nix

@@ -0,0 +1,51 @@
+# Software installation templates.
+#   pkg    — install a flat/distribution .pkg offline from the PE (`installer -target`)
+#   app    — copy an .app bundle (from a directory or zip) into /Applications offline
+#   script — run a shell script as root on the booted image (network available)
+{ pkgs, lib, ... }:
+rec {
+  pkg = { name, src, choices ? null }: {
+    name = "pkg-${name}";
+    files = [ { source = src; name = "${name}.pkg"; } ]
+      ++ lib.optional (choices != null) { source = choices; name = "${name}.choices.xml"; };
+    script = ''
+      echo "vmix: installing ${name}.pkg into $SYS"
+      installer -verboseR -pkg "$V/${name}.pkg" -target "$SYS" \
+        ${lib.optionalString (choices != null) ''-applyChoiceChangesXML "$V/${name}.choices.xml"''} \
+        || pe_fail "installer ${name}.pkg"
+    '';
+  };
+
+  app = { name, src }: {
+    name = "app-${name}";
+    files = [ { source = src; name = "${name}.app"; } ];
+    script = ''
+      echo "vmix: copying ${name}.app to $DATA/Applications"
+      mkdir -p "$DATA/Applications"
+      rm -rf "$DATA/Applications/${name}.app"
+      ditto "$V/${name}.app" "$DATA/Applications/${name}.app" || pe_fail "ditto ${name}.app"
+      chown -R 0:80 "$DATA/Applications/${name}.app"
+      xattr -dr com.apple.quarantine "$DATA/Applications/${name}.app" 2>/dev/null || true
+    '';
+  };
+
+  script = { name, script, files ? [], network ? true }: {
+    name = "script-${name}";
+    inherit files network;
+    bootScript = script;
+  };
+
+  # Homebrew (needs network; installs for the console user or the given user)
+  homebrew = { user ? null, formulae ? [], casks ? [] }: {
+    name = "homebrew";
+    bootScript = ''
+      U=${if user == null then "$CONSOLE_USER" else user}
+      [ -n "$U" ] || { echo "vmix: no user to install Homebrew for"; exit 1; }
+      launchctl asuser "$(id -u "$U")" sudo -u "$U" env NONINTERACTIVE=1 \
+        /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)" || exit 1
+      B=/usr/local/bin/brew
+      ${lib.optionalString (formulae != []) ''launchctl asuser "$(id -u "$U")" sudo -u "$U" $B install ${lib.escapeShellArgs formulae} || exit 1''}
+      ${lib.optionalString (casks != []) ''launchctl asuser "$(id -u "$U")" sudo -u "$U" $B install --cask ${lib.escapeShellArgs casks} || exit 1''}
+    '';
+  };
+}

lib/images/macos/tools/soak.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Repeatability check for a macOS image build: build the same attribute N times
+# (forcing a rebuild each time), keep every run's driver + serial logs, and print
+# a table of outcome / duration / which recovery mechanisms fired.
+#   tools/soak.sh <flake-dir> <attr> [runs] [outdir]
+# e.g. tools/soak.sh /root/vmix.nix macos.images.tahoe.upstream 3
+set -u
+FLAKE=${1:?flake dir}; ATTR=${2:?attribute}; RUNS=${3:-3}; OUT=${4:-/tmp/vmix-macos-soak}
+NAME=$(nix eval --impure --raw --expr "(builtins.getFlake \"path:$FLAKE\").lib.x86_64-linux.$ATTR.name" | sed 's/-vmix\.qcow2$//')
+DRV=$(nix eval --impure --raw --expr "(builtins.getFlake \"path:$FLAKE\").lib.x86_64-linux.$ATTR.drvPath")
+mkdir -p "$OUT"
+printf '%-4s %-8s %-9s %-6s %-7s %-7s %-6s %s\n' run result minutes boots resets panics tries note | tee "$OUT/summary.txt"
+for i in $(seq 1 "$RUNS"); do
+  D="$OUT/run-$i"; rm -rf "$D"; mkdir -p "$D"
+  rm -rf "/tmp/vmix-macos/$NAME"
+  t0=$(date +%s)
+  if [ "$i" -eq 1 ]; then nix build --no-link -L --option sandbox relaxed "$DRV^*" > "$D/build.log" 2>&1; rc=$?
+  else nix build --no-link -L --option sandbox relaxed --rebuild "$DRV^*" > "$D/build.log" 2>&1; rc=$?; fi
+  t1=$(date +%s)
+  cp "/tmp/vmix-macos/$NAME"/driver.log "/tmp/vmix-macos/$NAME"/serial.log "$D/" 2>/dev/null
+  cp "/tmp/vmix-macos/$NAME"/*.png "$D/" 2>/dev/null
+  L="$D/driver.log"
+  boots=$(grep -c 'guest kernel boot' "$L" 2>/dev/null); resets=$(grep -c 'system_reset' "$L" 2>/dev/null)
+  panics=$(grep -c 'kernel panic' "$L" 2>/dev/null); tries=$(grep -c 'startosinstall try' "$L" 2>/dev/null)
+  note=$(grep -oE 'prepare too slow[^,]*|PE did not[^,]*|guest halted|powering down|timeout reached' "$L" 2>/dev/null | sort | uniq -c | tr '\n' ';' | tr -s ' ')
+  # --rebuild makes nix exit non-zero when the (byte-wise different) qcow2 does not
+  # match the earlier output; judge the run by the builder's own completion line
+  if grep -q "install complete" "$D/build.log"; then res=OK; else res=FAIL; fi
+  printf '%-4s %-8s %-9s %-6s %-7s %-7s %-6s %s\n' "$i" "$res" "$(( (t1 - t0) / 60 ))" "$boots" "$resets" "$panics" "$tries" "$note" | tee -a "$OUT/summary.txt"
+done
+echo "logs: $OUT"

lib/images/macos/upstream.json

@@ -0,0 +1,56 @@
+{
+  "x86_64-linux": {
+    "tahoe": {
+      "installer": {
+        "version": "26.6.2",
+        "build": "25G83",
+        "url": "https://swcdn.apple.com/content/downloads/37/33/140-93587-A_GRFFH93NOL/f944yaqo1cjhh2m0kxrl0zhcpg9yb9qphv/InstallAssistant.pkg",
+        "hash": "sha256-N2kj10lM+jK2nzg7z9zkau7bYJ/mokLqEqbgFb+3e6Q="
+      },
+      "recovery": {
+        "shortname": "tahoe",
+        "sha256": "edddd0d5869caaa12e29e6996a04f11590280580976a119dbd42c24fa62fe18e",
+        "file": "/nix/store/fqpih1dmg826cfxcyyxn4qm08pvcxgz4-macos-tahoe-BaseSystem.dmg",
+        "version": "26.6.2",
+        "build": "25G83"
+      }
+    },
+    "opencore": {
+      "image": {
+        "url": "https://raw.githubusercontent.com/kholia/OSX-KVM/4c378a4b5e0b219783683012bec680325eb40719/OpenCore/OpenCore.qcow2",
+        "sha256": "6ed36c0c2a4206ccc695f6b1a734a1cc6f94d288b0517c705d351c63cb92a6f3"
+      },
+      "pkg": {
+        "version": "1.0.7",
+        "url": "https://github.com/acidanthera/OpenCorePkg/releases/download/1.0.7/OpenCore-1.0.7-RELEASE.zip",
+        "sha256": "2ffab6ebf58c7aefb0bcb3a1a385d207746823d6dd87d44bd666e1286939943e"
+      },
+      "fetchRecoveryScript": {
+        "url": "https://raw.githubusercontent.com/kholia/OSX-KVM/4c378a4b5e0b219783683012bec680325eb40719/fetch-macOS-v2.py",
+        "sha256": "39ac6d26bd265f5d32198062f515ad15ef93afb7a74e702be2b008090d5bd5f3"
+      },
+      "kexts": {
+        "Lilu": {
+          "version": "1.7.2",
+          "url": "https://github.com/acidanthera/Lilu/releases/download/1.7.2/Lilu-1.7.2-RELEASE.zip",
+          "hash": "sha256-U5Z9fc+qsBAjoz3y6WmolSLxPWZUpqVqxHEbYtq/Org="
+        },
+        "VirtualSMC": {
+          "version": "1.3.7",
+          "url": "https://github.com/acidanthera/VirtualSMC/releases/download/1.3.7/VirtualSMC-1.3.7-RELEASE.zip",
+          "hash": "sha256-EvHTeZafkmMG+pLZTdvzOzKzEXZYncQgidhkomsxtwA="
+        },
+        "WhateverGreen": {
+          "version": "1.7.0",
+          "url": "https://github.com/acidanthera/WhateverGreen/releases/download/1.7.0/WhateverGreen-1.7.0-RELEASE.zip",
+          "hash": "sha256-bW/+gzStYPeEpmJ5TmeyVgt511fVBoQdyMqZlKs5l5s="
+        },
+        "RestrictEvents": {
+          "version": "1.1.6",
+          "url": "https://github.com/acidanthera/RestrictEvents/releases/download/1.1.6/RestrictEvents-1.1.6-RELEASE.zip",
+          "hash": "sha256-mBcN+uGV3dKLXZXj8EASWhPKeDvLm9HluMWI4hexTuY="
+        }
+      }
+    }
+  }
+}

nixos/vms/config.nix

@@ -77,13 +77,23 @@ let
 
       hasOsDisk = vmCfg.disks.os.file != null;
 
-      # Auto-detect Windows from _vmixOsType marker on the disk image
+      # Auto-detect Windows / macOS from _vmixOsType marker on the disk image
-      isWindows = vmCfg.windows.enable || (hasOsDisk && (vmCfg.disks.os.file._vmixOsType or "linux") == "windows");
+      osType = if hasOsDisk then vmCfg.disks.os.file._vmixOsType or "linux" else "linux";
+      isWindows = vmCfg.windows.enable || osType == "windows";
+      isMacos = vmCfg.macos.enable || osType == "macos";
+      macosMac = if vmCfg.macos.mac != null then vmCfg.macos.mac
+        else if hasOsDisk then vmCfg.disks.os.file.macAddress or "52:54:00:c9:18:27"
+        else "52:54:00:c9:18:27";
+      # OpenCore marks this PCI slot built-in (en0)
+      macosNicPlacement = ",bus=pcie.0,addr=${vmixLib.macos.qemu.nicAddr}";
+      cpuArg = if isMacos && vmCfg.cpu.model == "host" then vmCfg.macos.cpu
+        else "${vmCfg.cpu.model}${optionalString (vmCfg.cpu.hideVirtualized && !isMacos) ",kvm=off,hv_vendor_id=1234567890ab,-hypervisor"}";
       # Interrupt remapping in the virtual IOMMU only works on a split irqchip,
       # so viommu wins over the full in-kernel irqchip hideVirtualized asks for.
+      # (macOS keeps the default irqchip: hideVirtualized does not apply to it.)
       machineIrqchipArg =
         if vmCfg.pci.viommu.enable then ",kernel-irqchip=split"
-        else optionalString vmCfg.cpu.hideVirtualized ",kernel_irqchip=on";
+        else optionalString (vmCfg.cpu.hideVirtualized && !isMacos) ",kernel_irqchip=on";
       # Functions of one physical device have to reach the guest as functions
       # of one device too. Giving each address its own root port splits a GPU
       # from its own HDMI audio, and Navi cannot then reset or power-manage
@@ -97,6 +107,42 @@ let
         (unique (map pciDeviceOf vmCfg.pci.passthrough));
 
 
+      # --- macOS: guest agent, virtio-fs shares, persistent home volume
+      macosQemu = vmixLib.macos.qemu;
+      qgaSock = "/run/vmix/qga-${vmCfg.name}.sock";
+      macosGuestAgent = isMacos && vmCfg.macos.guestAgent.enable;
+      macosShares = if isMacos then vmCfg.shares else {};
+      macosShareNames = attrNames macosShares;
+      macosAutomountShare = if macosShares ? automount then "automount"
+        else if macosShareNames != [] then head macosShareNames else null;
+      macosShareTag = n: if n == macosAutomountShare then macosQemu.automountTag else n;
+      macosShareSock = n: "/run/vmix/vfs-${vmCfg.name}-${n}.sock";
+      macosHome = isMacos && vmCfg.macos.homeDisk.enable;
+      macosFormatHome = if macosHome then vmixLib.macos.formatVolume {
+        image = vmCfg.disks.os.file; label = vmCfg.macos.homeDisk.label;
+      } else null;
+      # shares beyond the automounted one are mounted through the guest agent once it answers
+      macosMountSharesScript = pkgs.writeShellScript "${vmCfg.name}-macos-shares-vmix" ''
+        for i in $(seq 1 120); do
+          [ -S ${qgaSock} ] && printf '{"execute":"guest-ping"}\n' | ${pkgs.socat}/bin/socat -T5 - UNIX-CONNECT:${qgaSock} 2>/dev/null | grep -q return && break
+          sleep 5
+        done
+        ${concatMapStrings (n: optionalString (n != macosAutomountShare) ''
+        printf '%s\n' '{"execute":"guest-exec","arguments":{"path":"/bin/bash","arg":["-c","mkdir -p ${macosShares.${n}.target}; mount -t virtiofs ${n} ${macosShares.${n}.target}"]}}' \
+          | ${pkgs.socat}/bin/socat -T10 - UNIX-CONNECT:${qgaSock} >/dev/null 2>&1 || true
+        '') macosShareNames}
+      '';
+      seedHomeDiskScript = pkgs.writeShellScript "${vmCfg.name}-home-disk-vmix" ''
+        F="${vmCfg.macos.homeDisk.file}"
+        if [ ! -e "$F" ]; then
+          echo "Creating persistent home volume $F (${vmCfg.macos.homeDisk.size}, ${vmCfg.macos.homeDisk.format})..."
+          mkdir -p "$(dirname "$F")"
+          ${pkgs.qemu}/bin/qemu-img create -q -f ${vmCfg.macos.homeDisk.format} "$F" ${vmCfg.macos.homeDisk.size}
+          chmod 600 "$F"
+          ${macosFormatHome} "$F" ${vmCfg.macos.homeDisk.format}
+        fi
+      '';
+
       # Linux VMs: apply customizeImage with 9p fstab and machine-id setup
       linuxOsImage = vmixLib.linux.customizeImage vmCfg.disks.os.file {
         name = vmCfg.name;
@@ -108,9 +154,9 @@ let
         '';
       };
 
-      # Windows VMs: use disk image as-is (customization done at image build time)
+      # Windows/macOS VMs: use disk image as-is (customization done at image build time)
       storeImage = if !hasOsDisk then null
-        else if isWindows then vmCfg.disks.os.file
+        else if isWindows || isMacos then vmCfg.disks.os.file
         else linuxOsImage;
 
       # When persist = true, QEMU needs a mutable disk outside /nix/store.
@@ -130,7 +176,8 @@ let
         fi
       '';
 
-      persistExecStartPre = lib.optional (hasOsDisk && vmCfg.disks.os.persist) seedPersistentDiskScript;
+      persistExecStartPre = lib.optional (hasOsDisk && vmCfg.disks.os.persist) seedPersistentDiskScript
+        ++ lib.optional macosHome seedHomeDiskScript;
 
       # QEMU expects single-letter boot codes (e.g. c,d,n), while vmix uses readable names.
       bootOrderQemu =
@@ -165,6 +212,16 @@ let
       );
 
       qemuStartVMScript = pkgs.writeShellScript "${vmCfg.name}-qemu-vmix" ''
+        ${optionalString (isMacos && macosShareNames != []) ''
+          mkdir -p /run/vmix
+          ${concatMapStrings (n: ''
+          rm -f ${macosShareSock n}
+          ${pkgs.virtiofsd}/bin/virtiofsd --socket-path=${macosShareSock n} --shared-dir ${toString macosShares.${n}.source} --cache auto --sandbox none &
+          '') macosShareNames}
+          for i in $(seq 1 50); do ${concatMapStringsSep " && " (n: "[ -S ${macosShareSock n} ]") macosShareNames} && break; sleep 0.2; done
+          ${optionalString macosGuestAgent "${macosMountSharesScript} &"}
+        ''}
+        ${optionalString macosGuestAgent "mkdir -p /run/vmix; rm -f ${qgaSock}"}
         ${optionalString vmCfg.vnc.enable ''
           ${optionalString (vmCfg.vnc.passwordFile != null) ''
             if [ ! -r ${escapeShellArg vmCfg.vnc.passwordFile} ]; then
@@ -198,7 +255,7 @@ let
           ${optionalString vmCfg.vnc.enable "-vnc ${vncArgs}"} \
           ${optionalString (vmCfg.spice.enable && vmCfg.spice.passwordFile != null) "-object secret,id=spice-pass-${vmCfg.name},file=${escapeShellArg vmCfg.spice.passwordFile}"} \
           ${optionalString vmCfg.spice.enable "-spice addr=${vmCfg.spice.addr},port=${toString vmCfg.spice.port}${optionalString (vmCfg.spice.passwordFile == null) ",disable-ticketing=on"}${optionalString (vmCfg.spice.passwordFile != null) ",password-secret=spice-pass-${vmCfg.name}"}"} \
-          ${optionalString vmCfg.spice.enable (if vmCfg.spice.displayDevice == "qxl" && vmCfg.spice.vgamem != null then "-vga none -device qxl-vga,vgamem_mb=${toString vmCfg.spice.vgamem}" else "-vga ${vmCfg.spice.displayDevice}")} \
+          ${optionalString (vmCfg.spice.enable && !isMacos) (if vmCfg.spice.displayDevice == "qxl" && vmCfg.spice.vgamem != null then "-vga none -device qxl-vga,vgamem_mb=${toString vmCfg.spice.vgamem}" else "-vga ${vmCfg.spice.displayDevice}")} \
           ${optionalString (vmCfg.spice.enable && vmCfg.spice.agent.enable) "-device virtio-serial-pci -chardev spicevmc,id=vdagent,debug=0,name=vdagent -device virtserialport,chardev=vdagent,name=com.redhat.spice.0"} \
           ${# Guest agent channel — prevents qemu-ga from spinning when virtio-win guest tools are installed
             optionalString isWindows "${optionalString (!vmCfg.spice.enable || !vmCfg.spice.agent.enable) "-device virtio-serial-pci"} -chardev socket,path=/tmp/qga-${vmCfg.name}.sock,server=on,wait=off,id=qga0 -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0"} \
@@ -208,7 +265,7 @@ let
           -m ${toString vmCfg.mem.size} \
           ${optionalString vmCfg.mem.balloon "-device virtio-balloon-pci"} \
           -smp cores=${toString vmCfg.cpu.cores} \
-          -cpu ${vmCfg.cpu.model}${optionalString vmCfg.cpu.hideVirtualized ",kvm=off,hv_vendor_id=1234567890ab,-hypervisor"} \
+          -cpu ${cpuArg} \
           -machine type=${vmCfg.pc.type}${machineIrqchipArg} \
           ${optionalString vmCfg.bios.efi "-bios ${pkgs.OVMF.fd}/FV/OVMF.fd"} \
           ${optionalString vmCfg.bios.tpm "-chardev socket,id=chrtpm,path=/tmp/mytpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0"} \
@@ -218,22 +275,33 @@ let
           -device qemu-xhci -device usb-tablet \
           -global ICH9-LMB.disable_s3=1 -global ICH9-LMB.disable_s4=1 \
           ''} \
-          ${optionalString hasOsDisk "-drive file=${osDiskPath},format=qcow2,if=virtio${optionalString (vmCfg.disks.os.persist == false) ",snapshot=on"}"} \
+          ${# macOS: VirtualSMC, USB keyboard/tablet, AHCI system disk, VMware SVGA (also under SPICE),
+            # Apple's guest agent, virtio-fs shares (shared memory backend), virtio-blk home volume
+            optionalString isMacos ''
+          ${macosQemu.deviceArgs} ${if vmCfg.spice.enable && vmCfg.spice.displayDevice == "std" then "-vga std" else macosQemu.vgaArgs} \
+          ${optionalString macosGuestAgent (macosQemu.guestAgentArgs qgaSock)} \
+          ${optionalString (macosShareNames != []) (macosQemu.memBackendArgs vmCfg.mem.size)} \
+          ${concatMapStrings (n: "${macosQemu.virtioFsArgs { tag = macosShareTag n; sock = macosShareSock n; id = n; }} \\\n          ") macosShareNames} \
+          ${optionalString macosHome (macosQemu.virtioBlkArgs { id = "home"; file = vmCfg.macos.homeDisk.file; format = vmCfg.macos.homeDisk.format; })} \
+          ''} \
+          ${optionalString hasOsDisk (if isMacos
+            then "-drive id=os,if=none,file=${osDiskPath},format=qcow2${optionalString (vmCfg.disks.os.persist == false) ",snapshot=on"} -device ide-hd,bus=sata.0,drive=os"
+            else "-drive file=${osDiskPath},format=qcow2,if=virtio${optionalString (vmCfg.disks.os.persist == false) ",snapshot=on"}")} \
           ${optionalString (vmCfg.disks.iso.file != null) "-drive file=${toString vmCfg.disks.iso.file},media=cdrom,readonly=on"} \
           ${concatMapStrings (diskCfg: ''
             -drive file=${toString diskCfg.file},format=${diskCfg.format},if=${vmCfg.disks.bus} \
           '') (attrValues vmCfg.disks.add)} \
-          ${concatStrings (mapAttrsToList (shareName: shareCfg: ''
+          ${optionalString (!isMacos) (concatStrings (mapAttrsToList (shareName: shareCfg: ''
             -virtfs local,path=${toString shareCfg.source},security_model=passthrough,mount_tag=${shareName} \
-          '') vmCfg.shares)} \
+          '') vmCfg.shares))} \
           ${optionalString cfg.networks.user.enable "
             -netdev user,id=user \
-            -device ${vmCfg.nicModel},netdev=user \
+            -device ${vmCfg.nicModel},netdev=user${optionalString isMacos ",mac=${macosMac}${macosNicPlacement}"} \
           "} \
-          ${concatMapStrings (tapCfg: ''
+          ${concatStrings (imap1 (i: tapCfg: ''
-            -device ${vmCfg.nicModel},netdev=lan-${tapCfg.name},mac=${tapCfg.mac} \
+            -device ${vmCfg.nicModel},netdev=lan-${tapCfg.name},mac=${tapCfg.mac}${optionalString (isMacos && i == 1 && !cfg.networks.user.enable) macosNicPlacement} \
             -netdev tap,id=lan-${tapCfg.name},ifname=${tapCfg.iface},script=no,downscript=no \
-          '') allTaps} \
+          '') allTaps)} \
           ${concatStrings (imap1 (i: macvtap: ''
             -device ${vmCfg.nicModel},netdev=macvtap-${macvtap.name},mac=$(ip l show ${macvtap.iface} | awk '/link\/ether/{print $2}') \
             -netdev tap,id=macvtap-${macvtap.name},fd=${toString (i+2)} ${toString (i+2)}<>/dev/tap$(ip l show ${macvtap.iface} | awk -F':' '/${macvtap.iface}/{print $1}') \
@@ -264,6 +332,8 @@ let
         ProtectSystem = true;
         ProtectHome = true;
         PrivateNetwork = true;
+        RuntimeDirectory = "vmix";
+        RuntimeDirectoryPreserve = "yes";
       } // lib.optionalAttrs (vmCfg.pci.passthrough != []) {
         # VFIO passthrough needs raw device access — relax sandboxing
         ProtectSystem = lib.mkForce false;

nixos/vms/submoduleOptions.nix

@@ -93,9 +93,9 @@ with lib;
         };
       };
       displayDevice = mkOption {
-        type = types.enum [ "virtio" "qxl" "std" "none" ];
+        type = types.enum [ "virtio" "qxl" "std" "vmware" "none" ];
         default = "qxl";
-        description = "QEMU -vga type to use with SPICE (qxl, virtio, std, none).";
+        description = "QEMU -vga type to use with SPICE (qxl, virtio, std, vmware, none). macOS has no QXL/virtio-gpu driver: it always uses vmware (or std).";
       };
       vgamem = mkOption {
         type = types.nullOr types.int;
@@ -212,11 +212,11 @@ with lib;
           };
           target = mkOption {
             type = types.str;
-            description = "Target path inside the VM for the shared directory.";
+            description = "Target path inside the VM for the shared directory. macOS: the share named `automount` (or the first one) appears at /Volumes/My Shared Files; others are mounted at target through the guest agent.";
           };
         };
       });
-      description = "Shared directories.";
+      description = "Shared directories (9p for Linux, virtio-fs via virtiofsd for macOS).";
     };
 
     disks.bus = mkOption {
@@ -249,6 +249,56 @@ with lib;
       };
     };
 
+    macos = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Enable macOS QEMU flags (OpenCore/AppleSMC, Skylake CPU spoof, AHCI disk, pinned NIC). Auto-enabled when disks.os.file carries _vmixOsType = \"macos\" metadata.";
+      };
+      cpu = mkOption {
+        type = types.str;
+        default = vmixLib.macos.qemu.defaultCpu;
+        description = "QEMU -cpu string used for macOS VMs when cpu.model is \"host\".";
+      };
+      mac = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = "MAC address of en0. Defaults to the image's macAddress (must match OpenCore's ROM for Apple ID / iMessage).";
+      };
+      guestAgent.enable = mkOption {
+        type = types.bool;
+        default = true;
+        description = "Attach Apple's built-in QEMU guest agent (virtio console port org.qemu.guest_agent.0). Socket: /run/vmix/qga-<name>.sock; guest-exec runs as root.";
+      };
+      homeDisk = {
+        enable = mkOption {
+          type = types.bool;
+          default = false;
+          description = "Persistent home volume: a host disk image attached as virtio-blk, formatted APFS with label `label` by the PE on first start. The image must be generalized with persistHome = true (the user's home is /Volumes/<label>/<user>), which makes the OS disk safely ephemeral (disks.os.persist = false).";
+        };
+        file = mkOption {
+          type = types.str;
+          default = "";
+          description = "Path of the home disk image, e.g. /storage/vms/mac/home.qcow2 (created if missing).";
+        };
+        format = mkOption {
+          type = types.enum [ "qcow2" "raw" ];
+          default = "qcow2";
+          description = "Image format; use raw for a zvol/block device (created only for files).";
+        };
+        size = mkOption {
+          type = types.str;
+          default = "64G";
+          description = "Size when the image is created.";
+        };
+        label = mkOption {
+          type = types.str;
+          default = "vmix-home";
+          description = "APFS volume label (must match generalize's homeVolumeLabel).";
+        };
+      };
+    };
+
     tpm = {
       stateDir = mkOption {
         type = types.str;