Big news for virtualization: macOS 27.3 lets Core AI in Mac VMs use the host’s GPU and Neural Engine. In some tests, the new paravirtualized paths can run Core AI tasks up to 7× faster¹ than the guest CPU, achieving 50 to nearly 100% of the host’s native speed. The new Core AI accelerator currently requires private APIs and a restricted entitlement. Here's how to set it up: • Install macOS 27.3 on the host and guest. • Build a VM host app with com\.apple.security.virtualization and com\.apple.private.virtualization entitlements. You’ll need to relax AMFI for the second entitlement. • On VZVirtualMachineConfiguration, add the accelerators using _setAcceleratorDevices with: • _VZMacCoreAIDeviceConfiguration (GPU, adds PVAIDevice) • _VZMacNeuralEngineDeviceConfiguration (existing ANE accelerator, adds Neural Engine for Core AI) On the guest, enable the feature flag: sudo mkdir -p /Library/Preferences/FeatureFlags/Domain && \ sudo defaults write /Library/Preferences/FeatureFlags/Domain/ParavirtualizedCoreAI enable_pv_delegate -dict Enabled -bool true and restart the guest. You can now call Core AI on the guest. If set up properly, ComputeUnitKind.availableKinds should list gpu and neuralEngine. —— There's a second, currently disabled host-side feature flag (ParavirtualizedCoreAIHost/enable_save_restore). When enabled, the Core AI accelerator advertises support for saving and restoring VM state. —— 1. Tested on a Mac with an M4 Max chip using public models (YOLO, CLIP, Depth Anything) and matmul/convolution benchmarks. Crossing the VM boundary adds ~1 ms per inference call. Qwen3-0.6B in Apple’s llm-benchmark ran at about 10% of host speed. Core AI’s paravirtualized path repeatedly sets up host access to large shared KV-cache buffers for each generated token.

If you wanted even more clues that Apple is preparing to support Siri Extensions besides ChatGPT: 1. Screen Time on iOS and macOS mentions “Extensions with their own app.” 2. iOS 27 and macOS 27 ship with VIP and blocked lists for Siri Extension providers. The blocked list contains a list of apps which Apple will not allow to “donate” a Siri Extension. The OS will also remove an already-enabled Extension from a blocked app, and prevent its invocation. It’s currently empty. The VIP list adds Apple-curated provider candidates. So far, ChatGPT is the only entry. Apple can update both lists through MobileAsset without a full OS update. The company can therefore react in real time if an app ships a Siri Extension that goes rogue. You should be able to find both lists in macOS 27 under: /System/Library/AssetsV2/com_apple_MobileAsset_UAF_FM_Overrides/purpose_auto/6b4ba2562604ccd58e0f97ee9b6e5aaeb9bd4864.asset/AssetData/vipAndBlockedProvider