Apple Silicon and Virtual Machines: Beating the 2 VM Limit

Apple Silicon Macs are limited to 2 active macOS VMs simultaneously by macOS SLA and a kernel-level enforcement via the `hv_apple_isa_vm_quota` variable in XNU. Through reverse engineering the development kernel with IDA, the author discovered that this limit can be overridden using the `hv_apple_isa_vm_quota=` and `hypervisor=` boot-args, but only when the `AppleInternal` SIP flag is set. The workaround involves downloading a Kernel Debug Kit, building a custom development kernel collection with `kmutil`, disabling SIP in recoveryOS, and setting the appropriate boot-args — enabling up to 255 concurrent macOS VMs. The post also covers how to revert the setup before OS updates and discusses potential future improvements like a kext-based override.