Developer Finds Way to Bypass Apple Silicon 2 VM Limit
Original: Apple Silicon and Virtual Machines: Beating the 2 VM Limit (2023)
A Mac admin intern discovered how to bypass Apple Silicon's 2 virtual machine limit by modifying kernel parameters. Apple enforces this restriction through the hv_apple_isa_vm_quota variable in the XNU kernel's hv_vm_* stack functions.
A developer working with macOS virtual machines found Apple's 2 VM limit frustrating and investigated the technical implementation. Initially searching userspace frameworks like Virtualization.framework, they discovered the limitation is actually enforced in the closed-source XNU kernel. By comparing Intel and Apple Silicon kernels using IDA disassembler, they identified the hv_vm_* stack controls VM quotas through the hv_apple_isa_vm_quota variable. The kernel decrements/increments this counter as VMs start and stop via hv_trap_vm_create() and hv_vm_destroy_0() functions. Apple's software license agreement officially limits users to 2 concurrent macOS VMs for development, testing, or personal use. The developer was working as an intern at a consulting company and used UTM for VM development.
Why This Matters
Reveals technical details of Apple's VM restrictions for developers and researchers
Source
This article summarizes publicly available information from international media. It is not investment advice.