2026-08-31

A conversation about the most native possible virtual machine pushed the virtualization model past the usual fake-computer metaphor.

The durable idea is that a VM can be physical in its datapath and virtual in its authority. Hardware virtualization already runs guest instructions on the physical CPU and backs guest memory with physical DRAM. VFIO can go further by assigning a GPU, NVMe controller, USB controller, or NIC directly to the guest. The host remains responsible for the grant: memory translation, DMA reachability, interrupt routing, PCI ownership, reset, teardown, and reuse.

Created Virtual machines as authority over real resources and connected it to Authority, Runtime lifetimes, and Profiling the critical path.

The conversation also clarified a useful systems consequence from Linux Fieldwork: removing the VMM from the steady-state device path concentrates correctness in fewer transitions. Assignment, BAR movement, DMA maps, reset, teardown, and reuse become the places where two layers can disagree about who owns physical reality.

Workbench now carries both levels of the idea: The Map Boots Linux gains the passthrough limit case, while The Guest Gets the Territory develops the authority argument on its own.

Frontier

The next useful question is memory translation: walk one guest load from guest virtual address through guest page tables and second-stage translation to physical DRAM, then compare that path with device DMA through an IOMMU. The CPU and device are both reaching memory through layered authority, but the translation owners and failure modes differ.