The TCB would need to be open-source, e.g. Hyper-V, MinWin (or whatever the smallest core of windows is called these days). There are several virtualization-bas

The TCB would need to be open-source, e.g. Hyper-V, MinWin (or whatever the smallest core of windows is called these days). There are several virtualization-based security features in modern Windows, that would be especially useful if the hypervisor could be inspected and collaboratively developed, even if a Microsoft CLA were required for code contributions, and they retained patents. An OSS TCB would ensure absence of telemetry. They can still sell closed-source components that run on the OSS TCB.