Global context in Cross-VM calls

[conr2d]

Description

In Noir's Multi-VM architecture, each VM maintains its own local context. This context includes parameters like call depth, execution limits, and other runtime constraints, all managed independently within each VM.

However, this approach introduces potential vulnerabilities when Cross-VM calls come into play. Specifically:

• Cross-VM calls could unintentionally bypass local limits (e.g., call depth) by distributing execution across multiple VMs.
• This opens up a possibility for exceeding intended thresholds, potentially causing performance degradation or introducing security loopholes.

To address these concerns, the introduction of a Global Context might be necessary.