005 Virtual Machine Monitor
Context
The rust-vmm project provides shared components for building Virtual Machine Monitors (VMMs) in the Rust programming language. Rust’s focus on memory safety makes it a very compelling choice for Spectrum’s VMM.
The extant rust-vmm-based VMMs are crosvm Firecracker, and Cloud Hypervisor.
Firecracker does not support other virtio-devices than net or block.
In comparison to crosvm, Cloud Hypervisor has a more flexible IPC mechanisms, better hotplugging support, and a more engaging community as a Linux Foundation project. Cloud Hypervisor additionally has more core features - such as snapshotting, live migration. crosvm supports more devices we will also need.
It will be easier to port devices from crosvm to cloud-hypervisor than to port core features from cloud-hypervisor to crosvm.
Consequences
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Some devices need to be ported from crosvm to cloud-hypervisor.
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Spectrum functionality is expected to break and not supported if the primary VMM is swapped out.