Cappsule's hypervisor

This repository is part of Cappsule, and contains the hypervisor. Please refer to the documentation for more information.

Overview

CPU and memory are virtualized thanks to hardware virtualization technology (Intel VT-x and EPT). During the launch of the hypervisor, the running OS is bluepilled and a snapshot of the memory is done.

The hypervisor supports 2 kinds of VM:

• the trusted guest (1 instance): this is the bluepilled OS, which has no restrictions.
• the cappsules (0 to n instances): no access to the hardware is allowed, and the memory is a copy-on-write version of the snapshot.

In order to operate, Cappsule needs to insert 2 kernel modules (cappsule.ko and cappsule_guest.ko). A userland daemon (in the userland repository) is responsible of the communication between userland and the kernel module.

Architecture

• common/: code shared between trusted guest / host / cappsule.
• guest/: cappsules. This code is considered unsafe and is not trusted by the hypervisor. This code is executed in VMX non-root mode.
• host/: hypervisor. This code is executed in VMX root mode.
• include/: everything under cuapi/ can be included both from the hypervisor and the userland repositories.
• trusted/: trusted guest. This code is executed in VMX non-root mode, but is trusted by the hypervisor.