This is an interesting information regarding usage of GPL v3 and proprietary code in embedded devices.
Tivoization is the creation of a system that incorporates software under the terms of a copyleft software license, but uses hardware to prevent users from running modified versions of the software on that hardware. Richard Stallman coined the term and believes this practice denies users some of the freedom that the GNU General Public License (GNU GPL) was designed to protect. The term came about in reference to TiVo's use of GNU GPL licensed software on the TiVo brand digital video recorders (DVR).
Generally hypervisors is used to optimize IT Infrastructure with Virtualization. You can improve productivity and development w/ software such as XEN or VMware Software. Now there is a new usage for hypervisors:
This guest whitepaper explains how hypervisors can isolate proprietary software from GPLv2 and GPLv3-licensed software. Authored by a Trango product manager, it uses Trango's hypervisor as an example, showing how the technology could help safeguard copyright-encumbered multimedia content in a video playback device with a user-modifiable Linux OS component.
So how can hypervisors can defeat GPLv3's "anti-tivoization":
Use of a hypervisor can assist device vendors with GPL license compliance, both v2 and v3. It also allows vendors to maintain strong control over their other software components, and ensure that a modified version of GPL software cannot be used to gain access to their sensitive devices or data, or to modify the fundamental behavior of the system.