Imagination: Come back to MIPS, Wi-Fi router makers, we have an FCC ban workaround
VM isolation for OpenWRT
A fairly straightforward idea by Imagination Technologies could rescue American geeks' ability to run Openwrt on their routers.
The freedom to tinker with Wi-Fi routers has been a hot topic ever since the Federal Communications Commission issued an edict that devices be locked down to protect America's spectrum.
Its concern was that if World+Dog could write new firmware to their boxes, some would use that capability to breach the rules under which their devices are licensed. In particular, the FCC was worried about the 5GHz band, used both by Wi-Fi devices and US airports' weather radar.
If a user used Openwrt to turn off a device's Dynamic Frequency Switching (DFS), it would no longer sense a weather radar operating in its vicinity.
Imagination's open source Prpl Foundation reckons virtualisation can provide the necessary workaround. Its Prplwrt proposal is to put Openwrt in a virtual machine that doesn't have access to the chip's radio functions, but retains its other features.
It's posted this video to YouTube showing a demonstration of the idea.
Pitching itself as able to satisfy both tinkerers and the FCC isn't a purely altruistic move from Imagination: its MIPS processors are looking a little under siege from the popular ARM architecture. Most recently, Cavium made the shift to ARM for a new slew of network processors.
The underlying virtualisation comes from German company Kernkonzept, Imagination's partner in Prpl Foundation, in the form of the L4Re microkernel. L4Re is open source.
The demonstration runs on a MIPS Warrior CPU running at 1GHz.
On top of L4Re, there's a VM running Openwrt, with a second, isolated VM running the Wi-Fi driver. A third VM provides a sandbox for third-party applications.
Imagination describes the demonstration in more detail here. ®