Mobile Virtualization

According to Electronista, ARM’s next generation of chips for phones and tablets should start shipping in devices at the end of this year.

These chips are based on ARM’s big.LITTLE architecture. big.LITTLE chips aren’t just multi-core, they contain cores that are two different implementations of the same instruction set: a Cortex A7 and one or more Cortex A15s. The Cortex A7 has an identical instruction set to the A15, but is slower and more power efficient – ARM says it is the most power-efficient processor it has ever developed. The idea is that phones will get great battery life by mainly running on the slow, power-efficient Cortex A7, and great performance by using the A15 on the hopefully rare occasions when they need its muscle. Rare in this context is relative. Power management on modern phones involves powering up and powering down subsystems in microseconds, so a ‘rarely’ used core could still be activated several times in a single second.

The Cortex A15 and the Cortex A7 are innovative in another way, too: they are the first cores based on the ARMv7-A architecture. This is ARM’s first architecture with hardware support for virtualization.

Even without hardware support, virtualization on handsets has been around for a while; phone OEMs use it to make cheaper smartphones by running Android on the same CPU that runs the cellular baseband stack. ARM says:

Virtualization in the mobile and embedded space can enable hardware to run with less memory and fewer chips, reducing BOM costs and further increasing energy efficiency.

This application, running Android on the same core as the baseband, does not seem to have taken the market by storm. I presume because of performance. Even the advent of hardware support for virtualization may not rescue this application, since mobile chip manufacturers now scale performance by adding cores, and Moore’s law is rendering multicore chips cheap enough to put into mass-market smartphones.

So what about other applications? The ARM piece quoted above goes on to say:

Virtualization also helps to address safety and security challenges, and reduces software development and porting costs by man years.

In 2010 Red Bend Software, a company that specializes in manageability software for mobile phones, bought VirtualLogix, one of the three leading providers of virtualization software for phones (the other two are Trango, bought by VMWare in 2008 and OK Labs.)

In view of Red Bend’s market, it looks as if they acquired VirtualLogix primarily to enable enterprise IT departments to securely manage their employees’ phones. BYOD (Bring Your Own Device) is a nightmare for IT departments; historically they have kept chaos at bay by supporting only a limited number of devices and software setups. But in the era of BYOD employees demand to use a vast and ever-changing variety of devices. Virtualization enables Red Bend to add a standard corporate software load to any phone.

This way, a single phone has a split personality, and the hardware virtualization support keeps the two personalities securely insulated from each other. On the consumer side, the user downloads apps, browses websites and generally engages in risky behavior. But none of this impacts the enterprise side of the phone, which remains secure.

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