Well, people sure have short memories.
I’ve commented several times before (for instance, here [8 months ago!], here, here, or here), that Apple’s Intel Macs contain an Infineon TPM chip. This from the very first developer transition kit, up to the latest released machine.
It looks like Intel has embedded “Trusted Computing” DRM protection in its Infineon chip and forgot to tell people.
…nobody wants to admit that the Intel Macs currently on sale have a TPM chip.
This is not only old news, but has been extensively photographed and discussed. It’s well-known that Apple uses the TPM chip in increasing degree in Mac OS X 10.4.x, to prevent people installing it on generic PCs, and it’s certain that Mac OS X 10.5 will also do so.
Does Apple come right out and say so? Admittedly not. Indeed, the usual hardware developer notes which used to come out a few weeks after a new PowerPC Mac was released are still absent for all Intel Macs – not that these notes ever went into chip-level detail of any Apple hardware. At the same time, Apple withdrew publication of a few kernel source files for Darwin, the open-source base for Mac OS X. Both facts demonstrate that Apple’s security locks are still in flux and may change extensively in the near future. Will all these things be documented in the future? Hard to say. If the TPM chip’s encryption is sufficiently strong, they could be documented without defeating Apple’s purpose; but keeping details hidden always helps.
Is this evil? Well, depends on your definition of course. As Gruber points out, people who are incensed about this should also boycott Linux for its support of several TPM chips, including Infineon’s. Certainly, Apple has a right to enforce its current license terms which state that Mac OS X should run only on Apple hardware.
But what else will the chip be used for in the future? As I’ve repeatedly wrote here before, using it for DRM protection of media – which is what most of the critics claim to fear – isn’t likely. Mostly because, if you do the math, Intel Macs will be a minority for years and any such protected media would either not work at all or be open on PowerPC Macs, of which there are several tens of millions still in operation.
What’s far more likely – and we’ll know for sure in August – is that the TPM chip will be used to boot a trusted hypervisor at the EFI level. Apple has even patented a scheme to run tamper-resistant code and more than one OS at once. From the wording it’s obvious that the TPM chip is used for that:
In one embodiment the system comprises a processor and a memory unit coupled with the processor. In the system, the memory unit includes a translator unit to translate at runtime blocks of a first object code program into a blocks of a second object code program, wherein the blocks of the second object code program are to be obfuscated as a result of the translation, and wherein the blocks of the second object code program include system calls. The memory unit also includes a runtime support unit to provide service for some of the system calls, wherein the runtime support unit is to deny service for others of the system calls, and wherein service is denied based on a tamper resistance policy.
So, what I think likely is that the machine will boot into the trusted hypervisor. This will be encrypted into firmware and decrypted, and checked against tampering, by the TPM chip. Once this is running it will show a screen like the Boot Camp boot selector, with one important difference: you’ll be able to select more than one OS to boot up. All of them, including Mac OS X itself, will run inside a virtual machine.
What’s the advantage? Of course all OSes will run at near-native speeds if nothing else is running at the same time – the hypervisor’s overhead will be negligible. In fact, this scheme has been used and refined on mainframes for decades, where it is assisted by hardware; now that Intel’s Core processors have hardware virtualization support, it should be easy to do likewise.
But the main advantage is that the OSes for the virtual machines can be simplified. All the tricky little kexts and drivers you see on current PowerPC Macs will be substituted by one or two “generic” versions which will interface to the virtual peripherals simulated by the hypervisor, and the actual machine’s peripheral drivers will be in EFI or on the cards themselves. This reduces disk and RAM usage at the expense of performance, although this shouldn’t be a problem except for games – but then, as I said below, hardcore gamers will prefer to boot directly into “the most popular game loader” anyway.
Another extremely desirable gain for Apple will be that they’ll only have a version of Intel Mac OS X that runs on this trusted virtual machine. To get this running on a generic PC, people would have to reimplement the entire Apple hypervisor too, write drivers etc., and even this would be easily defeatable by the TPM chip. Still, it’s a major architectural change and for that reason we’ll only see this in Leopard.