Hvdos, a simple DOS emulator based on the OS X Hypervisor.framework

by LaSombra • 12 years ago

84 29 12 years ago

justinsb• 12 years ago

I hadn't seen Hypervisor.framework before. Has anyone looked into porting QEMU to it? It sounds like this would effectively be KVM for OSX.

TsukasaUjiie3• 12 years ago

Sounds like an interesting framework, my quick search didn't unearth any docs for it though? The only reference on Apples website is "we added this to 10.10"

arthurfm• 12 years ago

https://developer.apple.com/library/mac/releasenotes/MacOSX/...

Hypervisor (Hypervisor.framework). The Hypervisor framework allows virtualization vendors to build virtualization solutions on top of OS X without needing to deploy third-party kernel extensions (KEXTs). Included is a lightweight hypervisor that enables virtualization of the host CPUs.

gilgoomesh• 12 years ago

As with all Mac frameworks, the full headers are embedded in the framework and the headers all have full Javadoc-style API documentation for each function. Since there are only 24 functions in the whole framework, that's probably enough to work it out.

TsukasaUjiie3• 12 years ago

If only I had my mbp with be to read them :'(

thought_alarm• 12 years ago

A nice write-up that explains this code is available here: http://www.pagetable.com/?p=764

blinkingled2• 12 years ago

Gotta wonder who this is targeted towards - the likes of VMWare definitely not as I am sure they've spent a lot of time optimizing everything that happens in kernel space inside their drivers and surely there's more than 24 API calls they'll need inside the kernel to get something like Fusion working.

Maybe Apple is planning to provide a built-in hypervisor and this is just a start of it. Or maybe this is just for old DOS/Win games that'll sell for $9.99 in the appstore.

Also a cursory look shows the API is rather Intel specific. That's fine for the status quo but if they ever switch CPU vendors again wonder how this will work out.

toyg• 12 years ago

Or maybe this is just for old DOS/Win games that'll sell for $9.99 in the appstore.

Maybe it's the start of an "extreme sandbox" model, where appstore apps are all virtualized.

X-Istence• 12 years ago

This is something I've been thinking about. What if we could easily allow all programs to be sandboxed using virtualisation technology? Run your web browser or parts thereof inside of a VM so that any exploits are limited to just that VM.

blinkingled2• 12 years ago

That's way more heavy weight compared to regular seccomp like sandboxes that Chrome uses on Linux - and for too little gain.

mrsteveman12• 12 years ago

As someone else noted, QEMU is a likely match, perhaps another option for running Vagrant on OS X. But apple probably wouldn't go to this much effort and commit to supporting a hypervisor just to make virtualizing Linux easier. It's not an unmet need, and it's not their primary focus at all.

As you noted, all the existing VM players can provide their own and may want to continue doing that (unless Apple forces them to adopt this one... which is unlikely), so I'd bet on Apple itself being the primary consumer of it in some way.

As for what Apple itself might do with it in the future, perhaps this is just intended to be a low level component that will be used for other high level things in the OS itself, similar to the way XPC is now used all over the place as a core technology. As for what that might be with the hypervisor... I'd just be guessing. Guessing is fun though :)

They did say they were locking down /System soon, maybe that's going to be far more expansive than just the filesystem path, maybe a native hypervisor paired with VT-d allows them to "sandbox" things that currently can't be contained, even kexts? I'm thinking about Qubes OS when I say that http://en.m.wikipedia.org/wiki/Qubes_OS

protomyth2• 12 years ago

Where did they say they are locking down /System ?

clinton_sf• 12 years ago

This approach solves a few problems:

1. Apps in the Mac App Store can't ship their own kernel extensions along with the app. With the framework, it may not be necessary for virtualization products to do that -- enabling them to ship in the Mac App Store.

2. Compatibility breaks between OS version updates. Every time the kernel interface changes, someone shipping a kernel extension will need to ship an update as well. With this approach, it's possible to keep compatibility and let the implementation of the framework do all the heavy lifting.

3. If virtualization products are going to be in the kernel in order to run, it would be better for the host OS vendor to supply official supported interfaces instead.

Just as Intel is making it easier to do virtualization on their chips with VT-x and VT-d, Apple is making it easier to implement virtualization with Mac OS X as a host with this framework.

koenigdavidmj• 12 years ago

This reminds me of vx32[0], a user level emulation library that seems to target the same interface. One of the main applications using it is 9vx, which is basically a Plan 9 kernel running in userspace.

0: http://pdos.csail.mit.edu/~baford/vm/

Hvdos, a simple DOS emulator based on the OS X Hypervisor.framework

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