Re: [Qemu-devel] building a virus-proof PC with Qemu

[Paul Brook]

On Tuesday 23 November 2004 12:31, Piotras wrote:
> Hi!
>
> Imagine that with every byte stored on disk image, the emulated
> memory and CPU registers we associate a flag indicating if the
> byte come from "trusted" source. This information would propagate
> with every memory/disk access (data-flow tracking).
>
> Before Qemu would translate a block of code the trusted bits could
> be checked to see if the code is "trusted". Of course there are
> issues with dynamic loaders, dynamic compilers, etc. And it's not
> going to work well with scripted code.

I'd expect you could do most of this on real hardware with the NX bit. You're 
going to need OS support in either case, so AFAICS all your qemu hack gives 
you is finer granularity (per-byte rather than per-page).

Paul