Re: [Qemu-devel] Add Intel VT support to QEMU?

[Alexander Graf]

On 18.01.2009, at 19:33, Jason Martens wrote:

> Hello Everyone
>  I'm a part of a school group, and we are looking at adding Intel VT
> support to QEMU for a class project.  We would be implementing support
> for VT guests, so that other VMMs that rely on VT could be run/ 
> debugged
> using QEMU.  We are not familiar with QEMU code (yet!), so we are
> looking for some feedback from all of you experts.

Now that's good news :-). I would really love to see this implemented.

> 1. Has this been attempted before, or is there any existing code for
> this?  I saw some posts about a year ago that perhaps someone  
> started on
> it, but nothing after that.

Well - yes and no. I implemented SVM emulation support quite some time  
ago, so you can base on that. It should be possible to reuse some of  
that logic and the basic approach is the same anyways.

> 2. What would be required to implement this?  Any suggestions on where
> to start looking would be appreciated.  Obviously, the Intel VT docs  
> are
> going to be necessary.  Are there other things that you recommend we
> look at before we start?

If I were you I'd start with the instructions themselves. Look through  
the docs and see what each instruction does. Implement the easy ones  
first (VMXON and the CR4 bit), then go forward to VMENTER and  
implement the world switch. As soon as you are running code fine in  
the guest (check using -d in_asm,cpu) you can try and go for intercepts.

By the time you have these working, you should be pretty much done.

Good luck!

Alex