RE: [Xen-devel] Debugging the hypervisor

[Matthew Donovan <matthew@xxxxxxxxxxxxxx>]

> What do you require the IDT details for?

We're working on a security service using VM introspection to monitor the
state of a running guest.  We'd like to include the IDT as part of that
monitoring.

> The right approach to obtain those details is to issue an  hvm_save
hypercall and then 
> parse the returned guest state to find the IDT details for each VCPU.  I
can give 
> yous ome more direction on this if that is what you need to be able to do.

That would be great.

Thanks
-matthew



> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx] 
> Sent: Wednesday, May 21, 2008 12:40 PM
> To: Matthew Donovan; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] Debugging the hypervisor
> 
> On 21/5/08 17:43, "Matthew Donovan" <matthew@xxxxxxxxxxxxxx> wrote:
> 
> >  Well, maybe I'm not going about this the right way then.
> > 
> > Back in February, I asked some questions about getting the interrupt
> > descriptor table from an HVM guest with xc_vcpu_getcontext. 
>  You said the
> > only way to do it at the time was to do an hvm-save 
> hypercall and parse the
> > binary.  At the time, we put the whole issue to the side to 
> get some other
> > things working first.  Now we've come back to it and are 
> looking at getting
> > an HVM's IDT programmatically without doing the hvm_save() call.
> > 
> > I've been looking at the source but I really wanted to be 
> able to put in a
> > breakpoint and step through the code (if it's possible) to see how
> > everything really interacts.
> > 
> > If you can give me any direction (either for debugging Xen 
> or getting the
> > IDT) I would really appreciate it.
> 
> Well, debugging Xen and obtaining an HVM guest's IDT details 
> seem rather
> different things to want to do. What do you require the IDT 
> details for? The
> right approach to obtain those details is to issue an 
> hvm_save hypercall and
> then parse the returned guest state to find the IDT details 
> for each VCPU. I
> can give yous ome more direction on this if that is what you 
> need to be able
> to do. Getting serial gdbstub working is not the right path 
> to that end.
> 
>  -- Keir
> 
> 

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