RE: [Xen-devel] Get IDT from virtual machine

[Matthew Donovan <matthew@xxxxxxxxxxxxxx>]

 But one could get the IDTR for a para-virt guest?  Out of curiousity, how
hard would it be to do it for HVM guests?

-matthew

-----Original Message-----
From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx] 
Sent: Friday, February 01, 2008 3:40 AM
To: Matthew Donovan; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] Get IDT from virtual machine

That's very wishful code! Unfortunately the IDTR is not exposed via
vcpu_context for HVM guests. The only way to get it right now is to do a hvm
save hypercall and then parse the pickled state to find the IDTR. It
actually should be quite easy.

 -- Keir

On 31/1/08 21:31, "Matthew Donovan" <matthew@xxxxxxxxxxxxxx> wrote:

> 
> I'm trying to retrieve and print the interrupt descriptor table of a 
> guest OS but every address is coming out 0x00000000.
> 
> Here's what I'm doing:
> 
>     vcpu_guest_context_t ctx;
>     int i;
> 
>     int res = xc_vcpu_getcontext (xai->xc_handle, xai->domain_id, 0,
&ctx);
>     if (res < 0) {
>         fprintf (stderr, "xc_vcpu_getcontext failed!\n");
>         return;
>     }   
> 
>     for (i = 0 ; i < 256 ; ++i) {
>         printf ("Interrupt %d: Address 0x%08x\n",
>                 i,
>                 ctx.trap_ctxt[i].address);
>     }
> 
> 
> I'm using Xen 3.1.2 on Fedora Core 8.  The guest OS's have been XP Pro 
> and Vista Ultimate, though I assume that part doesn't matter since the 
> IDT is a processor structure.
> 
> Any help is greatly appreciated.
> -matthew
> 
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> http://lists.xensource.com/xen-devel



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