Re: Guest Debugging Facilities in KVM

[Avi Kivity <avi@redhat.com>]

On 09/17/2012 10:36 PM, Dean Pucsek wrote:
> Hello,
> 
> For my Masters thesis I am investigating the usage of Intel VT-x and branch tracing in the domain of malware analysis.  Essentially what I'm aiming to do is trace the execution of a guest VM and then pass that trace on to some other tools.  I've been playing KVM for a couple weeks now but from comments such as (in arch/x86/kvm/vmx.c): 
> 
>        /*
>         * Forward all other exceptions that are valid in real mode.
>         * FIXME: Breaks guest debugging in real mode, needs to be fixed with
>         *        the required debugging infrastructure rework.
>         */
> 
> And (from an email sent to the list in July 2008): 
> 
>         Note that guest debugging in real mode is broken now. This has to be
>         fixed by the scheduled debugging infrastructure rework (will be done
>         once base patches for QEMU have been accepted).
> 
> it is unclear to me how much support there is for guest debugging in KVM currently (I wasn't able to find any recent documentation on it) and what the debugging infrastructure referred to by these comments is.  I am interested in becoming involved with the KVM project in this respect however some guidance and direction on the guest debugging facilities would be greatly appreciated.

Guest debugging works (but not in real mode due to the issue above).
You can set hardware and software breakpoints and kvm will forward them
to userspace, and from there to the debugger.  I'll be happy to help, as
I'm sure Jan (as the author of most of the guest debugging code) will as
well.

-- 
error compiling committee.c: too many arguments to function