Ring 0 task

Daniel Waddington - SISA d.waddington at samsung.com
Thu Apr 11 22:51:20 CEST 2013

Hi Adam,
To set up the performance counters I have to configure the event select MSRs, thus an application or privileged server needs to execute wrmsr.  At the moment I have put back in your trap and emulate code (from an earlier version of the kernel)  so that the kernel will execute on behalf of the app.  Of course this is a major security hole.  It would be nice to allow a trusted process access to them.


> -----Original Message-----
> From: l4-hackers-bounces at os.inf.tu-dresden.de [mailto:l4-hackers-
> bounces at os.inf.tu-dresden.de] On Behalf Of Adam Lackorzynski
> Sent: Wednesday, April 10, 2013 2:53 PM
> To: l4-hackers at os.inf.tu-dresden.de
> Subject: Re: Ring 0 task
> Hi Daniel,
> On Tue Apr 09, 2013 at 23:07:47 +0000, Daniel Waddington - SISA wrote:
> > How do you create ring 0 tasks with Fiasco.OC? (I want them to execute
> > rdmsr/wrmsr)
> No such thing there currently. Care to share some more details which kind of
> MSR access? We were pondering on that as well a couple times already.
> Adam
> --
> Adam                 adam at os.inf.tu-dresden.de
>   Lackorzynski         http://os.inf.tu-dresden.de/~adam/
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