Re: [PATCH -v2] x86: Add an archinfo dumper module

From: Ingo Molnar
Date: Tue Feb 09 2016 - 07:23:12 EST



* H. Peter Anvin <hpa@xxxxxxxxx> wrote:

> On 02/04/16 07:22, Borislav Petkov wrote:
> > Here's v2 with the stuff we talked about, implemented. I've added
> > 'control_regs' file too so that you can do:
> >
> > $ cat /sys/kernel/debug/x86/archinfo/control_regs
> > CR4: [-|-|SMEP|OSXSAVE|-|-|-|-|OSXMMEXCPT|OSFXSR|-|PGE|MCE|PAE|PSE|-|-|-|-]: 0x1406f0
> >
> > for example. Yeah, only CR4 right now.
> >
> > Off the top of my head, we would need "msrs" which dumps EFER and a
> > bunch of other interesting MSRs along with the names of the set bits.
>
> Is there a reason why all this parsing has to be done in kernel space?

Ease of use I suspect, no need to locate some separate utility. Also, no need to
define an ABI for the information displayed - which keeps things simpler. Since
it's a kernel module there's no real bloat argument.

Thanks,

Ingo