Re: [git-pull -tip V2] x86: msr architecture debug code

From: Ingo Molnar <mingo@elte.hu>
To: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86 maintainers <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [git-pull -tip V2] x86: msr architecture debug code
Date: Thu, 5 Mar 2009 14:32:08 +0100	[thread overview]
Message-ID: <20090305133208.GC4322@elte.hu> (raw)
In-Reply-To: <20090305122157.GA7347@alberich.amd.com>

* Andreas Herrmann <andreas.herrmann3@amd.com> wrote:

> On Thu, Mar 05, 2009 at 02:19:56AM +0530, Jaswinder Singh Rajput wrote:
> > On Thu, 2009-03-05 at 00:46 +0530, Jaswinder Singh Rajput wrote:
> > 
> > > The following changes since commit 1d10914bf2c8a1164aef6c341e6c3518a91b8374:
> > >   Ingo Molnar (1):
> > >         Merge branch 'core/percpu'
> > > 
> > > are available in the git repository at:
> > > 
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/jaswinder/linux-2.6-tip-cpu.git master
> > > 
> > > Jaswinder Singh Rajput (1):
> > >       x86: msr architecture debug code
> 
> Hi,
> 
> Why do we need this in-kernel?
> We have already access to MSRs via /dev/cpu/*/msr
> 
> Did you have a look at x86info.  (see
> http://www.codemonkey.org.uk/projects/x86info/)
> Recent versions contain a tool called lsmsr -- which shows you MSRs
> and also decodes some bits, e.g.

Having debugfs access and a topical splitup of all MSRs (and 
possibly other CPU data - not necessarily MSR accessible - such 
as the CR bits, etc.) is a nice touch i think and allows the 
quick inspection of various properties of a CPU.

> - I've just one directory in debugfs
>   x86/cpu/msr/cpu0
>   The system has a quad-core CPU. So I guess there should be 4
>   directories -- one for each core.

Correct, most MSRs are per core - that needs to be fixed.

	Ingo