From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S932112Ab0CXQEB (ORCPT <rfc822;w@1wt.eu>);
	Wed, 24 Mar 2010 12:04:01 -0400
Received: from casper.infradead.org ([85.118.1.10]:44912 "EHLO
	casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753740Ab0CXQD7 convert rfc822-to-8bit (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 24 Mar 2010 12:03:59 -0400
Subject: Re: [RFC] Unify KVM kernel-space and user-space code into a single
 project
From: Peter Zijlstra <peterz@infradead.org>
To: Joerg Roedel <joro@8bytes.org>
Cc: Avi Kivity <avi@redhat.com>, Anthony Liguori <anthony@codemonkey.ws>,
       Ingo Molnar <mingo@elte.hu>, Pekka Enberg <penberg@cs.helsinki.fi>,
       "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
       Sheng Yang <sheng@linux.intel.com>, linux-kernel@vger.kernel.org,
       kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
       Jes Sorensen <Jes.Sorensen@redhat.com>, Gleb Natapov <gleb@redhat.com>,
       ziteng.huang@intel.com, Arnaldo Carvalho de Melo <acme@redhat.com>,
       Fr?d?ric Weisbecker <fweisbec@gmail.com>,
       Gregory Haskins <ghaskins@novell.com>
In-Reply-To: <20100324150137.GE14800@8bytes.org>
References: <20100323140608.GJ1940@8bytes.org> <4BA8EEDE.8070309@redhat.com>
	 <20100323182153.GA14800@8bytes.org> <4BA99BCB.5080501@redhat.com>
	 <20100324115900.GB14800@8bytes.org> <4BAA00B1.20407@redhat.com>
	 <20100324125043.GC14800@8bytes.org> <4BAA0DFE.1080700@redhat.com>
	 <20100324134642.GD14800@8bytes.org> <4BAA1A53.20207@redhat.com>
	 <20100324150137.GE14800@8bytes.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Date: Wed, 24 Mar 2010 17:03:42 +0100
Message-ID: <1269446622.5109.388.camel@twins>
Mime-Version: 1.0
X-Mailer: Evolution 2.28.1 
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, 2010-03-24 at 16:01 +0100, Joerg Roedel wrote:

> What I meant was: perf-kernel puts the guest-name into every sample and
> perf-userspace accesses /sys/kvm/guest_name/fs/ later to resolve the
> symbols. I leave the question of how the guest-fs is exposed to the host
> out of this discussion. We should discuss this seperatly.

I'd much prefer a pid like suggested later, keeps the samples smaller.

But that said, we need guest kernel events like mmap and context
switches too, otherwise we simply can't make sense of guest userspace
addresses, we need to know the guest address space layout.

So aside from a filesystem content, we first need mmap and context
switch events to find the files we need to access.

And while I appreciate all the security talk, its basically pointless
anyway, the host can access it anyway, everybody agrees on that, but
still you're arguing the case..