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Date: Wed, 24 Mar 2010 17:23:43 +0100
From: Joerg Roedel <joro@8bytes.org>
To: Peter Zijlstra <peterz@infradead.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>
Subject: Re: [RFC] Unify KVM kernel-space and user-space code into a single
	project
Message-ID: <20100324162343.GK14800@8bytes.org>
References: <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> <1269446622.5109.388.camel@twins>
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On Wed, Mar 24, 2010 at 05:03:42PM +0100, Peter Zijlstra wrote:
> 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.

With the filesystem approach all we need is the pid of the guest
process. Then we can access proc/<pid>/maps of the guest and read out the
address space layout, no?

	Joerg