From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [RFC] Unify KVM kernel-space and user-space code into a single
	project
Date: Wed, 24 Mar 2010 16:59:27 +0100
Message-ID: <20100324155927.GI14800@8bytes.org>
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Cc: Anthony Liguori <anthony@codemonkey.ws>,
	Ingo Molnar <mingo@elte.hu>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	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>
To: Avi Kivity <avi@redhat.com>
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On Wed, Mar 24, 2010 at 05:49:42PM +0200, Avi Kivity wrote:
> On 03/24/2010 05:46 PM, Joerg Roedel wrote:
>> On Wed, Mar 24, 2010 at 05:12:55PM +0200, Avi Kivity wrote:
>>    
>>> On 03/24/2010 05:01 PM, Joerg Roedel wrote:
>>>      
>>>> $ cd /sys/kvm/guest0
>>>> $ ls -l
>>>> -r-------- 1 root root 0 2009-08-17 12:05 name
>>>> dr-x------ 1 root root 0 2009-08-17 12:05 fs
>>>> $ cat name
>>>> guest0
>>>> $ # ...
>>>>
>>>> The fs/ directory is used as the mount point for the guest root fs.
>>>>        
>>> The problem is /sys/kvm, not /sys/kvm/fs.
>>>      
>> I am not tied to /sys/kvm. We could also use /proc/<pid>/kvm/ for
>> example. This would keep anything in the process space (except for the
>> global list of VMs which we should have anyway).
>>    
>
> How about ~/.qemu/guests/$pid?

That makes it hard for perf to find it and even harder to get a list of
all VMs. With /proc/<pid>/kvm/guest we could symlink all guest
directories to /proc/kvm/ and perf reads the list from there. Also perf
can easily derive the directory for a guest from its pid.
Last but not least its kernel-created and thus independent from the
userspace part being used.

	Joerg