From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: Accessing pv_info from userland
Date: Sat, 31 Jan 2009 13:36:05 -0600
Message-ID: <4984A825.3020904@codemonkey.ws>
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Cc: Bryan McLellan <btm@loftninjas.org>, kvm@vger.kernel.org
To: Glauber Costa <glommer@gmail.com>
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Glauber Costa wrote:
> On Sat, Jan 31, 2009 at 10:19 AM, Bryan McLellan <btm@loftninjas.org> wrote:
>   
>> Is there any way to access pv_info from userland? It would be useful
>> for determining what type of virtualization the machine was running
>> on.
>>     
>
> there are usually cpuid functions reserved for that.
>
> for kvm, you can run function 0x40000000, and if you get
> ebx =  0x4b4d564b
> ecx =  0x564b4d56
> edx =  0x4d
>
> you're running KVM.
>   

Since this is a pretty standard mechanism, it may make sense to include 
this signature in /proc/cpuinfo if someone is up to writing a patch.  It 
could also be useful to expose the PV features mask in cpuinfo too.

Regards,

Anthony Liguori