Re: Hypervisor detection from within a Linux VM

From: Anthony Liguori
Date: Tue Jun 29 2010 - 17:44:09 EST


On 06/29/2010 04:25 PM, Chetan Loke wrote:
Hello,


Requirement:
I have the need to support my apps(running on a Linux VM) on different
*nix hypervisors(ESX/Xen etc). I need to know on which hypervisor my
app is running. I read the CPUID usage thread -
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/22643 but to be
honest in the end I looked at
http://lxr.linux.no/#linux+v2.6.34/arch/x86/kernel/cpu/vmware.c#L88
The vmware_platform() detection code is straight forward.

Current-hack:
As a quick hack we just grep lspci for VMware's pci-ids.

Solution:
I can write a bare minimal driver, check the cpu-id as VMware's
balloon driver does and then emit a proc/sysfs node. The setup
packages and the apps can then check for this node-string.I'm
currently working on ESX and I am hoping that this thin-driver will
work.

It can be done entirely in userspace. Take a look at virt-what:

http://people.redhat.com/~rjones/virt-what/

Question:
Q1)Is it possible to get this functionality as part of the stock
kernel or is that a bad idea? I suspect there could be other
users/apps who would need to know what *nix hypervisor(or a
non-virtualized environment) they are
running on?
Q2)If this is not the right approach then can someone please suggest
another approach?

It might be reasonable to list the hypervisor signature as a field in /proc/cpuinfo. There's also a /sys/hypervisor where such information could go.

Regards,

Anthony Liguori

Regards
Chetan Loke
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