I'm working with a Xen host which is installed XenServer from Citrix by someone. He already installed a lot of CentOS 5.2 guests on the host. I wonder how to check those guests to know they are PV types or HVM types?
A quick note, there are actually 3 modes, not two when it comes to the drivers in use:
For a Xen guest/DomU you can do a very basic
Note: Generally you can do more with VMs that have the PV tools installed, so that can be quite an obvious pointer, however you can fake the presence of the PV tools to allow suspend/resume etc. so you cannot rely on that in general.
There is a better alternative to analyzing
With a standalone Xen installation, this could be achieved with
With XenServer or XCP, you could use
As for the virtualization modes, there is even more to come: Xen 4.3 introduced the new hybrid mode called PVH, which runs a fully PV system inside an HVM container without any hardware emulation. It's a special mode for 64-bit guests, the reason for this is that AMD64 architecture lacks some management features of i386 that Xen uses, which results in performance loss. It's not clear how PHV domains will be configured and how they will look in configuration dumps; my guess is that they may appear either as plain HVM domains (just like classic PV-on-HVM guests) or as a mixture HVM domain with some PV-specific directives.