I'm trying to install a Linux VM on a Citrix Xenserver namely an Endian efw.

Therefore I create a new vm in Citrix XenCenter and choose "other install media" to be able to install from dvd-drive.

When this new vm is set up, and I want to start it, I get the warning "HVM is required for this operation".

My motherboard is a MSI G31M3-L V2 with latest BIOS.
My processor is an Intel Pentium Dual Core E5200.

There is no Intel-VT support with my type of processor but this should not be necessary for Linux vm's, right ?!

I have installed the Citrix Linux Pack.

wigd guess; kernel has no Xen Paravisor support. it's not something you can load it at the boot (as a module). it has to be complied into the kernel.

HVM support allows Xen to load OSes without modifications. (or speed penalty).

check the distros docs about Xen support, if it's not there, compile one yourself.

howeven Xen might able to load unmodified OSes without HVM support. myabe your Xen does not allow it.

VT flag is necessary for HVM

When using the "other install media" Citrix XenServer automatically configures the guest as hvm. To install a para virt guest - it's a little bit different. For the CentOS and Debian options, it doesn't just mount the standard iso on an ide controller for the guest. The images have been modified to boot under para virt.

It may be documented how to install your distro as a paravirt guest in Xen or Citrix Xen, search their wiki or use google.