Dom0 Memory Setting in Xen openSUSE 12.2

I installed openSUSE 12.2 as a Xen host using Grub2. How do I tweak Dom0 for example to use 512MB, like in a dom0_mem=512M setting. I’ve tried putting it somewhere in Yast->Bootloader, but doesn’t seem to work. I don’t know if it even goes anywhere in the bootloader section. I tried adding GRUB_CMDLINE_XEN="dom0_mem=512MB to /etc/default/grub and updated the grub. After reboot though, neither method seems to work as dom0 still shows as using all of the memory. Not sure what to try next.

Been many years since I’ve only looked at anything closely related to what you’re asking so I doubt I can offer specific info but I’m curious why you would be trying to restrict the resources available to Dom0 on boot. Ordinarily, you wouldn’t be concerned about that, you would configure overall and VM specific resources to be allocated later, using your preferred VM manager.