Am Thu, 13 May 2021 13:29:32 +0100 schrieb Andrew Cooper : > Warning: NX (Execute Disable) protection not active There was a knob in the BIOS, it was set to "Disabled" for some reason. Once enabled, the flag is seen and the dom0 starts fine. If Xen is booted with 'cpuid=no-nx', the dom0 crashes again. Thanks for the help, Andrew. Olaf