On 03/02/2025 8:58 am, Guillaume wrote: > Oh cool, thanks a lot for the explanation. > I added the "vzeroupper" and Xen crashes so it looks like the CPUID > emulation is buggy. Also I was able to try it using a VM (same debian > testing) running on virt-manager+kvm and it works fine (Xen in debug > mode). I will have a look by printing the xstate when running on > virt-manager+KVM and I will also run the xen-cpuid command to see the > difference just by curiosity as with your test we already spotted the > issue. > Thanks again for your enlightenment. I will continue my testing later > today and if you need me to test something else you are welcome, just > ask I will do my best.
It sounds like KVM has a better CPUID emulation than VirtualBox. It would be ideal to report this bug with VirtualBox. But, as you identified originally, it's not nice that Xen simply like this. We should see about what to for Xen, seeing as we're close to the line on 4.20. I'm thinking maybe making the xstate checks non-fatal in the cpu_has_hypervisor case. Thoughts? ~Andrew
