Yesterday’s virt-what problem
If the qemu -cpu flag is used then “QEMU” no longer appears in /proc/cpuinfo, so virt-what fails to detect virtualization. Simple workaround of detecting KVMKVMKVM leaf in CPUID doesn’t work because Parallels Desktop also exports the same leaf (why?!?). A more complex fix is required.
Today’s virt-what problem
Xen full virt guests on IA64 are reportedly not detected by virt-what. I say “reportedly” because obviously no one uses IA64. So the first task is to locate an IA64 system, which I eventually manage (thanks Alexander Todorov). Secondly how to run the CPUID instruction on IA64 (thanks Paolo Bonzini). Thirdly to work out that there is nothing in CPUID which indicates virtualization on this peculiar platform. Number four to come up with a test (thanks again Paolo). Number five to write a patch and test everything several times over to make sure nothing has been broken or regressed …
At least in QEMU, can’t you look at the machine’s BIOS?
No BIOS on IA64 of course. We did try looking for something in the EFI settings, but couldn’t find anything conclusive that was both special to Xen and exposed to userspace.