According to my research an Intel Bloomfield CPU (more specific: a i7-920) should support Intel VT-x technology (http://ark.intel.com/products/37147/Intel-Core-i7-920-Processor-8M-Cache-2_66-GHz-4_80-GTs-Intel-QPI) but under linux /proc/cpuinfo does not include the vmx flag as expected:

$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 26
model name      : Intel(R) Core(TM) i7 CPU         920  @ 2.67GHz
stepping        : 5
microcode       : 0x11

  [...removed a few lines...]

flags           : fpu de tsc msr pae mce cx8 apic sep mca cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl nonstop_tsc pni monitor est ssse3 cx16 sse4_1 sse4_2 popcnt hypervisor lahf_lm ida dtherm

  [...repeating up to processor 7 (HT)...]


$ cat /proc/cpuinfo | grep vmx
<returns no result>

As far as I understand it shows up here when disabled in BIOS but it does not. Output from rdmsr tells me Intel VT-x is enabled...?!

$ rdmsr 0x3a

What am I missing here? Thanks!


The hypervisor flag shows this is a virtual machine so the vmx flag won't show inside it unless you enable additional options in the hypervisor to allow nested virtualisation.

  • This is a Dom0 (Xen hypervisor) so my assumption that the vmx flag would show up here was wrong - Thanks for your help! – posi Jul 24 '15 at 4:56

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