Nested Virtualization Under KVM Hypervisor

[Peter Grehan]

Hi Pete,

>    VT-x: (disabled in BIOS) PAT,HLT,MTF,PAUSE,EPT,UG,VPID,VID,PostIntr
  That's just a warning: bhyve will attempt to enable VT-x on module 
load, and will only fail if BIOS has locked the disable.

  Do you know if the vmm module fails to load ? (there will be an error 
in syslog "vmx_init: VMX operation disabled by BIOS")

> Hypervisor: Origin = "KVMKVMKVM"
> real memory  = 34359738368 (32768 MB)
> avail memory = 33365536768 (31819 MB)
> Event timer "LAPIC" quality 600
> ACPI APIC Table: <BOCHS  BXPCAPIC>
> 
> They did verify that VT-x pass through *is* enabled as mentioned above 
> (they shared with me the config file snippet on their end to verify), 
> and they did extensive testing on their end and were not able to get 
> FreeBSD to detect VT-x as being enabled.
> 
> I pinged them asking for more info on which Linux kernel their 
> hypervisors are running to see if I can help debug this on my end.  I 
> have two questions:
> 
> 1) is anyone else doing nested virtualization under KVM hypervisors.  i 
> am confident that this is possible, but am asking for confirmation on 
> this :)

  Yes: A bug report 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203994
   ... had the resolution that a kernel > 4.10 has to be used, and

  https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=246168
   ... requires posted interrupts to be disabled.

> 2) Are there any other requirements that FreeBSD requires to run Bhyve 
> nested under KVM?

  No - nested has been enabled by default with KVM for quite a while now.

later,

Peter.