Nested Virtualization Under KVM Hypervisor

[Pete Wright]

On 9/9/20 5:36 PM, Peter Grehan wrote:
> 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")

thanks for getting back to me Peter.  The vmm.ko does load:
$ kldstat|grep vmm
19    1 0xffffffff82ce1000   537420 vmm.ko
$

Sep 10 03:25:01 bells kernel: vmx_init: processor does not support 
desired basic capabilities
Sep 10 03:25:01 bells kernel: module_register_init: MOD_LOAD (vmm, 
0xffffffff82ce4d20, 0) error 22
Sep 10 03:25:01 bells kernel: driver bug: Unable to set devclass (class: 
fdc devname: (unknown))

I also received this input from the ISP, they are running this kernel:
  4.15.0-47-generic #50~16.04.1-Ubuntu SMP
>
>  https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=246168
>   ... requires posted interrupts to be disabled.
>

reading through that ticket i set this in loader.conf:
hw.vmm.vmx.use_apic_vid=0

and verified via sysctl:
$ sysctl hw.vmm.vmx.cap.virtual_interrupt_delivery
hw.vmm.vmx.cap.virtual_interrupt_delivery: 0
$

since you mention this is a possible bug with KVM is there some useful 
information i can relay to my ISP (they are a BSD friendly vendor) that 
they can try on their end as a workaround, or perhaps something they 
ping the linux/kvm community about?

thanks in advance!
-pete


-- 
Pete Wright
pete at nomadlogic.org
@nomadlogicLA