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Nested VMs / Linux in Linux: Only 32Bit available -> solved

Posted: 8. Jul 2020, 09:10
by KBong
Hi there,
I tried a lot of googling but nothing helped :-( Help me Obi Wan Kenobi, you are my only hope!

I try to install some Linux guests within a Linux VM but I can't select 64Bit-VMs.

My Setup:

Host:
- Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz
- VT-x is enabled in BIOS
- Linux Mint 19.3 Tricia / 64bit
- Virtualbox : 6.0.22 r137980 (Qt5.9.5)
- Virtualbox Extension installed

Guest (PAE/NX / VT-x/AMD-V / Nested Paging are enabled in this guest's VM-Config):
- Linux Mint 19.3 Tricia / 64bit
- virtualbox: 6.1.10 r138449 (Qt5.9.5)
- Virtualbox Guest Additions installed (From Host: Insert Guest Additions CD Image)
- Virtualbox Extension installed
- If a create new VM's within this guest there is only 32bit available...

Any ideas my friends?

Best Regards
KB0ng

Re: Nested VMs / Linux in Linux: Only 32Bit available

Posted: 8. Jul 2020, 12:08
by mpack
Support for nested virtualization on Intel hosts was not added until version 6.1.x, so your 6.0.22 host is a dud.

Also the feature requires 5th generation (Broadwell) or better, so again your 2nd generation Intel is a dud.

Finally, VirtualBox 6.1.x requires VT-x/AMD-v for all VMs, not just 64bit, so I'm surprised to see 32bit VMs being available - they aren't.

Re: Nested VMs / Linux in Linux: Only 32Bit available

Posted: 8. Jul 2020, 14:00
by KBong
Hi mpack,

thanks for your answer.
I upgraded my host to Version 6.1.10 r138449 (Qt5.9.5) and now the option "Nested VT-X/AMD-V" is grayed out in the config for my guest.
Maybe there was a GUI-Bug in 6.0.22 r137980?

As you said: my host is a dud... need a new computer :-(

Thanks anyway!

Best Regards
KB0ng

mpack wrote:Support for nested virtualization on Intel hosts was not added until version 6.1.x, so your 6.0.22 host is a dud.

Also the feature requires 5th generation (Broadwell) or better, so again your 2nd generation Intel is a dud.

Finally, VirtualBox 6.1.x requires VT-x/AMD-v for all VMs, not just 64bit, so I'm surprised to see 32bit VMs being available - they aren't.

Re: Nested VMs / Linux in Linux: Only 32Bit available

Posted: 8. Jul 2020, 19:25
by KBong
well, it's me again.

lessons learned for today: never give up!

I managed to run 64bit nested vm with Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz.... but to be honest: it is slow like a snail. :lol:

Following setup finally works:

Host:
- Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz
- VT-x is enabled in BIOS
- Linux Mint 19.3 Tricia / 64bit
- Virtualbox : 6.1.10 r138449 (Qt5.9.5)
- Virtualbox Extension installed

Guest:
- VT-x/AMD-V: In Virtualbox-GUI (on Host) this Option is "grayed out" but with the following command it could be finally enabled: On host: "$ vboxmanage modifyvm MyVM --nested-hw-virt on"
- PAE/NX: enabled
- Nested Paging: enabled
- Linux Mint 20 Ulyana
- virtualbox: 6.1.10 r138449 (Qt5.9.5)
- Virtualbox Guest Additions installed (From Host: Insert Guest Additions CD Image)
- Virtualbox Extension installed


-> Within the guest I can now create new VMs with 64bit and also create Vagrant Boxes (i.e. hashicorp/bionic64) \ :D /


@mpack, your hint about virtualbox 6.0 vs. 6.1 was really great, thank you very much man! *thumbsup*


BR
KB0ng


#####################
Additional Info for whoever:

Host:
grep flags /proc/cpuinfo

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 popcnt tsc_deadline_timer aes xsave avx lahf_lm epb pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid xsaveopt dtherm ida arat pln pts md_clear flush_l1d


Guest:
$ grep flags /proc/cpuinfo

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid tsc_known_freq pni pclmulqdq vmx ssse3 cx16 sse4_1 sse4_2 x2apic popcnt aes xsave avx hypervisor lahf_lm pti tpr_shadow flexpriority md_clear flush_l1d

Re: Nested VMs / Linux in Linux: Only 32Bit available -> solved

Posted: 8. Jul 2020, 20:04
by scottgus1
Using the 'force it' command does what that sounds like. It slams the square peg through the round hole, leaving peelings and splinters, so the guest boots, but:
KBong wrote:slow like a snail
In molasses. In June*. In Antarctica. :lol:

*Southern hemisphere, the seasons are the other way round...

If you can live with that, then OK. But if not, you...
KBong wrote:need a new computer

Re: Nested VMs / Linux in Linux: Only 32Bit available

Posted: 21. Jul 2020, 11:46
by batman78
KBong wrote: lessons learned for today: never give up!

I managed to run 64bit nested vm with Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz.... but to be honest: it is slow like a snail. :lol:
How did you enable unrestricted guest execution?