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#1 2013-12-03 03:34:00

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 14,996

[SOLVED]VirtualBox lost Vt-x capability

I use VirtualBox to run a Windows XP x64 guest.  With end of support approaching, I tried to build a Windows 7 x86 VM and was unable to get VirtualBox to provide a 64 bit environment.  I was able to build a 32 bit machine.   Thinking I must have been missing something, I tried to start my XP x64 VM[Edit: This assertion was incorrect see my post below].  It errors out complaining of the lack of Vt-x support in VirtualBox.

Any idea why I might have lost that capability?  Is there something in the latest kernels that might be grabbing that API and blocking VirtualBox from capturing it?

ewaller$@$odin ~ 1002 %uname -a
Linux odin 3.12.2-1-ARCH #1 SMP PREEMPT Fri Nov 29 21:14:15 CET 2013 x86_64 GNU/Linux
ewaller$@$odin ~ 1003 %pacman -Qs virtualbox
local/virtualbox 4.3.4-1
    Powerful x86 virtualization for enterprise as well as home use
local/virtualbox-host-modules 4.3.4-1
    Host kernel modules for VirtualBox
local/zsh-completions 0.10.0-1
    Additional completion definitions for Zsh.
ewaller$@$odin ~ 1004 %

Last edited by ewaller (2013-12-04 17:33:46)


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#2 2013-12-03 13:58:43

ajbibb
Member
Registered: 2012-02-12
Posts: 136

Re: [SOLVED]VirtualBox lost Vt-x capability

I run 32 bit XP in VirtualBox and after a system upgrade this weekend that installed Virtualbox 4.3.4 I was also getting a VT-x unavailable error.  Using Mr. Google and the error message I found this link: http://www.chakra-project.org/bbs/viewt … ?pid=77468.  The first 6 posts are a bit stale, the interesting parts start around post #7.  I know you said you could get 32 bit to work but not 64 bit, the exact opposite of my problem and the link, but I'm just putting it out there as maybe related.  In post #15 there is a comment that maybe the issue has something to do with using  XP in Virtualbox.

I read through all the links in the forum posts and I couldn't make sense of any of it.  In one of the links (dammed if I can find it now) it said the only solution is a downgrade.  I uninstalled 4.3.4 and downgraded to 4.3.2 (I think, I don't have access to that computer right now) and my XP fired right up.  Wish I could be of more help, but this is the best I've got right now.

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#3 2013-12-03 15:47:05

OldNuc
Member
Registered: 2013-09-02
Posts: 12

Re: [SOLVED]VirtualBox lost Vt-x capability

I also run 32 bit XP Pro SP-2 in VirtualBox and AMD processor in the host system. The error is AMD-V unavailable which is the AMD companion to VT-x for Intel processor. Google has more information on this error now and the consensus is that the problem is with VB 4.3.4. As of right now there does not seem to be any workaround other than to downgrade to VB 4.3.2.

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#4 2013-12-04 17:21:08

wollew
Member
Registered: 2007-08-08
Posts: 18

Re: [SOLVED]VirtualBox lost Vt-x capability

I have a similar problem here. Virtualbox (4.3.4) is running under an AMD-CPU, which has definitely no hardware acceleration (Acceleration-Tab in Virtualbox/System is greyed out)
Till yesterday all virtual machines (32bit: WinXP, Win7, Linux, ..) ran fine.
Today I got
AMD-V is not available. (VERR_SVM_NO_SVM).
Fehlercode:NS_ERROR_FAILURE (0x80004005)

One temporary solution i found out, is to create a new machine connected to the "old" vdi-disk. This works for all my virtual machines.

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#5 2013-12-04 17:33:17

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 14,996

Re: [SOLVED]VirtualBox lost Vt-x capability

I figured it out.....   All is not what I had thought.

It turns out that my machine does not support Vt-x;  It never has.   My confusion was that my XP VM would not start complaining about a lack of Vt-x support.
I could not build a Windows 7 x86_64 machine, only a 32 bit.

I had thought that the XP was 64 bit and would not start leading me to believe II had lost Vt-x capability.  I was wrong, it is (was, actually, I finished my migration to Windows 7) a 32 bit machine.

Apparently, newer versions of VirtualBox have a VM configuration option called LongMode (I am not certain as to the capitalization, I am not in front of my machine).  In the older versions of the XML file that defined the XP Virtual Machine, there had been no LongMode tag.  The Windows 7 VM, created by the latest incarnation of VirtualBox, had the tag and set it to false. 

It would seem that, missing that tag, the latest version of VirtualBox defaults to enabling LongMode which, in turn, requires Vt-x.  That is why the XP VM blew up.

There did not seem to be a GUI hook in the Oracle VM management tool to disable LongMode.  Hand editing the XML file that defined my XP VM and adding a tag disabling long mode to the CPU section of the file did the trick.  The latest version of VirtualBox would again run my 32 bit XP VM without barfing due to lack of Vt-x.


Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
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How to Ask Questions the Smart Way

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#6 2013-12-04 20:41:32

karamaz0v
Member
From: Argentina
Registered: 2012-07-18
Posts: 8

Re: [SOLVED]VirtualBox lost Vt-x capability

I started having the same problem on my notebook that does not support Vt-x.

as ewaller said the line to add in the <CPU> section of the xml is

<LongMode enabled="false"/>

and worked like a charm.

thanks

Last edited by karamaz0v (2013-12-04 20:42:01)

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#7 2013-12-07 16:15:55

adorableGNU
Member
Registered: 2013-05-27
Posts: 4

Re: [SOLVED]VirtualBox lost Vt-x capability

Thanks for the hint !!!

This is a quick way to change the value.

vboxmanage list vms

This will list all your vm's. To do the change run:

vboxmanage modifyvm <name or uuid of vm> --longmode off

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#8 2013-12-09 10:04:05

markkram
Member
Registered: 2013-12-09
Posts: 1

Re: [SOLVED]VirtualBox lost Vt-x capability

Thank you adorableGNU,
those two lines saved my day!

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#9 2016-12-17 03:17:30

Trooper4001
Member
Registered: 2016-11-01
Posts: 10

Re: [SOLVED]VirtualBox lost Vt-x capability

I've tried to use those two lines and tried to open Windows 10 on the VirtualBox but the Acceleration tab is grayed out and it is still saying 'VT-x/AMD-V hardware Acceleration is not available on your system'. I don't know how to open the xml file and modify it. I'm running the 32-bit version in the VirtualBox. I try to run without the accelerations and it doesn't get past the boot window with the Windows logo.

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#10 2016-12-17 16:08:25

WorMzy
Forum Moderator
From: Scotland
Registered: 2010-06-16
Posts: 7,157
Website

Re: [SOLVED]VirtualBox lost Vt-x capability

Please don't necrobump, Trooper4001.

https://wiki.archlinux.org/index.php/Co … bumping.22

Closing.


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Making lemonade from lemons since 2015.

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#11 2016-12-17 16:09:57

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 14,996

Re: [SOLVED]VirtualBox lost Vt-x capability

Hello Trooper4001.  Welcome to the Arch Linux forums.
When I started this thread, three years ago, I had a different computer.  Fortunately, this computer (HP Envy) does have VT-x; I have not thought about this issue in a long  time.
Thinking back, the problem was that a working 32 VM stopped working because the defaults inside VirtualBox changed, and the GUI was not updated to support it.  I believe this is all moot with recent versions of VirtualBox.  In other words, I am not sure you are chasing the same problem.

As this thread is old and solved, and as I am a moderator wink I am going to suggest you open a new thread on the topic that you will own.

Be sure to tell us about your machine (including make/model), its graphics subsystem, and which kernel you are running.  Does the Windows 10 VM work on other hosts? You assert that it won't get past the Windows logo without acceleration; why do you think that it will work with acceleration?

In the mean time, I am going to go ahead and close this old thread. https://wiki.archlinux.org/index.php/Co … bumping.22

Edit: Good morning (afternoon) WorMzy smile

Last edited by ewaller (2016-12-17 16:10:47)


Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
----
How to Ask Questions the Smart Way

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