XP crashes at startup if VT-x/AMD-V and 2 CPUs are enabled

[g_mocken]

My Windows XP installation (on Ubuntu 10.04), which used to run very well for several years and many VirtualBox versions, now crashes at startup if VT-x/AMD-V and 2 CPUs are enabled.
It's a "raw disk" installation, which still runs perfectly well when I boot natively into Windows.
But starting with the late 3.x series of Virtualbox and continuing with 4.x, XP freezes at the login screen (4.x) or drops into a "IRQL_NOT_LESS_OR_EQUAL" blue screen (3.x).

When I switch to single CPU-mode and disable VT-x/AMD-V, it runs stable, but unbearably slow.

Is there anything I can do?

G.

[tohuwawohu]

Did you find a solution for this problem? I encounter the same problem - Win XP guest on Linux, after Upgrade to Virtualbox 4 BSOD (IRQL_NOT_LESS_OR_EQUAL) when VT-x/AMD-V is activated. I found this ticket but the bug should be fixed in newer Virtualbox builds. Maybe a regression?

EDIT: Removing Avira Antivirus fixed the problem. So my issue seems not to be a virtualbox bug but a avira problem. Has anyone managed to get Win XP as Guest on Virtualbox 4.X AND Avira Antivurs running? I'll check other antivirus software...

[Perryg]

The issue with avira is that it uses VMX to speed up the scans. Since only one application at a time can use VMX this will stop VirtualBox from using it and that stops 64-bit or 32-bit smp guests. You should be able to see this in the guest log. Look for running in root mode which means something is using VMX.

[tohuwawohu]

The issue with avira is that it uses VMX to speed up the scans. Since only one application at a time can use VMX this will stop VirtualBox from using it and that stops 64-bit or 32-bit smp guests. You should be able to see this in the guest log. Look for running in root mode which means something is using VMX.

I'm not sure if i understand correctly. Does this apply for avira running "inside" VirtualBox, too? In my case, Avira isn't running on the host (Linux), it's running inside the guest VM (Win XP). But thnak your for your reply, i will test this tomorrow and check the VBox logs for any hints on "root mode".

[Perryg]

I don't know if it will work in the guest either without messing with the hardware virtualization of the guest. But you have already proven that it does affect the guest, so the next place would be Avira for some fix I would think. Or find a different Virus software. Personally I don't use them. I practice safe browsing and most of my units are Linux anyway. I never use Windows on the Internet except to update from MS.

[tohuwawohu]

After some more testing, i'm stuck. The problem is that i can't reach the options regarding VMX in Avira, since they are available only if more than one CPU is available to the VM. But if i set the VM to use tow CPUs, Win XP won't start (BSOD as described) with Avira installed. The Avira option seems to be selected by default, so i can't install and immediately disable VMX access in Avira, either. So there seems to be no way to use Avira with VirtualBox 4 with AMD-V/VT-x activated.

[stoneguy]

I'm guesting 32-bit XP (1 CPU, VT-x disabled) on a quad-core AMD64 Linux host. Also getting the BSODs. Any chance of you and Avira learning to play nice