virtualbox.org

I have VirtualBox 3.0.2 (w/Guest Additions) on Ubuntu 9.04 Host (32 bit), with an XP SP3 Guest OS. 3GB physical RAM; AMD Athlon 64 X2 4200+

Upon installation VirtualBox only saw 1 cpu.VT-x/AMD-V is enabled, as are PAE/NX, ACPI, and IO APIC (works fine when cpu=1)

When I change System Settings set to 2 CPUs, I restart the VM and it won't start - instead I get error:

Failed to start the virtual machine XP.
VT-x is not available. (VERR_VMX_NO_VMX).
Unknown error creating VM (VERR_VMX_NO_VMX).
Result Code:
NS_ERROR_FAILURE (0x80004005)
Component: Console
Interface: IConsole {0a51994b-cbc6-4686-94eb-d4e4023280e2}

Log attached.

Any ideas how to get 2nd core recognized?

Have you checked your bios to see that the hardware-v is turned on?
It may be that you have a 64bit processor but your bios does not support hardware virtualization.

Check if your CPU has VT-x, wich is needed in Virtualbox to enable multicore support: type #/proc/cpuinfo and look for the flag svm (that stands for AMD Pacifica hardware virtualization technology). You can do this just typing in a terminal # egrep '(vmx|svm)' /proc/cpuinfo.


Also check in the virtual machine logfile (.VirtualBox\Machines\VM\Logs\VBox.log) for the word VERR_VMX_NO_VMX. For example, in my case I get

-> 00:00:03.210 HWACCM: No VMX or SVM CPU extension found. Reason VERR_VMX_NO_VMX

which indicates that no vt-x/amd-v CPU is found, so even if you force by command line 2 or more CPUs, Virtualbox will not work.


I had a similar problem, but in a 32 bit Dual Core CPU, take a look to the following post: http://forums.virtualbox.org/viewtopic.php?f=7&t=20186


Hope this helps, cheers

64 bit CPU doesn't matter, most or all CPUs these days are 64 bit. 64 bit Hosts on the other hand, are a problem. They are not supported yet for SMP.

My BIOS virtualization setting was it. Thanks much.