AMD-V is not available error; apparently solved

[AlphaGJohn]

Hi Folks,

I'm running VBox 4.0.2 on CentOS 5.5 on an older 2-CPU AMD box. This box's Opteron 246 processors predate the AMD-V capability. So, in a sense, I was not surprised that I get this "No AMD-V" error when I try to start up a Windows XP guest on it, but I had a hard time trying to figure out what the critical setting was that was preventing using the software virtualization capability. Ultimately, the problem was apparently how much RAM I had configured for the VM, and the largest I could make it without getting the error was 3584 MB.

The error message:

Code: Select all

Failed to open a session for the virtual machine Win XP
AMD-V is not available. (VERR_SVM_NO_SVM)
Unknown error creating VM (VERR_SVM_NO_SVM)
Details:
Result code:  NS_ERROR_FAILURE (0x8000-4005)
Component:   Console
Interface:       IConsole {515e8e8f-f932-4d8e-9f32-79a52aead882}

The VBox version is the PEUL download w/ the extension pack installed. I have IO APIC enabled, and everything I could think of that might require AMD-V capability disabled:
System/Motherboard:

• Memory: 3840 (this seemed to be the problem--no value larger than 3584 MB worked)
  Enable EFI (I have tried this both enabled and disabled)
  Enable absolute pointing device

System/Processor

• Enable PAE/NX

USB

• Disabled

In just trying things, I dropped the RAM down to 2048 MB, that seemed to allow things to boot. Inching upward until it failed again with the above error, I determined that the magic limit is 3584MB--or exactly 3.5GB. So, if you're dealing with old gear and trying to run a 32-bit guest, that is apparently the absolute limit (w/o having the AMD-V-type capability on the CPU chip).

Hope this will help someone.

John

[rjimeno]

Your workaround was fine for me.

The system I was having trouble with is an Intel based (multiple processors and cores) running RHEL5. The guest OS is a 32-bit Ubuntu Desktop.

Maybe the error message should include a mention to the amount of memory in the guest or other more informative reference.

Thanks.