Enabling Virtual Machine support

[Thomas Charron]

On Sun, Sep 27, 2009 at 7:59 PM, Thomas Charron <twaffle at gmail.com> wrote:
> On Sun, Sep 27, 2009 at 7:36 PM, Michael ODonnell
> <michael.odonnell at comcast.net> wrote:
>> Not certain I understand what you're saying but processors in this family
>> come out of their power-on Reset state in their simplest, least capable
>> mode - interrupts disabled, MMU disabled, 20bit Real Mode addressing,
>> etc - and each increase in capability requires a deliberate action on the
>> part of the system code (typically the BIOS at first, then later the OS).
>> Virtual Machine mode is like Virtual 8086 mode in that it's a capability
>> that must be explicitly enabled once the OS has rigged itself to manage
>> it; this as opposed to somehow being a permanent, static feature of the
>> platform or CPU.  And also, AFAIK, no external HW support is required
>> of the platform for VM capabilities to be utilized - if the OS is coded
>> to support it and the CPU provides it, that's all you (should!)  need.
>  Intel's VT-x extensions *MUST* be enabled and supported by BIOS.
> I'm not sure why, I read it someplace after I bought my laptop and was
> trying to find a way around it.   Not sure about VT-d.

  In a quick search, it has something to do with the BIOS setting
certain flags within the processor, and then 'locking' the processor,
which cannot be undone without a restart.  Even enabling the VT bit
ion the BIOS requires a hard reset of the system to actually take.

-- 
-- Thomas