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RE: [Xen-devel] VMX disabled by Feature Control MSR

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, "Guillaume Thouvenin" <guillaume.thouvenin@xxxxxxxx>
Subject: RE: [Xen-devel] VMX disabled by Feature Control MSR
From: "Kamble, Nitin A" <nitin.a.kamble@xxxxxxxxx>
Date: Wed, 14 Jun 2006 11:26:43 -0700
Cc: LAURENT VIVIER <Laurent.Vivier@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, JEAN-PIERRE DION <Jean-Pierre.Dion@xxxxxxxx>
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Thread-index: AcaPsL5bVgsylMXWQYaMHkbFCs4hVwALvd8A
Thread-topic: [Xen-devel] VMX disabled by Feature Control MSR
Yes, Keir is correct. Once it is locked you can not unlock it by just
clearing the bit. Probably what you need is, enabling of VMX feature in
the BIOS, and then hard reset the system.

Thanks & Regards,
Nitin
------------------------------------------------------------------------
-----------
Open Source Technology Center, Intel Corp

>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
>bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Keir Fraser
>Sent: Wednesday, June 14, 2006 5:47 AM
>To: Guillaume Thouvenin
>Cc: LAURENT VIVIER; xen-devel@xxxxxxxxxxxxxxxxxxx; JEAN-PIERRE DION
>Subject: Re: [Xen-devel] VMX disabled by Feature Control MSR
>
>
>On 14 Jun 2006, at 13:35, Guillaume Thouvenin wrote:
>
>> If the "VMX disabled..." message is displayed, it means that the lock
>> bit is set to 1. Otherwise we set bit2 to 1. If I try to clear it
while
>> it is set it causes a general-protection fault. Is it possible to
>> modify
>> before Xen switches from real mode to protected mode?
>>
>> I will try to modify the arch/x86/boot/x86_64.S
>
>No, it's called a lock bit because it is sticky once set. The intention
>is presumably to allow OEMs an easy way (in their BIOS) to disable VMX
>on their systems if they don't want to have to support it.
>
>  -- Keir
>
>
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