Re: [ros-dev] [ros-diffs] [jgardou] 50991: [NTOSKRNL] - Print supported CPU features. - Simplify detection of non working but claimed SYSENTER support for intel processors - Workaround a virtualbox "feature" : claim that SY...

[Jérôme Gardou]

Official intel documentation :
http://www.intel.com/Assets/PDF/appnote/241618.pdf, page 30.

As to know how it's made on windows, well, I hope they follow intel docs ;-)

Le 07/03/2011 21:49, Aleksey Bragin a écrit :
>  
>
>  On Mar 7, 2011, at 4:33 PM, jgardou(a)svn.reactos.org wrote:
>
> >   Author: jgardou
> >               /* Check if the CPU is too old to support SYSENTER */
> >  -            if ((Prcb->CpuType < 6) ||
> >  -                ((Prcb->CpuType == 6) && (Prcb->CpuStep < 0x0303)))
> >  +            if ((Reg[0] & 0x0FFF3FFF) < 0x00000633)
> >               { 
>  It was intentionally done over CpuType and CpuStep. Now you
> criptified 
>  it back to a raw Reg[0] value and weird hardcoded constant. Could you 
>  please 1) elaborate this change and 2) if you still think it's 
>  correct, and if you still tihnk(!) Windows does it same way, then 
>  rework it to use Prcb->Cpu* instead of these magic values?
>
>  Not to say adding a hack for VirtualBox is far from being a beautiful, 
>  and would need to be *at least* marked so that it's not forgotten.
>
>  Thanks,
>  Aleksey Bragin.
>
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