Re: [Xen-devel] Doamin crash when trying to install disk encryption (PointSec) on Windows HVM

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

That chunk actually has no effect right now, as we should never load a non-user segment while in real mode. You could throw that patch chunk away if you like.

 -- Keir

On 26/04/2009 12:23, "Tom Rotenberg" <tom.rotenberg@xxxxxxxxx> wrote:

> Keir/Tim
>
> Why did u add the check in load_seg() function x86_emulate.c:
> diff -r 8b152638adaa xen/arch/x86/x86_emulate/x86_emulate.c
> --- a/xen/arch/x86/x86_emulate/x86_emulate.c    Thu Apr 23 16:22:48 2009 +0100
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c    Thu Apr 23 18:47:17 2009 +0100
> @@ -1099,7 +1099,7 @@
>           (ops->write_segment == NULL) )
>          return X86EMUL_UNHANDLEABLE;
>  
> -    if ( in_protmode(ctxt, ops) )
> +    if ( in_protmode(ctxt, ops) || !is_x86_user_segment(seg) )
>          return protmode_load_seg(seg, sel, ctxt, ops);
>
> Why is it needed? and what will happen in case we will need to emulate a load of user segment in protected mode? right now, it will just not be performed. is this even legal?



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