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Re: [Xen-devel] [RFC][PATCH] Emulate instructions in vm86 mode

To: Bastian Blank <bastian@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [RFC][PATCH] Emulate instructions in vm86 mode
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 07 Sep 2006 18:17:58 +0100
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On 7/9/06 14:59, "Bastian Blank" <bastian@xxxxxxxxxxxx> wrote:

> Seems to work partialy. The i810 driver can init the hardware but I get
> weird artefacts. It seems that some of the memory which is used for the
> cursor is overwriten by the real video output or so. Therefor I think
> that one of the segment registers which the bios uses is overwriten
> somewhere in this gpf handling.
> Hmm, the trap bounce code clears ds and es.

The trap bounce code clears fs and gs too, just as native hardware does on
an exception while in vm86 mode. The real values are saved on the exception
stack frame (hopefully!).

 -- Keir

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