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

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [RFC][PATCH] Emulate instructions in vm86 mode
From: Bastian Blank <bastian@xxxxxxxxxxxx>
Date: Fri, 8 Sep 2006 21:33:38 +0200
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On Fri, Sep 08, 2006 at 06:00:25PM +0100, Jan Beulich wrote:
> If the vm86 code isn't running with an i/o bitmap permitting access (which
> supposedly libint10 doesn't do), all i/o related faults should alread be
> reflected back to the guest, shouldn't they? If otoh there was permission
> granted from the kernel, then we shouldn't assume that code is prepared
> to deal with gp faults from respective port accesses.

Yes, but it does weird things, so I think there is something broken.

> However, the original patch would, if to be integrated, in my opinion need
> quite a bit of additional work - it should honor non-zero segment bases
> generally, and it should do proper limit checking for non-flat segments.

Isn't this already done by copy_from_user?


Ahead warp factor one, Mr. Sulu.

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