From: Andi Kleen <ak@muc.de>
To: virtualization@lists.osdl.org
Subject: Re: [PATCH 2/4] x86 paravirt_ops: paravirt_desc.h for native descriptor ops.
Date: Mon, 7 Aug 2006 07:40:23 +0200
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Cc: Rusty Russell <rusty@rustcorp.com.au>, Andrew Morton <akpm@osdl.org>,
       Chris Wright <chrisw@sous-sol.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Monday 07 August 2006 06:45, Rusty Russell wrote:
> Unfortunately, due to include cycles, we can't put these in
> paravirt.h: we use a separate header for these.
> 
> The implementation comes from Zach's [RFC, PATCH 10/24] i386 Vmi descriptor changes:
> 
>   Descriptor and trap table cleanups.  Add cleanly written accessors for
>   IDT and GDT gates so the subarch may override them.  Note that this
>   allows the hypervisor to transparently tweak the DPL of the descriptors
>   as well as the RPL of segments in those descriptors, with no unnecessary
>   kernel code modification.  It also allows the hypervisor implementation
>   of the VMI to tweak the gates, allowing for custom exception frames or
>   extra layers of indirection above the guest fault / IRQ handlers.

Nice cleanup. The old assembly mess was ripe to be killed for a long time.

-Andi

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