linux-kernel - Re: [PATCH 2/4] iommu/vt-d: Don't consider copied context entries as present

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Message-ID: <1434031622.3907.40.camel@infradead.org>
Date:	Thu, 11 Jun 2015 15:07:02 +0100
From:	David Woodhouse <dwmw2@...radead.org>
To:	Joerg Roedel <joro@...tes.org>
Cc:	iommu@...ts.linux-foundation.org, zhen-hual@...com, bhe@...hat.com,
	linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH 2/4] iommu/vt-d: Don't consider copied context entries
 as present

On Thu, 2015-06-11 at 15:47 +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@...e.de>
> 
> Hide the copied context entries from the IOMMU driver by
> considering them as non-present. This is implemented by
> setting the first AVL bit (bit 67) in the context entry to
> one. If this bit is set, the context_present() function
> returns false.
> 
> Signed-off-by: Joerg Roedel <jroedel@...e.de>

In the extended context entry, bit 67 is the PGE bit. There are no bits
which are available to software, to my knowledge.

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@...el.com                              Intel Corporation

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