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

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Message-ID: <20150611141256.GF16345@suse.de>
Date:	Thu, 11 Jun 2015 16:12:56 +0200
From:	Joerg Roedel <jroedel@...e.de>
To:	David Woodhouse <dwmw2@...radead.org>
Cc:	Joerg Roedel <joro@...tes.org>, iommu@...ts.linux-foundation.org,
	zhen-hual@...com, bhe@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] iommu/vt-d: Don't consider copied context entries as
 present

On Thu, Jun 11, 2015 at 03:07:02PM +0100, David Woodhouse wrote:
> 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.

Ah you are right, I was looking at the context-entry format without
PASID. Then I have to solve this differently. Thanks for pointing that
out.


	Joerg

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