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Message-ID: <20130430152143.GB25163@8bytes.org>
Date: Tue, 30 Apr 2013 17:21:43 +0200
From: Joerg Roedel <joro@...tes.org>
To: Suravee Suthikulanit <suravee.suthikulpanit@....com>
Cc: Don Dutile <ddutile@...hat.com>,
"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: RFC: IOMMU/AMD: Error Handling
On Tue, Apr 30, 2013 at 09:56:22AM -0500, Suthikulpanit, Suravee wrote:
> This sounds more like issue with the order of how things are
> initialized in the system.
No, the problem is that almost all BIOS-provided IVRS tables are buggy
because they do not define a unity-mapped region for devices that need
one (like USB controllers). So there is a time window from iommu driver
initialization to where the usb driver takes over the controller where
these io-page-faults can happen.
Joerg
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