Re: RFC: IOMMU/AMD: Error Handling

From: Joerg Roedel
Date: Tue Apr 30 2013 - 11:21:59 EST

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.


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