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From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Suravee Suthikulanit
	<suravee.suthikulpanit-5C7GfCeVMHo@public.gmane.org>
Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org"
	<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: RFC: IOMMU/AMD: Error Handling
Date: Tue, 30 Apr 2013 17:21:43 +0200	[thread overview]
Message-ID: <20130430152143.GB25163@8bytes.org> (raw)
In-Reply-To: <517FDB96.7060602-5C7GfCeVMHo@public.gmane.org>

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

WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Suravee Suthikulanit <suravee.suthikulpanit@amd.com>
Cc: Don Dutile <ddutile@redhat.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: RFC: IOMMU/AMD: Error Handling
Date: Tue, 30 Apr 2013 17:21:43 +0200	[thread overview]
Message-ID: <20130430152143.GB25163@8bytes.org> (raw)
In-Reply-To: <517FDB96.7060602@amd.com>

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



  parent reply	other threads:[~2013-04-30 15:21 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-29 19:45 RFC: IOMMU/AMD: Error Handling Suravee Suthikulanit
2013-04-29 19:45 ` Suravee Suthikulanit
     [not found] ` <517ECDDA.3000606-5C7GfCeVMHo@public.gmane.org>
2013-04-29 20:10   ` Don Dutile
2013-04-29 20:10     ` Don Dutile
2013-04-29 20:34     ` Duran, Leo
     [not found]       ` <BA42942F2D0DED45AFB0A6216D1E951D44CBE1F9-Vo+W8YXarrgxlywnonMhLEEOCMrvLtNR@public.gmane.org>
2013-04-29 21:42         ` Don Dutile
2013-04-29 21:42           ` Don Dutile
2013-04-29 22:31           ` Duran, Leo
     [not found]           ` <517EE940.8010005-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-04-30 14:56             ` Suravee Suthikulanit
2013-04-30 14:56               ` Suravee Suthikulanit
     [not found]               ` <517FDB96.7060602-5C7GfCeVMHo@public.gmane.org>
2013-04-30 15:09                 ` Don Dutile
2013-04-30 15:09                   ` Don Dutile
2013-04-30 15:21                 ` Joerg Roedel [this message]
2013-04-30 15:21                   ` Joerg Roedel
     [not found]     ` <517ED3A9.2050508-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-04-30 14:49       ` Suravee Suthikulanit
2013-04-30 14:49         ` Suravee Suthikulanit
     [not found]         ` <517FD9E8.8070802-5C7GfCeVMHo@public.gmane.org>
2013-04-30 15:06           ` Don Dutile
2013-04-30 15:06             ` Don Dutile
     [not found]             ` <517FDDF6.8090707-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-04-30 16:02               ` Alex Williamson
2013-04-30 16:02                 ` Alex Williamson

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