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From: Chip Coldwell <coldwell@redhat.com>
To: Andi Kleen <ak@suse.de>
Cc: Chris Wedgwood <cw@f00f.org>,
	Christoph Anton Mitterer <calestyo@scientia.net>,
	Robert Hancock <hancockr@shaw.ca>,
	linux-kernel@vger.kernel.org, knweiss@gmx.de,
	andersen@codepoet.org, krader@us.ibm.com, lfriedman@nvidia.com,
	linux-nforce-bugs@nvidia.com
Subject: Re: data corruption with nvidia chipsets and IDE/SATA drives (k8 cpu errata needed?)
Date: Wed, 17 Jan 2007 09:48:08 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0701170942560.2900@localhost.localdomain> (raw)
In-Reply-To: <200701170829.54540.ak@suse.de>

On Wed, 17 Jan 2007, Andi Kleen wrote:

> On Wednesday 17 January 2007 07:31, Chris Wedgwood wrote:
>> On Tue, Jan 16, 2007 at 08:52:32PM +0100, Christoph Anton Mitterer wrote:
>>> I agree,... it seems drastic, but this is the only really secure
>>> solution.
>>
>> I'd like to here from Andi how he feels about this?  It seems like a
>> somewhat drastic solution in some ways given a lot of hardware doesn't
>> seem to be affected (or maybe in those cases it's just really hard to
>> hit, I don't know).
>
> AMD is looking at the issue. Only Nvidia chipsets seem to be affected,
> although there were similar problems on VIA in the past too.
> Unless a good workaround comes around soon I'll probably default
> to iommu=soft on Nvidia.
>
> -Andi
> -
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> Please read the FAQ at  http://www.tux.org/lkml/

We've just verified that configuring the graphics aperture to be
write-combining instead of write-back using an MTRR also solves the
problem.  It appears to be a cache incoherency issue in the graphics
aperture.

This script does the trick:

[ -- cut here -- ]
#!/bin/bash

# Read the northbridge offset 0x90 to get the size of the aperture
size=0x`lspci -xxx -s 0:18.3 | awk '/^90:/ { print $2 }'`

# bit 0 indicates the aperture is enabled, bits 1 - 3 indicate the size
if [ $((size & 1)) -eq 0 ] ; then
     echo "GART disabled; exiting"
     exit 0
fi

shft=$(((size >> 1) & 7))
size=$((0x2000000 << shft))

# Read the northbridge offset 0x94 to get the base address of the aperture
base=0x`lspci -xxx -s 0:18.3 | awk '/^90:/ { print $6 }'`
base=$((base << 25))
basehex=`printf 0x%08x $base`

printf "IOMMU aperture found at base=0x%08x size=0x%08x (%d KiB)\n" $base $size $((size/1024))

if grep -q $basehex /proc/mtrr ; then
     echo "MTRR already configured for IOMMU aperture; exiting"
     exit 0
fi

echo "Configuring write-combining MTRR for IOMMU aperture"
printf "base=0x%08x size=0x%08x type=write-combining\n" $base $size >/proc/mtrr

exit 0
[ -- cut here-- ]

Chip

-- 
Charles M. "Chip" Coldwell
Senior Software Engineer
Red Hat, Inc
978-392-2426


  parent reply	other threads:[~2007-01-17 14:54 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.E9jVXDLMKzMZNCbslzUxjMhsInE@ifi.uio.no>
2007-01-03 23:41 ` data corruption with nvidia chipsets and IDE/SATA drives // memory hole mapping related bug?! Robert Hancock
2007-01-15 22:56   ` Christoph Anton Mitterer
2007-01-15 23:05     ` Christoph Anton Mitterer
2007-01-16  0:23       ` Robert Hancock
2007-01-16 13:54         ` Christoph Anton Mitterer
2007-01-16 14:26           ` Robert Hancock
2007-01-16 18:01             ` data corruption with nvidia chipsets and IDE/SATA drives (k8 cpu errata needed?) Chris Wedgwood
2007-01-16 19:52               ` Christoph Anton Mitterer
2007-01-16 20:31                 ` Chris Wedgwood
2007-01-16 21:29                   ` Andi Kleen
2007-01-17  1:17                     ` Christoph Anton Mitterer
2007-01-17 14:48                     ` Chip Coldwell [this message]
2007-01-17 19:46                       ` Chip Coldwell
2007-01-17 22:15                       ` Andi Kleen
2007-01-18 21:57                         ` Chip Coldwell
2007-01-18 22:49                           ` Andi Kleen
2007-01-18  9:29                     ` joachim
2007-01-18 14:34                       ` Christoph Anton Mitterer
2007-01-18 16:42                       ` Chris Wedgwood
2007-01-18 11:00                     ` Erik Andersen
2007-01-18 14:43                       ` Christoph Anton Mitterer
2007-01-18 16:36                       ` Chris Wedgwood
2007-01-18 23:23                       ` Andi Kleen
2007-02-21 17:03                     ` Chip Coldwell
2007-01-16 21:54                   ` Allen Martin
2007-01-17  1:12                   ` Christoph Anton Mitterer
2007-01-16 20:16               ` Arkadiusz Miskiewicz
2007-01-16 20:21                 ` Christoph Anton Mitterer
2007-01-16 20:31               ` Krzysztof Halasa
2007-01-16 20:35                 ` Chris Wedgwood
2007-03-22 12:32     ` data corruption with nvidia chipsets and IDE/SATA drives // memory hole mapping related bug?! Christoph Anton Mitterer
     [not found] <fa.Tb2r8Il/2H8l9dhmsGAAQB2WEZg@ifi.uio.no>
     [not found] ` <fa.MydhQJqKsehLS9lIc2JSZC8Q77A@ifi.uio.no>
     [not found]   ` <fa.M9SCVAz1qZ6vrR9HTrRb95KdBSY@ifi.uio.no>
     [not found]     ` <fa.5WKg4jbSxjbUXedux14VStNyV+8@ifi.uio.no>
     [not found]       ` <fa.lphwLNvMksoBFaqfqCzMG1UVhsA@ifi.uio.no>
2007-03-05  6:25         ` data corruption with nvidia chipsets and IDE/SATA drives (k8 cpu errata needed?) Robert Hancock
2007-03-12 13:06           ` Andi Kleen
2007-03-12 14:56             ` Jeff Garzik

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