From: Andi Kleen <ak@suse.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>,
Yinghai Lu <Yinghai.Lu@sun.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Vivek Goyal <vgoyal@in.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86-64: disable the GART before allocate aperture
Date: Fri, 22 Jun 2007 23:28:20 +0200 [thread overview]
Message-ID: <200706222328.21259.ak@suse.de> (raw)
In-Reply-To: <20070622213327.69663288@the-village.bc.nu>
On Friday 22 June 2007 22:33, Alan Cox wrote:
> On Fri, 22 Jun 2007 12:31:24 -0700
>
> Muli Ben-Yehuda <muli@il.ibm.com> wrote:
> > On Fri, Jun 22, 2007 at 12:19:15PM -0700, Yinghai Lu wrote:
> > > [PATCH] x86-64: disable the GART before allocate aperture
> > >
> > > For K8 system: 4G RAM with memory hole remapping enabled, or more
> > > than 4G RAM installed. when mem is allocated for GART, it will do
> > > the memset for clear. and for kexec case, the first kernel already
> > > enable that, the memset in second kernel will cause the system
> > > restart. So disable that at first before we try to allocate mem for
> > > it.
> >
> > Why does the memset in the second kernel cause a system restart?
>
> You've got mapped live gart pages from the previous kernel. Even if you
> disable the gart before a memset
It's probably too late then. It could also interfere with other operations.
If anything the GART should be disabled during kexec shutdown. Perhaps we just
need a suitable suspend function that does that. Eric, any preferences?
> you may well have the video card using
> gart translations and possibly live IOMMU mappings for devices using it
> via bus mastering - and those will cause you MCE exceptions with a
> corrupt cpu context flag (ie not nicely recoverable).
We disable those machine checks on K8 because they're not fully reliable.
-Andi
next prev parent reply other threads:[~2007-06-22 21:29 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-22 19:19 [PATCH] x86-64: disable the GART before allocate aperture Yinghai Lu
2007-06-22 19:31 ` Muli Ben-Yehuda
2007-06-22 19:38 ` Yinghai Lu
2007-06-22 19:49 ` Yinghai Lu
2007-06-22 20:33 ` Alan Cox
2007-06-22 21:28 ` Andi Kleen [this message]
2007-06-22 21:38 ` Yinghai Lu
2007-06-22 21:41 ` Eric W. Biederman
2007-06-22 21:32 ` Eric W. Biederman
2007-06-22 21:45 ` Muli Ben-Yehuda
2007-06-22 21:59 ` Yinghai Lu
2007-06-22 22:19 ` Alan Cox
2007-06-22 22:32 ` Eric W. Biederman
2007-06-22 22:43 ` Yinghai Lu
2007-06-22 22:54 ` Alan Cox
2007-06-22 22:57 ` Yinghai Lu
2007-06-22 23:04 ` Alan Cox
2007-06-22 23:14 ` Eric W. Biederman
2007-06-23 0:14 ` Andi Kleen
2007-06-23 0:27 ` Yinghai Lu
2007-06-23 0:35 ` Muli Ben-Yehuda
2007-06-23 0:38 ` Andi Kleen
2007-06-23 2:34 ` [PATCH] x86-64: disable the GART in shutdown Yinghai Lu
2007-06-23 10:39 ` Muli Ben-Yehuda
2007-06-23 10:59 ` Andi Kleen
2007-06-23 11:09 ` Muli Ben-Yehuda
2007-06-23 11:08 ` Andi Kleen
2007-06-25 0:18 ` Yinghai Lu
2007-06-23 16:52 ` Andrew Morton
2007-06-25 0:22 ` Yinghai Lu
2007-06-25 2:10 ` Muli Ben-Yehuda
2007-06-25 19:34 ` [PATCH] x86-64: disable the GART in shutdown v2 Yinghai Lu
2007-06-25 19:41 ` Muli Ben-Yehuda
2007-06-25 19:52 ` Yinghai Lu
2007-06-25 19:56 ` Muli Ben-Yehuda
2007-06-25 21:48 ` [PATCH 1/2] x86-64: disable the GART in shutdown Yinghai Lu
2007-06-25 21:49 ` [PATCH 2/2] x86_84: move iommu declaration from proto to iommu.h Yinghai Lu
2007-06-26 11:43 ` Muli Ben-Yehuda
2007-06-23 9:08 ` [PATCH] x86-64: disable the GART before allocate aperture Alan Cox
2007-06-23 11:12 ` Vivek Goyal
2007-06-23 13:14 ` Andi Kleen
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