linux-kernel - Re: [PATCH] x86-64: disable the GART before allocate aperture

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20070622235456.08999aa7@the-village.bc.nu>
Date:	Fri, 22 Jun 2007 23:54:56 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Yinghai.Lu@....COM
Cc:	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Muli Ben-Yehuda <muli@...ibm.com>, Andi Kleen <ak@...e.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Vivek Goyal <vgoyal@...ibm.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86-64: disable the GART before allocate aperture

On Fri, 22 Jun 2007 15:43:00 -0700
Yinghai Lu <Yinghai.Lu@....COM> wrote:

> Eric W. Biederman wrote:
> > The original design came from thinking about systems where using the iommu
> > was mandatory.  I think we almost always reserve memory below 1G for the kexec
> > on panic kernel so it really shouldn't be an issue in that case.  Except
> > we need to pass an option to force not using the iommu.  I don't think
> > noiommu or swiotlb is going to make any real difference.
> > 
> > So I'm totally in favor of turning off features if we don't need them and we
> > don't take a tremendous performance hit.  (People get grumpy when writing
> > all of memory to disk takes completely unreasonable amounts of time).
> 
> 
> So you prefer to
> add diable_gart in shutdown or suspend func and let kexec to use swiotlb comand line?

Don't disable it, just don't touch it or any of its mappings. Leave it
*alone*, and use swiotlb. That'll maximise the ability to recover stuff
from the kexec kernel (since for one you may want to dump the gart when a
3d app goes kerblam)

Alan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/