linux-kernel - Re: [Intel-gfx] [PATCH] intel-gtt: fix memory corruption with GM965 and >4GB RAM

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: <20110228064635.GE428@zhen-devel.sh.intel.com>
Date:	Mon, 28 Feb 2011 14:46:35 +0800
From:	Zhenyu Wang <zhenyuw@...ux.intel.com>
To:	Chris Wilson <chris@...is-wilson.co.uk>,
	Jan Niehusmann <jan@...dor.com>,
	intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [Intel-gfx] [PATCH] intel-gtt: fix memory corruption with
 GM965 and >4GB RAM

On 2011.02.26 00:05:27 +0100, Daniel Vetter wrote:
> On Fri, Feb 25, 2011 at 10:18:16PM +0000, Chris Wilson wrote:
> > So, I'm happy to use your patch to workaround the known erratum. I just
> > wish I had an explanation as to what is actually causing the corruption.
> > What I want to make sure is that we don't paper over a real bug by
> > thinking it is yet another silicon issue.
> 
> Actually, on style points I prefer your patch: The hw status page is
> allocated with drm_pci_alloc which calls dma_alloc_coherent, so setting
> the coherent mask is sufficient. The dma mask set in the gtt is
> essentially useless, because we call get_user_pages on everything anyway
> (in gem - iirc agp uses it). I just think it's confusing to limit the
> general dma mask and continue to happily map pages above 4G.
> 

Think about IOMMU engine, we need to set dma_mask properly for
returned dma mapping address be limited in max range that can be
handled in GTT entry. 

-- 
Open Source Technology Center, Intel ltd.

$gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827

Download attachment "signature.asc" of type "application/pgp-signature" (199 bytes)