From: olof@lixom•net (Olof Johansson)
To: Jake Moilanen <moilanen@austin•ibm.com>
Cc: paulus@samba•org, linuxppc-dev@ozlabs•org
Subject: Re: [PATCH] DMA 4GB boundary protection
Date: Thu, 29 Mar 2007 09:52:52 -0500 [thread overview]
Message-ID: <20070329145252.GA23270@lixom.net> (raw)
In-Reply-To: <1175175842.1398.54.camel@goblue>
On Thu, Mar 29, 2007 at 08:44:02AM -0500, Jake Moilanen wrote:
> On Thu, 2007-03-29 at 09:23 +1000, Benjamin Herrenschmidt wrote:
> > On Wed, 2007-03-28 at 13:17 -0500, Jake Moilanen wrote:
> >
> > > One more try.
> >
> > And patch is still mangled....
>
> Hrm....I should just go back to Sylpheed.
>
> Unmangled version:
>
>
> There are many adapters which can not handle DMAing acrosss any 4 GB
> boundary. For instance the latest Emulex adapters.
>
> This normally is not an issue as firmware gives dma-windows under
> 4gigs. However, some of the new System-P boxes have dma-windows above
> 4gigs, and this present a problem.
>
> During initialization of the IOMMU tables, the last entry at each 4GB
> boundary is marked as used. Thus no mappings can cross the boundary.
> If a table ends at a 4GB boundary, the entry is not marked as used.
>
> A boot option to remove this 4GB protection is given w/ protect4gb=off.
> This exposes the potential issue for driver and hardware development
> purposes.
>
> Signed-off-by: Jake Moilanen <moilanen@austin•ibm.com>
Acked-by: Olof Johansson <olof@lixom•net>
-Olof
next prev parent reply other threads:[~2007-03-29 14:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-02 21:49 [PATCH] DMA 4GB boundary protection Jake Moilanen
2007-03-02 22:27 ` Olof Johansson
2007-03-03 8:27 ` Benjamin Herrenschmidt
2007-03-03 23:25 ` Olof Johansson
2007-03-04 5:17 ` Christoph Hellwig
2007-03-04 5:52 ` Olof Johansson
2007-03-03 23:29 ` Olof Johansson
2007-03-03 23:32 ` Segher Boessenkool
2007-03-03 23:57 ` Olof Johansson
2007-03-21 21:05 ` Jake Moilanen
2007-03-21 21:39 ` Olof Johansson
2007-03-22 17:53 ` Olof Johansson
2007-03-22 17:47 ` Jake Moilanen
2007-03-22 22:52 ` Segher Boessenkool
2007-03-27 20:10 ` Jake Moilanen
2007-03-27 20:55 ` Benjamin Herrenschmidt
2007-03-27 23:48 ` Paul Mackerras
2007-03-28 15:56 ` Olof Johansson
2007-03-28 18:17 ` Jake Moilanen
2007-03-28 23:23 ` Benjamin Herrenschmidt
2007-03-29 13:44 ` Jake Moilanen
2007-03-29 14:52 ` Olof Johansson [this message]
2007-03-29 21:54 ` Benjamin Herrenschmidt
2007-04-23 12:22 ` Paul Mackerras
2007-04-24 3:07 ` Olof Johansson
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