From: olof@lixom.net (Olof Johansson)
To: Jake Moilanen <moilanen@austin.ibm.com>
Cc: linuxppc-dev@ozlabs.org, paulus@samba.org
Subject: Re: [PATCH] DMA 4GB boundary protection
Date: Fri, 2 Mar 2007 16:27:48 -0600 [thread overview]
Message-ID: <20070302222748.GA1206@lixom.net> (raw)
In-Reply-To: <1172872183.5310.145.camel@goblue>
On Fri, Mar 02, 2007 at 03:49:43PM -0600, Jake Moilanen wrote:
> 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 us dma-windows under
> 4gigs. However, some of the new System-P boxes have dma-windows above
> 4gigs, and this present a problem.
>
> I propose fixing it in the IOMMU allocation instead of making each
> driver protect against it as it is more efficient, and won't require
> changing every driver which has not considered this issue.
Sorry, but you need to fix the drivers. They might be used on a system
without an IOMMU, or with direct mapping. It's particularily likely in
the case of DAC-capable devices, and that's the only case for which you
can cross a 4GB boundary in the first place.
-Olof
next prev parent reply other threads:[~2007-03-02 22:16 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 [this message]
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
2007-03-29 21:54 ` Benjamin Herrenschmidt
2007-04-23 12:22 ` Paul Mackerras
2007-04-24 3:07 ` Olof Johansson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20070302222748.GA1206@lixom.net \
--to=olof@lixom.net \
--cc=linuxppc-dev@ozlabs.org \
--cc=moilanen@austin.ibm.com \
--cc=paulus@samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.