archive mirror
 help / color / mirror / Atom feed
From: Christoph Hellwig <>
To:, Alexey Kardashevskiy <>
Cc: Greg Kroah-Hartman <>,
	Robin Murphy <>,,
Subject: generic DMA bypass flag v3
Date: Tue, 14 Apr 2020 14:25:02 +0200	[thread overview]
Message-ID: <> (raw)

Hi all,

I've recently beeing chatting with Lu about using dma-iommu and
per-device DMA ops in the intel IOMMU driver, and one missing feature
in dma-iommu is a bypass mode where the direct mapping is used even
when an iommu is attached to improve performance.  The powerpc
code already has a similar mode, so I'd like to move it to the core
DMA mapping code.  As part of that I noticed that the current
powerpc code has a little bug in that it used the wrong check in the
dma_sync_* routines to see if the direct mapping code is used.

These two patches just add the generic code and move powerpc over,
the intel IOMMU bits will require a separate discussion.

The x86 AMD Gart code also has a bypass mode, but it is a lot
strange, so I'm not going to touch it for now.

Changes since v2:
 - move the dma mapping helpers out of line
 - check for possible direct mappings using the dma mask

Changes since v1:
 - rebased to the current dma-mapping-for-next tree
iommu mailing list

             reply	other threads:[~2020-04-14 12:25 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-14 12:25 Christoph Hellwig [this message]
2020-04-14 12:25 ` [PATCH 1/4] dma-mapping: move the remaining DMA API calls out of line Christoph Hellwig
2020-04-15  2:26   ` Alexey Kardashevskiy
2020-04-15  6:18     ` Christoph Hellwig
2020-04-15 11:21       ` Alexey Kardashevskiy
2020-04-17  7:58         ` Christoph Hellwig
2020-05-05  4:18           ` Alexey Kardashevskiy
2020-05-09  8:19             ` Christoph Hellwig
2020-05-09 14:07               ` Alexey Kardashevskiy
2020-06-03  4:13               ` Alexey Kardashevskiy
2020-07-07  0:43                 ` Alexey Kardashevskiy
2020-07-07 14:51                   ` Christoph Hellwig
2020-04-14 12:25 ` [PATCH 2/4] dma-mapping: inline the fast path dma-direct calls Christoph Hellwig
2020-04-14 12:25 ` [PATCH 3/4] dma-mapping: add a dma_ops_bypass flag to struct device Christoph Hellwig
2020-04-14 12:47   ` Greg Kroah-Hartman
2020-04-18 12:42   ` Joerg Roedel
2020-04-19  8:00     ` Christoph Hellwig
2020-04-19 12:25       ` Joerg Roedel
2020-04-19 14:46         ` Alexey Kardashevskiy
2020-04-14 12:25 ` [PATCH 4/4] powerpc: use the generic dma_ops_bypass mode Christoph Hellwig

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \

* 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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).