From: Christoph Hellwig <hch@lst.de>
To: iommu@lists.linux-foundation.org, Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: linuxppc-dev@lists.ozlabs.org,
Lu Baolu <baolu.lu@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org
Subject: generic DMA bypass flag
Date: Wed, 13 Nov 2019 14:37:29 +0100 [thread overview]
Message-ID: <20191113133731.20870-1-hch@lst.de> (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.
next reply other threads:[~2019-11-13 13:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-13 13:37 Christoph Hellwig [this message]
2019-11-13 13:37 ` [PATCH 1/2] dma-mapping: add a dma_ops_bypass flag to struct device Christoph Hellwig
2019-11-13 13:37 ` [PATCH 2/2] powerpc: use the generic dma_ops_bypass mode Christoph Hellwig
2019-11-13 14:45 ` generic DMA bypass flag Robin Murphy
2019-11-14 7:41 ` Christoph Hellwig
2019-11-15 18:12 ` Robin Murphy
2019-11-16 6:22 ` Christoph Hellwig
2019-11-19 17:41 ` Robin Murphy
2019-11-20 11:16 ` Christoph Hellwig
2019-11-21 7:34 ` Christoph Hellwig
2019-11-21 16:44 ` Robin Murphy
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