From: joro@8bytes.org (Joerg Roedel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] iommu/dma-iommu: properly respect configured address space size
Date: Thu, 10 Nov 2016 16:59:39 +0100 [thread overview]
Message-ID: <20161110155938.GI2078@8bytes.org> (raw)
In-Reply-To: <68e7a18b-739e-b73e-eacf-3cb6c1bd279a@arm.com>
On Tue, Nov 08, 2016 at 11:37:23AM +0000, Robin Murphy wrote:
> TBH I've been pondering ripping the size stuff out of dma-iommu, as it
> all stems from me originally failing to understand what dma_32bit_pfn is
> actually for.
The point of dma_32bit_pfn is to allocate dma-address below 4G by
default. This is a performance optimization so that even devices capable
of 64bit DMA are using SAC by default instead of DAC.
Since it is the goal to share a dma-iommu implemenation between
architectures, I would rather prefer not to rip this stuff out.
Joerg
next prev parent reply other threads:[~2016-11-10 15:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161107130625eucas1p2dd23c07010b4f3eddb6c6540ed802246@eucas1p2.samsung.com>
2016-11-07 13:06 ` [PATCH] iommu/dma-iommu: properly respect configured address space size Marek Szyprowski
2016-11-08 11:37 ` Robin Murphy
2016-11-08 13:41 ` Marek Szyprowski
2016-11-08 14:44 ` Robin Murphy
2016-11-08 14:53 ` Marek Szyprowski
2016-11-10 14:08 ` Robin Murphy
2016-11-10 15:59 ` Joerg Roedel [this message]
2016-11-10 16:17 ` Robin Murphy
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