From: hch@lst.de (Christoph Hellwig)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] arm64: do not set dma masks that device connection can't handle
Date: Tue, 10 Jan 2017 15:59:14 +0100 [thread overview]
Message-ID: <20170110145914.GE27156@lst.de> (raw)
In-Reply-To: <6116278.nQQUSuo3l4@wuerfel>
On Tue, Jan 10, 2017 at 02:42:23PM +0100, Arnd Bergmann wrote:
> It's a much rarer problem for the IOMMU case though, because it only
> impacts devices that are restricted to addressing of less than 32-bits.
>
> If you have an IOMMU enabled, the dma-mapping interface does not care
> if the device can do wider than 32 bit addressing, as it will never
> hand out IOVAs above 0xffffffff.
That's absolutely not the case. IOMMUs can and do generate addresses
larger than 32-bit. Also various platforms have modes where an IOMMU
can be used when <= 32-bit addresses are used and bypassed if full 64-bit
addressing is supported and I/O isolation is not explicitly requested.
next prev parent reply other threads:[~2017-01-10 14:59 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-09 7:30 [PATCH v2] arm64: do not set dma masks that device connection can't handle Nikita Yushchenko
2017-01-10 11:51 ` Will Deacon
2017-01-10 12:47 ` Nikita Yushchenko
2017-01-10 13:12 ` Arnd Bergmann
2017-01-10 13:25 ` Robin Murphy
2017-01-10 13:42 ` Arnd Bergmann
2017-01-10 14:16 ` Robin Murphy
2017-01-10 15:06 ` Arnd Bergmann
2017-01-11 12:37 ` Nikita Yushchenko
2017-01-11 16:21 ` Arnd Bergmann
2017-01-11 18:28 ` Robin Murphy
2017-01-10 14:59 ` Christoph Hellwig [this message]
2017-01-10 14:00 ` [PATCH] arm64: avoid increasing DMA masks above what hardware supports Nikita Yushchenko
2017-01-10 17:14 ` Robin Murphy
2017-01-11 7:59 ` Nikita Yushchenko
2017-01-11 11:54 ` Robin Murphy
2017-01-11 13:41 ` Nikita Yushchenko
2017-01-11 14:50 ` Robin Murphy
2017-01-11 16:03 ` Nikita Yushchenko
2017-01-11 16:50 ` Robin Murphy
2017-01-11 18:31 ` [PATCH 0/2] arm64: fix handling of DMA masks wider than bus supports Nikita Yushchenko
2017-01-11 18:31 ` [PATCH 1/2] dma-mapping: let arch know origin of dma range passed to arch_setup_dma_ops() Nikita Yushchenko
2017-01-11 21:08 ` Arnd Bergmann
2017-01-12 5:52 ` Nikita Yushchenko
2017-01-12 6:33 ` Nikita Yushchenko
2017-01-12 13:28 ` Arnd Bergmann
2017-01-12 13:39 ` Nikita Yushchenko
2017-01-12 12:16 ` Will Deacon
2017-01-12 13:25 ` Arnd Bergmann
2017-01-12 13:43 ` Robin Murphy
2017-01-13 10:40 ` kbuild test robot
2017-01-11 18:31 ` [PATCH 2/2] arm64: avoid increasing DMA masks above what hardware supports Nikita Yushchenko
2017-01-11 21:11 ` Arnd Bergmann
2017-01-12 5:53 ` Nikita Yushchenko
2017-01-13 10:16 ` kbuild test robot
2017-01-10 14:01 ` [PATCH v2] arm64: do not set dma masks that device connection can't handle Nikita Yushchenko
2017-01-10 14:57 ` Christoph Hellwig
2017-01-10 14:51 ` Christoph Hellwig
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