From: Christoph Hellwig <hch@lst.de>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Christoph Hellwig <hch@lst.de>,
Christoph Hellwig <hch@infradead.org>,
linux-kernel@vger.kernel.org
Subject: Re: ehci-pci breakage with dma-mapping changes in 5.4-rc2
Date: Tue, 8 Oct 2019 14:50:08 +0200 [thread overview]
Message-ID: <20191008125008.GA4829@lst.de> (raw)
In-Reply-To: <20191008115103.GA463127@rani.riverdale.lan>
On Tue, Oct 08, 2019 at 07:51:03AM -0400, Arvind Sankar wrote:
> What I mean is, do there exist devices (which would necessarily support
> 64-bit DMA) that want to DMA using bigger than 4Gb buffers. Eg a GPU
> accelerator card with 16Gb of RAM on-board that wants to map 6Gb for DMA
> in one go, or 5 accelerator cards that are in one IOMMU domain and want
> to simultaneously map 1Gb each.
If you allocate more than 32-bits worth of address space the IOMMU
address space allocator will dip into 64-bit values if the device
dma mask supports that.
next prev parent reply other threads:[~2019-10-08 12:50 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 2:24 Arvind Sankar
2019-10-07 7:34 ` Christoph Hellwig
2019-10-07 17:54 ` Arvind Sankar
2019-10-07 17:55 ` Christoph Hellwig
2019-10-07 17:56 ` Christoph Hellwig
2019-10-07 17:58 ` Arvind Sankar
2019-10-07 18:32 ` Arvind Sankar
2019-10-07 18:47 ` Christoph Hellwig
2019-10-07 22:10 ` Arvind Sankar
2019-10-07 23:54 ` Arvind Sankar
2019-10-08 7:32 ` Christoph Hellwig
2019-10-08 11:51 ` Arvind Sankar
2019-10-08 12:50 ` Christoph Hellwig [this message]
2019-10-08 15:47 ` Arvind Sankar
2019-10-09 6:50 ` Christoph Hellwig
2019-10-09 13:48 ` Arvind Sankar
2019-10-08 7:29 ` Christoph Hellwig
2019-10-08 14:33 ` [PATCH] iommu/vt-d: Return the correct dma mask when we are bypassing the IOMMU Arvind Sankar
2019-10-09 2:45 ` Lu Baolu
2019-10-09 6:51 ` Christoph Hellwig
2019-10-10 1:24 ` Lu Baolu
2019-10-10 1:26 ` Lu Baolu
2019-10-16 19:15 ` Arvind Sankar
2019-10-17 7:08 ` Christoph Hellwig
2019-10-17 15:55 ` Arvind Sankar
2019-10-18 9:50 ` Joerg Roedel
2019-10-18 15:14 ` Christoph Hellwig
2019-10-18 15:21 ` Joerg Roedel
2019-10-18 15:22 ` Christoph Hellwig
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