From: Christoph Hellwig <hch@infradead.org>
To: "Christian König" <christian.koenig@amd.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
David1.Zhou@amd.com, daniel@ffwll.ch,
dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org,
Logan Gunthorpe <logang@deltatee.com>
Subject: Re: [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function
Date: Mon, 16 Mar 2020 02:52:13 -0700 [thread overview]
Message-ID: <20200316095213.GA29212@infradead.org> (raw)
In-Reply-To: <eb567569-426a-0845-b443-a20155897705@amd.com>
On Mon, Mar 16, 2020 at 10:41:42AM +0100, Christian König wrote:
> Well I would prefer if the drivers can somehow express their requirements
> and get IOVA structures already in the form they need.
>
> Converting the IOVA data from one form to another is sometimes quite costly.
> Especially when it is only temporarily needed.
We basically have two ways to generate the IOVA:
- a linear translation for the direct mapping case or some dumb IOMMU
drivers - in that case case there is a 1:1 mapping between input
segments and output segments in DMA mapping
- a non-trivial IOMMU where all aligned segments are merged into
a single IOVA range
So I don't really see how the dma layer could help much with any
limitation beyond existing max size and dma boundary ones.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: "Christian König" <christian.koenig@amd.com>
Cc: linaro-mm-sig@lists.linaro.org, David1.Zhou@amd.com,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
Christoph Hellwig <hch@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
Logan Gunthorpe <logang@deltatee.com>,
linux-media@vger.kernel.org
Subject: Re: [Intel-gfx] [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function
Date: Mon, 16 Mar 2020 02:52:13 -0700 [thread overview]
Message-ID: <20200316095213.GA29212@infradead.org> (raw)
In-Reply-To: <eb567569-426a-0845-b443-a20155897705@amd.com>
On Mon, Mar 16, 2020 at 10:41:42AM +0100, Christian König wrote:
> Well I would prefer if the drivers can somehow express their requirements
> and get IOVA structures already in the form they need.
>
> Converting the IOVA data from one form to another is sometimes quite costly.
> Especially when it is only temporarily needed.
We basically have two ways to generate the IOVA:
- a linear translation for the direct mapping case or some dumb IOMMU
drivers - in that case case there is a 1:1 mapping between input
segments and output segments in DMA mapping
- a non-trivial IOMMU where all aligned segments are merged into
a single IOVA range
So I don't really see how the dma layer could help much with any
limitation beyond existing max size and dma boundary ones.
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Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2020-03-16 9:52 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 13:51 P2P for DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 13:51 ` [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 15:28 ` Christoph Hellwig
2020-03-11 15:28 ` [Intel-gfx] " Christoph Hellwig
2020-03-12 10:14 ` Christian König
2020-03-12 10:14 ` [Intel-gfx] " Christian König
2020-03-12 10:14 ` Christian König
2020-03-12 10:19 ` Christoph Hellwig
2020-03-12 10:19 ` [Intel-gfx] " Christoph Hellwig
2020-03-12 10:31 ` Christian König
2020-03-12 10:31 ` [Intel-gfx] " Christian König
2020-03-12 10:31 ` Christian König
2020-03-12 10:47 ` Christoph Hellwig
2020-03-12 10:47 ` [Intel-gfx] " Christoph Hellwig
2020-03-12 11:02 ` Christian König
2020-03-12 11:02 ` [Intel-gfx] " Christian König
2020-03-12 11:02 ` Christian König
2020-03-12 14:19 ` Jason Gunthorpe
2020-03-12 14:19 ` Jason Gunthorpe
2020-03-12 15:39 ` Christian König
2020-03-12 15:39 ` [Intel-gfx] " Christian König
2020-03-12 15:39 ` Christian König
2020-03-12 16:19 ` Jason Gunthorpe
2020-03-12 16:19 ` Jason Gunthorpe
2020-03-12 16:13 ` Logan Gunthorpe
2020-03-12 16:13 ` [Intel-gfx] " Logan Gunthorpe
2020-03-12 16:13 ` Logan Gunthorpe
2020-03-13 11:21 ` Christoph Hellwig
2020-03-13 11:21 ` [Intel-gfx] " Christoph Hellwig
2020-03-13 12:17 ` Jason Gunthorpe
2020-03-13 12:17 ` Jason Gunthorpe
2020-03-16 8:56 ` Christoph Hellwig
2020-03-16 8:56 ` [Intel-gfx] " Christoph Hellwig
2020-03-16 9:41 ` Christian König
2020-03-16 9:41 ` [Intel-gfx] " Christian König
2020-03-16 9:41 ` Christian König
2020-03-16 9:52 ` Christoph Hellwig [this message]
2020-03-16 9:52 ` [Intel-gfx] " Christoph Hellwig
2020-03-16 12:37 ` Jason Gunthorpe
2020-03-16 12:37 ` Jason Gunthorpe
2020-03-13 13:33 ` Christian König
2020-03-13 13:33 ` [Intel-gfx] " Christian König
2020-03-13 13:33 ` Christian König
2020-03-11 13:51 ` [PATCH 2/6] dma-buf: add peer2peer flag Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 13:51 ` [PATCH 3/6] drm/amdgpu: note that we can handle peer2peer DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 13:51 ` [PATCH 4/6] drm/amdgpu: add checks if DMA-buf P2P is supported Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 14:04 ` Jason Gunthorpe
2020-03-11 14:04 ` Jason Gunthorpe
2020-03-11 14:33 ` Christian König
2020-03-11 14:33 ` [Intel-gfx] " Christian König
2020-03-11 14:33 ` Christian König
2020-03-11 14:38 ` Jason Gunthorpe
2020-03-11 14:38 ` Jason Gunthorpe
2020-03-11 14:43 ` Christian König
2020-03-11 14:43 ` [Intel-gfx] " Christian König
2020-03-11 14:43 ` Christian König
2020-03-11 14:48 ` Jason Gunthorpe
2020-03-11 14:48 ` Jason Gunthorpe
2020-03-11 13:51 ` [PATCH 5/6] drm/amdgpu: add support for exporting VRAM using DMA-buf v2 Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 14:33 ` Jason Gunthorpe
2020-03-11 14:33 ` Jason Gunthorpe
2020-03-11 14:39 ` Jason Gunthorpe
2020-03-11 14:39 ` Jason Gunthorpe
2020-03-11 15:08 ` Alex Deucher
2020-03-11 15:08 ` [Intel-gfx] " Alex Deucher
2020-03-11 15:08 ` Alex Deucher
2020-03-11 13:51 ` [PATCH 6/6] drm/amdgpu: improve amdgpu_gem_info debugfs file Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 18:09 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/6] lib/scatterlist: add sg_set_dma_addr() function Patchwork
2020-03-11 18:34 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork
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