From: Christoph Hellwig <hch@lst.de>
To: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Halil Pasic <pasic@linux.ibm.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Lucas Stach <l.stach@pengutronix.de>
Subject: Re: Regression due to d98849aff879 (dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code)
Date: Tue, 6 Aug 2019 18:07:09 +0200 [thread overview]
Message-ID: <20190806160709.GA25586@lst.de> (raw)
In-Reply-To: <5bd42e33-8077-ea23-a9f3-c575db4edada@amd.com>
On Tue, Aug 06, 2019 at 03:59:40PM +0000, Lendacky, Thomas wrote:
> As long as two different cookie types (page pointer for encrypted DMA
> and virtual address returned from page_address() for unencrypted DMA)
> is ok. I'm just not familiar with how the cookie is used in any other
> functions, if at all.
DMA_ATTR_NO_KERNEL_MAPPING is intended for memory never used in the
kernel, either because it is just a buffer for device that are too cheap
to enough dram, or because it is a buffer for userspace to device
communication that the kernel just mediates.
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next prev parent reply other threads:[~2019-08-06 16:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-06 9:13 Regression due to d98849aff879 (dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code) Lucas Stach
2019-08-06 11:33 ` Christoph Hellwig
2019-08-06 12:20 ` Lucas Stach
2019-08-06 13:38 ` Lendacky, Thomas
2019-08-06 14:04 ` Christoph Hellwig
2019-08-06 14:06 ` Lucas Stach
2019-08-06 14:18 ` Lendacky, Thomas
2019-08-06 15:46 ` Christoph Hellwig
2019-08-06 15:59 ` Lendacky, Thomas
2019-08-06 16:07 ` Christoph Hellwig [this message]
2019-08-06 15:44 ` Christoph Hellwig
2019-08-07 15:24 ` Lucas Stach
2019-08-08 7:48 ` Christoph Hellwig
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