From: "Matwey V. Kornilov" <matwey.kornilov@gmail.com>
To: kvm@vger.kernel.org
Subject: IOMMU, DMA and legacy PCI board
Date: Fri, 15 Jan 2016 18:41:49 +0300 [thread overview]
Message-ID: <n7b3vt$ra8$1@ger.gmane.org> (raw)
Hello,
I am sorry, if I am asking this in a wrong place. I have an legacy
custom PCI board, which requires contiguous DMA memory region (about 4
MB) and does not support scatter/gather.
As contiguous DMA region cannot be allocated with the guaranty,
currently, the issue is solved by using mem= kernel command line
argument and using 'hidden memory' within first 3GB of RAM.
Happily, I have the kernel module source codes.
I am not quite familiar with the internals of IOMMU. The question is the
following. Is it possible to use IOMMU to emulate contiguous DMA region
consisted of smaller chunks on the other side?
If it is possible in theory, how could my PCI device driver use existing
kernel API to implement this?
Thank you.
next reply other threads:[~2016-01-15 15:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-15 15:41 Matwey V. Kornilov [this message]
2016-01-15 16:14 ` IOMMU, DMA and legacy PCI board Alex Williamson
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