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Date: Fri, 22 Nov 2013 07:02:16 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Akinobu Mita <akinobu.mita@gmail.com>
CC: LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        x86@kernel.org
Subject: Re: [PATCH] x86: enable DMA CMA with swiotlb
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On 11/22/2013 04:27 AM, Akinobu Mita wrote:
> 
> I'm currently working for integrating DMA CMA with intel-iommu which
> I can test.  Regardless of which dma ops is actually used, I would
> like to allocate large contiguous memory with dma_alloc_coherent()
> and tell the base address to the device.
> 
> We can use mem= or crashkernel= to reserve host memory, but it is
> complicated and unables to work with real IOMMU.
> 

If you have a real iotlb, why would you need contiguous memory?

	-hpa