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Re: [Xen-devel] Can I specify a physical memory region for a domU
- To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
- From: Eric Camachat <eric.camachat@xxxxxxxxx>
- Date: Thu, 8 Sep 2011 10:22:01 -0700
- Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
- Delivery-date: Thu, 08 Sep 2011 10:24:41 -0700
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On Thu, Sep 8, 2011 at 5:59 AM, Konrad Rzeszutek Wilk
> On Wed, Sep 07, 2011 at 05:47:46PM -0700, Eric Camachat wrote:
>> I am porting our drivers to XEN's PV domU (with PV PCI passthrouth), I
> Use the DMA API that Linux provides (I presume that is what you meant
> by PV DomU), and use the dma_alloc_coherent to set your regions.
That's what I thought before. We use a shared DMA region for multiple hardware.
Maybe I can dma_alloc_coherent for 1st and the others use the same region.
I will try it.
> Also pass in 'iommu=soft' on your Linux command line to enable the
> Xen SWIOTLB DMA system.
>> have to allocate a memory block and tell the hardware to access it.
>> But the hardware can address 32-bit only, so I want dedicate a region
>> of memory that below 2GB for the domU only.
> Uh, don't you mean 4GB? - 32bit is up to 4GB.
The hardware uses 32-bit addressing, but the system will crash if I
assigned above 2GB address to it.
So, 4GB from hardware spec, 2GB from my test. I am looking into that.
>> How do that in XEN?
>> Xen-devel mailing list
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