Re: [Xen-devel] Physical address mapping to user space in dom0 p

To:	Haw-Yuan Yang <hawyuan@xxxxxxxxx>, Keir Fraser <keir@xxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] Physical address mapping to user space in dom0 problem
From:	Keir Fraser <keir@xxxxxxxxxxxxx>
Date:	Sat, 17 Mar 2007 07:57:03 +0000
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You want to mmap() the dma_handle, not the CPU pointer.

-- Keir

On 17/3/07 00:36, "Haw-Yuan Yang" <hawyuan@xxxxxxxxx> wrote:

In driver I have an IOCTL option IO_DMA_ALLOC to allocate the DMA buffer by using pci_alloc_consistent() and return the allocated physical address to user space.

In user space testing program:

1. Call IOCTL IO_DMA_ALLOC to allocate a 64Kbyte DMA buffer. The physical address of the allocated buffer is 0x03bb0000.
2. Open /dev/mem and call mmap(0,64*1024,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0x03bb0000) ;

the return of mmap is -1.

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Re: [Xen-devel] Physical address mapping to user space in dom0 problem