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

[Keir Fraser <keir@xxxxxxxxxxxxx>]

On 17/3/07 21:52, "Haw-Yuan Yang" <hawyuan@xxxxxxxxx> wrote:

> I knew that pci_alloc_consistent() will return both kernel virtual address and physical address. If I pass the physical address (dma_handler) to mmap, it return -1. However if I pass the kernel virtual address to mmap, I got a pointer point to the worng memory. 

Oh, I see the problem. You can only mmap() MMIO regions using /dev/mem when running on Xen. Could your device (which you already implement ioctl() for) also implement mmap() itself? Then you can simply remap_pfn_range(virt_to_phys(cpu-ptr-returned-by-pci-alloc-consistent)). This would be a neater interface to userspace for your device anyway, imo.

 -- Keir



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