Hi, Julien Grall,
Could you give me some instructions about how to enable xen dom0 1:1 mapping?
Thank you.
在 2014-04-02 17:44:23，"Julien Grall" <julien.grall@xxxxxxxxxx> 写道：
>
>
>On 02/04/14 08:20, Ian Campbell wrote:
>> On Wed, 2014-04-02 at 00:10 +0800, 杜琪 wrote:
>>> Hi all,
>
>Hello,
>
>>> I have got this kernel with mmc driver on cubieboard2 from :
>>> https://github.com/jwrdegoede/linux-sunxi.git (test branch) .
>>> I have made the Xen's Dom0 configuration according
>>> this :http://wiki.xenproject.org/wiki/Mainline_Linux_Kernel_Configs.
>>> and the kernel can be booted by Xen4.4.
>>> The question we met is that some CMD can be
>>> accepted(CMD7,CMD0 ....) and but some can't(CMD52,CMD5,CMD51).
>>> We have found that the CMD51 is attempted to read the data from
>>> SD card to memory through DMA , so we replaced all the dma_ops with
>>> xen_dma_ops , where it is in struct "dma_map_ops xen_swiotlb_dma_ops"
>>> in arch/arm/xen/mm.c.
>
>Can you give more input? (Xen log, ...) DOM0 has a 1:1 mapping layout,
>so the swiotlb should not change anything.
>
>With the 1:1 mapping, the driver can safely use DMA, can you try to see
>which address is used by the DMA request?
>
>> Do I understand correctly that you have solved the issue by doing this?
>> If so then please could you send a patch. The process for submitting a
>> patch to Linux is described in Documentation/SubmittingPatches.
>
>Using swiotlb everywhere is just too slow. That's why Stefano took an
>hybrid approach (1:1 mapping + bouncing for foreign pages).
>
>Regards,
>
>--
>Julien Grall
