MFN on ARM

[luckybreak051779 <luckybreak051779@xxxxxxxxx>]

Xen Team:

I am running Xen 4.13.0 on a 32-bit ARM processor.  In a domU driver I use the dma_map_single() function to obtain a DMA address.
How can I get the MFN of that DMA address from inside the domU?  I need the MFN to be able to differentiate between
two identical domUs running the same driver code (e.g. both calling dma_map_single() ).

Thanks,
James