# \[Xen-devel\] \[PATCH 2/8\] xen: Make clear that swiotlb and biomerge are dealing with DMA address

- From: Julien Grall \<hidden\>
- Date: 2015-07-28 16:06:56 
- List: linux-arm-kernel
- Page: https://ratatoskr.run/linux-arm-kernel/2015/07/4545172
- Thread: https://ratatoskr.run/linux-arm-kernel/2015/07/4545099/t.md

```text
Hi David,

On 28/07/15 16:52, David Vrabel wrote:
> On 28/07/15 16:02, Julien Grall wrote:
>>
>> +/* Pseudo-physical <-> DMA conversion */
>> +static inline unsigned long pfn_to_dfn(unsigned long pfn)
> 
> Use BFN for bus frame number.  This is the terminology that is used in
> the (proposed) pv-iommu hypercall.

Good idea, I will use them in the next version.

Regards,

-- 
Julien Grall
```