Re: [PATCH v1 4/9] iommu/vt-d: Add bounce buffer API for domain map/unmap

[Lu Baolu]

Hi again,

On 3/13/19 10:04 AM, Lu Baolu wrote:
> Hi,
>
> On 3/13/19 12:38 AM, Christoph Hellwig wrote:
> > On Tue, Mar 12, 2019 at 02:00:00PM +0800, Lu Baolu wrote:
> > > This adds the APIs for bounce buffer specified domain
> > > map() and unmap(). The start and end partial pages will
> > > be mapped with bounce buffered pages instead. This will
> > > enhance the security of DMA buffer by isolating the DMA
> > > attacks from malicious devices.
> >
> > Please reuse the swiotlb code instead of reinventing it.

Just looked into the code again. At least we could reuse below
functions:

swiotlb_tbl_map_single()
swiotlb_tbl_unmap_single()
swiotlb_tbl_sync_single()

Anything else?

Best regards,
Lu Baolu

> I don't think we are doing the same thing as swiotlb here. But it's
> always a good thing to reuse code if possible. I considered this when
> writing this code, but I found it's hard to do. Do you mind pointing
> me to the code which I could reuse?
>
> Best regards,
> Lu Baolu