Re: [PATCH v4 1/2] iommu/io-pgtable-arm: Add way to debug pgtable walk

Jason Gunthorpe
2024-06-19T16:33:09Z

On Mon, Jun 17, 2024 at 04:13:41PM +0100, Robin Murphy wrote:
> On 23/05/2024 6:52 pm, Rob Clark wrote:
> > From: Rob Clark <robdclark@chromium.org>
> >
> > Add an io-pgtable method to walk the pgtable returning the raw PTEs that
> > would be traversed for a given iova access.
>
> Have to say I'm a little torn here - with my iommu-dma hat on I'm not super
> enthusiastic about adding any more overhead to iova_to_phys, but in terms of
> maintaining io-pgtable I do like the overall shape of the implementation...

If you mark arm_lpae_pgtable_walk() and the callbacks as
__always_inline then the compiler should generate the same code as
today for arm_lpae_iova_to_phys().

Jason