Re: [RFC PATCH 2/5] iommu/vt-d: Add generic IO page table support

[Jason Gunthorpe]

On Thu, Nov 09, 2023 at 12:10:59AM +0000, Zhang, Tina wrote:

> > If this is going to happen can we also convert vt-d to actually use the io page
> > table stuff directly and shuffle the code around so it is structured like the rest of
> > the io page table implementations?

> Converting VT-d driver to use io page table involves much code
> change. I made a local version of it, and it didn't prove much
> benefit.

Well, it structures the code in a similar way to all the other
drivers, though I admit to having not looked closely at the io page
table stuff.
 
> VT-d only supports one 1st-stage IO pgtable format and one 2nd-stage
> IO pgtable format. So, the current IO pgtable handling operations
> seems more efficient comparing to adding another layer callbacks in
> them.

I would like to de-virtualize those callbacks, is is completely
pointless when we have per-format iommu_domain ops now.

Jason