Re: [PATCH v5 07/15] iommupt: Add map_pages op

[Jason Gunthorpe]

On Tue, Oct 07, 2025 at 05:38:48PM +0530, Vasant Hegde wrote:
> > +           PT_WARN_ON(compute_best_pgsize(&pts, oa) != leaf_pgsize_lg2);
> 
> 
> If I select CONFIG_DEBUG_GENERIC_PT=y and boot AMD system with V1 (Host page
> table), in some cases we hit this warning. Code path looks ok. may be silence
> these warning?
> 
> [   31.985383] pt_iommu_amdv1_map_pages : oa 0x208b95d000 va 0xfef80000 
> last_va 0xfef9ffff pgsz_lg 0xc pgsize 0x1000 pgcount 0x20
                                                       ^^^^
> [   31.985384] __map_range_leaf oa 0x208b95e000 va 0xfef80000 last_va 
> 0xfef9ffff pgsize 0xd leaf_pgsize 0xc possible_sz 0x1ff000
                                             ^^^^

oa advanced but va didn't. It's a a little bug in the warning,
since it doesn't recompute the va each iteration.  I'm surprised the
random test didn't find it..

                if (IS_ENABLED(CONFIG_DEBUG_GENERIC_PT)) {
                        pt_index_to_va(&pts);
                        PT_WARN_ON(compute_best_pgsize(&pts, oa) !=
                                   leaf_pgsize_lg2);
                }

Thanks,
Jason