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

Vasant Hegde
2025-10-08T09:52:21Z

On 10/7/2025 6:41 PM, Jason Gunthorpe wrote:
> 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..

I have not tried unit tests. So far I am running on real HW.

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

Verified. This works.

Thanks
-Vasant