From: Pranjal Shrivastava <praan@google.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: iommu@lists.linux.dev, "Joerg Roedel (AMD)" <joro@8bytes.org>,
Jean-Philippe Brucker <jpb@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will@kernel.org>,
David Matlack <dmatlack@google.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
patches@lists.linux.dev, Samiullah Khawaja <skhawaja@google.com>,
Mostafa Saleh <smostafa@google.com>
Subject: Re: [PATCH v2 1/9] iommupt: Remove the sanity check for pt_num_items_lg2() at the top level
Date: Mon, 28 Sep 2026 23:03:41 +0000 [thread overview]
Message-ID: <arryTf6sRapjC1uW@google.com> (raw)
In-Reply-To: <1-v2-563ee63886f0+1209-iommupt_armv8_jgg@nvidia.com>
On Wed, Aug 12, 2026 at 05:09:17PM -0300, Jason Gunthorpe wrote:
> This was ill conceived, the existing formats work OK because they
> happen to support pt_num_items_lg2() at the top level. However the
> documentation is clear that is not permitted because ARMv8 has
> concatenated top levels and we do not want to calculate an exact
> pt_num_items_lg2() for the top level special case.
>
> The logic to compute the number of items of the top level is shown in
> pt_top_memsize_lg2() which is:
>
> num_items_lg2 = common->max_vasz_lg2 - pt_table_item_lg2sz(&pts);
>
> Which is pointless to try and sanity check.
>
> Reviewed-by: Mostafa Saleh <smostafa@google.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Thanks,
Praan
next prev parent reply other threads:[~2026-09-28 23:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-12 20:09 [PATCH v2 0/9] Use the generic iommu page table for SMMUv3 Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 1/9] iommupt: Remove the sanity check for pt_num_items_lg2() at the top level Jason Gunthorpe
2026-09-28 23:03 ` Pranjal Shrivastava [this message]
2026-08-12 20:09 ` [PATCH v2 2/9] iommupt/kunit: Skip test configs without supported features Jason Gunthorpe
2026-09-28 23:16 ` Pranjal Shrivastava
2026-09-29 14:20 ` Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 3/9] iommupt/armv8: Add the 64 bit ARMv8 page table format Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 4/9] iommupt/armv8: Add DBM support Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 5/9] iommupt/armv8: Implement the iommu specific components Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 6/9] iommu/arm-smmu-v3: Remove io-pgtable-arm from sva.c Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 7/9] iommu/arm-smmu-v3: Move the DMA API comment to flush_iotlb_all Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 8/9] iommu/arm-smmu-v3: Use the generic iommu page table Jason Gunthorpe
2026-08-12 20:09 ` [PATCH v2 9/9] iommu: Remove pgsize from iommu_iotlb_gather Jason Gunthorpe
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