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[34.142.211.105]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-87feac93380sm4714358b3a.33.2026.09.28.16.03.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Sep 2026 16:03:47 -0700 (PDT) Date: Mon, 28 Sep 2026 23:03:41 +0000 From: Pranjal Shrivastava To: Jason Gunthorpe Cc: iommu@lists.linux.dev, "Joerg Roedel (AMD)" , Jean-Philippe Brucker , linux-arm-kernel@lists.infradead.org, Robin Murphy , Will Deacon , David Matlack , Pasha Tatashin , patches@lists.linux.dev, Samiullah Khawaja , Mostafa Saleh Subject: Re: [PATCH v2 1/9] iommupt: Remove the sanity check for pt_num_items_lg2() at the top level Message-ID: References: <0-v2-563ee63886f0+1209-iommupt_armv8_jgg@nvidia.com> <1-v2-563ee63886f0+1209-iommupt_armv8_jgg@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1-v2-563ee63886f0+1209-iommupt_armv8_jgg@nvidia.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260929_000351_270740_C630F7A7 X-CRM114-Status: GOOD ( 14.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 > Signed-off-by: Jason Gunthorpe Reviewed-by: Pranjal Shrivastava Thanks, Praan