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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-9852a2b6c6csm211091241.5.2026.09.23.17.15.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Sep 2026 17:15:03 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1x9X78-0000000ExXK-1vqU; Wed, 23 Sep 2026 21:15:02 -0300 Date: Wed, 23 Sep 2026 21:15:02 -0300 From: Jason Gunthorpe To: Vijayanand Jitta Cc: Will Deacon , Robin Murphy , "Joerg Roedel (AMD)" , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Prakash Gupta Subject: Re: [PATCH v5] iommu/io-pgtable-arm: Add support for contiguous hint bit Message-ID: <20260924001502.GO1540250@ziepe.ca> References: <20260921-iommu_contig_hint-v5-1-e7fbd1c3774d@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260921-iommu_contig_hint-v5-1-e7fbd1c3774d@oss.qualcomm.com> On Mon, Sep 21, 2026 at 04:44:07PM +0530, Vijayanand Jitta wrote: > From: Prakash Gupta > > Add support for the contiguous hint (CONT) bit in ARM LPAE page tables. > When a set of consecutive PTEs map a naturally aligned contiguous block of > memory, set CONT on every descriptor in that group so the hardware can > combine translations and improve TLB reach. > > Advertise the supported CONT group sizes in pgsize_bitmap. Callers select > those sizes through the normal page-size selection path; io-pgtable-arm > then installs the corresponding tagged descriptors directly. A partial > unmap of a tagged CONT group is rejected before modifying any descriptor, > so a rejected request cannot leave the group partly unmapped. > > The IO_PGTABLE_QUIRK_ARM_NO_CONT_HINT quirk allows SMMU drivers to disable > CONT support for hardware with implementation-specific errata. smmuv3 has this errata, it must be disabled there too. I didn't notice it in this patch? Jason