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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9158a3b637esm580303885a.32.2026.06.04.07.16.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jun 2026 07:16:11 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wV8ri-00000008HMt-1ns6; Thu, 04 Jun 2026 11:16:10 -0300 Date: Thu, 4 Jun 2026 11:16:10 -0300 From: Jason Gunthorpe To: Guanghui Feng Cc: adrian.larumbe@collabora.com, airlied@gmail.com, alex@shazbot.org, alikernel-developer@linux.alibaba.com, baolu.lu@linux.intel.com, boris.brezillon@collabora.com, dri-devel@lists.freedesktop.org, dwmw2@infradead.org, iommu@lists.linux.dev, joro@8bytes.org, kevin.tian@intel.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, liviu.dudau@arm.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, oliver.yang@linux.alibaba.com, robh@kernel.org, robin.murphy@arm.com, shiyu.zsq@linux.alibaba.com, steven.price@arm.com, suravee.suthikulpanit@amd.com, tzimmermann@suse.de, wei.guo.simon@linux.alibaba.com, will@kernel.org, xlpang@linux.alibaba.com Subject: Re: [PATCH v3 01/32] iommu: introduce iova_to_phys_length in iommu_domain_ops Message-ID: <20260604141610.GX2487554@ziepe.ca> References: <20260602104637.1219810-1-guanghuifeng@linux.alibaba.com> <20260603151804.1963871-1-guanghuifeng@linux.alibaba.com> <20260603151804.1963871-2-guanghuifeng@linux.alibaba.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: <20260603151804.1963871-2-guanghuifeng@linux.alibaba.com> On Wed, Jun 03, 2026 at 11:17:33PM +0800, Guanghui Feng wrote: > +phys_addr_t iommu_iova_to_phys_length(struct iommu_domain *domain, > + dma_addr_t iova, > + size_t *mapped_length) > { This should take in an ending point so the accumulation knows when to stop, otherwise it is too hard to use. > - if (domain->type == IOMMU_DOMAIN_IDENTITY) > + phys_addr_t phys; > + > + if (domain->type == IOMMU_DOMAIN_IDENTITY) { > + if (mapped_length) > + *mapped_length = PAGE_SIZE; > return iova; > + } > > - if (domain->type == IOMMU_DOMAIN_BLOCKED) > - return 0; > + if (mapped_length) > + *mapped_length = 0; > + > + if (domain->ops->iova_to_phys_length) > + return domain->ops->iova_to_phys_length(domain, iova, mapped_length); > + > + /* Fallback to legacy iova_to_phys without length info */ > + if (!domain->ops->iova_to_phys) > + return PHYS_ADDR_MAX; > + > + phys = domain->ops->iova_to_phys(domain, iova); > + if (!phys) > + return PHYS_ADDR_MAX; And to properly clean up the callers all the non-iommupt paths should manually do accumulation here as well. Basically if you call this function you get a maximal contiguous physical range as efficiently as possible. Jason