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[142.68.128.5]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-46afc4597d3sm21460311cf.50.2025.01.02.12.18.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Jan 2025 12:18:31 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1tTReJ-00000000MFl-10vf; Thu, 02 Jan 2025 16:18:31 -0400 Date: Thu, 2 Jan 2025 16:18:31 -0400 From: Jason Gunthorpe To: Mostafa Saleh Cc: Robin Murphy , iommu@lists.linux.dev, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, robdclark@gmail.com, joro@8bytes.org, jean-philippe@linaro.org, nicolinc@nvidia.com, vdonnefort@google.com, qperret@google.com, tabba@google.com, danielmentz@google.com, tzukui@google.com Subject: Re: [RFC PATCH v2 55/58] drivers/iommu: Add deferred map_sg operations Message-ID: <20250102201831.GB26854@ziepe.ca> References: <20241212180423.1578358-1-smostafa@google.com> <20241212180423.1578358-56-smostafa@google.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Dec 19, 2024 at 02:24:05PM +0000, Mostafa Saleh wrote: > I had a quick look now at s390, and it seems a bit different as they only > notify the hypervisor about the iova range being changed, and don’t need > to provide iova->paddr mapping which pKVM does. Can you explain this statement some more. It seems strange to me, why would the pkvm side, which has it's own page table, need to be be told about the iova->paddr during range unmapping requests - and why would the host/guest side have to unnecessarily store this information? Jason