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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-5303301ddcdsm44166831cf.9.2026.09.03.07.47.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2026 07:47:30 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1x28iv-0000000HFle-2ikl; Thu, 03 Sep 2026 11:47:29 -0300 Date: Thu, 3 Sep 2026 11:47:29 -0300 From: Jason Gunthorpe To: "Aneesh Kumar K.V" Cc: Nicolin Chen , linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexey Kardashevskiy , Catalin Marinas , Dan Williams , Joerg Roedel , Jonathan Cameron , Marc Zyngier , Pranjal Shrivastava , Robin Murphy , Samuel Ortiz , Steven Price , Suzuki K Poulose , Will Deacon , Xu Yilun Subject: Re: [RFC PATCH v4 03/16] iommu/arm-smmu-v3: Add initial pSMMU realm viommu plumbing Message-ID: <20260903144729.GJ2890729@ziepe.ca> References: <20260427085344.941627-4-aneesh.kumar@kernel.org> <20260901143445.GC56830@ziepe.ca> <20260902121700.GC2890729@ziepe.ca> <20260902193014.GF2890729@ziepe.ca> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Sep 03, 2026 at 10:58:06AM +0530, Aneesh Kumar K.V wrote: > > Do you mean the SMMUv3 driver triggers RD creation? That feels > > wrong. Did you mean the VMM just does it earlier? > > Currently, CCA creates the realm lazily as part of another operation. > Realm creation is triggered by kvm_arm_rmi_populate() or > kvm_arch_vcpu_run_pid_change() Okay, that's not what I would have guessed. But critically is there some way for userspace to specify any realm creation parameters (like rpv, ats_plane and so one) prior to the lazy creation? Why lazy? Why not just have userspace provide the creation parameters and create the RD right then? Jason