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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id af79cd13be357-93ef5009ca3sm227528285a.7.2026.10.13.05.44.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Oct 2026 05:44:01 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1xGbrM-00000009Wdr-3fVQ; Tue, 13 Oct 2026 09:44:00 -0300 Date: Tue, 13 Oct 2026 09:44:00 -0300 From: Jason Gunthorpe To: Robin Murphy Cc: Nicolin Chen , Peng Fan , Will Deacon , "Joerg Roedel (AMD)" , Jean-Philippe Brucker , Thierry Reding , Krishna Reddy , Jonathan Hunter , linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, Peng Fan Subject: Re: [PATCH RFC v6 5/5] iommu/arm-smmu-v3: Wire up shared-SID STE ordering and feature gating Message-ID: <20261013124400.GI14213@ziepe.ca> References: <20261011-smmu-shared-sid-v6-0-cb76b89dc612@nxp.com> <20261011-smmu-shared-sid-v6-5-cb76b89dc612@nxp.com> Precedence: bulk X-Mailing-List: iommu@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 Tue, Oct 13, 2026 at 12:22:06PM +0100, Robin Murphy wrote: > If we're not going to support PASID for shared streams (which I suggest we > don't...) than we shouldn't strictly need to worry about CD tables anyway. > So rather than having to special-case CD table sharing for shared streams, > perhaps it might make sense to generalise back to a "default" per-domain CD > for non-PASID use, which can then get switched for the private per-stream > cd_table if and when a device does enable PASID? If we have stared STEs then the group becomes the per-STE data structure not the master.. We don't have any way right now to do that, but it would make some sense for the group to store the shared CD Jason