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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cda1fda77bsm593097185a.18.2026.03.13.09.49.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Mar 2026 09:49:00 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1w15h5-00000007JXP-3T3m; Fri, 13 Mar 2026 13:48:59 -0300 Date: Fri, 13 Mar 2026 13:48:59 -0300 From: Jason Gunthorpe To: Shameer Kolothum Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, baolu.lu@linux.intel.com, kevin.tian@intel.com, nicolinc@nvidia.com, nathanc@nvidia.com, mochs@nvidia.com, kjaju@nvidia.com Subject: Re: [PATCH 1/2] iommu: Add device ATS not supported capability Message-ID: <20260313164859.GF1704121@ziepe.ca> References: <20260303150348.233997-1-skolothumtho@nvidia.com> <20260303150348.233997-2-skolothumtho@nvidia.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: <20260303150348.233997-2-skolothumtho@nvidia.com> On Tue, Mar 03, 2026 at 03:03:47PM +0000, Shameer Kolothum wrote: > @@ -271,6 +271,8 @@ enum iommu_cap { > */ > IOMMU_CAP_DEFERRED_FLUSH, > IOMMU_CAP_DIRTY_TRACKING, /* IOMMU supports dirty tracking */ > + /* ATS is not supported and not used on this device */ > + IOMMU_CAP_PCI_ATS_NOT_SUPPORTED, Actually, on second thought, the kdoc should have more details about what supported means. Does this mean ATS is available and could be turned on ? Or does it mean ATS is on *right now* ? The drivers should be changing ATS dynamically depending on what domain is attached. I think the implementation follows the first option? Jason