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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8caf9ee8593sm1019180385a.36.2026.02.10.04.43.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Feb 2026 04:43:57 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vpn5x-0000000315A-13dh; Tue, 10 Feb 2026 08:43:57 -0400 Date: Tue, 10 Feb 2026 08:43:57 -0400 From: Jason Gunthorpe To: Jiri Pirko Cc: John Stultz , dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, iommu@lists.linux.dev, linux-media@vger.kernel.org, sumit.semwal@linaro.org, benjamin.gaignard@collabora.com, Brian.Starkey@arm.com, tjmercier@google.com, christian.koenig@amd.com, m.szyprowski@samsung.com, robin.murphy@arm.com, leon@kernel.org, sean.anderson@linux.dev, ptesarik@suse.com, catalin.marinas@arm.com, aneesh.kumar@kernel.org, suzuki.poulose@arm.com, steven.price@arm.com, thomas.lendacky@amd.com, john.allen@amd.com, ashish.kalra@amd.com, suravee.suthikulpanit@amd.com, linux-coco@lists.linux.dev Subject: Re: [PATCH 4/5] dma-buf: heaps: allow heap to specify valid heap flags Message-ID: <20260210124357.GD943673@ziepe.ca> References: <20260209153809.250835-1-jiri@resnulli.us> <20260209153809.250835-5-jiri@resnulli.us> <20260210002927.GC943673@ziepe.ca> 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, Feb 10, 2026 at 10:14:08AM +0100, Jiri Pirko wrote: > >I'd advocate that the right design is for userspace to positively > >signal via this flag that it wants/accepts shared memory and without > >the flag shared memory should never be returned. > > We can have the same behaviour with the separate heap, can't we? > Userpace positively signals it wants/accepts the shared memory by > choosing "system_cc_decrypted" heap name. So what do the other heap names do? Always private? Do you ever get heaps that are unknowably private or shared (eg MMIO backed?) Jason