From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk2-f12.google.com (mail-qk2-f12.google.com [74.125.230.204]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05E1651A742 for ; Fri, 18 Sep 2026 16:53:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.230.204 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789750400; cv=none; b=BmaYTG+o/J7wB0b3zAi6S6fFGBudRKwRVesF6Os2qg63o8CVz8kgJ2Yc6nn8qmDyQXz/slB2KMuFKFi1lVGZcaRBaj7umMuiJd5xKADYeu905eRrdxuBeBdN1ODvtRAxbLSdEpDLeMFdNQv89vRIe3PFKi8QNQv7gWLGXpuP6D0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789750400; c=relaxed/simple; bh=QHr3HItRfGIiXW33vm4AJyjNNIRgLrxwO2wwjz3RPCc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jdoKsTa+9NwC2UVB73322rV8P+Om6ZNTmaB0EqGA53wUavNBv1DugCmrC8gfKEwQCWklDQX6v4SeqtqlJzJG2E+xEIhiyUlEknMvwWJFrILkw3NVeRVOJClFOPR9BfRILAWYUmDL2185dB0Cpp4CUa7esJDZy7Gt4nBSCd2PihA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=U7vp+en0; arc=none smtp.client-ip=74.125.230.204 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="U7vp+en0" Received: by mail-qk2-f12.google.com with SMTP id af79cd13be357-939ca12ab70so116476985a.1 for ; Fri, 18 Sep 2026 09:53:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1789750397; x=1790355197; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :content-type:mime-version:references:message-id:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to:content-type; bh=xZHhNZflcpTf7gpMtfLnrd+b6TKn7wbbrgvwwdWjf0M=; b=U7vp+en0xBHHHVMOPfWIA21xFHJ0hvVIilacvNWFNRJ8MgODO/uRp+uEu3kFYELNZI bO+sM3kE3DPXYUKidivRR8gVSxH6vyAqBJ+va7kVfh5YyHoitPT1KXIyuUZf/l58tACn ik/bsjzkUc5ClTls8Cv+fsfh35252lxvMfdbxdT2VSquyTxx44uh0xNcruY3lYZtHEpX ll3IQDglg6utCqwTciSCoiATeaI75QxNEMhKVQiau/fjgIVOUKw3pyU/3rDmmvhS6NBl 1mHDfTtd0nNoipNAlHs9Q52s+kqWd4sUdhvuimAcSXMIGzExKT8R0s7I4PYf0EMDpBPF BOVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789750397; x=1790355197; h=in-reply-to:content-transfer-encoding:content-disposition :content-type:mime-version:references:message-id:subject:cc:to:from :date:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=xZHhNZflcpTf7gpMtfLnrd+b6TKn7wbbrgvwwdWjf0M=; b=bOuY/G/STSS0vK2372csQbGFBAy3IOn+nBrax9Jy1PqQWplgJChfsphrkfYFy48BlF HE+SAwsVnvyyFtwDILr07jpzXrub4TuKXnRlI3lGQnmLNpWdugG9ThPvpP+vtHtp9LPv iETiQyqBrUAYNzpfkGrhN+lWSNyZf+Cnq97fZFSlj6GmSS2uB/ON/aE5Ef5KJkvkow6S 1GwT0uGCG5YLAFPP7B5fEJ2tQMo5aFidXn0QOjGIxFunVbXEk+GeiyebqLGeM6fcmluM V7OCR7C4yjCSzSPbcx3polP1QaHe/oLsdJk+JwZW3vndent+NaoKvnkDrfh2pNPtZxkj GvPA== X-Forwarded-Encrypted: i=1; AKwUvBxjMVcW6YwAFsZf/PPFu02gDQc1ybJuexXDke5uDnysOWjqq2fdOZ8LzZmwZtBVi94gr8mBESuqknPMgwU=@vger.kernel.org X-Gm-Message-State: AFuF++nzFRvHZRe2nGiJiWn5UQTlo0iDpEFBHjiKZjl6x8wm7ElLZ/yz Zg5N0nmNMdRTEhKCYfh8XAxcI0hdyokgkz1euj+AWQqyv33FPbda4HNWx77TFpVT5tc= X-Gm-Gg: AYBFou2FBsvrqTo+FhH141/XZPQbO4P1BqA7vp5ddTQbIY7l8Eyf4URfXub5ADhDVsi l70XgnmCNAjBI0Gx21xuo2PuxzX2fo2MUdl1AfMARsSB1PEBqPzzp7dfdwFa2RacRyxOOMyCnYq WYDB5BjPoeYc7S77VpIV9TUzAlsJO1DxPLgBoH0X4t7TWDx88Ne/SdNV9qon5XqGOQIHzrSkB4t Uuom26bY5nfMzbIi0qcTY72Ez4UE8SBVtwy7hQxPIrej/iNrcR8f7mw31xMKnfOqC+/SFhM6Eqv VyXe4P2SRP9b+FTcaSGAaZa8kqrI0KSBUJ5l9B1s8io3ZviV6+5LDDI3/37eJMLm94snO2AKqWS eGmM5e377BhbwQpHuPiqeUxP551WUIB6MUnN3aNB56/VWq7qi7Hr0uBZCgrDac6ppw938tFUT1I 0ZG0EWcBMdDFWqc1WJGQhQOGXGpLPG+87MMyBX3Tr9f4u3utWch0CzBMVg2RyM+QakANLs8XRik GAilgyFQ4F10P6Ed9OG6Wyd3vxo9S1qvPXVzN99i5etBh3oTum+d6be X-Received: by 2002:a05:620a:1a17:b0:939:ee44:36bf with SMTP id af79cd13be357-93bdc72000dmr495588285a.29.1789750396680; Fri, 18 Sep 2026 09:53:16 -0700 (PDT) Received: from ziepe.ca (hlfxns010zw-159-2-239-150.pppoe-dynamic.high-speed.ns.bellaliant.net. [159.2.239.150]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-91260a60f21sm68476d6.19.2026.09.18.09.53.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Sep 2026 09:53:16 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1x7bpr-00000001yyx-21Yo; Fri, 18 Sep 2026 13:53:15 -0300 Date: Fri, 18 Sep 2026 13:53:15 -0300 From: Jason Gunthorpe To: Christian =?utf-8?B?S8O2bmln?= Cc: Catalin Marinas , "Aneesh Kumar K.V (Arm)" , linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Suzuki K Poulose , Thomas Gleixner , Will Deacon , Sumit Semwal , "T.J. Mercier" Subject: Re: [PATCH v6 7/9] dma-buf: system_heap: Enforce shared-granule alignment for cc-shared buffers Message-ID: <20260918165315.GF11599@ziepe.ca> References: <97c30fce-9bda-4c61-b1b9-10297b89c8d9@amd.com> <20260918153642.GD11599@ziepe.ca> 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 Fri, Sep 18, 2026 at 05:39:55PM +0200, Christian König wrote: > > Arch code can figure out how to do it. If some ARM configs only give > > order 4 folios or whatever then dmabuf heap doesn't care. > > The fundamental problem is that DMA allocations are highly > architecture and device specific while Linux memory allocation APIs > are generic. This isn't a dma allocation, this is a memory allocation. We made things so the CC shared folios are DMA mappable through the DMA API. From the heap perspective the only difference is passing an additional DMA_ATTR_CC_SHARED when DMA mapping the folio. Jason