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Thu, 27 Mar 2025 13:36:06 +0000 Date: Thu, 27 Mar 2025 09:36:02 -0400 From: Dan Williams To: "Zhijian Li (Fujitsu)" , Ira Weiny , "linux-cxl@vger.kernel.org" CC: Jonathan Cameron , Dave Jiang , Alison Schofield , "Vishal Verma" , Dan Williams , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] cxl/acpi: Verify CHBS length for CXL2.0 Message-ID: <67e5544237027_13cb29432@dwillia2-mobl3.amr.corp.intel.com.notmuch> References: <20250326074450.937819-1-lizhijian@fujitsu.com> <67e4c9aaedd08_138d3294ca@iweiny-mobl.notmuch> <1ed912df-42c7-4319-8765-3167963df7b3@fujitsu.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1ed912df-42c7-4319-8765-3167963df7b3@fujitsu.com> X-ClientProxiedBy: MW4PR03CA0182.namprd03.prod.outlook.com (2603:10b6:303:b8::7) To PH8PR11MB8107.namprd11.prod.outlook.com (2603:10b6:510:256::6) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH8PR11MB8107:EE_|SJ2PR11MB7473:EE_ X-MS-Office365-Filtering-Correlation-Id: 391352fb-651a-443f-61de-08dd6d345361 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|1800799024; 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But did a platform have issues with this? > > Not really, actually, I discovered it while reviewing the code and > CXL specification. > > Currently, this issue arises only when I inject an incorrect length > via QEMU environment. Our hardware does not experience this problem. > > > > Does this need to be backported? > I remain neutral :) What does the kernel do with this invalid CHBS from QEMU? I would be happy to let whatever bad effect from injecting a corrupted CHBS just happen because there are plenty of ways for QEMU to confuse the kernel even if the table lengths are correct. Unless it has real impact I would rather not touch the kernel for every possible way that QEMU can make a mistake. I.e. if it was a widespread problem that affected multiple QEMU users by default then maybe. Just your local test gone awry? Maybe not.