From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 16C99C369BD for ; Wed, 16 Apr 2025 23:49:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version:Content-Type: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LfAMt/qGnbnF3B3ukDM+Fm9a0gCEH4GtSe4R/UEIRDY=; b=KW2WjfbSpSFasrrFkWLprzc7nu c9JPhIvwMn9zrgkQtH8iLy1WXkbWo02LNQnGNTbakY1LKqPih5VVOXwXiYWsUAwy3IZQIbqMohTHc 2F2SDNac3f1tFRKp7Mc9PqZl1bbJ5vea1oktEs5/ezAyKwuGWmDRvT3UqRqt+NvFCrc5o1064ApNe /HjTNauLZ4JkFpXH8DYpb+xh/VZHDQeEsaFyUygxTkoZyKkYa6SoEU6qICdLgqioQXY5ca9etq9C5 nicR0Lm+ItjtoRdvDJuCCGATUH8CADg5CU93DTHbHwQHKO0G6W4Lz/BibC0i5i44U2vaaB5olmKVE s7qJdMcA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u5CUv-0000000BCM1-0aGU; Wed, 16 Apr 2025 23:48:53 +0000 Received: from mail-mw2nam10on2070f.outbound.protection.outlook.com ([2a01:111:f403:2412::70f] helo=NAM10-MW2-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u5CT2-0000000BC9Q-2SzY for linux-arm-kernel@lists.infradead.org; Wed, 16 Apr 2025 23:46:57 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=o31YOEC6wObrvvm/e8OGi8t8JeMw0ORj21O+FexgvNwJomr/XZMBjBrQKpt9rb9qT1+XnPA8bxkolzzOKUDourMwfNhsOsB0CfkkCwdmMe//udFOuujqkHej8vpy7jIm2+pc0ocOci1VKdF4wN5wv+UvrF+u+Xj7o1KIgBWUp4hKEuJiBaZ/CRIlHRpkCUmkSWM/jYby5gx7AzhH2RZI/jSKhk5vJCGQXUViBt2j7AvsIyhjBJMLHilgpcIUAva8JgjGDWtiY0dV8129Ug5dmho+amVy1Efew4Z9PWFVDE1yi4Fcrq8EmrgqoUz4iLZNBb1F7FTgvq8tlaEcApc95A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=LfAMt/qGnbnF3B3ukDM+Fm9a0gCEH4GtSe4R/UEIRDY=; b=tlighLxzYQv4J8CSnHYALQN3S6gbwSvkv/E4gqncRNav4ntyn7xeJaU0VdPbjdS/fYWbC1ShmDj0rMjhLg5hsWM9k6D6cbhooLBcY+uA8c+Pav9e2uLLOM26CYnsWY2wXervS48oACzFCpWuJlfejYeoffUfPw6OM8++pGSquy5pBQIOz/nhcUCOZj9l6AGtT3hhn2UWJCg2VR8ooFM6RKB9eXCPIm3iFq8oOTtwXHVkw+RdwXVOgZDKnNVjnP5UTTgCwHCi43s+Ax1n3fG+tDphGL56xPTMZ/J6+kXezBF4oBefDkTI+BQgsEszZJURkZ0UklV9jyHu1leh9kTZrQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=os.amperecomputing.com; dmarc=pass action=none header.from=os.amperecomputing.com; dkim=pass header.d=os.amperecomputing.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=os.amperecomputing.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=LfAMt/qGnbnF3B3ukDM+Fm9a0gCEH4GtSe4R/UEIRDY=; b=VdcHCAj9Q62l5yWDWX9M8vYG+ghInY8wESsgPcsi3LGipshTdidhPrRQbkUzwvitjhNVyb2cmu5f+zLQNFTUf/K/vB+Xq/8C1oIVqRl4RO4q6kZ2fNfzCP7g/7u3fpR1NJ0G3exDxN4Ej3FgozzUzzjQqR2tHBjd+cnucQSaWao= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=os.amperecomputing.com; Received: from LV2PR01MB7792.prod.exchangelabs.com (2603:10b6:408:14f::10) by CO1PR01MB9009.prod.exchangelabs.com (2603:10b6:303:275::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8655.22; Wed, 16 Apr 2025 23:46:51 +0000 Received: from LV2PR01MB7792.prod.exchangelabs.com ([fe80::2349:ebe6:2948:adb9]) by LV2PR01MB7792.prod.exchangelabs.com ([fe80::2349:ebe6:2948:adb9%5]) with mapi id 15.20.8655.022; Wed, 16 Apr 2025 23:46:51 +0000 From: D Scott Phillips To: Oliver Upton Cc: Marc Zyngier , Catalin Marinas , James Clark , James Morse , Joey Gouly , Kevin Brodsky , Mark Brown , Mark Rutland , "Rob Herring (Arm)" , Shameer Kolothum , Shiqi Liu , Will Deacon , Yicong Yang , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, open list Subject: Re: [PATCH 2/2] arm64: errata: Work around AmpereOne's erratum AC04_CPU_23 In-Reply-To: References: <20250415154711.1698544-1-scott@os.amperecomputing.com> <20250415154711.1698544-2-scott@os.amperecomputing.com> <864iypgjjc.fsf@scott-ph-mail.amperecomputing.com> Date: Wed, 16 Apr 2025 16:05:19 -0700 Message-ID: <86plhbyafk.fsf@scott-ph-mail.amperecomputing.com> Content-Type: text/plain X-ClientProxiedBy: CY5PR19CA0039.namprd19.prod.outlook.com (2603:10b6:930:1a::29) To LV2PR01MB7792.prod.exchangelabs.com (2603:10b6:408:14f::10) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR01MB7792:EE_|CO1PR01MB9009:EE_ X-MS-Office365-Filtering-Correlation-Id: f1507d4f-7cd2-45ff-8cae-08dd7d40f5f9 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|52116014|366016|7416014|376014|1800799024|38350700014|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?eSZwLW6g39/9lzNEk41KcqX8Bdaz4C6XWnGzZc9X2W2Q3zo4xaCUTu48UcXI?= =?us-ascii?Q?ixCH4WEE2W7ZMbLc51i9v3Cwe4HXJ/vOdIvO3hInFpXWG8GSYhdAfdn7zeXs?= =?us-ascii?Q?/VS+zJIE03ODOnwhrDSlnoRBDZHz0Tt5N3cNmyW4rOyZHC5saVblvYyEZllu?= =?us-ascii?Q?WPNd6vIiYv4pEFRcY6rcW65+l2+gqFI3iqywco59rNNgB1jL//CoOVvL9qVV?= =?us-ascii?Q?50BEWp7ClL7/konGAM+2/UOUhjrjUq+o4NGl9Gc9NrlQXf2DdfCxJcyzR1R9?= =?us-ascii?Q?Y4QZTu0HfO+EIG4f9OxQAP9DqoudH1i+OUYzzaGDhV37OBz80j/6n1Ka26IK?= =?us-ascii?Q?RSn7qAv7YHrqlfrAxjE32O1YI424Aq07xBa7e+3SOYIJv9EYPukUyJAH9niC?= =?us-ascii?Q?ShzhdezH5/CnbijkENgu8+rnbIDlOX54pNpjDIU6W/RRF5k/jowbup25SYjx?= =?us-ascii?Q?GVM05DspLFRyASxduiLz9tuZycrrifC+rf0zSWaETv0jKqIYtIWyppFOuppl?= =?us-ascii?Q?ZMAKXFgW+1hy3hZczB4rVgwp07GOp8Tm/lAAo4OXwby0BnDqpLv0mWL6b3SX?= =?us-ascii?Q?Rd6N11NIwc/AJxYDF4/tUTERT1QoAEPO1yIeyEOo4v//J/ko/pu57mc0eXe7?= =?us-ascii?Q?6k+eaNeb1aWzWHKGyigVKPLPwc9lIvGlMJJnbyvg4+ROHwdsBKbYagRPlEeT?= =?us-ascii?Q?HadQiaezwXUlciUBF3aTm3xO9XDZnFVuZcsrWoVWjtPcu2YO1AO6jon5YSbE?= =?us-ascii?Q?XaD9aZ7jdDKzWaa7tRPJifeoN/mgBoP46lacXnMl1prHXpqPkWyb6amQg/Pp?= =?us-ascii?Q?4pVk0QqPuU22av6f7Eg0vRCgJrCAeDgZTxxE0NBFhgmm4JmqCRXIwNgs+lt+?= =?us-ascii?Q?zm6nnAbbA7hdELE/FhQaSkbYH8Gagt8DZhLgwiSfTFhlUJx2+W4vrZmnk/UM?= =?us-ascii?Q?iZHzfH4EU97q29eOjTqIIS2gzzbwzPy4NaAiplyE1BTITGwWLlQQImttCak9?= =?us-ascii?Q?A8KsnmzHEtEuUJn5oyJJOoDi3eRhg/jqOjhcqmjECx+La0bOPUQtGe1RLF+V?= =?us-ascii?Q?QmKISgzYX8qUZ6fZk8BeMGxHtEzJ/4tqL6ebpa3tZAnL4xVDBBEtKB0Sy89p?= =?us-ascii?Q?ru8rdLGIaJg1lW3gEWtZEN5EBfkBmFvTc49nL57QMGCITktF3wiGmllbyF7q?= =?us-ascii?Q?agI2Xy0ftq1823TPX/KRS3fOr+ggOK9q41SomFOIWP/3t4a5wUXuzyJeAnaK?= =?us-ascii?Q?1AP9KjUaMB98cw47DlfP6IrDTfs97RHc2IYzD8zXsCC0ttYEpAesRl35KoYW?= =?us-ascii?Q?Ch3H7Wr82Tecz9+iuE240Tg9OToFBRDJxqzhWun5rosJRzyUvlSJIMGi2JhT?= =?us-ascii?Q?dOvmqDmlN2xj9QeZN2oFsXfFo3haeKxOGrN/+5d1vJSuO57Y/BNIQH2a9b83?= =?us-ascii?Q?faCuzIYHjPzCn9Xh3CGY3MVhpofjChAzST310WNVgjlDrhOToMBZAg=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV2PR01MB7792.prod.exchangelabs.com;PTR:;CAT:NONE;SFS:(13230040)(52116014)(366016)(7416014)(376014)(1800799024)(38350700014)(7053199007);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?9qvq8oXQAINDZ3i+eclWm51H6wNwN405th7evJJtwaXfBQ3rfTEtliNq58nv?= =?us-ascii?Q?Uj6r2Au7+VtuTqg/04vfO+Mqxk7ftzAYEPriuZNYL/DoCdXm9aRmO6212H3e?= =?us-ascii?Q?SqDpvaxifLija8TsnXH6vD01Q7ReBm850ZlUtpL3XQzJNZGmb/YUPa2XZdMq?= =?us-ascii?Q?z9nv5FBwyG1zo9QxaqwYnaZBj0NxWxznoA+sC9pCRe3qfZEXJkNgj13jslfi?= =?us-ascii?Q?l/yBlAR4e+BBAny5u3dN7Ptl94GDa09acbfxNwfvJVCep1UnRBM2QCXMMxXG?= =?us-ascii?Q?vtin8r4HLSbAAvxCXFZqJH4iOSdBfoF9e/FX1gO+UPhK90aglQOwQwsE83f1?= =?us-ascii?Q?HVGvQm8jDCXSWfCh5LVo29U1cGh0xzWKv1ygYW18MKk7eJK6agzVaCwpQhA+?= =?us-ascii?Q?UIMKEr3FdAQ/Vk+ZELMq3aQ5CLjNQCOcQsYb0tvs1sXQYZDKNyuWz6xTB41J?= =?us-ascii?Q?20DZhHoEO/uZKKvP/JXjOcJn8l+bwqQF6RgpJzg3JaNRWErBRphNzZrk0+R0?= =?us-ascii?Q?ztTuq4Kd8ipLyHYHdfeflf086uvBf6rxRcujMDJ8hSRhD7XWvqSpun4lzEC2?= =?us-ascii?Q?GNO+w6za0ZAUNmVZuxjLc6ajxU6kjKSdVqida8J8pK1cftKB2xgOKE808Jrj?= =?us-ascii?Q?/b//Mrpo6SOVrDhwTrGbuJAl/ThrNVWKVx0imOZ7li+l5V6Y42gnPnnwGN2w?= =?us-ascii?Q?ECGECXfm4FC6kbQV9xAsJMPsIZCl733qQahgjUaSR06tgMDVyOAxQOGBHdZQ?= =?us-ascii?Q?t5GWcDsZjeBi0Fs35hvL6jCZbjWwpPQrEKrJe2vT21QuAAcqskfMdM/l/sCA?= =?us-ascii?Q?f7f4irDe3cLjxDXOgrKJ3VZ7cJ3/0qs9FQiGWQpaqKH6K63eCI/EXVSdpEVc?= =?us-ascii?Q?NetoqE76FwiPK4aG14YVWxpZuJp/y75K+HGkODdH9EprSDWGaJHgiVg1uknj?= =?us-ascii?Q?goXnBq/J0nJmV7x3JhR8eEPleq2I3uAsjMadF38JFGwTMf55APpVRLrFLRkt?= =?us-ascii?Q?y3QLrfwY81u1jRA8d0KwH2uWiUGHRuRGNNDtOT7qUw8vtz6jZx0wrd0a7sv5?= =?us-ascii?Q?Wr1tKTwVTyKlwZlnjfnkbtK8pvNlq7SLGB/2i9dSfEsLQ/KPhe4Z908qM6kG?= =?us-ascii?Q?DCLm0brlMft3/k0rzd6ToV3VTJhZ0tXyuNRHGxP+hmsl3EVEdcFkVsNrw88Y?= =?us-ascii?Q?NHt49GHQUPdhY0fety30Q7XM+Z2RKbC+G3y56dZFulS1a19j+lSLNo2D6dCY?= =?us-ascii?Q?2hj2gkXKvwBHgvutX5iCaAt66XkVFk3Q9eAEque/tyBA1FkcMa+xmhRmZd20?= =?us-ascii?Q?gzV9ugynUXYxRFNQSYxDW8feppqX/ltW3aUz4gN1O3zvoVhdKv4Nm53zbiaV?= =?us-ascii?Q?oYredeHdNHA6to1m/eAkimyvxtHwRTicZVCqD+KnbSecXdCepm7qIkIo5mDh?= =?us-ascii?Q?r5JaBcxOpUU38LhIxLiakU8ni7W5ojVy0OjUa0sV22XkDU60llQdbR04zEOA?= =?us-ascii?Q?k3k2xhXsY/C3jbj5q/XvlPOAIIUN8On94MBvmlGOjLhU9CVt/EXzJxNqcQS9?= =?us-ascii?Q?cLdqwSUsGjrdfc3+6GFqHyjUiKweYpaffb9q3ZTqn4lUcjjT7ue0eyf0EKaE?= =?us-ascii?Q?K1kaxQ30xakYeCc9mO/7pJY=3D?= X-OriginatorOrg: os.amperecomputing.com X-MS-Exchange-CrossTenant-Network-Message-Id: f1507d4f-7cd2-45ff-8cae-08dd7d40f5f9 X-MS-Exchange-CrossTenant-AuthSource: LV2PR01MB7792.prod.exchangelabs.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Apr 2025 23:46:51.6044 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3bc2b170-fd94-476d-b0ce-4229bdc904a7 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: kRFig8TiYE2j6mYmueH0lVpKLhpqCw71GNbrRREefBsaG/aWK7z9iYaB3ftTOOFiAldyGFTEUctTD2shD5X4o+ddUMchUAZnrO/GqG807YKn9rD+HV4qVQrYBF1n2KG3 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CO1PR01MB9009 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250416_164656_628443_64252471 X-CRM114-Status: GOOD ( 17.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Oliver Upton writes: > On Tue, Apr 15, 2025 at 03:13:43PM -0700, D Scott Phillips wrote: >> > At least from your erratum description it isn't clear to me that this >> > eliminates the problem and only narrows the window of opportunity. >> > Couldn't the implementation speculatively fetch translations with an >> > unsynchronized HCR up to the ISB? Do we know what translation regimes >> > are affected by the erratum? >> >> Hi Oliver, I got some clarification from the core folks. The issue >> affects the data side of the core only, not the instruction side. I'll >> update my description to include that. >> >> Speculation after the `msr hcr_el2` couldn't launch a problem >> translation when the `msr` is followed by an `isb` like this. > > Thanks, agree that the subsequent ISB protects against speculative > behavior relating to the instruction stream. To be absolutely certain, > there's no risk of, say, a TLB prefetcher pulling in a problematic > translation in this window? IOW, there's no behavior that meets the ARM > ARM definition of a Speculative operation that can lead to a corrupted > translation. Yes, that's right, it's just translations from load/store instructions, and the DSB before closes the window where earlier instructions can get corrupted, and then the ISB after prevents the window for corruption from later instructions from overlapping with the write to HCR. > Sorry to hassle about these issues but they're helpful for maintaining > the workaround in the future. If you can fold all the extra details into > the patch for v2 that'd be great. No worries, and sorry to not have the description more clear originally. I'll include a more complete description in the next version.