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Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, Pavel Tikhomirov References: <20260422175000.1544258-1-khorenko@virtuozzo.com> Content-Language: en-US, ru, sr From: Konstantin Khorenko In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: AS4P190CA0053.EURP190.PROD.OUTLOOK.COM (2603:10a6:20b:656::17) To PA6PR08MB10708.eurprd08.prod.outlook.com (2603:10a6:102:3c7::20) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PA6PR08MB10708:EE_|DB9PR08MB7421:EE_ X-MS-Office365-Filtering-Correlation-Id: 53c95346-138f-4441-0637-08dea115b409 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|56012099003|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PA6PR08MB10708.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(7416014)(1800799024)(56012099003)(22082099003)(18002099003);DIR:OUT;SFP:1102; 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The odds of guest CR2 matching host CR2 are basically zero. > In practice, this likely adds two extra CR2 writes on the majority of entry/exit > transitions. Thank you very much for the review, Sean. Agreed on the window: the patch only narrows the exposure, it doesn't close it. I also mis-sold the cost. "One extra MOV to CR2 under unlikely()" is just wrong, how could i think of it, and thus it becomes expensive on a hot path, you are right. With both points in hand, the patch doesn't carry its weight. Dropping it. -- Konstantin