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Message-ID: Date: Thu, 14 Sep 2023 14:49:45 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v2] x86/amd: do not expose HWCR.TscFreqSel to guests Content-Language: en-US To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: Andrew Cooper , Wei Liu , =?UTF-8?Q?Sol=c3=a8ne_Rapenne?= , xen-devel@lists.xenproject.org References: <20230913145220.11334-1-roger.pau@citrix.com> From: Jan Beulich In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: FR3P281CA0125.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:94::7) To DU2PR04MB8790.eurprd04.prod.outlook.com (2603:10a6:10:2e1::23) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DU2PR04MB8790:EE_|DUZPR04MB10040:EE_ X-MS-Office365-Filtering-Correlation-Id: b7701323-eebf-494f-3d8e-08dbb5211466 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:DU2PR04MB8790.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(136003)(366004)(376002)(346002)(396003)(39860400002)(451199024)(1800799009)(186009)(26005)(2616005)(5660300002)(8936002)(4326008)(8676002)(31686004)(6512007)(53546011)(6666004)(6506007)(6486002)(83380400001)(66574015)(66476007)(66946007)(54906003)(66556008)(38100700002)(6916009)(966005)(478600001)(316002)(41300700001)(36756003)(31696002)(86362001)(2906002)(43740500002)(45980500001);DIR:OUT;SFP:1101; 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Hmm, yes, that's one way to look at things. Yet exposing plain zero is pretty clearly not within spec here, and any such quirks we add generally want justifying imo (as they might bite us again later). >>> Reported-by: Solène Rapenne >>> Link: https://github.com/QubesOS/qubes-issues/issues/8502 >>> Fixes: 14b95b3b8546 ('x86/AMD: expose HWCR.TscFreqSel to guests') >>> Signed-off-by: Roger Pau Monné >> >> As mentioned before, with this Fixes: tag I think the description >> absolutely needs to mention the (changed) view on the Linux log message >> that had triggered the original change. It certainly helps here that >> Thomas has already signaled agreement to a Linux side change. > > Sure, what about: > > "The motivation for exposing HWCR.TscFreqSel was to avoid warning > messages from Linux. It has been agreed that Linux should be changed > instead to not complaint about missing HWCR.TscFreqSel when running > virtualized." Reads okay to me, thanks. Jan