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spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=0jyhp6/3v76sM6Q3RtGKoOHvPaFj/rDSryuOdH6rfSI=; b=CN8bqEMZflIP10G9CdYpMAfY5uQKsRpt/RTMHXVBwWNQ5WfqpGGGL0yKFwXpsw4WIjx6KE5q1JrV2+cdhcDdkA3LkwIgYVYoCnpysgP62vV/No2iytIeul3+Ex6NO1Xn5LVf37jhFspzufIi2Hi6F5o4XppJQIhs16pislIVImU= From: Bertrand Marquis To: Jan Beulich CC: Ian Jackson , Stefano Stabellini , Stefano Stabellini , "andrew.cooper3@citrix.com" , "george.dunlap@citrix.com" , "julien@xen.org" , "wl@xen.org" , "xen-devel@lists.xenproject.org" Subject: Re: [PATCH v4 1/2] xen: EXPERT clean-up and introduce UNSUPPORTED Thread-Topic: [PATCH v4 1/2] xen: EXPERT clean-up and introduce UNSUPPORTED Thread-Index: AQHW82EN9R2ynrmbqk6EAVX0Oyalkao5otWAgAAc8QCAAAFygIAAAbYAgAAfFACAAAKIAIAAAG4AgAAAOoA= Date: Tue, 26 Jan 2021 13:20:14 +0000 Message-ID: References: <20210125212747.26676-1-sstabellini@kernel.org> <8F34AC6E-2337-42C3-B612-A5414F9E16BE@arm.com> <01da05ea-6c34-8d8e-4277-e29bc54cb67d@suse.com> <5CB981E5-27BC-4B7E-B494-EFFDE8A4A1A9@arm.com> <1199ab03-ecfe-386c-7488-ca4f794b0683@suse.com> <24592.5760.197643.853055@mariner.uk.xensource.com> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3608.120.23.2.4) Authentication-Results-Original: suse.com; 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X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2021 13:20:22.3987 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 062561d3-dc0d-4840-c178-08d8c1fd22a8 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[63.35.35.123];Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-AuthSource: VE1EUR03FT038.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB6PR0802MB2326 > On 26 Jan 2021, at 13:19, Jan Beulich wrote: >=20 > On 26.01.2021 14:17, Ian Jackson wrote: >> Jan Beulich writes ("Re: [PATCH v4 1/2] xen: EXPERT clean-up and introdu= ce UNSUPPORTED"): >>> On 26.01.2021 12:17, Bertrand Marquis wrote: >>>> Maybe something we could explain more clearly in the UNSUPPORTED/EXPER= T >>>> config parameters instead ? >>>> We could also make that more clear in the help of such parameters dire= ctly. >>>>=20 >>>> I do not see how we could make that more clear directly in the prompt = (as >>>> making it too long is not a good solution). >>>=20 >>> My main request is that such tags be added only if there's >>> absolutely no ambiguity. Anything else (requiring longer >>> explanations in many cases) should be expressed in the help >>> text of the option, or in yet other ways (a referral to >>> SUPPORT.md comes to mind). >>=20 >> Is >>=20 >>>>>>> + bool "Harden the branch predictor against aliasing attacks (disab= ling UNSUPPORTED)" if UNSUPPORTED >>=20 >> too long ? >=20 > It may be tolerable, but it is getting longish imo. I am also not quite sure this is making things clearer. Bertrand >=20 > Jan