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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 7C8D1C77B78 for ; Tue, 18 Apr 2023 14:39:28 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.522945.812613 (Exim 4.92) (envelope-from ) id 1pomU1-0005Xp-3x; Tue, 18 Apr 2023 14:39:01 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 522945.812613; Tue, 18 Apr 2023 14:39:01 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pomU1-0005Xi-1G; Tue, 18 Apr 2023 14:39:01 +0000 Received: by outflank-mailman (input) for mailman id 522945; Tue, 18 Apr 2023 14:38:59 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pomTz-0005XB-C6 for xen-devel@lists.xenproject.org; Tue, 18 Apr 2023 14:38:59 +0000 Received: from EUR05-DB8-obe.outbound.protection.outlook.com (mail-db8eur05on20608.outbound.protection.outlook.com [2a01:111:f400:7e1a::608]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id c0ad611f-ddf6-11ed-b21f-6b7b168915f2; Tue, 18 Apr 2023 16:38:58 +0200 (CEST) Received: from AS9PR06CA0394.eurprd06.prod.outlook.com (2603:10a6:20b:461::27) by DU0PR08MB8090.eurprd08.prod.outlook.com (2603:10a6:10:3e9::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6298.45; Tue, 18 Apr 2023 14:38:56 +0000 Received: from AM7EUR03FT034.eop-EUR03.prod.protection.outlook.com (2603:10a6:20b:461:cafe::b5) by AS9PR06CA0394.outlook.office365.com (2603:10a6:20b:461::27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6298.47 via Frontend Transport; Tue, 18 Apr 2023 14:38:56 +0000 Received: from 64aa7808-outbound-1.mta.getcheckrecipient.com (63.35.35.123) by AM7EUR03FT034.mail.protection.outlook.com (100.127.140.87) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6319.20 via Frontend Transport; Tue, 18 Apr 2023 14:38:56 +0000 Received: ("Tessian outbound 8b05220b4215:v136"); Tue, 18 Apr 2023 14:38:56 +0000 Received: from fbd32eaa3ee3.1 by 64aa7808-outbound-1.mta.getcheckrecipient.com id 4CEF2662-0269-499D-A059-62FD0BF2E09B.1; Tue, 18 Apr 2023 14:38:55 +0000 Received: from EUR05-VI1-obe.outbound.protection.outlook.com by 64aa7808-outbound-1.mta.getcheckrecipient.com with ESMTPS id fbd32eaa3ee3.1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384); Tue, 18 Apr 2023 14:38:55 +0000 Received: from AM6PR08MB3784.eurprd08.prod.outlook.com (2603:10a6:20b:85::25) by AS4PR08MB8069.eurprd08.prod.outlook.com (2603:10a6:20b:588::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6298.45; Tue, 18 Apr 2023 14:38:36 +0000 Received: from AM6PR08MB3784.eurprd08.prod.outlook.com ([fe80::8e01:7058:6f40:90e1]) by AM6PR08MB3784.eurprd08.prod.outlook.com ([fe80::8e01:7058:6f40:90e1%7]) with mapi id 15.20.6298.045; Tue, 18 Apr 2023 14:38:36 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c0ad611f-ddf6-11ed-b21f-6b7b168915f2 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=0EljlqRfyBN5u+AH1HiyHn2aQySznZuUmDSCl1CQLBk=; b=WgJDP4m2tu+uq9RO4gSQiIzM4YXBb9SUy/d6sZSXrBowyRXIRhU56nJvZvgPBOSUM8Ha1zo+urqBuyH16evPmgfWi555+m6UjjwPQyYJGHHFF2XEyI0CyoqqgY3ZTjLQIGuLKAwFCGz95udU9PKPJ/JLS7opFT6ZVoXtC+vcQEY= X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 63.35.35.123) smtp.mailfrom=arm.com; dkim=pass (signature was verified) header.d=armh.onmicrosoft.com;dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 63.35.35.123 as permitted sender) receiver=protection.outlook.com; client-ip=63.35.35.123; helo=64aa7808-outbound-1.mta.getcheckrecipient.com; pr=C X-CheckRecipientChecked: true X-CR-MTA-CID: 0baeb10b0392f62e X-CR-MTA-TID: 64aa7808 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=RJQLbCLWUn9N0l2FtTkWuWDoi2XLZluyPrjtfa0w2wDmnF2nB+UKTAzQOWFRgRE6hw5+LaE+PLNqd1a8QRfz/ihVozllX7LI2NQnQ335ik1Ymb9bS1GB93SncBD9HEfmTcDk2nA+9hc9u4iHqAqfDl0UylUiwlfPIOjy823SDMmQfKt8ayndDtRAhZriwzptguQfUvluMmJWNT3aaybMZ+2wuP61ljv064bdxxx7WnWA+pTAwvtct2kD2qyjLrp1eecFEXHfEvmoWgX9Ii8HKekT3WVE/2FcxZ0FA2QqKIkL5Mc2BgjbHhgfsPVuM+jHA7c9VScMMFvx6o4cSrRLng== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=0EljlqRfyBN5u+AH1HiyHn2aQySznZuUmDSCl1CQLBk=; b=T8uFi8y9Q8DzJ1/KYjhPu6Yjn4LTi7qKHKanKjhxTMeCB1wR688EtFPdvFpLpFRACraPCRUf3G2SCCe9EAG6VrZmXwbY0/O2cMJsw/ATmBwWfr1uksc2mbssep6M5vWW24rDmDH5bLkaDQw05R1YVaDzM6+nGba4waCD9Hj2ScIAE/+M1dvq1on0Ubp7Ky/Ou5hFNTeDUqhMLjLB4lr7GI16ppVRycTHTXGvfp5mug0yq5GKiuD5Vx8iIrKGhYst6qNWG8LRAUhLLuUPUjQuSnYQnYK4D/+NDt5qjENqh5yrgzGJvw2a/vn19vUWt48fqjKk20FRrjegAa2crQDmsQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; 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=0EljlqRfyBN5u+AH1HiyHn2aQySznZuUmDSCl1CQLBk=; b=WgJDP4m2tu+uq9RO4gSQiIzM4YXBb9SUy/d6sZSXrBowyRXIRhU56nJvZvgPBOSUM8Ha1zo+urqBuyH16evPmgfWi555+m6UjjwPQyYJGHHFF2XEyI0CyoqqgY3ZTjLQIGuLKAwFCGz95udU9PKPJ/JLS7opFT6ZVoXtC+vcQEY= From: Bertrand Marquis To: Julien Grall CC: Luca Fancellu , Xen-devel , Wei Chen , Stefano Stabellini , Volodymyr Babchuk , Andrew Cooper , George Dunlap , Jan Beulich , Wei Liu , =?iso-8859-1?Q?Roger_Pau_Monn=E9?= , Nick Rosbrook , Anthony PERARD , Juergen Gross , Christian Lindig , David Scott , =?iso-8859-1?Q?Marek_Marczykowski-G=F3recki?= , Henry Wang , Community Manager Subject: Re: [PATCH v5 00/12] SVE feature for arm guests Thread-Topic: [PATCH v5 00/12] SVE feature for arm guests Thread-Index: AQHZbSQqKlfgrZX3xkqta7+H+1gq3K8xFMoAgAAUHYCAAAOtgA== Date: Tue, 18 Apr 2023 14:38:36 +0000 Message-ID: <5D0FF62F-AA83-4A35-8A39-74A2F0D29603@arm.com> References: <20230412094938.2693890-1-luca.fancellu@arm.com> <08BE4F94-C4B5-4B05-AD92-61C5C5D24F39@arm.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 (2.3731.500.231) Authentication-Results-Original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; x-ms-traffictypediagnostic: AM6PR08MB3784:EE_|AS4PR08MB8069:EE_|AM7EUR03FT034:EE_|DU0PR08MB8090:EE_ X-MS-Office365-Filtering-Correlation-Id: ca23d725-2619-4928-afa1-08db401aa3eb x-checkrecipientrouted: true nodisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0; X-Microsoft-Antispam-Message-Info-Original: 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 X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM6PR08MB3784.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(4636009)(376002)(366004)(396003)(136003)(39860400002)(346002)(451199021)(36756003)(33656002)(76116006)(4326008)(6916009)(54906003)(316002)(66446008)(64756008)(66946007)(66556008)(66476007)(91956017)(71200400001)(478600001)(41300700001)(5660300002)(6486002)(8676002)(8936002)(2906002)(7416002)(38070700005)(86362001)(122000001)(38100700002)(2616005)(6506007)(186003)(53546011)(6512007)(83380400001)(45980500001);DIR:OUT;SFP:1101; Content-Type: text/plain; charset="iso-8859-1" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS4PR08MB8069 Original-Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: AM7EUR03FT034.eop-EUR03.prod.protection.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: 2983b8be-a258-4754-a81a-08db401a97d3 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:63.35.35.123;CTRY:IE;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:64aa7808-outbound-1.mta.getcheckrecipient.com;PTR:ec2-63-35-35-123.eu-west-1.compute.amazonaws.com;CAT:NONE;SFS:(13230028)(4636009)(346002)(136003)(376002)(39860400002)(396003)(451199021)(36840700001)(46966006)(40470700004)(6486002)(478600001)(54906003)(2616005)(82310400005)(186003)(53546011)(6512007)(26005)(336012)(6506007)(5660300002)(2906002)(6862004)(8676002)(70586007)(70206006)(8936002)(4326008)(41300700001)(33656002)(86362001)(40480700001)(316002)(36756003)(40460700003)(36860700001)(83380400001)(47076005)(356005)(82740400003)(81166007);DIR:OUT;SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Apr 2023 14:38:56.5891 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: ca23d725-2619-4928-afa1-08db401aa3eb 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: AM7EUR03FT034.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU0PR08MB8090 Hi Julien, > On 18 Apr 2023, at 16:25, Julien Grall wrote: >=20 >=20 >=20 > On 18/04/2023 14:13, Bertrand Marquis wrote: >> Hi Luca, >=20 > Hi, >=20 >> On this serie I would like to open a discussion on how to handle the vec= tor size >> and the corresponding command line / configuration / device tree paramet= ers. >> In general the user must either give a vector size it wants or has a sol= ution to >> just request the maximum supported size. >> In the current implementation if a size bigger than the supported one is= provided: >> - we silently disable SVE for dom0 >> - we silently disable SVE for dom0less >> - we do not create a guest when done through tools >> This is not completely coherent and i think we should aim for a coherent= behaviour >> unless we have arguments for this status. >=20 > +1. >=20 >> Is there any good reason to silently disable for Dom0 and dom0less only = ? >> I see some possible solutions here: >> - modify parameter behaviour to use the supported size if parameter is b= igger than >> it. This would at least keep SVE enabled if a VM depends on it and could= simplify >> some of the handling by using 2048 to use the maximum supported size. >=20 > My concern with this approach and the third one is the user may take some= time to realize the problem in the xl.cfg. So... Good point >=20 >> - coherently stop if the parameter value is not supported (including if = sve is >> not supported) >=20 > ... this is my preferred approach because it would be clear that the valu= e passed to Xen is bogus. I agree: we should not silently ignore configuration parameters or try to "= fix" them. Cheers Bertrand