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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=W8mWuvGkwapgAk0R2YH82Gc/Yo4jqu8ktC4qkn3vmlA=; b=aSh8oQWyQS+3YBLqD67OdbbiV3ur3YppkPQTX1NnFQ5mJGn/xJYi8vo1TEbjh1jKB9bkb+qdzkDDr40FUw4gILkTETEBJmR34zSa/YCESD14COOlLQV2TkXA5w040XcyYc9Xjy6qqGKduAdUi8cG3nNz8LyAtUmMRUpZPOzY60Y= Authentication-Results-Original: suse.com; dkim=none (message not signed) header.d=none;suse.com; dmarc=none action=none header.from=arm.com; Content-Type: text/plain; charset=us-ascii Subject: Re: [PATCH] public/gnttab: relax v2 recommendation From: Luca Fancellu In-Reply-To: Date: Fri, 30 Apr 2021 08:42:49 +0100 Cc: "xen-devel@lists.xenproject.org" , Andrew Cooper , George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Wei Liu Content-Transfer-Encoding: quoted-printable Message-Id: <5AE0C026-A231-473A-B5E7-2D8B1E8E1B45@arm.com> References: To: Jan Beulich X-Mailer: Apple Mail (2.3654.60.0.2.21) X-Originating-IP: [82.8.129.65] X-ClientProxiedBy: LO4P123CA0501.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1ab::20) To VI1PR08MB3629.eurprd08.prod.outlook.com (2603:10a6:803:7f::25) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: cf8a7013-1db2-4970-0ce2-08d90bab9789 X-MS-TrafficTypeDiagnostic: VI1PR08MB3086:|AM8PR08MB5730: X-Microsoft-Antispam-PRVS: x-checkrecipientrouted: true NoDisclaimer: true X-MS-Oob-TLC-OOBClassifiers: OLM:8882;OLM:8882; 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X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Apr 2021 07:43:05.9220 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: cf8a7013-1db2-4970-0ce2-08d90bab9789 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: DB5EUR03FT009.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM8PR08MB5730 > On 29 Apr 2021, at 14:10, Jan Beulich wrote: >=20 > With there being a way to disable v2 support, telling new guests to use > v2 exclusively is not a good suggestion. >=20 > Signed-off-by: Jan Beulich >=20 > --- a/xen/include/public/grant_table.h > +++ b/xen/include/public/grant_table.h > @@ -121,8 +121,10 @@ typedef uint32_t grant_ref_t; > */ >=20 > /* > - * Version 1 of the grant table entry structure is maintained purely > - * for backwards compatibility. New guests should use version 2. > + * Version 1 of the grant table entry structure is maintained largely fo= r > + * backwards compatibility. New guests are recommended to support using > + * version 2 to overcome version 1 limitations, but to be able to fall b= ack > + * to version 1. > */ > #if __XEN_INTERFACE_VERSION__ < 0x0003020a > #define grant_entry_v1 grant_entry >=20 Reviewed-by: Luca Fancellu Cheers, Luca