From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM11-CO1-obe.outbound.protection.outlook.com (mail-co1nam11on2065.outbound.protection.outlook.com [40.107.220.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B702D2C81 for ; Fri, 15 Oct 2021 16:11:30 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=LBS8pBDsLU+B85pqtY9W/4XVaowiUxDpEVT24VQerAzh0vYNxonOWtuBs6rjlptWWii7qWKcU71/2o6tueEp0zrs8Ntoavptuwju2nvspdYYDJzxAOD67lyjyFPFQ1Y5IDk5EQpZW6UJeNzmDU1DXgUaTH0ij/F+BH0r1UUHZe0yaH87OjQJymEYTEbfDl0jDNlZye6SuPTHmhj96l2MEe2nR7QZhwvpR6JqI1KyX185Et68ud83tTzoZZXUc4JSkmPAfr0lGOR1oqeeg1Q+8YpVnA4Pv8HBU7ScqWhVSN2efqQJjV1Rtw8L0Omh08pVv7InasI3vP7eGcA+8UWukw== 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=Uq7/NuFf/d3yzPcuywje+WYhSpMHuIZV/SFp2je7/D4=; b=j1wO00n5jefo5iO2G8qX40JgDg8qwItuCDDDS2ddNBzY5SocRhlxDKUralqSxmnuoetdoFsRZeCQ5tBRZSnoFNLZUgVxMqxr1U7DnZLo7IJIypMfjVqmAvxTEMNyS8KTXtgSswWJYFUVZOWCj9aU5X3Cq0EJnMqwy+IL/Qyk2bi1Sjwr8nKwkfNM1N6bCYjG3BpYQz42nlJ2fsyQRFwo6K2+MhFpO9Ia505BJC7/mG4lt0mRi9ZP9I6QWVMePLWfU2Z8W3VP5O9gyim3kO7Ax5JTsfMy0mIN3f7i3KfWMKn9mDyrv7PrS46sp3GBmO4SUM3Mh2kO6CJFLzcCarGQkg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Uq7/NuFf/d3yzPcuywje+WYhSpMHuIZV/SFp2je7/D4=; b=QatLbzyuoP50zvOx1jYsOwBFD/956qhsh9qSDWeNWGudfs0gkXY9tP3xD7LosxCyJVphBySVXm7kInqzk3dQzWJXOEVqUtxKSz2pGKm99l4TQwPFwphKqINkWOOWJxw9uSj3Nw6FrgvqLfUu9VLWb086G3+XKfua+pxuK6///yA= Authentication-Results: linux.intel.com; dkim=none (message not signed) header.d=none;linux.intel.com; dmarc=none action=none header.from=amd.com; Received: from SN6PR12MB2718.namprd12.prod.outlook.com (2603:10b6:805:6f::22) by SA0PR12MB4557.namprd12.prod.outlook.com (2603:10b6:806:9d::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4608.17; Fri, 15 Oct 2021 16:11:27 +0000 Received: from SN6PR12MB2718.namprd12.prod.outlook.com ([fe80::78b7:7336:d363:9be3]) by SN6PR12MB2718.namprd12.prod.outlook.com ([fe80::78b7:7336:d363:9be3%6]) with mapi id 15.20.4587.032; Fri, 15 Oct 2021 16:11:27 +0000 Cc: brijesh.singh@amd.com, x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Joerg Roedel , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Borislav Petkov , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH Part2 v5 34/45] KVM: SVM: Do not use long-lived GHCB map while setting scratch area To: Sean Christopherson References: <20210820155918.7518-1-brijesh.singh@amd.com> <20210820155918.7518-35-brijesh.singh@amd.com> From: Brijesh Singh Message-ID: Date: Fri, 15 Oct 2021 11:11:19 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-ClientProxiedBy: BN8PR15CA0042.namprd15.prod.outlook.com (2603:10b6:408:80::19) To SN6PR12MB2718.namprd12.prod.outlook.com (2603:10b6:805:6f::22) Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Received: from Brijeshs-MacBook-Pro.local (165.204.84.11) by BN8PR15CA0042.namprd15.prod.outlook.com (2603:10b6:408:80::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4608.15 via Frontend Transport; Fri, 15 Oct 2021 16:11:22 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: de844917-7623-4dd9-23b9-08d98ff67152 X-MS-TrafficTypeDiagnostic: SA0PR12MB4557: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; 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:SN6PR12MB2718.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(366004)(7406005)(83380400001)(31696002)(7416002)(4326008)(508600001)(6916009)(54906003)(6512007)(86362001)(26005)(44832011)(6486002)(31686004)(53546011)(8936002)(5660300002)(66556008)(956004)(66476007)(6666004)(66946007)(2616005)(8676002)(316002)(38100700002)(36756003)(2906002)(186003)(6506007)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?aVFLY0xaTGZxS2lRQVNSQ0VaRHBKV1RlL3dRMUZWVTFOV3lLNUlvVzVwYTVW?= =?utf-8?B?WTR1V3FMUmJGait0a3A0WkdMT0hSblB4amk2UXI3NWdoSnp1VkJWUFdEZlMw?= =?utf-8?B?QlVnODJjMGY3a2xmQU9mbE9rY2ZIUHBqeGhqcXVHUkZkSzNrRHlMcmVhdDVG?= =?utf-8?B?dUM4RDl3OXppdlhCSURLSW55ZmxaKzBpSGRHbDBsZ2p0NTMySzltSWRSUUc4?= =?utf-8?B?bUR1YkxCYWVIRXJSNEJLYXBrQ1pRbXZpRzZmYkZYa2tIS05COUJXU0FZQXJU?= =?utf-8?B?RFRvbkRTaVU2Tzd6bXlzMHJwV2NLZ1hSRUxiYUpGTmtJVmJjS2JuV3c1TnUr?= =?utf-8?B?UjgrVS9iUXJYamI5b3VlbWdxanJJclRHaVV6amwyMHF2clIzbVh3RXAzMHdk?= =?utf-8?B?UHhrWEVETko2clI3YTBMOUJBeUZxeFRWem51bCtxR2cxdEJJUlZnbkFLVml3?= =?utf-8?B?WDNsQ0Zwc3hYSStkMUhqODdwQlJmYzVQY2xlZE5LemwyMkFvVS9aNnl4ZEcw?= =?utf-8?B?UVI3bXF6cGUwK21MY21NSFM2ck1oTWpZU3hHSFR1VG5HN1lzdWxaWWtxcXlE?= =?utf-8?B?Uk0zd2pPY3dDOXlibWEyZ2pNd01sT0JUd3FzQ2ZiTklyMy9ZYWZiSFZPL2FN?= =?utf-8?B?cFpna256SXE0cU9xSWV4WG5MTnJLVFpMbzZFT2R5elpyYndWN2tyZnlIcDFL?= =?utf-8?B?d3NBcWtBcFlWeUxOMFJ5eXdWYXpMeWQ5czNiSzA0ZmJLd1d6WjZWcDlhMlZM?= =?utf-8?B?UzN0VFZkVXdlcmF1R1ZoTzlLdEdLMFkvTUhOWVpWb2xOZkZZTVhTd1RGZHRh?= =?utf-8?B?dXZra0ozL0NFNzI4bXo2VFg4T3ZzcDlHdTFvdTFvMExzcE9FVTN5L0FkbjN2?= =?utf-8?B?ZFlLNDJUd3FJOFh4ZC9RQkpaMEtTQS9kRFA2cWN0RFo1K1RiTEN1SVMrVmxl?= =?utf-8?B?bDBiSDd3TTFOQzhveGFrOVF6Tk85UjNLMVhGNzZUOTJXeS90MlFtNDVwMWtS?= =?utf-8?B?TDcrMnQrVTAwS0g0a2JiY055QlR2QnVCU3J5VDFaYW5uWS9Ua0pzaVVNazRU?= =?utf-8?B?WGR3MFY3bDN2UTFwMlNadmFGdm1hTEltSkdORVRqOFhiSVFxVURQa1BpRGEw?= =?utf-8?B?Tm5WUzNHSzRtaVprZG84MEF0clkxcm1iRVlqajNQWk1LbEQ5QXptTTBPQnN6?= =?utf-8?B?Ky8xTUhoNGNaMzZwRVdKSWlKcytkS05HYU5FNzZoV2VoKzFkM2Y4eUdKaTNU?= =?utf-8?B?eEJQVE1UdkloNmRMeXNxRTRDZGVzMWlXT2dtcGpyK1FSUTFXSFJwR0lMenpw?= =?utf-8?B?TncweWczcDZVc1F4SjNyeW1VQUlWZzhLZmkvRjljbHFiTDMzWFdyOGdacWty?= =?utf-8?B?anhBYkhPbGU3OThCc2IrczJxcEF5YUZuUExUcUJJdVhYRDJpeFBUWFZZVk52?= =?utf-8?B?MzAvVjNaWTdsazdVMGdLNjZPbmhPR3ZlbUJZZENiRURNQWNIZGZRRkU4ajUw?= =?utf-8?B?UXY1ZG83RzRKUlZCMk9rYXhhSHdPM1JhQlk3ZFhzcy9mMzNicnlTMFNydW1V?= =?utf-8?B?RHJrSDcwZG03dTVCV20vRU5JY0NzMzdNWlAvU2lVUDNUcEJTd01ZNklqLzVY?= =?utf-8?B?am9jNnZacUZ5RmVxMmRmY1FXV3ltR3JYWjVqV04xY1ZncFdKaFhJdjdjbXRJ?= =?utf-8?B?eUFBdDlqM0VSRVVRakxZaTluekhqdnhXVWhES1JaWXhSUmhYankrS2Q3aWJV?= =?utf-8?Q?QriKnxLN/8KRSREHcZ3alWpRmC056+16aU9zUBy?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: de844917-7623-4dd9-23b9-08d98ff67152 X-MS-Exchange-CrossTenant-AuthSource: SN6PR12MB2718.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Oct 2021 16:11:27.7410 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: rTxsPtNLoGEsMPsvv/aUjWY/3jZnJYWqqKz2NNQyvBFViPJuYsLKxOmTyAuZcpjd1GtksVUN7EMEvM0OD2IZYQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4557 On 10/13/21 2:20 PM, Sean Christopherson wrote: > On Fri, Aug 20, 2021, Brijesh Singh wrote: >> The setup_vmgexit_scratch() function may rely on a long-lived GHCB >> mapping if the GHCB shared buffer area was used for the scratch area. >> In preparation for eliminating the long-lived GHCB mapping, always >> allocate a buffer for the scratch area so it can be accessed without >> the GHCB mapping. > Would it make sense to post this patch and the next (Remove the long-lived GHCB > host map) in a separate mini-series? It's needed for SNP, but AFAICT there's > nothing that depends on SNP. Getting this merged ahead of time would reduce the > size of the SNP series by a smidge. While testing with random configs, I am seeing some might_sleep() warns. This is happening mainly because during the vmrun the GHCB is accessed with preempt disabled. The kvm_vcpu_map() -> kmap() reports the warning. I am leaning towards creating a cache on the vmgexit and use that cache instead of the doing a kmap() on every access. Does that sound okay to you ? -Brijesh