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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F8ABC2D0CE for ; Tue, 21 Jan 2020 20:09:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58DAF2073A for ; Tue, 21 Jan 2020 20:09:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amdcloud.onmicrosoft.com header.i=@amdcloud.onmicrosoft.com header.b="VSLj6DYT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728741AbgAUUJ6 (ORCPT ); Tue, 21 Jan 2020 15:09:58 -0500 Received: from mail-bn8nam11on2060.outbound.protection.outlook.com ([40.107.236.60]:6134 "EHLO NAM11-BN8-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726926AbgAUUJ6 (ORCPT ); Tue, 21 Jan 2020 15:09:58 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=nNYAksSQ/a1DjbhCeDLSTqkvNbwhipSIaKoj6evXs9S4dHNixxywnlsJ5lzFwia89ncntKa8aylR7imPFzOM6AAkia1yc4McD+uyysBJOookKbmrsMXBbN5CAPsTqC3NPHd5NIewYdb9gcVKMxS+eAqrsiICI/evABU8vz0hlJphynnJCwgderM6ryoBBAskqhs3Yt7mC3tHgbKnuS3PW7nQJiqcmck8PXMGw8S8IH5iBLCz/asIiLWRUApOyKakpZ/Xzxkn1Uc0N9BhEMhDIN/4QUhGkCYz/ijd9DYx1Lj9M3ZSVIXRn2onzBuNc1QKldtMLF4ZMCMlpDRAuWUhuA== 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-SenderADCheck; bh=RI0cBqZKuGRuC4ia8Flphx2so19JCK0sC27NUbcrKNc=; b=NkK1bPbtghSml9i1XNZ4pL3V7wZ/p+Ev9w7OSLln0YhtHrseMXB8ncaBqIs57ILn29GTSVpqC7NuQJSmzzjYzKuyBt573M4Y8KcBjporJKpKxhOHs754nfXueO/cqqi4PWDd4Gu+6BNxbRS2JzqLDfsXV2/ZgdinQclgpfIVSSKUPW9u01LorEM0H3tvYR3575C7GyoEasxTdBx9+evhQScANF1k7ZmI0qjQEZ3DYCOuWaUIBuEr557oDGR7i+TP52sRv/AzwcHHK1u9xvSTjc/1WDjJWAbGjBYcMpM0sN8T7Q8URR1QZpxNEl+AjRpmokkQ80JqIArDs0DRdFcdZQ== 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=amdcloud.onmicrosoft.com; s=selector2-amdcloud-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=RI0cBqZKuGRuC4ia8Flphx2so19JCK0sC27NUbcrKNc=; b=VSLj6DYTLrzyrhSIHOpPZpqUXW4x7n+DVeYUtTPz86ghhSYdc2dm3D/2T9ftM5YpZnWR8L+wt4w2BCkp6l6BZDaZ3Fl1L398tVvLfvG6R1oyOl9NygPL9pm8YoJZubkZPNNmwiWPHv8x9DRMmBGBcbxyKibwdBhnUDj8GNQjTCw= Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=Ashish.Kalra@amd.com; Received: from SN1PR12MB2528.namprd12.prod.outlook.com (52.132.196.33) by SN1SPR01MB0001.namprd12.prod.outlook.com (52.132.193.146) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.23; Tue, 21 Jan 2020 20:09:55 +0000 Received: from SN1PR12MB2528.namprd12.prod.outlook.com ([fe80::fd48:9921:dd63:c6e1]) by SN1PR12MB2528.namprd12.prod.outlook.com ([fe80::fd48:9921:dd63:c6e1%7]) with mapi id 15.20.2644.026; Tue, 21 Jan 2020 20:09:55 +0000 Date: Tue, 21 Jan 2020 20:09:47 +0000 From: Ashish Kalra To: Konrad Rzeszutek Wilk Cc: hch@lst.de, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, luto@kernel.org, peterz@infradead.org, dave.hansen@linux-intel.com, konrad.wilk@oracle.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, brijesh.singh@amd.com, Thomas.Lendacky@amd.com Subject: Re: [PATCH v2] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests. Message-ID: <20200121200947.GA24884@ashkalra_ubuntu_server> References: <20191209231346.5602-1-Ashish.Kalra@amd.com> <20191220015245.GA7010@localhost.localdomain> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191220015245.GA7010@localhost.localdomain> User-Agent: Mutt/1.9.4 (2018-02-28) X-ClientProxiedBy: DM3PR12CA0136.namprd12.prod.outlook.com (2603:10b6:0:51::32) To SN1PR12MB2528.namprd12.prod.outlook.com (2603:10b6:802:28::33) MIME-Version: 1.0 Received: from ashkalra_ubuntu_server (165.204.77.1) by DM3PR12CA0136.namprd12.prod.outlook.com (2603:10b6:0:51::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.20 via Frontend Transport; Tue, 21 Jan 2020 20:09:53 +0000 X-Originating-IP: [165.204.77.1] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: bcf013a8-e6ee-4958-0d49-08d79eade199 X-MS-TrafficTypeDiagnostic: SN1SPR01MB0001:|SN1SPR01MB0001: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-Forefront-PRVS: 0289B6431E X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(4636009)(366004)(396003)(136003)(39860400002)(376002)(346002)(199004)(189003)(86362001)(4326008)(33716001)(8676002)(81156014)(26005)(6916009)(9686003)(55016002)(186003)(16526019)(5660300002)(2906002)(33656002)(316002)(956004)(52116002)(6666004)(478600001)(6496006)(44832011)(81166006)(66476007)(8936002)(66946007)(1076003)(7416002)(66556008);DIR:OUT;SFP:1101;SCL:1;SRVR:SN1SPR01MB0001;H:SN1PR12MB2528.namprd12.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; Received-SPF: None (protection.outlook.com: amd.com does not designate permitted sender hosts) X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: ie4qgwXp1ydlBdCqOrXhC2LO/SizoSAEnRpLgf4ZyuIsQIcTS3Lb1DM9M0y5d66Nb8AK3klFdJkFDA0IgluhcBs3tieHqOooSyzE06PAOKqFYJhg+teDZRrwVTVfg+skk8IW65BnpfLdUD5ho+IZGeuuh8lHynnwWi2fj62y6E4PfETvEtfNIZ7/gvzvzaJK2De4DdQxXNYw0sSK8eMVLL2eEBC8/YGOm+7UiyXFYUMcZ5HjysZCcXlSXPFPpkkq5EG2S0Eq6HjGn+58vS0+t6+XAQ9pVfqlZGqsYMFPAZfpiiH1m8/0BMhSmuv3MIktGVula1qKGl4TgpQpQVetofOcF/3+rNAI7Yb9erEPva9oqJxD/Ub+668nrSW4D+/tlrWa84m+IrdQwMf2QkZn9PJkDjL8wHFAT+U1inCDXBvehM1bEq10rJi3FMb9NR3l X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: bcf013a8-e6ee-4958-0d49-08d79eade199 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Jan 2020 20:09:55.1177 (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: O44NrDU3q8CMjr8EonvHqIQkwyz6jRmFHFqmfFmZ3ARI6L4j0g47engoxBXwYVaGIUaEZthwXkf9nUnSyB9Lpw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN1SPR01MB0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 19, 2019 at 08:52:45PM -0500, Konrad Rzeszutek Wilk wrote: > On Mon, Dec 09, 2019 at 11:13:46PM +0000, Ashish Kalra wrote: > > From: Ashish Kalra > > > > For SEV, all DMA to and from guest has to use shared > > (un-encrypted) pages. SEV uses SWIOTLB to make this happen > > without requiring changes to device drivers. However, > > depending on workload being run, the default 64MB of SWIOTLB > > might not be enough and SWIOTLB may run out of buffers to > > use for DMA, resulting in I/O errors. > > > > Increase the default size of SWIOTLB for SEV guests using > > a minimum value of 128MB and a maximum value of 512MB, > > determining on amount of provisioned guest memory. > > > > The SWIOTLB default size adjustment is added as an > > architecture specific interface/callback to allow > > architectures such as those supporting memory encryption > > to adjust/expand SWIOTLB size for their use. > > What if this was made dynamic? That is if there is a memory > pressure you end up expanding the SWIOTLB dynamically? As of now we want to keep it as simple as possible and more like a stop-gap arrangement till something more elegant is available. > >> Also is it worth doing this calculation based on memory or >> more on the # of PCI devices + their MMIO ranges size? Additional memory calculations based on # of PCI devices and their memory ranges will make it more complicated with so many other permutations and combinations to explore, it is essential to keep this patch as simple as possible by adjusting the bounce buffer size simply by determining it from the amount of provisioned guest memory. 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Received: from SN1PR12MB2528.namprd12.prod.outlook.com (52.132.196.33) by SN1SPR01MB0001.namprd12.prod.outlook.com (52.132.193.146) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.23; Tue, 21 Jan 2020 20:09:55 +0000 Received: from SN1PR12MB2528.namprd12.prod.outlook.com ([fe80::fd48:9921:dd63:c6e1]) by SN1PR12MB2528.namprd12.prod.outlook.com ([fe80::fd48:9921:dd63:c6e1%7]) with mapi id 15.20.2644.026; Tue, 21 Jan 2020 20:09:55 +0000 Date: Tue, 21 Jan 2020 20:09:47 +0000 From: Ashish Kalra To: Konrad Rzeszutek Wilk Subject: Re: [PATCH v2] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests. Message-ID: <20200121200947.GA24884@ashkalra_ubuntu_server> References: <20191209231346.5602-1-Ashish.Kalra@amd.com> <20191220015245.GA7010@localhost.localdomain> Content-Disposition: inline In-Reply-To: <20191220015245.GA7010@localhost.localdomain> User-Agent: Mutt/1.9.4 (2018-02-28) X-ClientProxiedBy: DM3PR12CA0136.namprd12.prod.outlook.com (2603:10b6:0:51::32) To SN1PR12MB2528.namprd12.prod.outlook.com (2603:10b6:802:28::33) MIME-Version: 1.0 Received: from ashkalra_ubuntu_server (165.204.77.1) by DM3PR12CA0136.namprd12.prod.outlook.com (2603:10b6:0:51::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.20 via Frontend Transport; Tue, 21 Jan 2020 20:09:53 +0000 X-Originating-IP: [165.204.77.1] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: bcf013a8-e6ee-4958-0d49-08d79eade199 X-MS-TrafficTypeDiagnostic: SN1SPR01MB0001:|SN1SPR01MB0001: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-Forefront-PRVS: 0289B6431E X-Forefront-Antispam-Report: SFV:NSPM; SFS:(10009020)(4636009)(366004)(396003)(136003)(39860400002)(376002)(346002)(199004)(189003)(86362001)(4326008)(33716001)(8676002)(81156014)(26005)(6916009)(9686003)(55016002)(186003)(16526019)(5660300002)(2906002)(33656002)(316002)(956004)(52116002)(6666004)(478600001)(6496006)(44832011)(81166006)(66476007)(8936002)(66946007)(1076003)(7416002)(66556008); DIR:OUT; SFP:1101; SCL:1; SRVR:SN1SPR01MB0001; H:SN1PR12MB2528.namprd12.prod.outlook.com; FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; A:1; MX:1; Received-SPF: None (protection.outlook.com: amd.com does not designate permitted sender hosts) X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: ie4qgwXp1ydlBdCqOrXhC2LO/SizoSAEnRpLgf4ZyuIsQIcTS3Lb1DM9M0y5d66Nb8AK3klFdJkFDA0IgluhcBs3tieHqOooSyzE06PAOKqFYJhg+teDZRrwVTVfg+skk8IW65BnpfLdUD5ho+IZGeuuh8lHynnwWi2fj62y6E4PfETvEtfNIZ7/gvzvzaJK2De4DdQxXNYw0sSK8eMVLL2eEBC8/YGOm+7UiyXFYUMcZ5HjysZCcXlSXPFPpkkq5EG2S0Eq6HjGn+58vS0+t6+XAQ9pVfqlZGqsYMFPAZfpiiH1m8/0BMhSmuv3MIktGVula1qKGl4TgpQpQVetofOcF/3+rNAI7Yb9erEPva9oqJxD/Ub+668nrSW4D+/tlrWa84m+IrdQwMf2QkZn9PJkDjL8wHFAT+U1inCDXBvehM1bEq10rJi3FMb9NR3l X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: bcf013a8-e6ee-4958-0d49-08d79eade199 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Jan 2020 20:09:55.1177 (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: O44NrDU3q8CMjr8EonvHqIQkwyz6jRmFHFqmfFmZ3ARI6L4j0g47engoxBXwYVaGIUaEZthwXkf9nUnSyB9Lpw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN1SPR01MB0001 Cc: Thomas.Lendacky@amd.com, brijesh.singh@amd.com, dave.hansen@linux-intel.com, konrad.wilk@oracle.com, peterz@infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, mingo@redhat.com, bp@alien8.de, luto@kernel.org, hpa@zytor.com, tglx@linutronix.de, hch@lst.de X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Thu, Dec 19, 2019 at 08:52:45PM -0500, Konrad Rzeszutek Wilk wrote: > On Mon, Dec 09, 2019 at 11:13:46PM +0000, Ashish Kalra wrote: > > From: Ashish Kalra > > > > For SEV, all DMA to and from guest has to use shared > > (un-encrypted) pages. SEV uses SWIOTLB to make this happen > > without requiring changes to device drivers. However, > > depending on workload being run, the default 64MB of SWIOTLB > > might not be enough and SWIOTLB may run out of buffers to > > use for DMA, resulting in I/O errors. > > > > Increase the default size of SWIOTLB for SEV guests using > > a minimum value of 128MB and a maximum value of 512MB, > > determining on amount of provisioned guest memory. > > > > The SWIOTLB default size adjustment is added as an > > architecture specific interface/callback to allow > > architectures such as those supporting memory encryption > > to adjust/expand SWIOTLB size for their use. > > What if this was made dynamic? That is if there is a memory > pressure you end up expanding the SWIOTLB dynamically? As of now we want to keep it as simple as possible and more like a stop-gap arrangement till something more elegant is available. > >> Also is it worth doing this calculation based on memory or >> more on the # of PCI devices + their MMIO ranges size? Additional memory calculations based on # of PCI devices and their memory ranges will make it more complicated with so many other permutations and combinations to explore, it is essential to keep this patch as simple as possible by adjusting the bounce buffer size simply by determining it from the amount of provisioned guest memory. Thanks, Ashish _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu