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 ADB45C35247 for ; Tue, 4 Feb 2020 19:35:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DB752084E for ; Tue, 4 Feb 2020 19:35:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amdcloud.onmicrosoft.com header.i=@amdcloud.onmicrosoft.com header.b="FKiKqLJD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727537AbgBDTfM (ORCPT ); Tue, 4 Feb 2020 14:35:12 -0500 Received: from mail-dm6nam10on2057.outbound.protection.outlook.com ([40.107.93.57]:58465 "EHLO NAM10-DM6-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727331AbgBDTfM (ORCPT ); Tue, 4 Feb 2020 14:35:12 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=kfjjpdq4I0M8DUKMAE3b7crxpvesulZVLtSWyuHcxkKwL6ev4M4ZQVoWlMry3BD3BUEWeEn1bO1cLoqBaQkx75yMYGe9aS5rpFoUxwlsYdiZz7JJPMNpmh0kdrZqOQz5M4rOdV905pG3ATb+okOxP/wpHkzPudS7yXzj3VbdW9bfUB2E9U8WCjFqwK7IppX0fn3Br+SwVxSUQBlrXtXa/JRScNEvtDpp5w06rza+lSGjd/x+2Abbrtw4SqYM+l3CRGADiM2edQzuxlIOnLCUaB1KjnQYOpLo4K+zyD8GSHjVpHpChLnXmTu8hLek3xFA0QMioCYulT82XLNVH0iRKA== 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=sTCqv7CIbLEb8n6bWDSiAwYCunqHTJX2eiwdvnI/TZs=; b=Dye/qR8kRAbgx0wpCzRv6cFAXvc4YVK9XtSD6Xs3yOTxyIocimkIJUwD73bDuYSvzbEenspZF/jgi8yPZm2BU7rMrwPEG3QvawYFWV9IYQkInV2T6CeU5823gLS9KLaHwEBX0nwqZSFbMYk1JOp+nohhsPL4mrbi4qf2n3lNzZ5DoUQNmt1mALD1F3Mwv1m+eCHwpDlDnbGjGjf1z9ogABPwV1jk6ei89Z/FFb8ur40loy9Fr2YmOkwXfXfABhWSVoHKDOJoL7kwjFdjl5ysnsTQMboUJ4WvgNg9v6/wvDYOPuZ9U22Y1pTWMuLEgw8vXky+QIsJsCcFHfNShjvfqw== 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=sTCqv7CIbLEb8n6bWDSiAwYCunqHTJX2eiwdvnI/TZs=; b=FKiKqLJDfSkVbaIvoRydEvTaYyHBv9LfcwXVyIoGlqlHnDZEbN6oyLpjLVZoKqazg71qs+/g5cQ3XG4wCZdxB/CQolJdJ2RJOYGnB7N5qTtS8Xjd8bK1b5AFzjk9hUPt6YluJXtP4DOE6NItVNvk2V6y8I96McZHZCSsWMBl40E= 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 SN1PR12MB2559.namprd12.prod.outlook.com (52.132.196.158) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2686.32; Tue, 4 Feb 2020 19:35:08 +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 15.20.2686.034; Tue, 4 Feb 2020 19:35:08 +0000 Date: Tue, 4 Feb 2020 19:35:00 +0000 From: Ashish Kalra To: Konrad Rzeszutek Wilk Cc: Konrad Rzeszutek Wilk , 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, 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: <20200204193500.GA15564@ashkalra_ubuntu_server> References: <20191209231346.5602-1-Ashish.Kalra@amd.com> <20191220015245.GA7010@localhost.localdomain> <20200121200947.GA24884@ashkalra_ubuntu_server> <20200121205403.GC75374@Konrads-MacBook-Pro.local> <20200124230008.GA1565@ashkalra_ubuntu_server> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200124230008.GA1565@ashkalra_ubuntu_server> User-Agent: Mutt/1.9.4 (2018-02-28) X-ClientProxiedBy: SN4PR0501CA0004.namprd05.prod.outlook.com (2603:10b6:803:40::17) 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 SN4PR0501CA0004.namprd05.prod.outlook.com (2603:10b6:803:40::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2707.15 via Frontend Transport; Tue, 4 Feb 2020 19:35:07 +0000 X-Originating-IP: [165.204.77.1] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: 6a38b3e2-3bdb-4f35-2f57-08d7a9a9578e X-MS-TrafficTypeDiagnostic: SN1PR12MB2559:|SN1PR12MB2559: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-Forefront-PRVS: 03030B9493 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(4636009)(376002)(346002)(366004)(39860400002)(136003)(396003)(189003)(199004)(478600001)(8936002)(33716001)(8676002)(2906002)(16526019)(186003)(81156014)(81166006)(26005)(6496006)(66946007)(33656002)(316002)(52116002)(66476007)(66556008)(5660300002)(55016002)(1076003)(7416002)(9686003)(6916009)(86362001)(6666004)(44832011)(956004)(4326008);DIR:OUT;SFP:1101;SCL:1;SRVR:SN1PR12MB2559;H:SN1PR12MB2528.namprd12.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A: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: Rbs21gOhmbR4qjSqpSPf65FSrOlt9JT1X4owQYd6kcFsPiUpkmWuxiaWSqlNDBZppKgJV2mOIz3QehHTN8GFmkTD7CokUfLa8dQxajJ2mYtTJHS0iERz0xJcYyP/GiR0UvTikqHBxNV6V/53Qh+juaxMOvOOYCZM6fboWdJ+UxJwZvye3kWAB/cqd1sl8X4v8vPa3i7A1DB7kaDY1eI1oOrbZ70QVz06lpxaIhPnzhhB7Spz2OMtSpEN+DS1QO+X667u38yPOrt544oTQwaWWc8YUgnJCKpkaBKInUvOOIAZ0JcdLbQn8x/kWsmGxY6g3mitS1tebPtsmybBD1xPG/WQlsdLJ7mKkqNvmIZv8hAKqjFsPgk7wq4j7CrLFdAjfH0G1cnueD7Hn+2b0WvHrzvi6p0lreoeSgeZ1sqTfp3vuuZmPH7RFLZ6G74gq/4S X-MS-Exchange-AntiSpam-MessageData: wnSnxm5ZDgCIlYxpChf+hWTpf/5uFR4M9VCHWMv/9JGU1johEaR5cyShNJVeYj6c5eTgEz59Pa/XVzt92OaTnnlcqEx+uSd+WOmSSfT6P56x2504dZvsXTdDKUzRKI2U+Op0oOJoB9GbToOuwnNefQ== X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6a38b3e2-3bdb-4f35-2f57-08d7a9a9578e X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Feb 2020 19:35:08.5294 (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: kPlOCNddt85RM0luILDny1ZZ1DCPLWD9dQn3VfNLrw5vDUiKvhrdqJOhQfHPm/KDvWXzR9zxbw8V/+2EJEcjuw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN1PR12MB2559 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Konrad, Looking fwd. to your feedback regarding support of other memory encryption architectures such as Power, S390, etc. Thanks, Ashish On Fri, Jan 24, 2020 at 11:00:08PM +0000, Ashish Kalra wrote: > On Tue, Jan 21, 2020 at 03:54:03PM -0500, Konrad Rzeszutek Wilk wrote: > > > > > > 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. > >> > >> Please rework the patch to: > >> > >> - Use a log solution instead of the multiplication. > >> Feel free to cap it at a sensible value. > > Ok. > > >> > >> - Also the code depends on SWIOTLB calling in to the > >> adjust_swiotlb_default_size which looks wrong. > >> > >> You should not adjust io_tlb_nslabs from swiotlb_size_or_default. > > >> That function's purpose is to report a value. > >> > >> - Make io_tlb_nslabs be visible outside of the SWIOTLB code. > >> > >> - Can you utilize the IOMMU_INIT APIs and have your own detect which would > >> modify the io_tlb_nslabs (and set swiotbl=1?). > > This seems to be a nice option, but then IOMMU_INIT APIs are > x86-specific and this swiotlb buffer size adjustment is also needed > for other memory encryption architectures like Power, S390, etc. > > >> > >> Actually you seem to be piggybacking on pci_swiotlb_detect_4gb - so > >> perhaps add in this code ? Albeit it really should be in it's own > >> file, not in arch/x86/kernel/pci-swiotlb.c > > Actually, we piggyback on pci_swiotlb_detect_override which sets > swiotlb=1 as x86_64_start_kernel() and invocation of sme_early_init() > forces swiotlb on, but again this is all x86 architecture specific. > > Thanks, > Ashish