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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0AEBC19F2B for ; Wed, 3 Aug 2022 21:03:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238797AbiHCVDp (ORCPT ); Wed, 3 Aug 2022 17:03:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236280AbiHCVDn (ORCPT ); Wed, 3 Aug 2022 17:03:43 -0400 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (mail-dm6nam11on2071.outbound.protection.outlook.com [40.107.223.71]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D2925C970 for ; Wed, 3 Aug 2022 14:03:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=i6yWaiSwZYs/DidEJEGTjkmpNiDEvS3Zsy+fyLO0allxPTBw0ZSi+AmbW+Whjn7hKuJfOTkoFDgH3cS0SEIHavjAd5BapplnJF72FesvSbTQHYIQWYp1yrZGuzUZhyiG48tx+aIkBlBFHSz+p9jl3WrsOX7i4b1g2knlk1YV984QHKuh76L33EWRFt533Yp9CdG2afErjZXxkUzoB40kFCFjiZb8hRUn5vd1qCh9E0KCMv1/FZKSjTbFBHI4C5+8Jk1Je6rEf/BYAwpCqX8pk6j5kB2zkM8UXLKloU9hqnfVlPEFAg4oZ6zwSGB/iC8uTUX8b6RX9nL2KDRD7movOg== 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=BqdfyEq1ak1O4RW3eyqDgSxMAz7IaHeijbnLVlh3EFI=; b=bdUCLgkOhMJBezLa/A8hDAc7SquchVRJqjwn+y8d0C59x2ijPcG5tGD68APA2sOT91j+zsOLqrcpUuu/Xq0/aMghr6bFaqc/sy4TanqLJFY5O7stpV95INB5t+h1VPUE8EHA7vOEG9JlthCgN2XbXhYx1PgK2Vc3guZS2iLCDmVS4bvCMPo6Q3ZDkqlne63nbGh2obae+ccfkvJOgl3GSd2HDSmnbc+Y0Iq+/ZfgMngXP5c8lj6Vxk0HWpxgQCw4iTU6Fz2puTz+7ERDz0v4ePzodWzVQ6Dofm+RfHhK6qfsgw0gswX7tFz7ljYHhsGTdwpqhkZRqWXWzxAQ6Cs2ag== 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=BqdfyEq1ak1O4RW3eyqDgSxMAz7IaHeijbnLVlh3EFI=; b=1jZIMwK3uFPScQeEifeJk8quSTvfPe0dD4BmwDfdSjEDyZz8Yk3aFT1U4lVPJfv5ozOwFkaUtsPB6OKJnI+HQxrPh7tREqXNuNsDcer/hpfeFyv3hkDVkkLemNdRkdB4PVbV/+jfs7eWPX1Srliv7dmSR8Ae8aVapP346+qLjm0= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from DM4PR12MB5229.namprd12.prod.outlook.com (2603:10b6:5:398::12) by SJ0PR12MB6736.namprd12.prod.outlook.com (2603:10b6:a03:47a::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5504.14; Wed, 3 Aug 2022 21:03:39 +0000 Received: from DM4PR12MB5229.namprd12.prod.outlook.com ([fe80::1dac:1301:78a3:c0d0]) by DM4PR12MB5229.namprd12.prod.outlook.com ([fe80::1dac:1301:78a3:c0d0%4]) with mapi id 15.20.5482.016; Wed, 3 Aug 2022 21:03:39 +0000 Message-ID: <0eccea46-648d-ff70-dcc6-fdca88ff1234@amd.com> Date: Wed, 3 Aug 2022 16:03:35 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v1.1 1/2] x86/sev: Use per-CPU PSC structure in prep for unaccepted memory support Content-Language: en-US To: Dave Hansen , linux-kernel@vger.kernel.org, x86@kernel.org Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "Kirill A. Shutemov" , "H. Peter Anvin" , Michael Roth , Joerg Roedel , Andy Lutomirski , Peter Zijlstra References: <1b50311c-448b-96aa-1d96-f4bfed409c1f@amd.com> <2a2adc3570ae9c24d03fff877c4fe79ed43605e0.1659550264.git.thomas.lendacky@amd.com> <9f47ed0f-99cc-a237-f09b-45291feffcd3@amd.com> From: Tom Lendacky In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: BL0PR05CA0003.namprd05.prod.outlook.com (2603:10b6:208:91::13) To DM4PR12MB5229.namprd12.prod.outlook.com (2603:10b6:5:398::12) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 5d04896b-62ca-46c0-a527-08da7593a367 X-MS-TrafficTypeDiagnostic: SJ0PR12MB6736:EE_ 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:DM4PR12MB5229.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(396003)(376002)(366004)(346002)(136003)(39860400002)(6506007)(316002)(8936002)(4744005)(36756003)(31686004)(4326008)(478600001)(8676002)(5660300002)(54906003)(6486002)(66556008)(66476007)(66946007)(7416002)(2616005)(26005)(6666004)(6512007)(186003)(41300700001)(2906002)(53546011)(83380400001)(38100700002)(31696002)(86362001)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?QkxtNUpLM3d6T3BBU1k4Vm0xMW1ZVlVENTJuMmhkMmRHS3V6c0x2emJmR1NR?= =?utf-8?B?UTdOVDYvVGZBb2RhdnRMSjlYRUtCU0lwa040WVBtRUc0UHQzZGQ2UHBad2F4?= =?utf-8?B?K3Q5djBHblRic2trd3ljOElwT2JoNFp5Zjc5R01kcTdkR1JNdjUvcHQ0SURH?= =?utf-8?B?UTNnN25DT0hwTjdtaThFclhKWUVFSkR2NnNDSjhaVDBqM3pWb1VnNWVncE04?= =?utf-8?B?ZFlodEUzOUh4QVhySGpFMnVUSjVxdWV5UlNWd1FUMytBYm9jRGorNHhhMFND?= =?utf-8?B?eTRaY0dsRUFDK0dUREY5ZUhqWWRReE1GTjV0blJjeEs0bXIwd2JCYVZyV2sw?= =?utf-8?B?dWtER2dDK1dsc1o2cVE3MXV3VzIwQ2xCWlMvSVlXRk03Uk1mUW5COEt5VERC?= =?utf-8?B?OWxsZ05sQnhuVG02RmtUSUJNL2RLZ3dHR09VeXAwdGdjMkh5QWp5VmV4V2lE?= =?utf-8?B?QmdoZmVQM1dxUVhVcHZ1UlgxSytLNWwzMUFGUldzeDVrdVR3VE5vME4rVmRi?= =?utf-8?B?M053MUZsMzBvelM5Tm5UNGk5TW1WNC9VWi9OTG1YUlViVnNXNnlmVitGWmdM?= =?utf-8?B?blJiaFN1WDB4cWROdU5LcHl6TnltcnNxVGtJQXczdExlZW4vZFdudEthSWNv?= =?utf-8?B?RExDanBsNm13bHlSOTk5VkRMWHE0ejBHeXhzUnhoTEVTd1BnWGI0SkRSYUU2?= =?utf-8?B?Wm5sTnE3RE9maXcrU3VuK2duRlBTdlp4c2Z1TDhxUjRzbjk5blhNNlF0bW1S?= =?utf-8?B?WUtFcUZhZWxTV0NOYjEvOTJqOVJkWUVKTUpFOGxXSG9keTYrVjlURzYyZm90?= =?utf-8?B?b3BnWnIrNWNXUVV0R3BKUDJOQlZjWWRwRjlVdmtYT2QvSFFRank1SWlKWHNu?= =?utf-8?B?QnFwV2VGWEJNajBsT0owU2pwVnFrOXZ0eXZKcnRHd2FFS0hnUU5IWUtnWlc5?= =?utf-8?B?WlNGWklHT1o3N2M0enRkeWxPdHJQRWx2aGJLeUQ0ZTdVNnhnKzhIRXZQM3Bm?= =?utf-8?B?TzFsclZLRXFyaFJid2ovcGVybTVDVXowTExzSE1Ka2FZRlYwYU9iWWNGYXZ0?= =?utf-8?B?b2JHQlpocGtxMVRUTWFPTE5SSldxZGgyd0o5SlJudzBoejRxTE1uTzhRU2lO?= =?utf-8?B?SnNua0N2WTVmWTJOdHdTZjJJWFNlaFhTdUNHaW9qMGhHOEhYUXdPRG52UlVm?= =?utf-8?B?MVJ2a3Ara3BYMVE2allPM2kyNExIcVVOSXdoWGVrdFVNQmRpS0lqTndlOWJu?= =?utf-8?B?ZGRyZVNYVFUyNEo4cGQzaXkwSGU2TERMZlMxRDVhNFExTS9tR3l3TVFnOE1K?= =?utf-8?B?V2Mybmp0ZlBueVhrL0FuNmg3Q3NOdDdRSkJENW9TNFltbk9sRk5GS09FWDFD?= =?utf-8?B?WTNZRkJiNDVaNlc2Z0F6dVlEUUJyRHA3RTFiY09DZXFtYlQ0TkxpL0pGK29S?= =?utf-8?B?VFIxbkIyd3FyWFBRWnF4eHZkbHpHVkltdFNFNEF3SFAwNTFCOFlsajJkaHQ4?= =?utf-8?B?TjBuV0hxNUZHU0w0OUJ4Ly95MzN0TEUyYjROSFdXcStCQ2UzYVRPU0ZSQ09v?= =?utf-8?B?Y0RpSE9JRUJweDhBbmNKSHo3TFQwUEorNjhkWmlFbGRSa2ljM2t3ZjZWZUxy?= =?utf-8?B?d3g4VkJKYk93SVl4eVFJOWtZcmZ2Wk9kWWlwdmpMdmNGbUhLekdrQmtCYnRa?= =?utf-8?B?R2dxTFdUQmErSHZQZ1ZDMjRKNkRwUnBNNjUwejBKMUdVWUFZQk9hcmgvR3Y3?= =?utf-8?B?eXJIT0Z0NWNiMEFNa0xwTkEyNm1wWi9UeStpUCt5cGNMUnBiZC9GaisydzlX?= =?utf-8?B?M0dMc0dVUWNYWHYwY2V2VUNPRmc5cCtPUHFKTEp4OTdqWkFCb1phdy9VNUNO?= =?utf-8?B?blhZR0t6RWZyNUk5QVFmZzlBcnFKc0tmc3VwdVc3c1EreUIzNHdYVFdFaG1G?= =?utf-8?B?NmRmSzZSNTNDSDRxNXdkY1U0a2VNMUord3VFQ01RQjdpTnlObko1NnptOVB4?= =?utf-8?B?LzhHRDg4a1FKRUZNbnErSFZjcTNoWUpvUjZQdXNQSEZvaTBzdHNOYUFBMnZK?= =?utf-8?B?M1BMSWRwVzZIR1pEUFNqZjl4REg3emh1MndCekhncTA1OVBuMStPUVEwZ01K?= =?utf-8?Q?V6AfIsX3zCzWjkzxGXBuH5+XH?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5d04896b-62ca-46c0-a527-08da7593a367 X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB5229.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Aug 2022 21:03:39.0342 (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: CgblsJKJ1NRtjGy4v2T5NhyGbpI+1l12MS6v4SRsnY7RmDk2gltvaW692CAJ2g4XNeIOAUT0H8t4pc6tyHNxQQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB6736 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/3/22 13:24, Dave Hansen wrote: > On 8/3/22 11:21, Tom Lendacky wrote: >>> Would it be simpler to just do a spin_trylock_irqsave()?  You fall back >>> to early_set_pages_state() whenever you can't acquire the lock. >> >> I was looking at that and can definitely go that route if this approach >> is preferred. > > I prefer it for sure. > > This whole iteration does look good to me versus the per-cpu version, so > I say go ahead with doing this for v2 once you wait a bit for any more > feedback. I'm still concerned about the whole spinlock and performance. What if I reduce the number of entries in the PSC structure to, say, 64, which reduces the size of the struct to 520 bytes. Any issue if that is put on the stack, instead? It definitely makes things less complicated and feels like a good compromise on the size vs the number of PSC VMGEXIT requests. Thanks, Tom