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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81465C433FE for ; Wed, 20 Oct 2021 18:36:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5ED47610D0 for ; Wed, 20 Oct 2021 18:36:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231256AbhJTSii (ORCPT ); Wed, 20 Oct 2021 14:38:38 -0400 Received: from mail-dm6nam08on2071.outbound.protection.outlook.com ([40.107.102.71]:39368 "EHLO NAM04-DM6-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S230076AbhJTSie (ORCPT ); Wed, 20 Oct 2021 14:38:34 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=jXdm2LdA7s7N5DlbxIbdqjPPyGtNTRwYxmWcDM4gkmWFXUaM52jYhQmgiwcmr/b/HjDlw1Bv+6eDruEJUvKSgyJvr8nrAsAzzd762WwNZ/Zg1irG72svFh4AjJilebMjDTgaJz5z/T6D4WFOjRuJYoLSd9gKG2NKX12F5FFMt9fA8eakJIPGzXlld0xptOKRBn+/r2VcuY1UMHrIfiNm/MXDzJGFDaS9OEzzi1tMn9LEP8EP1WFVG7kOh4OpGJMaLjaR8bC6obM6B/YsyZgwv9qiWdPooJUrpenehO1vRgIYkxU3WzhDvy5pTmqdDmatsJt4DzabM4ZMy9R+zzNvpw== 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=2dPpTbpwA93qUaaz/xyyv0u9FmeW9sMASkSDdSjb9xg=; b=jELX7MH31L3Vt3mRB0ShAw1BL1b/kBqbVeHURYE7xKBj0+IRhWJ6rxIpOlz4FtvZy5CvkbEBa6f0d8BIbVwDXLSWp3vjvapLiE714fTZAHPD0jwWqHjX87fcaGjn8ZzfrJA/1P5BqZWhDQEM38G8da6eHBH3+aMqtiDhbca8bwZctNBBJuSNbVLSMix3kPRqtdqra7VDskTgTt9rDO92kHcgegXxncGdBk+ODd2KULzdFvYpt0JweODUtx89cYiPBL8V65zkcpfJe+AMMGsEFtQU0UFaBCm8kxjO8PjjBn3+UBv0K899U89+lQWP+E3AVBPunHbLA5WfOwcMjqxSXQ== 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=2dPpTbpwA93qUaaz/xyyv0u9FmeW9sMASkSDdSjb9xg=; b=YmeCobADVS/H6npT8gsM/Ha5sGK8hj3kTtJR/ABlZ7lsPfp3oWN8f5j7RGjXveu1KVY/9tCJYl6cAKQecT4jxV5WJK893UkG1EVLguSTeSrF5G4IvZVhS9lQr4yWRGONIM9TbbtdggGGiZfUREqDYQgcoYiATfOEBnoWCOYivi8= Authentication-Results: suse.de; dkim=none (message not signed) header.d=none;suse.de; dmarc=none action=none header.from=amd.com; Received: from DM4PR12MB5229.namprd12.prod.outlook.com (2603:10b6:5:398::12) by DM4PR12MB5232.namprd12.prod.outlook.com (2603:10b6:5:39c::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4608.16; Wed, 20 Oct 2021 18:36:18 +0000 Received: from DM4PR12MB5229.namprd12.prod.outlook.com ([fe80::a87d:568d:994f:c5f9]) by DM4PR12MB5229.namprd12.prod.outlook.com ([fe80::a87d:568d:994f:c5f9%7]) with mapi id 15.20.4628.016; Wed, 20 Oct 2021 18:36:18 +0000 Subject: Re: [PATCH v5 4/6] KVM: SVM: Add support to handle AP reset MSR protocol To: Sean Christopherson , Joerg Roedel Cc: Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , x86@kernel.org, Brijesh Singh , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Joerg Roedel References: <20211020124416.24523-1-joro@8bytes.org> <20211020124416.24523-5-joro@8bytes.org> From: Tom Lendacky Message-ID: <2ae35ebd-aaed-a3df-c74e-5a3be378b8af@amd.com> Date: Wed, 20 Oct 2021 13:36:15 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: CH0PR03CA0093.namprd03.prod.outlook.com (2603:10b6:610:cd::8) To DM4PR12MB5229.namprd12.prod.outlook.com (2603:10b6:5:398::12) MIME-Version: 1.0 Received: from [10.236.30.241] (165.204.77.1) by CH0PR03CA0093.namprd03.prod.outlook.com (2603:10b6:610:cd::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4628.15 via Frontend Transport; Wed, 20 Oct 2021 18:36:17 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: a190dd46-ca02-4eda-c53f-08d993f8815a X-MS-TrafficTypeDiagnostic: DM4PR12MB5232: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; 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:(4636009)(366004)(6486002)(7416002)(36756003)(83380400001)(31696002)(86362001)(26005)(53546011)(4744005)(186003)(4326008)(38100700002)(956004)(2616005)(5660300002)(508600001)(2906002)(31686004)(66476007)(54906003)(66946007)(66556008)(316002)(110136005)(16576012)(8936002)(8676002)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?Windows-1252?Q?J/n4VU0iPuJGCLBuaGM0iipc0kGPVxMGZm7L0RuAtrG7zJe9Ua6exnF6?= =?Windows-1252?Q?hdQUbJFR0IhMkW8n8K4pqaGnlNb4sAHsBe36cBsRAU4Y/D+c1v6uQ7H2?= =?Windows-1252?Q?DTiiAU/hGdxIoAvWJ1ep4ICZ7P/4z1pZVpngZ++81Uy38jNAsLd9B2A+?= =?Windows-1252?Q?ULI5a83no6zETOfpctc3AhVxicfnR8hqmaVKPd7rdxlwwtZvdftJ4QV7?= =?Windows-1252?Q?4tZolalCLsX7fe6JayXn4nnFV5pN6XVPA7wuqdvOIvQPDs7X7AOTwChD?= =?Windows-1252?Q?zVVHEnd2A/L1KUHUPOfFrPjragiEmjvTmcDm33FsBAghHScsCdB/PP2w?= =?Windows-1252?Q?IbLWn3Z0QGyXXxk6JSOQiNiHkJlbM7jYBXR/5GVtBcN8IjzFG2cszDYY?= =?Windows-1252?Q?C4dFLeQ+oYwM+OTgJnUCncUEwGH5fark6OTHL3BIpeSTTSvwYyfCPhB3?= =?Windows-1252?Q?vXlEg7rR7mlnaaKNXpo0dTSWrRApdJJL6A1WjdvdYzR9hZT1TQX8h9O5?= =?Windows-1252?Q?Gd2AX3KfUr5zMG1WYzDajZv2Qv0+z9bFZxVzeRm2dUD/+QopJawQuPCG?= =?Windows-1252?Q?DUEGqDAvBgqmJx5RKblia0tVUwZXK3XDD6Fl2ieYJsQvK47hKoJD2/Ht?= =?Windows-1252?Q?X1RGB0aPptrQT8J/Kwg4pevgdqqjchocJyiN0phLdlL9YJfQgIRkObTw?= =?Windows-1252?Q?bx06asGvY9h+KByY3VXB6LJNJEx+1hrxmy1tUyksKTgACBgWBdYQqoQA?= =?Windows-1252?Q?TzllerWJqzvdNGlvxJe5waxTSftpQh8EO7+HyGNNd4/g4/XvwfjUzO52?= =?Windows-1252?Q?FV74DZsgE/anonZHdZJp++x1OOf7o9+h0iUGD9orEkvt53oBsvWwered?= =?Windows-1252?Q?RDvm3HB6We3Ls6ZAJcLbLkWMbWY6ORNgDp4QWRbkGI/G2VFvz4Sd66Hq?= =?Windows-1252?Q?X4I8T6HS/vBm7VKJWA+M3YvB6XghJW3sSLQVmn992ZlOfwfG82g05KAs?= =?Windows-1252?Q?w9bFTFJ9px8o0ZOfO4hH2LAvDRmJPlG9e0M51+oEM3+lxvEnwE3lOeIZ?= =?Windows-1252?Q?jfcy67OZTF2POzsb9dcluK3NhbcOqb9MrnH9yYCvCsswAOWsBd/pfcwr?= =?Windows-1252?Q?FNTxjmEzxHSU+yp2OA7gYAYwFVDd3d2jMbo7BcSZxWQ1Phc+j5LDfIXO?= =?Windows-1252?Q?TXyHnlVD7wIG62yMjZTE/6J0w5mbKnyLpd3A0naujJxxE1Z46E5bcdx4?= =?Windows-1252?Q?NA3ojVOQ3ePz/5pn0GSNUGOJvdbKFlKl5UOaasMg3m72c4Nny29L10qC?= =?Windows-1252?Q?JMejIG2HqDG3D3FFM++kfsiEyZxp6b7M97KJaKlqwvz/4lTgV4aLFfvD?= =?Windows-1252?Q?bDlqUrixfr1Q8zXHNuMfFQ9M/wqPJq5iSYDINb9viIWJt/VFHDYTvTwO?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: a190dd46-ca02-4eda-c53f-08d993f8815a X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB5229.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Oct 2021 18:36:18.2441 (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: tlendack@amd.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5232 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/20/21 12:40 PM, Sean Christopherson wrote: > On Wed, Oct 20, 2021, Joerg Roedel wrote: > > Tying into above, handling this in SIPI is flawed. For example, if the guest > does INIT-SIPI-SIPI without a reset hold, KVM would incorrect set sw_exit_info_2 > on the SIPI. Because this mess requires an INIT, KVM has lost track of whether > the guest was in KVM_MP_STATE_AP_RESET_HOLD and thus can't know if the SIPI > arrived after a reset hold. Looking at KVM, IIUC, this bug is why the hack > "received_first_sipi" exists. The received_first_sipi is because the APs have to be started the very first time in the traditional way. The AP can't issue an AP reset hold if it hasn't started to begin with in which case there would be no GHCB mapped. After the check to see if the GHCB is mapped was added to sev_vcpu_deliver_sipi_vector(), the "received_first_sipi" could probably have been deleted at that point. Thanks, Tom