Received: by 2002:a05:6a10:6d25:0:0:0:0 with SMTP id gq37csp1826249pxb; Mon, 13 Sep 2021 06:25:25 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxFxvzWJMYGyr63BUho0Fz5JEcGNnXlOfQCIN3705FNL+ak7j7RX3i/mJUqKm44j82F5/9n X-Received: by 2002:a05:6e02:1c2b:: with SMTP id m11mr7743441ilh.242.1631539525770; Mon, 13 Sep 2021 06:25:25 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1631539525; cv=pass; d=google.com; s=arc-20160816; b=YrUa5mcs1RphXK4VIR4l5IFZCuQi8Mx/Nl9fG1McYycxnruBcuJf3+b5yEvermRn3K 688X94Jo74lLa076NgwTMVHS5pCv2nWERShCxTEk7lpkUT/Ae6RbSCVh9pccn9mvonha pOJJ+IDMafRA447P5KP0EJU+sQe1vTsDQ3MYbYXycIpzW47h3ZedCTxOJOlKiT/k6HZd gbqBe8BHfSC3Vgd2jVN5fUDml6XnXZOQOLo0ZZb/dE2fpL8oErq5gjp6wN+Cjj/tzhrf pQhN+TUfmO+eKqVP9rtl/fUtIvJMJYNLALARl+EcY/u56Shhc1HO5B9lkuzrzTBHvise U06w== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:user-agent:message-id:in-reply-to :date:references:subject:cc:to:from:dkim-signature:dkim-signature :dkim-signature; bh=IMOSH4tm0knY1eywg+CumHDM+BIKSpl3RI+CmUhPSG8=; b=P8K5BuLQ37SVkChkBwEyCPxvmUU1V76jjoStmZJfZ5kAKb8Mf7K1tOJGV52JXZ2tow 5+BCA+g/0tTx8aCUos2nVSXsIlbx0TzcKR85ksd3apLcZqeh8SxAsMVeW5R/c1zBiVfN rL6Mfi2TLUJubYlZp0klDfXLjiGrj1CwXxKsC+1CclA3tZAH7XGChk7QVRbQfIAMvPG/ aUlaC1sF+CbFAfCRtoK0jfGm+fqi+zxSesHwy6ZoHVyaBzB6uwDa/BA7LOnc6tgL1JMs 7pxuTTc1vzero5piR/qLBImu6zGTCu1UsXlhhW1V5Ah6QbWcXOZvTzEiDkwC9eWQvZ/7 tT9A== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2021-07-09 header.b=xzleg+kJ; dkim=pass header.i=@oracle.com header.s=corp-2020-01-29 header.b=sMqg9Xq8; dkim=pass header.i=@oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=rUbpcfRJ; arc=pass (i=1 spf=pass spfdomain=oracle.com dkim=pass dkdomain=oracle.com dmarc=pass fromdomain=oracle.com); spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id x8si7580263jaq.91.2021.09.13.06.25.13; Mon, 13 Sep 2021 06:25:25 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2021-07-09 header.b=xzleg+kJ; dkim=pass header.i=@oracle.com header.s=corp-2020-01-29 header.b=sMqg9Xq8; dkim=pass header.i=@oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=rUbpcfRJ; arc=pass (i=1 spf=pass spfdomain=oracle.com dkim=pass dkdomain=oracle.com dmarc=pass fromdomain=oracle.com); spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240468AbhIMNZC (ORCPT + 99 others); Mon, 13 Sep 2021 09:25:02 -0400 Received: from mx0a-00069f02.pphosted.com ([205.220.165.32]:21308 "EHLO mx0a-00069f02.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240435AbhIMNV4 (ORCPT ); Mon, 13 Sep 2021 09:21:56 -0400 Received: from pps.filterd (m0246617.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 18DD5scd015554; Mon, 13 Sep 2021 13:19:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : references : date : in-reply-to : message-id : content-type : mime-version; s=corp-2021-07-09; bh=IMOSH4tm0knY1eywg+CumHDM+BIKSpl3RI+CmUhPSG8=; b=xzleg+kJ99HLLZ+fQYUE4bURpHGaE1MCgZrIEUufQ4OY8OQyV539LSZg0F1xL+nOdOOg CibdTUG2UECwZ1bLuK2Doe3bLF8faCGSsav4nmyNZMyQsQe3JqdBi+p8qeFbIT2CwM70 XdZlQ4S2/NYhQmv5IiUz2SbsZt2u7DYwP96xatRzxQc6/fSl/F6thzf5/tvlWQWE8Ocu eIPzA8lHQ5BWgkoJsdIvuQ4c42N0v8oSbsyJ9Sp1oMT7HaoOdu57hvaFlvLJH+XNLIpe Y8vb7RpBVe+Gu8kA5Wn1T3SXQnmkFEFTwmg10CbFRsdbFsxBt66IxWPMioKrNWw+epnw zQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : references : date : in-reply-to : message-id : content-type : mime-version; s=corp-2020-01-29; bh=IMOSH4tm0knY1eywg+CumHDM+BIKSpl3RI+CmUhPSG8=; b=sMqg9Xq8n5of1I+AK2HiWc66AyxF9VG9kS2CnhUa/4nSHUk0+YxYoiMHGBAKZCjBXcNC xcaMlGrCwk3w2nAVphqTCi8jDCT0GJpDACrYvsD25Y7NM7DL1L4Tao/B1KG/Du5RHY7s h5eh/5XfDAlgYvp6ydmLRKnSE1G54RmVYBp4Ndd+gydHg8CnjpJh4/Dbur7uL+kSjfN5 txnjx5o5T/S9hxpum+9b5gbt7LEr6tNi0OsfVwpKdsf3g2R7QRSu1WvWAg94bNKpXHUq SknEzF77pkMkIfVxovoC50irxszvfCGJA69HXme+oxQPKHBbS9ufN03Vm2yZlj9gzNJd fQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by mx0b-00069f02.pphosted.com with ESMTP id 3b1k1sajbh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Sep 2021 13:19:38 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 18DDGSLE065777; Mon, 13 Sep 2021 13:19:37 GMT Received: from nam11-dm6-obe.outbound.protection.outlook.com (mail-dm6nam11lp2168.outbound.protection.outlook.com [104.47.57.168]) by aserp3030.oracle.com with ESMTP id 3b0jgbgta9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Sep 2021 13:19:37 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ZxcEIkyTrsszjWMQeYPXujYt80n3OmGnVJ8wuVLa7jlY7yrKLdEWO5AqupaJf8+Kaf+MeqeKFcltODM5DLpuZp9BAwmWcP6lSFHgDR8x+X9O+ncgbT0+/Iprny4qOdFy4kNIkFSWREhchWVhhjbD6RRoKiS1Yum+DTbZEQ/ksjGfADKAveBGwnbCPT7Bu9YSUiJcDaRxKNMu4WBlf3Cs0WSc3FSRzbhF/Yi5uJBz2yrodBWvm13SbWjoV93O5onDA0EU3WMxSguyp4c9l650ySA6hcbLXbEnJ2N9OR1ADHjcKskVFV0nb1o9JGhYmsyJTDsW8+HRQ8tpX35eW81Bog== 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; bh=IMOSH4tm0knY1eywg+CumHDM+BIKSpl3RI+CmUhPSG8=; b=EcrYV+uMM7m/XDC+pW/j5NiEb0cEoHmmCeQLKVhSYHUOf9oK0MpZDwtuQ106UlaJe3LVlDQuUr0HxXcWpeLod0OwJYNswglRryGq2l2ardTO6BwYCsy1h4RqT1sDA2JqlF87EIDBIzbnOp/Om257Y7oLuRChrIW9AzVNUHx7Y3aXfmDhqYwfC7cBgk0IFZfPBjt6kSIDSGgWeYJXKtvQMVXtgeD0v6xx6Q83EuTxxfGLzgVyqoPwoj1BKWGgWL/dE44MAsnOJX0w3pCC8aEoZCAqs0AK7sYNNTA6ui49ZTsklPEK3AUxM/NzId9A6G2AzfNS6yTqXhtVHHI45vBmew== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=IMOSH4tm0knY1eywg+CumHDM+BIKSpl3RI+CmUhPSG8=; b=rUbpcfRJ++Adx6z9jMOQZjZrJTMDLMvBhsX1GY+QQT/FljnYkeYZdCvW5dRPtjlhiFr+KCEQ5g+8LcXRnAE9rYeAkXzbmEqj3L5eWWqTjL1j6zJ1TBpRknTBdlPJ8qWFX1cK2gIb9DKgTjSVj0QQ/wxmCpIMOkcXh4LHCuFTYMc= Authentication-Results: oracle.com; dkim=none (message not signed) header.d=none;oracle.com; dmarc=none action=none header.from=oracle.com; Received: from DM6PR10MB3148.namprd10.prod.outlook.com (2603:10b6:5:1a4::21) by DM6PR10MB3386.namprd10.prod.outlook.com (2603:10b6:5:1a1::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4500.14; Mon, 13 Sep 2021 13:19:35 +0000 Received: from DM6PR10MB3148.namprd10.prod.outlook.com ([fe80::7c73:f280:20d6:35cf]) by DM6PR10MB3148.namprd10.prod.outlook.com ([fe80::7c73:f280:20d6:35cf%3]) with mapi id 15.20.4500.019; Mon, 13 Sep 2021 13:19:35 +0000 From: David Edmondson To: Sean Christopherson Cc: linux-kernel@vger.kernel.org, Jim Mattson , Borislav Petkov , Paolo Bonzini , Vitaly Kuznetsov , "H. Peter Anvin" , Thomas Gleixner , Wanpeng Li , Ingo Molnar , Joerg Roedel , David Matlack , x86@kernel.org, kvm@vger.kernel.org, Joao Martins Subject: Re: [PATCH v4 3/4] KVM: x86: On emulation failure, convey the exit reason, etc. to userspace References: <20210813071211.1635310-1-david.edmondson@oracle.com> <20210813071211.1635310-4-david.edmondson@oracle.com> Date: Mon, 13 Sep 2021 14:19:28 +0100 In-Reply-To: (Sean Christopherson's message of "Thu, 2 Sep 2021 18:39:33 +0000") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Content-Type: text/plain X-ClientProxiedBy: LO2P265CA0252.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:8a::24) To DM6PR10MB3148.namprd10.prod.outlook.com (2603:10b6:5:1a4::21) MIME-Version: 1.0 Received: from disaster-area (2001:8b0:bb71:7140:64::1) by LO2P265CA0252.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:8a::24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4500.14 via Frontend Transport; Mon, 13 Sep 2021 13:19:33 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 5abee6ec-9af4-4de2-6e87-08d976b9214a X-MS-TrafficTypeDiagnostic: DM6PR10MB3386: 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: rw4Ef5LMbGF/HJhtjKDP4gb8JKm7V2kWQ6JdaYAy62VPUpYt5maI63VFksxwEoJBpezuYuHt3rsjGcZfdpoh65wWJ+vAfx/HagmHpG23a5H1kKvousb+P3mYxFG3lDewfUMQewHm+0ClbsLPwFkCWIrAfYGFrdoJjtKdmAL0E6M7qxwCPj9pmUCJdKR0Yb69BPS55prRptxfvXPbBYVmVQRQuAHWxsLypbU/PgrAU4WzfGUMCLy9FtAzRADinRTfkF0I4xzkJo70dEQnAcV1DFZxIHcdiHiMxMfqSqeSaYYzZK7viO04piG6l9LntvDkUFTGID8tpEgSO0383YsvGP+Cqh+HPONp52TdWspXRQLXe8fcfOMIPP9JzvxlR/yIMXbwHjJ5r8cj+12dbDaMZIrCuMLf+DEAQONhLT1D/rXCYjegfYITqYOgt7LOU3dQHweYpgPjibYUJOc3Z4fHd3Fw32JFOzxWReAEU0lya4aAUusCIk4EiIKJUB5ZcFbWSr4C0qg9O5z2yccj6IVsj9a7cZKS0AFALZZFDerb9SUZlz5vVekf+PuplH7vKsXUCvW5vgkAvWHJhu9KSCxbniqKe8Us1FOB/2ugVdwvnYIaobYolFI+lRmjtoUAEIvg37nhpqFeYpGA8mv0Vt2hew== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM6PR10MB3148.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(39860400002)(376002)(136003)(396003)(366004)(346002)(6666004)(186003)(316002)(66476007)(8676002)(44832011)(52116002)(6496006)(66946007)(4326008)(66556008)(2906002)(107886003)(54906003)(478600001)(2616005)(36756003)(5660300002)(6486002)(6916009)(8936002)(86362001)(38100700002)(83380400001)(7416002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?xX4gmtij87eKetv/NAzvlg4LosmUeJkPFJJ3tc6qHIfpIID1ogleroo8Fey1?= =?us-ascii?Q?UJo25FsOKmLBY7D0YqV/ThWq13DH+abCVN2e/9jfXrFextmshAVQSurDYqjP?= =?us-ascii?Q?fslLdzdRb1oWF4uMQtiliUzhquP5UaIlgp7zJqpcjufC0RX7cdcYaeIpRqko?= =?us-ascii?Q?T4mGAx4vS2M7UUPObsC4rR7Q1NgBWoD6A6T7RXbkvMtl5O2y5dD125tbe8sM?= =?us-ascii?Q?5cz97wLC1+05knGWNEAq2Tdahx2loCu0S5tMYKL+Z/luA2a38UmszfvWQdpA?= =?us-ascii?Q?479QGZLKgX8NJVvKh9L9TVZHTdr5x4fo4Ou0d9xvl/kP2Ai9pxaUkZAyg1xt?= =?us-ascii?Q?O8JHx088qKZ5Wr4//yYQvEGn8KfWgpuevX8Ilw87fJ71RhGnqGtkzXHgJDkF?= =?us-ascii?Q?eZ0Ci6wr6cdIQigGrTS9rQAP5RHaBlujkClBd7LxBaxHXvXM2OeTwvAyjLWF?= =?us-ascii?Q?WdLnBN9vup9DxKjL+VGL9CgsYuUNBrtq+0CETjwfB1xBvGJ4n5YYIw1Fncqz?= =?us-ascii?Q?i3PC1dBA7Gqq/awe30P/TBoqHcw8in2EWprWaF/xbYPlaiD1S5LC93qmQBxB?= =?us-ascii?Q?PkcM2wvCg0grzZ4KW9YVuIyGMfI/DLNkUTZV7v/mKic72AZi7SIjiJnaaXNv?= =?us-ascii?Q?uXB9ERTeVyPuBUD+MVvrp3VwLRN0QlNFs6gh1stLMib6TVERaFg25hvLFIcs?= =?us-ascii?Q?SA/XXZ/9/wjvyehqSZessR+9pPoSU50oZ0hRpokUYwlwvPOb/Ep5fTA4Qk69?= =?us-ascii?Q?iwygwgleFgmuUba59qe8NnbB3B+ZKuEm8OsCIhrn7ad3Gp3IfEHtafCmAHEf?= =?us-ascii?Q?apyMN0NquCuT7McHwawaodmGFfAcR/8oPiDl89CgAo9s6/8b+W468jDQd7on?= =?us-ascii?Q?PRYfn+uVHjFQAGa9kVo36LBTHbGhsEbhf+zUcK9oCPyILooeWwS601Unq2iI?= =?us-ascii?Q?LHkKFQnTxcPvaPjomAQrAv/iff/amy3BfmiPfHOjWJ2M8R9uvZtJ3RpLp0lj?= =?us-ascii?Q?QaZRLrUu5ACQROPXsMfrOT9s5y4wMa3GOsmuqn3QKTTTrnGQi9aY4dsAXe1x?= =?us-ascii?Q?S3syc6FvndwXUW682lZxWCyGe5Z3Ct4imj7Rzr9E/p1r8UeHPGeDDxexeg18?= =?us-ascii?Q?RxBGm9ctO+3jA6GIVwUoHMu5hONMMQEBiQlyT+mcPOxykg18LpG4+Bj8vNDz?= =?us-ascii?Q?DEhbZaTO5kRU4Vc3tGS4RE3DHOSDGUUhk0/3PbyJ67JESbsQS+hW2IV4oyjU?= =?us-ascii?Q?Os/Ln0ib1W4eDOk04io+n4jNolTx4LUNaL6FcVZy0ThPK7B40e03KLuRdUhx?= =?us-ascii?Q?6enGOn5L7pH/DJZxbt3HgKEH378ujR0t788uuJNIHGJauw=3D=3D?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5abee6ec-9af4-4de2-6e87-08d976b9214a X-MS-Exchange-CrossTenant-AuthSource: DM6PR10MB3148.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Sep 2021 13:19:35.1747 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: EpcD4eYHHLdZ2X8m6Frv9weWMpUutEEivGMS5LMvuC43vGj6ZmGS5Hemvqub8JI6uCVIkJfw/8XAZRf8Bf5OKs4Q4uclJrMkQBcyF6rjPuI= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR10MB3386 X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10105 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 bulkscore=0 spamscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109130089 X-Proofpoint-ORIG-GUID: uqg3cSOQUfU0unzzsoFtMnIieU7zCQ3h X-Proofpoint-GUID: uqg3cSOQUfU0unzzsoFtMnIieU7zCQ3h Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sean Christopherson writes: > On Fri, Aug 13, 2021, David Edmondson wrote: >> -static void prepare_emulation_failure_exit(struct kvm_vcpu *vcpu) >> +static void prepare_emulation_failure_exit(struct kvm_vcpu *vcpu, u64 *data, >> + u8 ndata, u8 *insn_bytes, u8 insn_size) >> { >> - struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt; >> - u32 insn_size = ctxt->fetch.end - ctxt->fetch.data; >> struct kvm_run *run = vcpu->run; >> + u8 ndata_start; >> + u64 info[5]; >> + >> + /* >> + * Zero the whole array used to retrieve the exit info, casting to u32 >> + * for select entries will leave some chunks uninitialized. >> + */ >> + memset(&info, 0, sizeof(info)); >> + >> + static_call(kvm_x86_get_exit_info)(vcpu, (u32 *)&info[0], &info[1], >> + &info[2], (u32 *)&info[3], >> + (u32 *)&info[4]); >> >> run->exit_reason = KVM_EXIT_INTERNAL_ERROR; >> run->emulation_failure.suberror = KVM_INTERNAL_ERROR_EMULATION; >> - run->emulation_failure.ndata = 0; >> + >> + /* >> + * There's currently space for 13 entries, but 5 are used for the exit >> + * reason and info. Restrict to 4 to reduce the maintenance burden >> + * when expanding kvm_run.emulation_failure in the future. >> + */ >> + if (WARN_ON_ONCE(ndata > 4)) >> + ndata = 4; >> + >> + /* Always include the flags as a 'data' entry. */ >> + ndata_start = 1; >> run->emulation_failure.flags = 0; >> >> if (insn_size) { >> - run->emulation_failure.ndata = 3; >> + ndata_start += (sizeof(run->emulation_failure.insn_size) + >> + sizeof(run->emulation_failure.insn_bytes)) / >> + sizeof(u64); > > Hrm, I like the intent, but the end result ends up being rather convoluted and > unnecessarily scary, e.g. this would do the wrong thing if the combined size of > the fields is not a multiple of 8. That's obviously is not true, but relying on > insn_size/insn_bytes being carefully selected while simultaneously obscuring that > dependency is a bit mean. What about a compile-time assertion with a more reader > friendly literal for bumping the count? > > BUILD_BUG_ON((sizeof(run->emulation_failure.insn_size) + > sizeof(run->emulation_failure.insn_bytes) != 16)); > ndata_start += 2; Okay. >> run->emulation_failure.flags |= >> KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES; >> run->emulation_failure.insn_size = insn_size; >> memset(run->emulation_failure.insn_bytes, 0x90, >> sizeof(run->emulation_failure.insn_bytes)); >> - memcpy(run->emulation_failure.insn_bytes, >> - ctxt->fetch.data, insn_size); >> + memcpy(run->emulation_failure.insn_bytes, insn_bytes, insn_size); >> } >> + >> + memcpy(&run->internal.data[ndata_start], info, sizeof(info)); > > Oof, coming back to this code after some time away, "ndata_start" is confusing. > I believe past me thought that it would help convey that "info" is lumped into > the arbitrary data, but for me at least it just ends up making the interaction > with @data and @ndata more confusing. Sorry for the bad suggestion :-/ > > What about info_start? IMO, that makes the memcpy more readable. Another option > would be to have the name describe the number of "ABI enries", but I can't come > up with a variable name that's remotely readable. > > memcpy(&run->internal.data[info_start], info, sizeof(info)); > memcpy(&run->internal.data[info_start + ARRAY_SIZE(info)], data, > ndata * sizeof(data[0])); Okay. >> + memcpy(&run->internal.data[ndata_start + ARRAY_SIZE(info)], data, >> + ndata * sizeof(u64)); > > Not that it really matters, but it's probably better to use sizeof(data[0]) or > sizeof(*data). E.g. if we do screw up the param in the future, we only botch the > output formatting, as opposed to dumping kernel stack data to userspace. Agreed. >> + >> + run->emulation_failure.ndata = ndata_start + ARRAY_SIZE(info) + ndata; >> } >> >> +static void prepare_emulation_ctxt_failure_exit(struct kvm_vcpu *vcpu) >> +{ >> + struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt; >> + >> + prepare_emulation_failure_exit(vcpu, NULL, 0, ctxt->fetch.data, >> + ctxt->fetch.end - ctxt->fetch.data); >> +} >> + >> +void __kvm_prepare_emulation_failure_exit(struct kvm_vcpu *vcpu, u64 *data, >> + u8 ndata) >> +{ >> + prepare_emulation_failure_exit(vcpu, data, ndata, NULL, 0); >> +} >> +EXPORT_SYMBOL_GPL(__kvm_prepare_emulation_failure_exit); >> + >> +void kvm_prepare_emulation_failure_exit(struct kvm_vcpu *vcpu) >> +{ >> + __kvm_prepare_emulation_failure_exit(vcpu, NULL, 0); >> +} >> +EXPORT_SYMBOL_GPL(kvm_prepare_emulation_failure_exit); >> + >> static int handle_emulation_failure(struct kvm_vcpu *vcpu, int emulation_type) >> { >> struct kvm *kvm = vcpu->kvm; >> @@ -7502,16 +7551,14 @@ static int handle_emulation_failure(struct kvm_vcpu *vcpu, int emulation_type) >> >> if (kvm->arch.exit_on_emulation_error || >> (emulation_type & EMULTYPE_SKIP)) { >> - prepare_emulation_failure_exit(vcpu); >> + prepare_emulation_ctxt_failure_exit(vcpu); >> return 0; >> } >> >> kvm_queue_exception(vcpu, UD_VECTOR); >> >> if (!is_guest_mode(vcpu) && static_call(kvm_x86_get_cpl)(vcpu) == 0) { >> - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; >> - vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; >> - vcpu->run->internal.ndata = 0; >> + prepare_emulation_ctxt_failure_exit(vcpu); >> return 0; >> } >> >> @@ -12104,9 +12151,7 @@ int kvm_handle_memory_failure(struct kvm_vcpu *vcpu, int r, >> * doesn't seem to be a real use-case behind such requests, just return >> * KVM_EXIT_INTERNAL_ERROR for now. >> */ >> - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; >> - vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; >> - vcpu->run->internal.ndata = 0; >> + kvm_prepare_emulation_failure_exit(vcpu); >> >> return 0; >> } >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 6c79c1ce3703..e86cc2de7b5c 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -397,6 +397,12 @@ struct kvm_run { >> * "ndata" is correct, that new fields are enumerated in "flags", >> * and that each flag enumerates fields that are 64-bit aligned >> * and sized (so that ndata+internal.data[] is valid/accurate). >> + * >> + * Space beyond the defined fields may be used to > > Please run these out to 80 chars. Even 80 is a soft limit, it's ok to run over > a bit if the end result is (subjectively) prettier. > >> + * store arbitrary debug information relating to the >> + * emulation failure. It is accounted for in "ndata" >> + * but otherwise unspecified and is not represented in > > Explicitly state the format is unspecified? > >> + * "flags". > > And also explicitly stating the debug info isn't ABI, e.g. > > * Space beyond the defined fields may be used to store arbitrary > * debug information relating to the emulation failure. It is > * accounted for in "ndata" but the format is unspecified and > * is not represented in "flags". Any such info is _not_ ABI! Okay. >> */ >> struct { >> __u32 suberror; >> @@ -408,6 +414,7 @@ struct kvm_run { >> __u8 insn_bytes[15]; >> }; >> }; >> + /* Arbitrary debug data may follow. */ >> } emulation_failure; >> /* KVM_EXIT_OSI */ >> struct { >> -- >> 2.30.2 >>